KR102224984B1 - Diamine compound and polyimide precursor and polyimide film prepared by using same - Google Patents

Abstract

The present invention can provide a polyimide precursor having a remarkably increased molecular weight due to improved reactivity during polymerization by including a sulfonyl group and a novel diamine having asymmetry as a polymerization component. Accordingly, while maintaining the optical properties of the polyimide containing a sulfonyl group, it is possible to provide a polyimide film having significantly improved mechanical and thermal properties.

Description

A diamine compound, and a polyimide precursor and a polyimide film using the same TECHNICAL FIELD {DIAMINE COMPOUND AND POLYIMIDE PRECURSOR AND POLYIMIDE FILM PREPARED BY USING SAME}

The present invention relates to a novel diamine compound and a polyimide film with improved physical properties prepared using the same, and a precursor thereof.

In recent years, light weight and miniaturization of products are becoming important in the display field, and the glass substrates currently used are heavy, brittle, and have limitations in that continuous processing is difficult, so a plastic substrate that has the advantage of being light, flexible, and capable of continuous processing as a substitute for glass substrates. Research is being actively conducted to apply the technology to mobile phones, notebook computers, and PDAs.

In particular, polyimide (PI) resins are easy to synthesize, can make thin films, and have the advantage of not needing a crosslinker for curing, so they are integrated into semiconductor materials such as LCD and PDP due to the recent light weight and precision phenomenon of electronic products. It is widely applied, and many studies are being conducted to use PI for a flexible plastic display board having a light and flexible property.

A polyimide (PI) film is produced by forming a film of the polyimide resin, and in general, the polyimide resin is a solution polymerization of an aromatic dianhydride and an aromatic diamine or an aromatic diisocyanate to prepare a polyamic acid derivative solution. It is manufactured by coating a silicon wafer or glass and curing it by heat treatment.

Flexible devices involving a high-temperature process require heat resistance at high temperatures. In particular, in the case of an OLED (organic light emitting diode) device using a low temperature polysilicon (LTPS) process, the process temperature may approach 500°C. However, at this temperature, even polyimide having excellent heat resistance is likely to undergo thermal decomposition by hydrolysis. 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 in which thermal decomposition by hydrolysis does not occur even at a high temperature process.

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

Another problem to be solved by the present invention is to provide a polyimide precursor for manufacturing 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.

Further, the present invention is to provide a flexible device containing the polyimide film and a manufacturing process thereof.

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

[Formula 1]

In Formula 1,

X ₁ to X ₈ are each independently a carbon atom or a nitrogen atom, but not a nitrogen atom at the same time, and R ₁ and R ₂ are each independently a C 1 to C 10 alkyl group, a C 1 to C 10 haloalkyl group, a C 6 to C 18 It is selected from aryl groups,

n1 and n2 are each independently an integer of 0 to 4.

According to an embodiment, in Formula 1, _{at least one of X 1} to X ₄ is necessarily a carbon atom, and at least one of _{X 5} to X _{8 is necessarily a carbon atom.}

According to an embodiment, R ₁ and R ₂ are each independently an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms.

According to an embodiment, all of X ₁ to X ₈ may be carbon atoms.

According to an embodiment, all of X ₁ to X ₄ may be carbon atoms, and _{one or two of X 5} to X ₈ may be nitrogen atoms.

According to an embodiment, one of X ₁ to X ₄ may be a nitrogen atom, and one or two of X ₅ to X _{8 may be a nitrogen atom.}

According to an embodiment, the diamine of Formula 1 may be selected from compounds of Formulas 1-1 to 1-25.

.

.

The present invention is also a polyimide precursor obtained by polymerizing a polymerization component containing at least one diamine and at least one acid dianhydride, wherein the diamine in the polymerization component contains a diamine represented by the above formula (1). Provides.

According to an embodiment, the weight average molecular weight of the polyimide precursor prepared by 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 an embodiment, applying a polyimide precursor composition including the polyimide precursor on a carrier substrate; And

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

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

The present invention also,

Applying the polyimide precursor composition onto 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 provides a novel diamine having asymmetry while containing a sulfonyl group, and by using it as a polymerization component, a polyimide precursor having a remarkably increased molecular weight due to improved reactivity during polymerization can be provided. Accordingly, while maintaining the optical properties of the polyimide containing a sulfonyl group, it is possible to provide a polyimide film having significantly improved mechanical and thermal properties.

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

In the present specification, all compounds or organic groups 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, and a hydroxy group. , It means 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.

Aromatic polyimide is widely used in high-tech industries such as microelectronics, aerospace, insulating materials and refractory materials due to its excellent comprehensive properties such as thermal oxidation stability, high mechanical strength, and good mechanical strength. However, aromatic polyimide with strong absorbance in the ultraviolet-visible region exhibits a strong coloration from pale yellow to dark brown, which limits its wide application in the optoelectronics area, where transparency and colorless properties are basic requirements. The reason why coloration appears in the aromatic polyimide resin is that it forms charge transfer complexes (CT-complexes) between alternating electron donors (dianhydride) and electron acceptors (diamine) and between internal molecules in the polymer backbone.

To solve this problem, in order to develop an optically transparent PI film having a high glass transition temperature (Tg), a functional group is introduced, a bulky attachment pendant group, a fluorinated functional group, etc. are introduced into the polymer main chain. , Methods of introducing flexible units (-S-, -O-, -CH2-, etc.) have been studied.

