KR20200058812A - Diamine compound, polyimide precursor and polyimide film prepared by using same - Google Patents

Abstract

The present invention can provide a polyimide precursor which has a significantly improved molecular weight by improved reactivity during polymerization by containing novel diamine containing a nitrogen atom in an aromatic ring structure as a polymerization component while including a sulfonyl group. Therefore, it is possible to provide a polyimide film which maintains optical properties of polyimide containing a sulfonyl group, and at the same time, has significantly improved mechanical and thermal properties.

Description

Diamine compound, polyimide precursor and polyimide film using the same {DIAMINE COMPOUND, POLYIMIDE PRECURSOR AND POLYIMIDE FILM PREPARED BY USING SAME}

The present invention relates to a novel diamine and a polyimide precursor using the same and a polyimide film having improved physical properties.

In the field of display, weight reduction and miniaturization of products are considered important in recent years, and currently used glass substrates are heavy, easily broken, and there is a limitation that the continuous process is difficult. Research has been actively conducted to apply the technology to mobile phones, notebooks, PDAs, and the like.

In particular, polyimide (PI) resin is easy to synthesize, can make a thin film, and has the advantage of not requiring a crosslinker for curing. Recently, it has been integrated into semiconductor materials such as LCD and PDP due to the light weight and precision of electronic products. As a result, many studies have been conducted to use PI for a flexible plastic display board having light and flexible properties.

The polyimide (PI) film is produced by filming the polyimide resin, and in general, the polyimide resin is solution-polymerized with an aromatic dianhydride and an aromatic diamine or an aromatic diisocyanate to prepare a polyamic acid derivative solution. It is manufactured by a method of coating on a silicon wafer or glass and curing by heat treatment.

Flexible devices that involve high-temperature processes require heat resistance at high temperatures. In particular, in the case of organic light emitting diode (OLED) devices using low temperature polysilicon (LTPS) processes, process temperatures may approach 500 ° C. However, even at a polyimide having excellent heat resistance at this temperature, thermal decomposition by hydrolysis is likely to occur. Therefore, in order to manufacture a flexible device, it is necessary to develop a polyimide film capable of exhibiting excellent chemical resistance and storage stability that does not cause thermal decomposition by hydrolysis even in a high temperature process.

The problem to be solved by the present invention is to provide a new diamine capable of producing a polyimide with improved physical properties.

Another problem to be solved by the present invention is to provide a polyimide precursor for producing a polyimide film with improved physical properties.

Another problem to be solved by the present invention is to provide a polyimide film using the polyimide precursor.

In addition, the present invention is to provide a flexible device comprising the polyimide film and its manufacturing process.

In order to solve the problems of the present invention, to provide a diamine represented by the formula (1).

 [Formula 1]

In Chemical Formula 1,

X ₁ to X ₈ are each independently a carbon atom or a nitrogen atom, at least one is a nitrogen atom,

R ₁ , R ₂ , R ₃ and R ₄ are each independently selected from an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms,

n1 to n4 are each independently an integer of 0 to 4.

According to a preferred embodiment, in Formula 1, X ₁ to X ₈ have a structure other than a nitrogen atom at the same time.

According to an embodiment, in Formula 1, R _1, R ₂ , R ₃ and R ₄ may each independently be an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms.

According to one embodiment, in Formula 1, X ₁ to X ₄ are all carbon atoms, and at least one of X ₅ to X ₈ may be a nitrogen atom.

According to one embodiment, in Formula 1, at least one of X ₁ to X ₄ may be a nitrogen atom and at least one of X ₅ to X ₈ may be a nitrogen atom.

According to one embodiment, in Formula 1, n1 and n4 are not simultaneously 0.

According to an embodiment, the diamine of Chemical Formula 1 may be selected from compounds of Chemical Formulas 1-1 to 1-32.

.

.

The present invention is also a polyimide precursor obtained by polymerizing a polymerization component comprising at least one diamine and at least one acid dianhydride,

It provides a polyimide precursor that the diamine in the polymerization component includes the diamine represented by the formula (1).

According to one embodiment, the weight average molecular weight of the polyimide precursor prepared using the diamine of Formula 1 as a polymerization component may be 45,000 g / mol or more.

The present invention also provides a polyimide film prepared using the polyimide precursor.

According to one embodiment, applying a polyimide precursor composition comprising the polyimide precursor on a carrier substrate; And

It may be prepared by a method comprising the step of heating and curing the polyimide precursor composition.

In order to solve another problem of the present invention, there is provided a flexible device comprising the polyimide film as a substrate.

The present invention also

Applying the polyimide precursor composition on a carrier substrate;

Heating the polyimide precursor composition to imidize polyamic acid to form a polyimide film;

Forming a device on the polyimide film; And

It provides a manufacturing process of a flexible device comprising the step of peeling the polyimide film on which the device is formed from the carrier substrate.

According to an embodiment, the manufacturing process may include an LTPS (low temperature polysilicon) process, an ITO process, or an oxide process.

The present invention can provide a polyimide precursor whose molecular weight is significantly increased by improving reactivity during polymerization by including a new diamine containing a sulfonyl group (sulfonyl) and containing a nitrogen atom in an aromatic ring structure as a polymerization component. Therefore, while maintaining the optical properties of the polyimide containing a sulfonyl group, it is possible to provide a polyimide film that is also significantly improved in mechanical and thermal properties.

The present invention can be applied to various transformations and may have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention. In the description of the present invention, if it is determined that a detailed description of known technologies related to the present invention may obscure the subject matter of the present invention, the detailed description will be omitted.

All compounds or organic groups herein may be substituted or unsubstituted unless otherwise specified. Here, 'substituted' means that at least one hydrogen contained in the compound or organic group is 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, a hydroxyl group , Substituted with a substituent selected from the group consisting of alkoxy groups having 1 to 10 carbon atoms, carboxylic acid groups, aldehyde groups, epoxy groups, cyano groups, nitro groups, amino groups, sulfonic acid groups and derivatives thereof.

Aromatic polyimides are widely used in high-tech industries such as microelectronics, aerospace, insulating materials and refractory materials due to their excellent overall properties such as thermal oxidation stability, high mechanical strength, and excellent mechanical strength. However, aromatic polyimides having strong absorbance in the ultraviolet-visible region exhibit strong coloration from pale yellow to dark brown, which limits wide application in the optoelectronics area, where transparency and colorless properties are the basic requirements. The reason for the coloration in the aromatic polyimide resin is that it forms charge-transfer complexes (CT-complexes) between the alternating electron donor and the electron acceptor in the polymer main chain and between internal molecules.