In particular, in _{the case of aromatic polyimide containing DDS (4,4'-Diaminodiphenylsulfone) with sulfone (-SO 2} -) introduced, the bond of sulfone with high electronegativity prevents the formation of CT-complexes inside or between molecules. As a result, it not only has the properties of low phase difference, low YI, and high transmittance, but also exhibits thermally stable properties.

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

In order to solve these conventional problems, the present invention,

As a polyimide precursor obtained by polymerizing a polymerization component containing at least one diamine and at least one acid dianhydride,

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

[Formula 1]

In Formula 1,

X ₁ to X ₈ are each independently a carbon atom or a nitrogen atom, but not a nitrogen atom at the same time,

R ₁ and R ₂ 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 and n2 are each independently an integer of 0 to 4.

In the present invention, in order to suppress the formation of conjugation of the sulfonyl group in the molecule or in the molecule, by using a diamine having an asymmetric structure containing a sulfonyl group, steric hindrance and charge transfer complexation of the polyimide main chain can be effectively suppressed. As a result, the reactivity may be improved and the molecular weight of the resulting polyimide may be increased.

According to an embodiment, the weight average molecular weight of the polyimide precursor prepared using the diamine having an asymmetric structure may be 45,000 g/mol or more, and preferably 50,000 g/mol or more. If the molecular weight is less than 45,000 g/mol, the viscosity of the solution may decrease due to the decrease in polyimide reactivity, and the viscosity of the solution is low compared to the solid content, making it difficult to control the film thickness during the solution coating process and the final curing process. In addition, when the molecular weight is low, mechanical properties may be deteriorated, resulting in a problem of lowering the film strength.

According to an embodiment, by including a nitrogen atom in the aromatic ring, intramolecular conjugation of the sulfonyl group can be more effectively suppressed, and thus optical properties that can be expressed from the sulfonyl group can be further improved.

According to an embodiment, in Formula 1, R ₁ and R ₂ are each independently an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms.

According to an embodiment, in Formula 1, all of X ₁ to X ₈ may be carbon atoms.

According to an embodiment, in Formula 1, all of X ₁ to X ₄ may be carbon atoms, and _{one or two of X 5} to X ₈ may be nitrogen atoms.

According to an embodiment, in Formula 1, one of X ₁ to X ₄ may be a nitrogen atom, and one or two of X ₅ to X _{8 may be a nitrogen atom.}

According to an embodiment, in Formula 1, n1 and n2 are each independently 0 or 1.

According to an embodiment, the diamine of Formula 1 may be a compound of Formulas 1-1 to 1-25.

.

.

In Formula 1, a substituent containing fluorine (F), for example, a substituent such as a fluoroalkyl group, can reduce packing within the polyimide structure or between chains, and due to steric hindrance and electrical effects, It is possible to exhibit high transparency in the visible light region by weakening the electrical interaction between the liver.

The polyimide precursor according to the present invention may contain a diamine or an acid dianhydride having a structure represented by the following formula (2) as a polymerization component:

[Formula 2]

In Formula 2,

R ₃ and R ₄ 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 Formula 2-1,

R is a C1-C10 alkyl group or a C6-C24 aryl group,

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 an amount of 5 to 50% by weight based on the total weight of the polymerization component, and preferably may be included in an amount of 10 to 20% by weight based on the total weight of the polymerization component.

If the polymerization component including the structure of Formula 2 is added excessively with respect to the total weight, mechanical properties such as modulus of the polyimide may be deteriorated, and the film strength may be reduced, such that the film is torn 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, and from this, Tg appears at a low process temperature of 350°C or less. During the inorganic film deposition process, wrinkles may occur on the film surface due to the flow phenomenon of the polymer, and the inorganic film may be cracked.

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

On the other hand, the polyimide according to the present invention can maintain Tg at 390°C or higher even though it contains a silicone oligomer in an amount of 10% by weight or more based on the total polymerization component. Therefore, while maintaining the glass transition temperature above 390°C, the effect of reducing residual stress due to the silicon 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 refers to the weight average molecular weight, and the molecular weight calculation is performed using NMR analysis or acid base titration method. A method of calculating the equivalent of the 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 reduced, for example, the glass transition temperature (Tg) of the prepared polyimide is decreased, or the coefficient of thermal expansion It can increase excessively.

According to the present invention, since 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, it has a continuous phase, while 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 heat resistance and mechanical properties are remarkably reduced, making it difficult to use in the process.

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

It is preferable that the portion (domain) containing the silicon 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 without phase separation in the polyimide matrix, so that the haze property is lowered to obtain a polyimide having more transparent properties, as well as a silicone oligomer structure. Since is present in a continuous phase, the mechanical strength and stress relaxation effect of the polyimide can be more efficiently improved. From these properties, the composition according to the present invention can provide a flat polyimide film by reducing not only thermal properties and optical properties, but also a phenomenon in which the substrate is warped after coating-curing.

In the present invention, by inserting the silicone oligomer structure into the polyimide structure, it is possible to appropriately improve the modulus strength of the polyimide and also relieve stress caused by an external force. At this time, the polyimide containing the silicon oligomer structure may exhibit polarity, and phase separation may occur due to the difference in polarity from the polyimide structure not including the siloxane structure, and due to this, the siloxane structure is distributed unevenly throughout the polyimide structure. Can be. In this case, not only it is difficult to exhibit the effect of improving the strength of the polyimide due to the siloxane structure and the effect of relieving stress, but also the haze may increase due to phase separation, thereby reducing the transparency of the film. In particular, when a diamine containing a siloxane structure has a high molecular weight, the polarity of the polyimide prepared therefrom is more pronounced, and a phase separation phenomenon between the polyimides may be more pronounced. At this time, in the case of using siloxane diamine having a low molecular weight structure, a large amount must be added in order to exhibit an effect such as stress relief, which may cause process problems such as Tg generation at a low temperature. Due to this, the physical properties of the polyimide film may be deteriorated. Accordingly, when a high molecular weight siloxane diamine is added, the relaxation segment can be formed large in the molecule, and thus, the stress relaxation effect can be effectively exhibited even with a small amount compared to the addition of a low molecular weight. Accordingly, in the present invention, by using the compound of Formula 2 having a siloxane structure having a high molecular weight, it can be more evenly distributed on a polyimide matrix without phase separation.

According to an embodiment, the acid dianhydride used to polymerize the polyimide precursor may be a tetracarboxylic dianhydride. For example, as the tetracarboxylic dianhydride, intramolecular aromatic, alicyclic, Alternatively, as an aliphatic tetravalent organic group or a combination thereof, a tetracarboxylic dianhydride containing a tetravalent organic group in which aliphatic, alicyclic or aromatic tetravalent organic groups are connected to each other through a crosslinked structure may be used. Preferably, it may include an acid dianhydride having a monocyclic or polycyclic aromatic, monocyclic or polycyclic alicyclic, or a structure in which two or more of them are linked by a single bond or a functional group. Or, tetracarboxylic acid containing a tetravalent organic group having a rigid structure such as a single or fused heterocyclic ring structure, or a structure linked by a single bond. May contain dianhydrides.

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

[Formula 3a]

[Formula 3b]

[Formula 3c]

[Chemical Formula 3d]

[Formula 3e]

In Formulas 3a to 3e, R11 to R17 are each independently a halogen atom selected from -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group (-SH), and 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, and an aryl group having 6 to 20 carbon atoms,

A1 is an integer of 0 to 2, a2 is an integer of 0 to 4, a3 is an integer of 0 to 8, a4 and a5 are each independently an integer of 0 to 3, a6 and a9 are each independently an integer of 0 to 3 , And a7 and a8 may each independently be an integer of 0 to 7,

The 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 a phenylene group and a combination 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 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, and an aryl group having 6 to 20 carbon atoms. For example, the halogen atom may be fluoro (-F), and the halogenoalkyl group is a fluoroalkyl group having 1 to 10 carbon atoms including a fluoro atom, and a fluoromethyl group, perfluoroethyl group, trifluoro The alkyl group may be selected from methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, pentyl group, hexyl group, and the aryl group may be selected from phenyl group and naphthalenyl group. It may be, and more preferably, it may be a substituent including a fluoro atom such as a fluoro atom and a fluoroalkyl group.

Alternatively, the tetracarboxylic dianhydride has an aromatic ring or an aliphatic 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 is It may include a tetravalent organic group including a directly linked heterocyclic structure.

According to an embodiment, at the time of polymerization of the polyimide precursor, one or more diamines may be further included in addition to the formula 1 diamine, for example, a monocyclic or polycyclic aromatic divalent organic group having 6 to 24 carbon atoms, and 6 to carbon atoms. 18 monocyclic or polycyclic alicyclic divalent organic groups, or diamines containing a divalent organic group structure selected from a divalent organic group including a structure in which two or more of them are linked with a single bond or a functional group, and , Or, selected from divalent organic groups having a rigid structure such as a single or fused heterocyclic ring structure, or a structure linked by a single bond Can be

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

[Formula 5a]

[Formula 5b]

[Formula 5c]

[Formula 5d]

[Formula 5e]

In Formulas 5a to 5e,

R ₂₁ to R ₂₇ are each independently a halogen atom selected from -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group (-SH), a nitro group (-NO ₂ ), and a cyanide group. It may be selected from the group consisting of a no 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"- (herein, R'and R" are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (for example, Selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a pentyl group, etc.) and a haloalkyl group having 1 to 10 carbon atoms (e.g., trifluoromethyl group, etc.) ), -C(=O)-, -C(=O)O-, -C(=O)NH-, -S-, -SO-, -SO2-, -O[CH ₂ CH ₂ O] y- (y is an integer of 1 to 44), -NH(C=O)NH-, -NH(C=O)O-, a monocyclic or polycyclic cycloalkylene group having 6 to 18 carbon atoms (e.g. , Cyclohexylene group, etc.), a monocyclic or polycyclic arylene group having 6 to 18 carbon atoms (e.g., a phenylene group, a naphthalene group, a fluorenylene group, etc.), and a combination thereof. There is,

b1 is an integer of 0 to 4, b2 is an integer of 0 to 6, b3 is an integer of 0 to 3, b4 and b5 are each independently an integer of 0 to 4, b7 and b8 are each independently 0 to 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 in which an aromatic ring or an aliphatic structure forms a rigid chain 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 heterocyclic ring structure in which each ring is directly fused. For example, the diamine may be one containing a divalent organic group selected from Formulas 6a to 6p below.

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

According to an embodiment of the present invention, the molar ratio of the total content of the tetracarboxylic dianhydride and the content of diamine may be 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 conventional polymerization method of polyimide or a precursor thereof, such as solution polymerization.