To solve this problem, for the development of an optically transparent PI film having a high glass transition temperature (Tg), functional groups are introduced, bulky attached pendant groups, fluorinated functional groups, etc. are introduced into the polymer main chain or However, methods of introducing flexible units (-S-, -O-, -CH _2- , etc.) have been studied.

In particular, in the case of aromatic polyimide containing DDS (4,4'-Diaminodiphenylsulfone) in which sulfone (-SO _2- ) is introduced, the binding of sulfone with high electronegativity prevents the formation of internal or intermolecular CT-complexes It can do not only have low phase difference, low YI, and high transmittance, but also can exhibit thermally stable properties.

However, the sulfonyl group of DDS (4,4'-Diaminodiphenylsulfone) may reduce intramolecular and intermolecular conjugation, thereby reducing reactivity during the polymerization reaction of the polyimide precursor, and thus, may not reach the molecular weight for obtaining target properties. .

In order to solve this conventional problem, the present invention provides a diamine represented by the following formula (1).

[Formula 1]

In Chemical Formula 1,

X ₁ to X ₈ are each independently a carbon atom or a nitrogen atom, at least one or more nitrogen atoms, X ₁ to X ₈ are not nitrogen atoms at the same time,

R ₁ , R _2, R ₃ , and R ₄ are each independently selected from an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms,

n1 to n4 are each independently an integer of 0 to 4.

The diamine according to the present invention, by using a diamine in which an aromatic ring containing a nitrogen atom is further bonded based on a DDS structure containing a sulfonyl group, in order to inhibit the formation of an intermolecular or intramolecular sulfonyl group conjugation, polyimide It is possible to effectively suppress the charge transfer complexation in the main chain, thereby improving the permeability and increasing the optical properties of the polyimide. In addition, the amino group of the benzene ring on the outside is not in one plane with the hetero ring containing the sulfonyl group on the inside, so it is possible to more effectively suppress intramolecular conjugation, thereby improving the reactivity and polymerizing the polymer with improved molecular weight than DDS. Can be.

According to a preferred embodiment, in Formula 1, X ₁ to X ₈ have a structure other than a nitrogen atom at the same time.

In addition, the compound of Formula 1 may have left and right asymmetric structures based on the central group S (= O) ₂ . By having an asymmetric structure, it is also possible to effectively suppress the steric hindrance of the polyimide main chain and charge transfer complexation during polyimide polymerization.

According to another embodiment, in Formula 1, R _1, R ₂ , R ₃ and R ₄ may each independently be an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms.

According to one embodiment, in Formula 1, X ₁ to X ₄ are all carbon atoms, and at least one of X ₅ to X ₈ may be a nitrogen atom.

According to another embodiment, in Formula 1, at least one of X ₁ to X ₄ may be a nitrogen atom and at least one of X ₅ to X ₈ may be a nitrogen atom.

According to a preferred embodiment, in Formula 1, n1 and n4 are not simultaneously 0.

According to an embodiment, the diamine of Chemical Formula 1 may be a compound of Chemical Formulas 1-1 to 1-32.

In Chemical Formula 1, a substituent including fluorine (F), for example, a substituent such as a fluoroalkyl group, can reduce packing within a polyimide structure or between chains, and a color source due to steric hindrance and electrical effects. It is possible to weaken the electrical interaction of the liver, thereby exhibiting high transparency in the visible region.

According to another aspect of the present invention, a polyimide precursor obtained by polymerizing a polymerization component comprising at least one diamine and at least one acid dianhydride, wherein the polyamine in the polymerization component includes the diamine represented by Formula 1 Provide a mid precursor.

According to an embodiment, the weight average molecular weight of the polyimide precursor prepared using the diamine may be 45,000 g / mol or more, and preferably 50,000 g / mol or more. When the molecular weight is less than 45,000 g / mol, the viscosity of the solution is lowered due to the decrease in polyimide reactivity, and the viscosity compared to the solid content is low, so it may not be easy to control the film thickness during the solution coating process and the final curing process. In addition, if the molecular weight is low, mechanical properties may deteriorate, resulting in a problem that the film strength is lowered .

The polyimide precursor according to the present invention may include a diamine or an acid dianhydride having the structure of Formula 2 as a polymerization component:

[Formula 2]

In Chemical Formula 2,

R ₅ and R ₆ are each independently a monovalent organic group having 1 to 20 carbon atoms, and h is an integer of 3 to 200.

More specifically, the compound of Formula 2 may be a diamine compound of Formula 2-1.

[Formula 2-1]

In Chemical Formula 2-1,

R is an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 24 carbon atoms,

p and q are mole fractions, when p + q = 100, p is 70 to 90, and q is 10 to 30.

The compound of Formula 2 may be included in 5 to 50% by weight based on the total weight of the polymerization component, preferably 10 to 20% by weight relative to the total weight of the total polymerization component.

When the polymerization component containing the structure of Formula 2 is excessively added with respect to the total weight, mechanical properties such as modulus of the polyimide may be deteriorated, and film strength may be reduced, resulting in tearing of the film in the process. Physical damage may occur. In addition, when the diamine having the structure of Formula 2 is excessively added, Tg derived from the polymer having the siloxane structure may appear, from which Tg appears at a low process temperature of 350 ° C. or lower, and 350 ° C. or higher During the inorganic film deposition process, wrinkles may occur on the film surface due to the flow phenomenon of the polymer, which may cause the inorganic film to crack.

In general, in the case of a polyimide containing 10% by weight or more of a diamine or an acid dianhydride containing a silicone oligomer structure as in Chemical Formula 2, the effect of reducing residual stress may be increased, and in a composition higher than 50% by weight Tg is lower than 390 ℃ heat resistance may be lowered.

On the other hand, the polyimide according to the present invention can maintain Tg at 390 ° C. or higher despite containing silicone oligomer at 10% by weight or more with respect to the total polymerization component. Therefore, while maintaining the glass transition temperature at 390 ° C or higher, the effect of reducing the residual stress due to the silicone oligomer structure can also be obtained.

The molecular weight of the silicone oligomer structure contained in the diamine or acid dianhydride having the structure of Formula 2 may be 4000 g / mol or more, wherein the molecular weight means the weight average molecular weight, and the molecular weight calculation is performed using NMR analysis or an acid group titration method. A method of calculating the equivalent weight of a reactor such as amine or dianhydride can be used.

When the molecular weight of the silicone oligomer structure including the structure of Formula 2 is less than 4000 g / mol, heat resistance may be lowered, for example, the glass transition temperature (Tg) of the prepared polyimide may be lowered, or the coefficient of thermal expansion may be reduced. It may increase excessively.