As organic solvents that can be used in the polyamic acid polymerization reaction, gamma-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 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 (cellosolve) such as dipropylene glycol diethyl ether and triethylene glycol monoethyl ether; 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 Propionamide (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, and one of them alone or a mixture of two or more may be used.

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

In addition, the organic solvent having a positive partition coefficient as described above can reduce the clouding phenomenon caused by phase separation due to the polarity difference 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, but it is possible to reduce the clouding phenomenon by only using the organic solvent as described above, and thus a more transparent polyimide film can be prepared.

In order to solve the above problem, there is a method of using a mixture of a polar solvent and a non-polar solvent, but polar solvents tend to have high volatility, and therefore, problems such as volatilization in advance during the manufacturing process may occur. Not only may a problem such as a decrease in reproducibility of the polyimide film, but also a phase separation problem may not be completely improved, and thus haze of the manufactured polyimide film may increase, resulting in a decrease in transparency.

More specifically, by using a solvent containing a structure in which the molecule of the solvent has an amphiphilic structure, not only can the problem of the process caused by the use of a polar solvent be solved, but also one type of Even if only a solvent is used, the polyimide can be evenly distributed, which is very suitable for solving the problem due to phase separation, and thus, a polyimide having remarkably improved haze properties can be provided.

When the partition 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 a polyimide precursor composition is prepared using a specific solvent having a positive partition coefficient value, the edge back phenomenon is improved. there was. In addition, in the present invention, by using a solvent having a positive log P as above, it is possible to control the edge back phenomenon of the solution without using an additive that adjusts 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 not only possible to eliminate quality and process problems such as containing low molecular weight substances in the final product, but also to more efficiently form a polyimide film having uniform properties. There is.

For example, in a process of coating a polyimide precursor composition on a glass substrate, edge back phenomenon may occur due to shrinkage of the coating layer during curing or under a condition of leaving the coating liquid under a humidity condition. The edge-back phenomenon of the coating solution can lead to variations in the thickness of the film, resulting in a phenomenon in which the film is broken due to the lack of bending resistance of the film or the edges are broken during cutting, resulting in poor workability in the process and a decrease in yield. Problems can arise.

In addition, when a fine foreign material having polarity is introduced into the polyimide precursor composition applied on the substrate, in the polyimide precursor composition containing a polar solvent having a negative log P, the position of the foreign material is based on the polarity of the foreign material. However, when a hydrophobic solvent with a positive log P is used, the occurrence of thickness change due to cracking of the coating is reduced or suppressed even when fine foreign substances with polarity are introduced. Can be.

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

[Equation 1]

Edge white rate (%) = [(A-B)/A]x100

In Equation 1 above,

A: The area in a state where the polyimide precursor composition is completely coated on the substrate (100mmΥ100mm),

B: The area after the edge-back phenomenon occurs from the edge of the substrate coated with the polyimide precursor composition or PI film.

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

After coating the polyimide precursor composition according to the present invention on a substrate, the edge white rate of the coated resin composition solution after being left in a humidity condition for 10 minutes or more, such as 10 minutes or more, such as 40 minutes or more, 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% , In each humidity condition of 80%, for example, even after leaving for 10 to 50 minutes in a humidity condition of 50%, a very small edge white rate of 0.1% or less may be exhibited, preferably 0.05%, more preferably almost It can represent an edge percentage close to 0%.

The edge white rate as described above is maintained even after curing, for example, 10 minutes or more after coating the polyimide precursor composition on the substrate, for example, at a temperature of 20 to 30° C., under a humidity condition of 40% or more, more specifically Is allowed to stand for 10 to 50 minutes in a humidity condition of 40% to 80%, i.e., 40%, 50%, 60%, 70%, 80% of each humidity condition, for example, 50% humidity condition, and then cured. The edge-back ratio of the resulting polyimide film may be 0.1% or less, that is, the edge-back phenomenon may hardly occur or may not occur even in the curing process by heat treatment, specifically, the edge close to 0.05%, more preferably close to 0%. It can represent percentage.

The polyimide precursor composition according to the present invention can obtain a polyimide film having more uniform properties by solving such an edge back phenomenon, thereby further 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 solvent in which LogP is a positive number is, for example, N,N-diethylacetamide (N,Ndiethylacetamide, DEAc), N,N-diethylformamide (N,N-diethylformamide, DEF), N-ethylpyrroly It may be at least one selected from don (N-ethylpyrrolidone, NEP), dimethylpropionamide (DMPA), and diethylpropionamide (DEPA).

The organic solvent may have a boiling point of 300° C. or less, and more specifically, a partition 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 the ACD/Percepta platform of ACD/Labs, and the ACD/LogP module uses an algorithm based on the quantitative structure-property relationship (QSPR) methodology using the 2D structure of the molecule. Use.

Further, 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 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 an excess polyamino group or acid anhydride group, the molecular end is reacted with a dicarboxylic acid anhydride or a monoamine to further add a terminal sealing agent that seals the end of the polyimide. I can.

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

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

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

It is preferable to include a solid content in the polyamic acid solution prepared according to the above-described manufacturing method in an amount such that the composition has an appropriate viscosity in consideration of fairness such as coatability during the film formation process.

The polyimide precursor composition containing the polyamic acid may be in the form of a solution dissolved in an organic solvent, and in the case of having such a form, for example, when the polyimide precursor is synthesized in an organic solvent, the solution is the obtained reaction solution. It may be itself, or may be one obtained by diluting this reaction solution with another solvent. In addition, when the polyimide precursor is obtained as a solid powder, it may be dissolved in an organic solvent to obtain a solution.