According to the present invention, the size of the silicon oligomer domains distributed in the polyimide matrix is nano-sized, for example, 1 nm to 50 nm, or 5 nm to 40 nm, or 10 nm to 30 nm, so that it has a continuous phase, thus maintaining heat resistance and mechanical properties. Residual stress can be minimized. In the case of not having such a continuous phase, there may be a residual stress reduction effect, but it is difficult to use in the process due to a significant decrease in heat resistance and mechanical properties.

Here, the domain of the silicone oligomer means a region in which a polymer having a silicone oligomer structure is distributed, and its size refers to the diameter of a circle surrounding the region.

It is preferable that the part (domain) containing the silicone oligomer structure is connected in a continuous phase in the polyimide matrix, wherein the continuous phase means a shape in which nano-sized domains are uniformly distributed.

Therefore, although the present invention is a silicone oligomer having a high molecular weight, it can be uniformly distributed within the polyimide matrix without phase separation, so that haze characteristics are lowered to obtain a polyimide having more transparent characteristics, as well as a silicone oligomer structure. Because it exists as a continuous phase, the mechanical strength and stress relieving effect of polyimide can be improved more efficiently. From these properties, the composition according to the present invention can provide a flat polyimide film by reducing the thermal and optical properties, as well as the phenomenon of substrate warping after coating-curing.

In the present invention, by inserting the silicone oligomer structure into the polyimide structure, the modulus strength of the polyimide can be appropriately improved, and stress caused by external force can also be relieved. At this time, a polyimide containing a silicone oligomer structure may exhibit polarity, and phase separation may occur due to a polarity difference with a polyimide structure that does not include a siloxane structure, whereby the siloxane structure is unevenly distributed throughout the polyimide structure. Can be. In this case, it is not only difficult to exhibit a property improvement effect such as strength improvement and stress relaxation effect of the polyimide due to the siloxane structure, but also haze increases due to phase separation, so that transparency of the film may be deteriorated. In particular, when the diamine containing the siloxane structure has a high molecular weight, the polarity of the polyimide prepared therefrom may be more vivid, and the phase separation phenomenon between the polyimides may be more vivid. At this time, when using a siloxane diamine having a low molecular weight structure, a large amount must be added in order to exhibit an effect such as stress relaxation, which may cause process problems such as Tg occurring at a low temperature. Due to this, physical properties of the polyimide film may be deteriorated. Accordingly, when a high molecular weight siloxane diamine is added, a relaxation segment may be largely formed in the molecule, and thus, a stress reduction effect may be effectively exhibited even in a small amount compared to the addition of a low molecular weight. Therefore, the present invention can be more evenly distributed without phase separation on the polyimide matrix by using the compound of Formula 2 having the siloxane structure having the high molecular weight.

According to one embodiment, as the acid dianhydride used to polymerize the polyimide precursor, tetracarboxylic dianhydride may be used,

For example, as the tetracarboxylic dianhydride, intramolecular aromatic, alicyclic, or aliphatic tetravalent organic groups, or combinations thereof, aliphatic, alicyclic, or aromatic tetravalent organic groups crosslink each other through a crosslinked structure. Tetracarboxylic dianhydrides containing linked tetravalent organic groups can be used. Preferably, monocyclic or polycyclic aromatic, monocyclic or polycyclic alicyclic, or two or more of these may include an acid dianhydride having a structure connected by a single bond or a functional group. Or, a tetracarboxylic acid containing a tetravalent organic group having a rigid structure such as a heterocyclic ring structure in which a ring structure such as aromatic or cycloaliphatic is single or fused, or a structure connected by a single bond. It may contain dianhydride.

For example, the tetracarboxylic dianhydride may include a tetravalent organic group having a structure of Formulas 3a to 3e:

[Formula 3a]

[Formula 3b]

[Formula 3c]

[Formula 3d]

[Formula 3e]

In the formulas 3a to 3e, the R ₁₁ to R ₁₇ are each independently a halogen atom selected from -F, -Cl, -Br and -I, hydroxyl group (-OH), thiol group (-SH), nitro A group (-NO ₂ ), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms,

The a1 is an integer from 0 to 2, a2 is an integer from 0 to 4, a3 is an integer from 0 to 8, a4 and a5 are each independently an integer from 0 to 3, a6 and a9 are each independently an integer from 0 to 3 , And a7 and a8 may be each independently an integer of 0 to 7,

A ₁₁ and A ₁₂ are each independently a single bond, -O-, -CR ₁₈ R _19- , -C (= O)-, -C (= O) NH-, -S-, -SO _2- , It may be selected from the group consisting of phenylene groups and combinations thereof, wherein R ₁₈ and R ₁₉ 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. It can be.

Alternatively, the tetracarboxylic dianhydride may include a tetravalent organic group selected from the group consisting of the following Chemical Formulas 4a to 4n.

At least one hydrogen atom in the tetravalent organic group of the formulas 4a to 4n is a halogen atom selected from -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 having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms. For example, the halogen atom may be fluoro (-F), the halogenoalkyl group is a fluoroalkyl group having 1 to 10 carbon atoms containing a fluoro atom, fluoromethyl group, perfluoroethyl group, trifluoro It may be selected from methyl groups, and the alkyl group may be selected from methyl groups, ethyl groups, propyl groups, isopropyl groups, t-butyl groups, pentyl groups, and hexyl groups, and the aryl groups are selected from phenyl groups and naphthalenyl groups. It may be, and more preferably, it may be a substituent containing a fluoro atom such as a fluoro atom and a fluoroalkyl group.

Alternatively, in the tetracarboxylic dianhydride, an aromatic ring or an aliphatic structure is a structure in which each ring structure is rigid, that is, a single ring structure, a structure in which each ring is bonded by a single bond, or each ring It may be to include a tetravalent organic group containing a heterocyclic structure directly connected.

According to one embodiment, when polymerizing the polyimide precursor, one or more diamines may be further included in addition to the diamine of Formula 1, for example, a monocyclic or polycyclic aromatic divalent organic group having 6 to 24 carbon atoms, and 6 to 18 carbon atoms. A monocyclic or polycyclic alicyclic divalent organic group of, or a diamine containing a divalent organic group structure selected from a divalent organic group comprising a structure in which two or more of them are connected by a single bond or a functional group may be included, Or, a ring structure compound such as aromatic or cycloaliphatic is selected from a divalent organic group having a rigid structure such as a single or fused heterocyclic ring structure or a structure connected by a single bond. Can be.

For example, the diamine may include a divalent organic group selected from the following formulas 5a to 5e.

[Formula 5a]

[Formula 5b]

[Formula 5c]

[Formula 5d]

[Formula 5e]

In the above formulas 5a to 5e,

R ₂₁ to R ₂₇ are each independently a halogen atom selected from -F, -Cl, -Br and -I, hydroxyl group (-OH), thiol group (-SH), nitro group (-NO ₂ ), cyan It may be selected from the group consisting of a furnace group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms,

In addition, A ₂₁ and A ₂₂ are each independently a single bond, -O-, -CR'R "-(where R 'and R" are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (for example, Methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, tert-butyl group, pentyl group, etc.) and a haloalkyl group having 1 to 10 carbon atoms (for example, trifluoromethyl group, etc.) Will be), -C (= O)-, -C (= O) O-, -C (= O) NH-, -S-, -SO-, -SO _2- , -O [CH ₂ CH ₂ O ] y- (y is an integer from 1 to 44), -NH (C = O) NH-, -NH (C = O) O-, monocyclic or polycyclic cycloalkylene group having 6 to 18 carbon atoms (for example For example, a cyclohexylene group, etc., a monocyclic or polycyclic arylene group having 6 to 18 carbon atoms (for example, a phenylene group, a naphthalene group, a fluorenylene group, etc.), and combinations thereof Can,

b1 is an integer from 0 to 4, b2 is an integer from 0 to 6, b3 is an integer from 0 to 3, b4 and b5 are each independently integers from 0 to 4, and b7 and b8 are each independently 0 to 0 It is an integer of 9, and b6 and b9 are each independently an integer of 0-3.

Alternatively, the diamine may include a divalent organic group forming a rigid chain structure of an aromatic ring or an aliphatic structure, for example, a single ring structure, a structure in which each ring is bonded by a single bond, or Each ring may include a divalent organic group structure including a fused heterocyclic ring structure.

According to an embodiment of the present invention, the total content of the tetracarboxylic dianhydride and the content of the diamine may be reacted in a molar ratio of 1: 1.1 to 1.1: 1, preferably for improving reactivity and improving processability, It is preferable that the total content of the tetracarboxylic dianhydride is reacted in excess relative to the diamine, or that the content of diamine is reacted in excess relative to the total content of tetracarboxylic dianhydride.

According to one embodiment of the present invention, the molar ratio of the total content of the tetracarboxylic dianhydride and the content of diamine may be preferably reacted at 1: 0.99 to 0.99: 1, preferably 1: 0.98 to 0.98: 1. .

The polymerization reaction of the acid dianhydride and the diamine-based compound may be carried out according to a polymerization method of a conventional polyimide or its precursor, such as solution polymerization.

Examples of the organic solvent that can be used in the polyamic acid polymerization reaction include gamma-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, and 4-hydroxy-4. Ketones such as -methyl-2-pentanone; Aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; Ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether , Glycol ethers such as dipropylene glycol diethyl ether and triethylene glycol monoethyl ether (cellosolve); Ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethanol, propanol, ethylene glycol, propylene glycol, carbitol, dimethyl Dimethylpropionamide (DMPA), diethylpropionamide (DEPA), dimethylacetamide (DMAc), N, N-diethylacetamide, dimethylformamide (DMF), diethylformamide (DEF), N -Methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N, N-dimethylmethoxyacetamide, dimethylsulfoxide, pyridine, dimethylsulfone, hexamethylphosphoramide, tetramethylurea, N- Methylcaprolactam, tetrahydrofuran, m-dioxane, P-dioxane, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane , Bis [2- (2-methoxyethoxy)] ether, Equamide M100, Equamide B100, and the like, or a mixture of two or more of them may be used.

According to one embodiment, as the organic solvent for polymerizing the polymerization component, a solvent having a positive distribution coefficient LogP may be used. By using an organic solvent in which LogP is a positive number, Tg can be maintained at a high temperature of 390 ° C. or higher even in a composition in which methylphenylsilicone oligomer is contained in an amount of 10 wt% or more.

In addition, the organic solvent having a positive partition coefficient as described above may reduce cloudiness caused by phase separation due to polarity differences between a flexible polyimide repeating structure and a polyimide structure including a siloxane structure such as a silicone oligomer. have. Conventionally, two types of organic solvents have been used to solve the phase separation. However, the whitening phenomenon can be reduced by using only the organic solvents described above, so that a more transparent polyimide film can be produced.

In order to solve the above problems, there is a method of mixing and using a polar solvent and a non-polar solvent, but in the case of a polar solvent, volatile tends to be high, and thus problems such as volatilization in advance in the manufacturing process may occur. Not only may problems such as deterioration of reproducibility, but the phase separation problem may not be completely improved, and the haze of the prepared polyimide film may increase, resulting in a decrease in transparency.

More specifically, by using a solvent containing a structure in which the molecules of the solvent have an amphiphilic structure, it is possible to solve a process problem due to the use of a polar solvent, as well as one type due to the molecular structure having an amphiphilic property. Even if only a solvent is used, the polyimide can be evenly distributed, which makes it very suitable for solving problems caused by phase separation, thereby providing a polyimide in which haze characteristics are significantly improved.

When the distribution coefficient value is positive, it means that the polarity of the solvent is hydrophobic. According to the research of the present inventors, it can be seen that when the polyimide precursor composition is prepared using a specific solvent having a positive distribution coefficient value, the edge back phenomenon is improved. there was. In addition, according to the present invention, by using a solvent in which Log P has a positive number as described above, it is possible to control the edge back phenomenon of the solution without using additives that control the surface tension of the material such as a leveling agent and the smoothness of the coating film, This does not use additional additives such as additives, so it is possible to remove the quality and process problems such as the low-molecular substance content in the final product, as well as to form a polyimide film with uniform properties more efficiently. There is.

For example, in the process of coating the polyimide precursor composition on the glass substrate, an edge back phenomenon may occur due to shrinkage of the coating layer during curing or under the condition of leaving the coating solution in a humidity condition. The edge back phenomenon of such a coating solution may cause a variation in the thickness of the film, resulting in the film being cut or a corner being broken when cutting due to a lack of flex resistance of the film, resulting in poor process workability and reduced yield. Problems may arise.

In addition, when a fine foreign matter having polarity is introduced into the polyimide precursor composition applied on the substrate, in the polyimide precursor composition including a solvent having a polarity in which Log P is negative, the position of the foreign matter is referenced by the polarity of the foreign matter. As a result, sporadic cracking or thickness changes may occur, but when a hydrophobic solvent having a positive log P is used, the occurrence of thickness changes due to cracking of the coating is reduced or suppressed even when fine foreign matter having polarity is introduced. Can be.

Specifically, in the polyimide precursor composition including a solvent in which Log P is a positive number, an edge back ratio defined by the following Equation 1 may be 0% to 0.1% or less.