According to an embodiment, the content of the composition may be adjusted by adding an organic solvent so that the content of the total polyimide precursor is 8 to 25% by weight, preferably 10 to 25% by weight, more preferably 10 to 20% by weight. It can be adjusted below %.

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 during the processing of the polyimide film decreases, so that not only the efficiency of the process, but also the surface roughness of the produced film is poor due to the generation of bubbles, so that the electrical, optical, and mechanical properties are poor. It can be degraded.

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

According to an embodiment, 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, glass, metal substrate, plastic substrate, etc. may be used without particular limitation, and among them, it has excellent thermal and chemical stability during the imidization and curing process for the polyimide precursor, and without a separate 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, and specifically, a spin coating method, a bar coating method, a roll coating method, an air-knife method, a gravure method, a reverse roll method, a kiss roll method, a doctor blade method, Spray method, dipping method, brushing method, etc. may be used. Among these, a continuous process may be possible, and it may be more preferable to perform a casting method capable of increasing the imidation rate of the polyimide.

In addition, the polyimide precursor composition may be applied on the substrate in a thickness range such that the polyimide film finally produced has a thickness suitable for a display substrate.

Specifically, it may be applied in an amount such that it has a thickness of 10 to 30 μm. After the polyimide precursor composition is applied, a drying process for removing the solvent present in the polyimide precursor composition may be optionally further 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. When the drying process is performed at a temperature of less than 80°C, the drying process is prolonged, and when it exceeds 140°C, imidization proceeds rapidly, making it difficult to form a polyimide film having a 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 be in the range of 300 to 500°C, preferably 320 to 480°C, and the temperature It can also be carried out in a multi-stage heat treatment within the range. The heat treatment process may be performed for 20 to 70 minutes, and preferably may be performed for a time of about 20 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. 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, and for example, a thermal decomposition temperature (Td_1%) at which a mass decrease of 1% occurs may be 500°C or higher.

The polyimide film prepared as described above may have a modulus of 3 to 4 GPa. If the modulus (modulus of elasticity) is less than 0.1 Gpa, the film has low rigidity and is easily fragile by external impact. If the modulus of elasticity exceeds 4 Gpa, the coverlay film has excellent rigidity but cannot secure sufficient flexibility. I can.

In addition, the polyimide film may have an elongation of 20% or more, preferably 50% or more, and a tensile strength of 130 MPa or more, preferably 140 MPa or more.

In addition, the polyimide film according to the present invention may have excellent thermal stability according to temperature change, for example, the coefficient of thermal expansion after n+1 heating and cooling processes in a temperature range of 100°C to 350°C is -10 It may have a value of to 100 ppm/°C, preferably a value of -7 to 90 ppm/°C, more preferably 80 ppm/°C 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 retardation in the thickness direction (R th} ) of -150 nm to +150 nm, preferably -130 nm to +130 nm, thereby improving visibility. .

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

In addition, the present invention,

Applying the polyimide precursor composition onto 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 dehydrogenation 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, the carrier substrate and the polyimide film are peeled off by laser peeling or the like, thereby obtaining a flexible device including the LTPS layer.

The oxide thin film process can 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℃±50℃, and the heat treatment temperature of the oxide TFT process is 350℃±50℃. Can be

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

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

After dissolving the compounds of formula A (20.0g, 127.4 mmol) and formula B (24.0, 127.4 mmol) in DMSO (200mL), potassium carbonate (26.4g, 191.1 mmol) was added and stirred at 90°C. After 12 hours, water (200ml) was added and the solid obtained by filtration was washed with water and ethanol to prepare a compound of Formula C (32.5g, yield 82.5%).

MS[M+H] ⁺ =309

In a nitrogen atmosphere, the compounds of formula C (20g, 61.8 mmol) and formula D (10.3g, 61.8mmol) were dissolved in THF (200mL), potassium carbonate (17.1g, 123.6mmol) was dissolved in water (100mL), and then added. Heated. In the state of refluxing, palladium tetratriphenylphosphine (0.71g, 0.62mmol) was added and stirred for 5 hours. After the reaction was completed, the temperature was lowered 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 E (18.5g, yield 85%).

MS[M+H] ⁺ =353

After dispersing the formula E (7.9g, 22.4mmol) in glacial acetic acid (120mL), potassium permanganate (10.6g, 67.2mmol) was added at 0°C, stirred for 1 hour, and then heated to room temperature and stirred for 7 hours. After completion of the reaction, water (120 ml) was added and the solid obtained after filtration was recrystallized with ethanol to prepare a compound of formula F (7.8 g, yield 91.3%).

MS[M+H] ⁺ =385

Compound F (10g, 26.1mmol) was dispersed in ethanol (100mL) in a nitrogen atmosphere, and then tin chloride (19.8g, 104mmol) was added thereto, followed by heating, followed by stirring at 50°C for 8 hours. After completion of the reaction, 120 mL of water was added to obtain a solid. The solid obtained after filtration was recrystallized with ethanol to prepare a compound of Formula 1-1 (6.4g, yield 75.2%).

MS[M+H] ⁺ =325

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

After dissolving the compounds of formula G (20.0g, 127.4 mmol) and formula H (24.3, 127.4 mmol) in DMSO (200mL), potassium carbonate (26.4g, 191.1 mmol) was added and stirred at 90°C. After 12 hours, water (200ml) was added and the solid obtained by filtration was washed with water and ethanol to prepare a compound of formula I (35.1g, yield 88.9%).