[Equation 1]

Edge percentage (%) = [(A-B) / A] x 100

In the above formula 1,

A: The area in the state where the polyimide precursor composition is completely coated on the substrate (100 mm x 100 mm),

B: This is the area after the edge back phenomenon occurs from the edge end of the polyimide precursor composition or the PI film coated substrate.

The edge back phenomenon of the polyimide precursor composition and the film may occur within 30 minutes after coating the polyimide precursor composition solution, and in particular, the thickness of the edge may be increased by starting to roll from the edge.

After coating the polyimide precursor composition according to the present invention on a substrate for 10 minutes or more, for example 10 minutes or more, for example, 40 minutes or more, the edge percentage of the coated resin composition solution after being left in a humidity condition is 0.1 % Or less, for example, at a temperature of 20 to 30 ° C., a humidity condition of 40% or more, more specifically, a humidity condition in the range of 40% to 80%, that is, 40%, 50%, 60%, 70% , 80% in each humidity condition, for example, even after standing for 10 to 50 minutes at a humidity condition of 50% may exhibit a very small edge percentage of less than 0.1%, preferably 0.05%, more preferably almost It can show an edge percentage close to 0%.

The edge percentage as described above is maintained even after curing, for example, poly

After coating the mid precursor composition on the substrate for 10 minutes or more, for example, at a temperature of 20 to 30 ° C, a humidity condition of 40% or more, more specifically, a humidity condition in the range of 40% to 80%, that is, 40%, 50 %, 60%, 70%, 80% in each of the humidity conditions, for example, at 50% humidity condition after 10 to 50 minutes, the cured polyimide film may have an edge percentage of 0.1% or less, that is, heat treatment Even in the curing process by the edgeback phenomenon may hardly occur or may be present, specifically, 0.05%, and more preferably, may exhibit an edgeback rate close to 0%.

By solving this edge back phenomenon, the polyimide precursor composition according to the present invention can obtain a polyimide film having more uniform characteristics, thereby improving the yield of the manufacturing process.

In addition, the density of the solvent according to the present invention is ASTM as determined using the standard measurement method D1475, 1g / cm ³ can be less than a density of 1 g / If having a cm ³ or more values, it may increase the relative viscosity of the process the Efficiency can be reduced.

The LogP is a positive solvent, for example, N, N-diethylacetamide (N, Ndiethylacetamide, DEAc), N, N-diethylformamide (N, N-diethylformamide, DEF), N-ethylpyrroli It may be one or more selected from money (N-ethylpyrrolidone, NEP), dimethyl propionamide (DMPA) and diethyl propionamide (DEPA).

The organic solvent may have a boiling point of 300 ° C. or less, and more specifically, the distribution coefficient LogP value may be 0.01 to 3, or 0.01 to 2, or 0.1 to 2.

The distribution coefficient can be calculated using the ACD / LogP module of ACD / Percepta platform of ACD / Labs, and the ACD / LogP module uses a 2D structure of the molecule to implement an algorithm based on the QSPR (Quantitative Structure-Property Relationship) methodology. To use.

In addition, aromatic hydrocarbons such as xylene and toluene may be further used, and in order to promote dissolution of the polymer, an alkali metal salt or an alkaline earth metal salt of about 50% by weight or less based on the total amount of the solvent may be further added to the solvent.

In addition, in the case of synthesizing polyamic acid or polyimide, in order to inactivate excess polyamino group or acid anhydride group, a molecular terminal is reacted with dicarboxylic acid anhydride or monoamine to further add a terminal sealant to seal the polyimide end. Can be.

The method for reacting the tetracarboxylic dianhydride with diamine may be carried out according to a conventional polyimide precursor polymerization production method such as solution polymerization. Specifically, after diamine is dissolved in an organic solvent, it can be prepared by adding a tetracarboxylic dianhydride to the resulting mixed solution for polymerization.

The polymerization reaction may be performed under an inert gas or nitrogen stream, and may be performed under anhydrous conditions.

In addition, the reaction temperature during the polymerization reaction may be carried out at -20 to 80 ℃, preferably 0 to 80 ℃. When the reaction temperature is too high, the reactivity becomes high and the molecular weight may increase, and the viscosity of the precursor composition increases, which may be disadvantageous in the process.

It is preferable that the polyamic acid solution prepared according to the above-described manufacturing method contains solids in an amount to allow the composition to have an appropriate viscosity in consideration of fairness such as coatability during the film forming process.

The polyimide precursor composition containing the polyamic acid may be in the form of a solution dissolved in an organic solvent, and when it has such a form, for example, when a polyimide precursor is synthesized in an organic solvent, the solution is a reaction solution obtained. It may be itself, or this reaction solution may be diluted with another solvent. Moreover, when obtaining a polyimide precursor as a solid powder, you may melt | dissolve this in an organic solvent and make it a solution.

According to one embodiment, the content of the composition may be adjusted by adding an organic solvent such that the total polyimide precursor content is 8 to 25% by weight, preferably 10 to 25% by weight, more preferably 10 to 20% by weight % Or less.

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 It is preferable to adjust to have the following viscosity. When the viscosity of the polyimide precursor composition exceeds 10,000 cP, the efficiency of defoaming decreases during processing of the polyimide film, and thus, not only the process efficiency, but also the prepared film has poor surface roughness due to the generation of bubbles, resulting in poor electrical, optical, and mechanical properties. It may degrade.

Subsequently, a transparent polyimide film may be prepared by imidizing the polyimide precursor obtained as a result of the polymerization reaction using a chemical or thermal imidization method.

According to one embodiment, the step of applying a polyimide precursor composition on a carrier substrate; And

A polyimide film may be prepared by a method including heating and curing the polyimide precursor composition.

At this time, as the carrier substrate, a glass, metal substrate, or plastic substrate may be used without particular limitation, and among them, excellent thermal and chemical stability during the imidation and curing process for the polyimide precursor, without additional release agent treatment, A glass substrate that can be easily separated without damage to the polyimide-based film formed after curing may be desirable.

In addition, the coating process may be performed according to a conventional coating method, specifically, spin coating method, bar coating method, roll coating method, air-knife method, gravure method, reverse roll method, kiss roll method, doctor blade method, Spray method, immersion method or brushing method may be used. Among them, a continuous process is possible, and it may be more preferable to be carried out by a casting method capable of increasing the imidation rate of polyimide.

In addition, the polyimide precursor composition may be applied over the substrate in a thickness range that allows the final manufactured polyimide film to have a suitable thickness for a display substrate.

Specifically, it may be applied in an amount to make the thickness of 10 to 30㎛. After application of the polyimide precursor composition, a drying process for removing the solvent present in the polyimide precursor composition may be selectively performed prior to the curing process.