MS[M+H] ⁺ =310

In a nitrogen atmosphere, the compounds of Formula I (25g, 80.7 mmol) and Formula D (13.5g, 80.7mmol) were dissolved in THF (250mL), potassium carbonate (22.3g, 161mmol) was dissolved in water (125mL), added, and heated. . In the state of refluxing, palladium tetratriphenylphosphine (0.94g, 0.81mmol) was added and stirred for 5 hours. After the reaction was completed, the temperature was lowered 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 J (24.8g, yield 87%).

MS[M+H] ⁺ =354

After dispersing the formula J (20g, 56.7mmol) in glacial acetic acid (200mL), potassium permanganate (26.8g, 170mmol) was added at 0° C., stirred for 1 hour, and then heated to room temperature and stirred for 7 hours. After completion of the reaction, water (200 ml) was added, and the solid obtained after filtration was recrystallized with ethanol to prepare a compound of formula K (20.3 g, yield 93%).

MS[M+H] ⁺ =386

Compound K (15g, 39.0 mmol) was dispersed in ethanol (150 mL) in a nitrogen atmosphere, and then tin chloride (30.0g, 156 mmol) was added thereto, followed by heating, followed by stirring at 50° C. for 8 hours. After completion of the reaction, 150 mL of water was added to obtain a solid. The solid obtained after filtration was recrystallized with ethanol to prepare a compound of Formula 1-2 (10.7 g, yield 84.7%).

MS[M+H] ⁺ =326

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

After dissolving the compounds of formula L (20.0g, 128.2 mmol) and formula H (24.5, 128.2 mmol) in DMSO (200mL), potassium carbonate (26.5g, 192.3 mmol) was added and stirred at 90°C. After 12 hours, water (200ml) was added and the solid obtained by filtration was washed with water and ethanol to prepare a compound of Formula M (32.0g, yield 80.3%).

MS[M+H] ⁺ =311

In a nitrogen atmosphere, the compounds of formula M (20g, 64.3 mmol) and formula D (10.7g, 64.3mmol) are dissolved in THF (200mL), potassium carbonate (17.7g, 128.6mmol) is dissolved in water (100mL), and then heated. I did. In the state of refluxing, palladium tetratriphenylphosphine (0.74g, 0.64mmol) was added and stirred for 5 hours. After the reaction was completed, the temperature was lowered 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 N (20.3g, yield 89.4%).

MS[M+H] ⁺ =355

After dispersing the compound of Formula N (10g, 28.3mmol) in glacial acetic acid (130mL), potassium permanganate (13.4g, 84.9mmol) was added at 0°C, stirred for 1 hour, and then heated to room temperature and stirred for 7 hours. After completion of the reaction, water (130 ml) was added, and the solid obtained after filtration was recrystallized with ethanol to prepare a compound of formula O (8.9 g, yield 81.1%).

MS[M+H] ⁺ =387

After dispersing the compound of Formula O (8.9g, 23.1mmol) in ethanol (90mL) in a nitrogen atmosphere, tin chloride (17.5g, 92.4mmol) was added, heated, and stirred at 50°C for 8 hours. After completion of the reaction, 90 mL of water was added to obtain a solid. The solid obtained after filtration was recrystallized with ethanol to prepare a compound of Formula 1-3 (6.5g, yield 86.8%).

MS[M+H] ⁺ =327

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

After dissolving the compounds of formula G (20.0g, 127.4 mmol) and formula P (24.4, 127.4 mmol) in DMSO (200mL), potassium carbonate (26.4g, 191.1 mmol) was added and stirred at 90°C. After 12 hours, water (200ml) was added and the solid obtained by filtration was washed with water and ethanol to prepare the compound of Formula Q (34.7g, yield 87.8%).

MS[M+H] ⁺ =311

In a nitrogen atmosphere, the compounds of formula Q (22g, 70.8 mmol) and formula D (11.8g, 70.8mmol) are dissolved in THF (220mL), potassium carbonate (19.5g, 141.6mmol) is dissolved in water (110mL), and then heated. I did. In the state of refluxing, palladium tetratriphenylphosphine (0.82g, 0.71mmol) was added and stirred for 5 hours. After the reaction was completed, the temperature was lowered 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 R (22.3g, yield 89.1%).

MS[M+H] ⁺ =355

After dispersing the compound of Formula R (15g, 42.4mmol) in glacial acetic acid (150mL), potassium permanganate (20.1g, 127.2mmol) was added at 0°C, stirred for 1 hour, and then heated to room temperature and stirred for 7 hours. After completion of the reaction, water (150 ml) was added and the solid obtained after filtration was recrystallized with ethanol to prepare a compound of formula S (15.7 g, yield 95.8%).

MS[M+H] ⁺ =387

After dispersing the compound of Formula S (11g, 28.5mmol) in ethanol (100mL) in a nitrogen atmosphere, tin chloride (21.6g, 114mmol) was added, heated, and stirred at 50°C for 8 hours. After completion of the reaction, 100 mL of water was added to obtain a solid. The solid obtained after filtration was recrystallized with ethanol to prepare a compound of Formula 1-4 (7.3g, yield 78.8%).