The drying process may be performed according to a conventional method, and specifically, may be performed at a temperature of 140 ° C. or less or 80 ° C. to 140 ° C. If the temperature of the drying process is less than 80 ° C, the drying process becomes longer, and if it exceeds 140 ° C, imidization proceeds rapidly, making it difficult to form a polyimide film of uniform thickness.

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

The residual stress immediately after curing of the polyimide film prepared as described above may be 40 MPa or less, and the residual stress change value after leaving the polyimide film at 25 ° C. and 50% humidity for 3 hours may be 5 MPa or less. .

The yellowness of the polyimide film may be 15 or less, and preferably 13 or less. In addition, the haze of the polyimide film may be 2 or less, and preferably 1 or less.

In addition, the transmittance at 450 nm of the polyimide film may be 75% or more, the transmittance at 550 nm may be 85% or more, and the transmittance at 630 nm may be 90% or more.

The polyimide film may have high heat resistance, for example, a thermal decomposition temperature (Td_1%) in which mass loss is 1% may be 500 ° C or higher.

The polyimide film prepared as described above may have a modulus of 3.5 GPa or less and an elongation of 20% or more. When the modulus (modulus of elasticity) is less than 0.1 Gpa, the rigidity of the film is low and easily fragile to external impact. When the modulus of elasticity exceeds 3.5 Gpa, the rigidity of the coverlay film is excellent, but sufficient flexibility cannot be obtained. Can be.

In addition, the polyimide film according to the present invention may have excellent thermal stability according to a temperature change, for example, a thermal expansion coefficient after a heating and cooling process n + 1 times in a temperature range of 100 ° C to 350 ° C -10 It may have a value of 100 ppm / ℃, preferably, a value of -7 to 90 ppm / ℃, more preferably 80 ppm / ℃ or less (where n is an integer greater than or equal to 0).

In addition, the polyimide film according to the present invention may exhibit optical isotropy by having a thickness direction retardation (R _th ) of -150 nm to +150 nm, preferably -130 nm to +130 nm, thereby improving visibility. .

According to one embodiment, the polyimide film may have an adhesive strength with a carrier substrate of 5 gf / in or more, and preferably 10 gf / in or more.

In addition, the present invention,

Applying the polyimide precursor composition on a carrier substrate;

Heating the polyimide precursor composition to imidize polyamic acid to form a polyimide film;

Forming a device on the polyimide film; And

It provides a manufacturing process of a flexible device comprising the step of peeling the polyimide film on which the device is formed from the carrier substrate.

In particular, the manufacturing process of the flexible device may include a low temperature polysilicon (LTPS) process, an ITO process or an oxide process.

For example, forming a blocking layer containing SiO ₂ on the polyimide film;

Depositing an a-Si (Amorphous silicon) thin film on the blocking layer;

A dehydrogen annealing step of heat-treating the deposited a-Si thin film at a temperature of 450 ± 50 ° C; And

After the LTPS thin film manufacturing process including the step of crystallizing the a-Si thin film with an excimer laser or the like, by peeling the carrier substrate and the polyimide film by laser peeling, a flexible device including the LTPS layer can be obtained.

The oxide thin film process may be heat treated at a lower temperature than the process using silicon, for example, the heat treatment temperature of the ITO TFT process may be 240 ° C ± 50 ° C, and the heat treatment temperature of the oxide TFT process may be 350 ° C ± 50 ° C. Can be

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

<Production Example 1> Preparation of the compound of Formula 1-1

After dissolving the compounds of Formula A (20.0g, 104.8mmol) and Formula B (19.7g, 104.8mmol) in DMSO (200mL), potassium carbonate (21.7g, 157.2mmol) was added and stirred at 90 ° C. After 12 hours, water (200 ml) was added and the solid obtained by filtration was washed with water and ethanol to prepare a compound of Formula C (33.8 g, yield 93.8%).

MS [M + H] ⁺ = 343

In a nitrogen atmosphere, the compounds of Formula C (20g, 58.3mmol) and Formula D (27.4g, 116.6mmol) were dissolved in THF (150ml), potassium carbonate (32.2g, 233.2mmol) was dissolved in water (75ml), and then added. Heated. In reflux, palladium tetratriphenylphosphine (1.35 g, 1.17 mmol) was added and stirred for 5 hours. After the reaction was completed, the temperature was reduced to room temperature and ethanol was added to obtain a solid. The solid obtained after filtration was washed with water and ethanol to prepare the compound of Formula E (26.8 g, yield 81.4%).

MS [M + H] ⁺ = 566

After dispersing glacial acetic acid (250 ml) of the compound of Formula E (25 g, 44.3 mmol), potassium permanganate (20.9 g. 132 mmol) was added at 0 ° C., stirred for 1 hour, heated to room temperature, and stirred for 7 hours. After completion of the reaction, water (250 ml) was added, and the solid obtained after filtration was recrystallized with ethanol to prepare a compound of formula F (23.6 g, yield 89.1%).

MS [M + H] ⁺ = 598

After dispersing Formula F (20g, 33.5mmol) in ethanol (200ml) in a nitrogen atmosphere, tin chloride (25.4g, 134mmol) was added and then heated and stirred at 50 ° C for 8 hours. After completion of the reaction, water (200 ml) was added to obtain a solid. The solid obtained after filtration was recrystallized with ethanol to prepare a compound of Formula 1-1 (14.8 g, yield 82.3%).

MS [M + H] ⁺ = 538

<Production Example 2> Preparation of a compound of Formula 1-2

The compound of Formula G (25g, 190.9mmol) and Formula B (35.9g, 190.9mmol) was dissolved in DMSO (350mL) and potassium carbonate (39.5g, 286.5mmol) was added thereto and stirred at 90 ° C. After 12 hours, water (350 ml) was added and the solid obtained by filtration was washed with water and ethanol to prepare a compound of Formula H (52.5 g, yield 91.9%).

MS [M + H] ⁺ = 299

In a nitrogen atmosphere, the compounds of Formula H (30.0g, 100.7mmol) and Formula D (23.7g, 100.7mmol) were dissolved in THF (200ml) and potassium carbonate (27.8g, 201.4mmol) was dissolved in water (100ml). After heating. In reflux, palladium tetratriphenylphosphine (1.15g, 1.0mmol) was added and stirred for 5 hours. After the reaction was completed, the temperature was reduced to room temperature and ethanol was added to obtain a solid. The solid obtained after filtration was washed with water and ethanol to prepare the compound of Formula I (34.3 g, yield 83.7%).