MS[M+H] ⁺ =327

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

After dissolving the compounds of formula G (20.0g, 127.4 mmol) and formula T (22.3, 127.4 mmol) in DMSO (200mL), potassium carbonate (26.4g, 191.1 mmol) was added and stirred at 90°C. After 12 hours, water (200ml) was added and the solid obtained by filtration was washed with water and ethanol to prepare a compound of Formula U (36.2g, yield 91.8%).

MS[M+H] ⁺ =310

In a nitrogen atmosphere, the compounds of formula U (30g, 96.8 mmol) and formula D (16.2g, 96.8mmol) are dissolved in THF (300mL), potassium carbonate (26.7g, 193.6mmol) is dissolved in water (150mL), and then heated. I did. In the state of refluxing, palladium tetratriphenylphosphine (1.1g, 0.97mmol) was added and stirred for 5 hours. After the reaction was completed, the temperature was lowered 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 V (27.5g, yield 80.6%).

MS[M+H] ⁺ =354

After dispersing the compound of Formula V (20 g, 56.7 mmol) in glacial acetic acid (200 mL), potassium permanganate (26.8 g, 170 mmol) was added at 0° C., stirred for 1 hour, and then heated to room temperature and stirred for 7 hours. After completion of the reaction, water (200 ml) was added, and the solid obtained after filtration was recrystallized with ethanol to prepare a compound of formula W (18.8 g, yield 86.2%).

MS[M+H] ⁺ =386

In a nitrogen atmosphere, the compound of Formula W (15g, 39.0mmol) was dispersed in ethanol (150mL), and then tin chloride (29.6g, 156mmol) was added thereto, followed by heating, followed by stirring at 50°C for 8 hours. After completion of the reaction, 150 mL of water was added to obtain a solid. The solid obtained after filtration was recrystallized with ethanol to prepare a compound of Formula 1-5 (10.4 g, yield 81.8%).

MS[M+H] ⁺ =326

<Preparation Example 6> Preparation of the compound of Formula 1-14

A compound of Formula Y was prepared in the same manner as for preparing the compound of Formula Q, except that the compound of Formula X was used instead of Formula G in Preparation Example 4.

Next, a compound of Formula Z was prepared in the same manner as for preparing a compound of Formula R, except that the compound of Formula Y was used instead of Formula Q.

A compound of Formula AA was prepared in the same manner as for preparing Formula S, except that the compound of Formula Z was used instead of Formula R.

The compound of Formula 1-14 was prepared in the same manner as the method of preparing Formula 1-4, except that the compound of Formula AA was used instead of Formula S.

MS[M+H] ⁺ =395

<Preparation Example 7> Preparation of the compound of Formula 1-16

A compound of Formula CC was prepared in the same manner as the method of preparing Formula C, except that Formula BB was used instead of Formula A in Preparation Example 1.

Next, the compound of Formula EE was prepared in the same manner as the method of preparing Formula E, except for using the compound of Formula CC and Formula DD instead of Formula C and Formula D.

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

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

MS[M+H] ⁺ =461

<Preparation Example 8> Preparation of the compound of Formula 1-17

A compound of Formula HH was prepared in the same manner as in the method of preparing Formula I, except that Formula BB and Formula GG were used instead of Formula G and Formula H of Preparation Example 2.

Next, the compound of Formula II was prepared in the same manner as the method of preparing Formula J, except for using Formula HH and Formula DD instead of the compounds of Formula I and Formula D.

The compound of Formula JJ was prepared in the same manner as the method of preparing Formula K, except that the compound of Formula II was used instead of Formula J.

The compound of Formula 1-17 was prepared in the same manner as the method of preparing the compound of Formula 1-2, except that the compound of Formula JJ was used instead of Formula K.

MS[M+H] ⁺ =462

<Preparation Example 9> Preparation of the compound of Formula 1-18

A compound of Formula LL was prepared in the same manner as in preparing Formula HH, except that the compound of Formula KK was used instead of Formula BB of Preparation Example 8.

Next, the compound of Formula MM was prepared in the same manner as the method of preparing Formula II, except that the compound of Formula LL was used instead of Formula HH.

The compound of Formula NN was prepared in the same manner as the method of preparing Formula JJ, except that Formula MM was used instead of Formula II.

The compound of Formula 1-18 was prepared in the same manner as the method of preparing the compound of Formula 1-17, except that Formula NN was used instead of Formula JJ.

MS[M+H] ⁺ =463

<Example 1> PMDA/Chemical Formula 1-1

After filling 200 g of DEAc (Diethylacetamide) into a reactor through which a nitrogen stream flows, 0.09619 mol of diamine of Formula 1-1 prepared in 1 was added and 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, 0.09619 mol of PMDA (pyromellitic dianhydride) was added together with 57 g of DEAc and reacted for 48 hours to prepare a polyimide precursor solution.

<Example 2> PMDA/Formula 1-14

After filling 200 g of DEAc (Diethylacetamide) in a reactor through which a nitrogen stream flows, 0.09619 mol of diamine of Formula 1-14 prepared in Preparation Example 6 was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. To the solution to which the diamine of Formula 1-14 was added, 0.09619 mol of PMDA (pyromellitic dianhydride) was added together with 52 g of DEAc and reacted for 48 hours to prepare a polyimide precursor solution.

<Example 3> PMDA/Formula 1-16

After filling 200 g of DEAc (Diethylacetamide) in a reactor through which a nitrogen stream flows, 0.09619 mol of diamine of Formula 1-16 prepared in Preparation Example 7 was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. To the solution to which the diamine of Formula 1-16 was added, 0.09619 mol of PMDA (pyromellitic dianhydride) was added together with 60 g of DEAc and reacted for 48 hours to prepare a polyimide precursor solution.