MS [M + H] ⁺ = 411

In a nitrogen atmosphere, the compounds of Formula I (20g, 48.8mmol) and Formula J (14.9g, 58.6mmol) were dissolved in 1,4-dioxane (200ml) and potassium acetate (14.1g, 146.5mmol) was added. Pd (dba) ₂ (Bis (dibenzylideneacetone) palladium (0)) (0.56g, 0.98mmol) and PCy ₃ (Tricyclohexylphosphine) (0.55g, 1.96mmol) prepared by dissolving in 1.4-dioxane (20ml) in advance under reflux After the solution was added, the mixture was stirred for 8 hours. After the reaction was completed, the temperature was lowered to room temperature, and then 150 mL of the solvent was concentrated, and then normal hexane (200 ml) was added to obtain a solid. The solid obtained after filtration was washed with normal hexane to prepare the compound of Formula K (18.5 g, yield 75.3%).

MS [M + H] ⁺ = 503

In a nitrogen atmosphere, compounds of formula K (18.5 g, 36.9 mmol) and formula L (7.4 g, 36.9 mmol) are dissolved in THF (100 ml), potassium carbonate (10.2 g, 73.8 mmol) is dissolved in water (50 ml) and heated after addition. Did. In reflux, palladium tetratriphenylphosphine (427mg, 0.037mmol) was added and stirred for 5 hours. After the reaction was completed, the temperature was reduced to room temperature and ethanol was added to obtain a solid. The solid obtained after filtration was washed with water and ethanol to prepare a compound of Formula M (16.1 g, yield 87.8%).

MS [M + H] + = 498

After dispersing glacial acetic acid (160 ml) of the compound of formula M (16.1g, 32.4mmol), potassium permanganate (15.3g. 97.2mmol) was added at 0 ° C, stirred for 1 hour, heated to room temperature, and stirred for 7 hours. After completion of the reaction, water (160 ml) was added, and the solid obtained after filtration was recrystallized with ethanol to prepare a compound of Formula N (16.8 g, yield 97.9%).

MS [M + H] + = 530

After dispersing the formula N (16.8 g, 31.8 mmol) in ethanol (170 ml) in a nitrogen atmosphere, tin chloride (20.1 g, 127.2 mmol) was added and then heated and stirred at 50 ° C. for 8 hours. After completion of the reaction, water (170 ml) was added to obtain a solid. The solid obtained after filtration was recrystallized with ethanol to prepare a compound of Formula 1-2 (10.5 g, yield 70.6%).

MS [M + H] ⁺ = 470

<Production Example 3> Preparation of the compound of Formula 1-4

The compound of Formula P was prepared in the same manner as the method of preparing Formula H, except that the compound of Formula O was used instead of Formula G.

The compound of formula (Q) was prepared in the same manner as the method of preparing formula (I), except that the compound of formula (P) was used instead of the formula (H).

The compound of formula R was prepared in the same manner as the method of preparing formula K, except that the compound of formula Q was used instead of the formula I.

The compound of Formula T was prepared in the same manner as the method of preparing Formula M, except that the compound of Formula S was used instead of Formula R and Formula L instead of Formula K.

A compound of formula U was prepared in the same manner as in the method of preparing formula N, except that the compound of formula T was used instead of the formula M.

The compound of Formula 1-4 was prepared in the same manner as the method of preparing the compound of Formula 1-2, except that the compound of Formula U was used instead of Formula N.

MS [M + H] + = 539

<Production Example 4> Preparation of the compound of Formula 1-9

The compound of formula (X) was prepared in the same manner as the method of formula (C) except that the compound of formula (W) was used instead of formula (V) and formula (B) instead of the formula (A).

The compound of formula Y was prepared in the same manner as the method of preparing formula E, except that the compound of formula X was used instead of the formula C.

The compound of Formula Z was prepared in the same manner as the method of preparing Formula F, except that the compound of Formula Y was used instead of Formula E.

The compound of Formula 1-9 was prepared in the same manner as the method of preparing Formula 1-1, except that the compound of Formula Z was used instead of Formula F.

MS [M + H] ⁺ = 539

<Production Example 5> Preparation of the compound of Formula 1-16

The compound of Formula BB was prepared in the same manner as the method of preparing Formula C, except that the compound of Formula W instead of Formula AA and Formula B was used instead of Formula A.

The compound of Formula DD was prepared by the same method as the method of Formula E, except that the compound of Formula B was used instead of Formula BB and Formula D instead of Formula C.

The compound of Formula EE was prepared in the same manner as the method of Formula F, except that the compound of Formula DD was used instead of Formula E.

A compound of Formula 1-16 was prepared in the same manner as the method of preparing Formula 1-1, except that the compound of Formula EE was used instead of Formula F.

MS [M + H] ⁺ = 432

<Production Example 6> Preparation of the compound of Formula 1-17

The compound of Formula GG was prepared by the same method as the method of preparing Formula C, except that the compound of Formula V and Formula B were used instead of Formula A and Formula B.

The compound of formula HH was prepared in the same manner as the method of preparing formula E, except that the compound of formula GG was used instead of the formula C.

The compound of Formula II was prepared by the same method as the method of preparing Formula F, except that the compound of Formula HH was used instead of Formula E.

The compound of Formula 1-17 was prepared in the same manner as the method of preparing Formula 1-1, except that the compound of Formula II was used instead of Formula F.

MS [M + H] ⁺ = 606

<Production Example 7> Preparation of the compound of Formula 1-18

The compound of formula KK was prepared in the same manner as the method of preparing formula C, except that the compound of formula JJ was used instead of the formula A.

The compound of Formula LL was prepared in the same manner as the method of Formula E, except that the compound of Formula KK was used instead of Formula C.

The compound of Formula MM was prepared in the same manner as the method of Formula F, except that the compound of Formula LL was used instead of Formula E.

The compound of Formula 1-18 was prepared in the same manner as the method of preparing Formula 1-1, except that the compound of Formula MM was used instead of Formula F.

MS [M + H] ⁺ = 606

<Production Example 8> Preparation of a compound of Formula 1-22

The compound of Formula OO was prepared by the same method as the method of Formula H, except that the compound of Formula NN and Formula B instead of Formula G were used instead of Formula G.

The compound of formula PP was prepared in the same manner as the method of preparing formula I, except that the compound of formula OO was used instead of the formula H.

The compound of formula QQ was prepared in the same manner as the method of preparing formula K, except that the compound of formula PP was used instead of the formula I.

The compound of formula RR was prepared in the same manner as the method of preparing formula M, except that the compound of formula QQ was used instead of the formula K.

A compound of formula SS was prepared in the same manner as the method of preparing formula N, except that the compound of formula RR was used instead of the formula M.