<Example 4> PMDA/Chemical Formula 1-17

After filling 200 g of DEAc (Diethylacetamide) in a reactor through which a nitrogen stream flows, 0.09619 mol of diamine of Formula 1-17 prepared in Preparation Example 8 was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. To the solution to which the diamine of Formula 1-17 was added, 0.09619 mol of PMDA (pyromellitic dianhydride) was added together with 62 g of DEAc and reacted for 48 hours to prepare a polyimide precursor solution.

<Comparative Example 1>

After filling 200 g of DEAc (Diethylacetamide) in a reactor through which a nitrogen stream flows, 0.09619 mol of 4,4'-Diaminodiphenylsulfone (DDS) was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. To the prepared solution to which DDS was added, 0.09619 mol of PMDA (pyromellitic dianhydride) was added together with 52 g of DEAc and reacted for 48 hours to prepare a polyimide precursor solution.

<Experimental Example 1>

The viscosity of the polyimide precursor solution prepared in Examples 1, 2, and 3 and Comparative Example 1 and the molecular weight of the polyamic acid were measured, and are shown in Table 1 below. The viscosity was measured using Viscotek's TDA 302, and the molecular weight was measured using Viscotek GPCmax VE2001.

<Experimental Example 2>

Each of the polyimide precursor solutions prepared in Examples 1, 2 and 3 and Comparative Example 1 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, and the curing process was carried out by holding at 80°C for 30 minutes, 250°C for 30 minutes, and 400°C for 30 to 40 minutes. A polyimide film was prepared. The physical properties of each film were measured and shown in Table 1 below.

<Modulus (GPa), tensile strength (MPa), elongation (%)>

A film having a length of 5 mm X 50 mm and a thickness of 10 μm was stretched at a speed of 10 mm/min in a tensile tester (manufactured by Instron Co., Ltd.: Instron 3342) to measure modulus (GPa), tensile strength (MPa), and elongation (%).

Comparative Example 1
PMDA_DDS Example 1
PMDA_Chemical Formula 1-1 Example 2
PMDA_Chemical Formula 1-14 Example 3
PMDA_Chemical Formula 1-16 Example 4
PMDA_Chemical Formula 1-17 Sol. Con.(wt%) 22.6 16.2 18.2 19.5 19.2 Viscosity(cps) 3424 3320 3600 3100 3240 Mw 40,000 73,000 61,000 53,000 54,000 Curing 5℃/min
80℃,30min→
250℃,30min 400℃ 30min 400℃ 40min 400℃ 40min 400℃ 40min 400℃ 40min Thikness(㎛) 9.8 10.1 9.9 10.3 10.1 Modulus(Gpa) 2.3 3.5 3.3 3.6 3.7 Tensile strength (Mpa) 125 148 142 149 150 Strain(%) 90 98 93 97 93

As can be seen from the results of Table 1, the polyimide precursor solution containing diamine according to the present invention may have a viscosity of 3000 cps or more at a solid content concentration of 20 wt% or less, and is higher than that of Comparative Example 1 using DDS. It can be seen that a polyamic acid having a molecular weight was prepared. In addition, it can be seen that the polyimide film prepared from the polyamic acid having such a high molecular weight has improved mechanical strength compared to the polyimide film of Comparative Example 1.

As described above, a specific part of the present invention has been described in detail, and for those of ordinary skill in the art, it is obvious that this specific technique is only a preferred embodiment, and the scope of the present invention is not limited thereby. something to do. Therefore, it will be said that the practical scope of the present invention is defined by the appended claims and their equivalents.

Claims (14)

Diamine represented by the following formula (1):
[Formula 1]

In Formula 1,
X ₁ to X ₈ are each independently a carbon atom or a nitrogen atom, but not a nitrogen atom at the same time, and R ₁ and R ₂ are each independently a C 1 to C 10 alkyl group, a C 1 to C 10 haloalkyl group, a C 6 to C 18 It is selected from aryl groups,
n1 and n2 are each independently an integer of 0 to 4. The method of claim 1,
At _{least one of X 1} to X ₄ is a carbon atom, and at least one of X ₅ to X ₈ is a carbon atom. The method of claim 1,
R ₁ and R ₂ are each independently a C 1 to C 5 alkyl group or a C 1 to C 5 haloalkyl group diamine. The method of claim 1,
Diamines in which X ₁ to X ₈ are all carbon atoms. The method of claim 1,
A _{diamine wherein X 1} to X ₄ are all carbon atoms, and one or both of _{X 5} to X _{8 are nitrogen atoms.} The method of claim 1,
One of X ₁ to X ₄ is a nitrogen atom, and one or two of _{X 5} to X _{8 are nitrogen atoms.} The method of claim 1,
The diamine of Formula 1 is selected from the compounds of Formulas 1-1 to 1-25:

. As a polyimide precursor obtained by polymerizing a polymerization component containing at least one diamine and at least one acid dianhydride,
A polyimide precursor in which the diamine of the polymerization component contains 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 of a polyimide precursor prepared by using the diamine of Formula 1 as a polymerization component. A polyimide film prepared using the polyimide precursor according to claim 8. The method of claim 10,
Applying a polyimide precursor composition including the polyimide precursor onto 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
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. 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.