The compound of Formula 1-22 was prepared in the same manner as the method of preparing the compound of Formula 1-2, except that the compound of Formula SS was used instead of Formula N.

MS [M + H] ⁺ = 606

<Comparative Example 1> PMDA / DDS

After nitrogen stream filled 50 g of DEAc (Diethylacetamide) in the reactor, 0.0458 mol of 4,4'-DDS (4,4'-diaminodiphenyl sulfone) was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25 ° C. . To the solution to which the DDS was added, 0.0458 mol of PMDA (pyromellitic dianhydride) was added together with 50 g of DEAc, and then reacted for 48 hours to prepare a polyimide precursor solution.

<Comparative Example 2> BPDA / DDS

After nitrogen stream filled 40 g of DEAc (Diethylacetamide) in the reactor, 0.03395 mol of 4,4'-DDS (4,4'-diaminodiphenyl sulfone) was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25 ° C. . To the solution to which DDS was added, 0.03395 mol of BPDA (3,3'-biphenyltetracarboxylic dianhydride) was added with 46 g of DEAc, and then reacted for 48 hours to prepare a polyimide precursor solution.

<Example 1> PMDA / Formula 1-1 compound

After filling 191 g of DEAc in a reactor in which a nitrogen stream was flowing, 0.069 mol of diamine of Formula 1-1 prepared in Preparation Example 1 was dissolved at the same temperature while maintaining the temperature of the reactor at 25 ° C. A polyimide precursor solution was prepared by adding 0.069 mol of PMDA to which diamine of Formula 1-1 was added together with 100 g of DEAc and reacting for 48 hours.

<Example 2> BPDA / Formula 1-1 compound

After filling 297 g of DEAc in a reactor in which a nitrogen stream was flowing, 0.085 mol of diamine of Formula 1-1 prepared in Preparation Example 1 was dissolved at the same temperature while maintaining the temperature of the reactor at 25 ° C. To the solution to which the diamine of Formula 1-1 was added, 0.085 mol of BPDA was added together with 100 g of DEAc, and then reacted for 48 hours to prepare a polyimide precursor solution.

<Experimental Example 1>

Each polyimide precursor solution prepared in Examples 1 and 2 and Comparative Examples 1 and 2 was spin coated on a glass substrate. The glass substrate coated with the polyimide precursor solution was placed in an oven and heated at a rate of 5 ° C./min.The curing process was performed by maintaining 30 minutes at 80 ° C., 30 minutes at 250 ° C., and 30-40 minutes at 410 ° C. A polyimide film was prepared. Table 1 shows the physical properties of each film.

<Yellowness (YI)>

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

<Haze>

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

<Transmittance>

The transmittance was measured according to JIS K 7105 with a transmittance meter (model name HR-100, manufactured by Murakami Color Research Laboratory) at 450 nm, 550 nm, and 630 nm wavelengths.

Sample Comparative Example 1
PMDA_DDS Comparative Example 2
BPDA_DDS Example 1
PMDA_Formula 1-1 Example 2
BPDA_Formula 1-1 Sol. Con. (wt%) 22.6 21.5 15.1 16.3 Viscosity (cps) 3424 3020 3640 3840 Mw 40,000 46,000 78,600 74,500 Curing condition (5 ℃ / min)
80 ℃ 30min →
250 ℃ 30min 400 ℃ 30min 400 ℃ 40min 400 ℃ 40min 400 ℃ 40min Thickness (㎛) 9.8 9.53 10.3 9.98 YI 18.2 4.3 11.2 2.6 Haze 0.1 0.3 0.2 0.2 Transmittance% 450nm 71.4 83.2 78.6 86.6 550nm 84.3 89.9 88.7 90.2 630nm 86.1 90.3 89.2 90.3

As can be seen from the results of Table 1, when using the diamine according to the present invention, the reactivity is improved compared to the case of using DDS to obtain a polyamic acid having a higher molecular weight. In addition, the polyimide film according to the present invention may have improved optical properties, such as YI and transmittance, compared to the case of using DDS in a polyimide film made of the same acid dianhydride. Therefore, the polyimide film prepared using the diamine according to the present invention can not only improve heat resistance and mechanical properties from an increase in molecular weight due to improved reactivity, but also improve optical properties, thereby providing a more colorless and transparent polyimide film. have.

Since the specific parts of the present invention have been described in detail above, it is obvious to those skilled in the art that this specific technique is only a preferred embodiment, and the scope of the present invention is not limited thereby. something to do. Therefore, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (14)

Diamine having the structure of Formula 1:
[Formula 1]

In Chemical Formula 1,
X ₁ to X ₈ are each independently a carbon atom or a nitrogen atom, at least one is a nitrogen atom,
R ₁ , R _2, R ₃ , and R ₄ are each independently selected from an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms,
n1 to n4 are each independently an integer of 0 to 4. According to claim 1,
Diamines wherein X ₁ to X ₈ are not nitrogen atoms at the same time. According to claim 1,
R _1, R ₂ , R ₃ and R ₄ are each independently a C 1 to C 5 alkyl group or a C 1 to C 5 haloalkyl group diamine. According to claim 1,
Diamine wherein X ₁ to X ₄ are all carbon atoms, and at least one of X ₅ to X ₈ is a nitrogen atom. According to claim 1,
Diamine wherein at least one of X ₁ to X ₄ is a nitrogen atom, and at least one of X ₅ to X ₈ is a nitrogen atom. The diamine according to claim 1, wherein n1 and n4 are not simultaneously 0. According to claim 1,
Diamine of the formula (1) is selected from the following formula 1-1 to 1-32 compounds:

A polyimide precursor obtained by polymerizing a polymerization component comprising at least one diamine and at least one acid dianhydride,
A polyimide precursor, wherein the diamine comprises the diamine of any one of claims 1 to 7. The method of claim 8,
A polyimide precursor having a weight average molecular weight of 45,000 g / mol or more. A polyimide film prepared using the polyimide precursor according to claim 8. Applying a polyimide precursor composition comprising the polyimide precursor according to claim 8 on a carrier substrate; And
A polyimide film prepared by a method comprising heating and curing the polyimide precursor composition. A flexible device comprising the polyimide film according to claim 10 as a substrate. Applying a polyimide precursor composition comprising the polyimide precursor of claim 8 on a carrier substrate;
Heating the polyimide precursor composition to imidize polyamic acid to form a polyimide film;
Forming a device on the polyimide film; And
And peeling the polyimide film on which the element is formed from the carrier substrate. The method of claim 13,
The manufacturing process of a flexible device, wherein the manufacturing process includes an LTPS (low temperature polysilicon) process, an ITO process, or an oxide process.