KR20200095745A - Diamine compound, polyimide precursor and polyimide film prepared by using same - Google Patents

Abstract

The present invention discloses a novel diamine including benzene rings connected by functional groups on both sides of a p-terphenyl structure in which three benzene rings are connected, and having a structure in which the benzene rings are substituted with various substituents. In addition, the present invention can provide a polyimide film having improved physical properties by including the novel diamine as a polymerization component.

Description

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

The present invention relates to a novel diamine compound, a polyimide precursor and a polyimide film using the same.

In the recent display field, product weight reduction and miniaturization are becoming important, 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 by replacing the glass substrate. Research is being actively carried out to apply to mobile phones, laptops, PDAs, etc.

In particular, polyimide (PI) resins are easy to synthesize, can make thin films, and have the advantage of not requiring 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.

The polyimide (PI) film is prepared by filming the polyimide resin, and in general, the polyimide film 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 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, 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.

In addition, aromatic polyimide has strong absorbance in the ultraviolet-visible range, and aromatic polyimide exhibits strong coloration from pale yellow to dark brown, which is widely applied in the optoelectronics area where transparency and colorless properties are basic requirements. Limit. 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-, -CH ₂ -, etc.) have been studied.

The problem to be solved by the present invention is to provide a novel 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 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 comprising the polyimide film and a manufacturing process thereof.

In order to solve the problem of the present invention, a diamine having a structure represented by the following formula (1) is provided.

[Formula 1]

In Chemical Formula 1,

Z is O, S, SS, C(=O), -C(=O)O-,-OC(=O)- CH(OH), S(=O) ₂ , CR'R", -C( =O)NH-, -NHC(=O)-, and a functional group selected from the group consisting of a combination thereof, and R'and R" are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a carbon number of 1 to 10 It is selected from the group consisting of fluoroalkyl groups,

R ₁ to R ₅ 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 cyano A no group (-CN), a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms,

n1 to n5 are each independently an integer of 0 to 4.

According to an embodiment, the diamine of Formula 1 may be selected from compounds of Formulas 1-1 to 1-4 below.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

In Formulas 1-1 to 1-4, definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

According to an embodiment, R ₁ to R ₅ are each independently a halogen atom selected from -F, -Cl, -Br and -I, a cyano group (-CN), an alkyl group having 1 to 5 carbon atoms, and 1 to 4 carbon atoms. It may be one selected from a halogenoalkoxy group and a halogenoalkyl group having 1 to 5 carbon atoms.

According to an embodiment, the diamine of Formula 1-1 may be prepared by the same reaction as in Scheme 1 below.

[Scheme 1]

In Reaction Scheme 1, the definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

According to an embodiment, the diamine of Formula 1-2 may be prepared by the same reaction as in Scheme 2 below.

[Scheme 2]

In Reaction Scheme 2, definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

According to an embodiment, the diamine of Formula 1-3 may be prepared by the same reaction as in Scheme 3 below.

[Scheme 3]

In Reaction Scheme 3, definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

According to an embodiment, the diamine of Formula 1-4 may be prepared by the same reaction as in Scheme 4 below.

[Scheme 4]

In Reaction Scheme 4, the definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

In order to solve other problems of the present invention,

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

The diamine provides a polyimide precursor containing the novel diamine.

The present invention also provides a polyimide film manufactured using a polyimide precursor.

According to an embodiment, the polyimide film,

Applying a polyimide precursor composition including the polyimide precursor onto a carrier substrate; And

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

According to an embodiment, the refractive index in the surface direction may be 1.73 or more, and the refractive index in the thickness direction may be 1.53 or more.

According to an embodiment, the coefficient of thermal expansion (CTE) may be 12 ppm/°C or less.

The present invention also provides a flexible device comprising a polyimide film as a substrate.

The present invention also

Applying a polyimide precursor composition including the polyimide precursor 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 formed with the device 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 discloses a novel diamine having a structure in which three benzene ring groups are linked by a functional group on both sides of a p-Terphenyl structure, and the benzene rings are substituted with various substituents.

In addition, the present invention can provide a polyimide film having improved physical properties by including such a novel diamine as a polymerization component.

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 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, when 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.

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, 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.

The present invention provides a diamine represented by the following formula (1).

[Formula 1]

In Chemical Formula 1,

Z is O, S, SS, C(=O), -C(=O)O-,-OC(=O)- CH(OH), S(=O)2, CR'R", -C( =O)NH-, -NHC(=O)-, and a functional group selected from the group consisting of a combination thereof, and R'and R" are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a carbon number of 1 to 10 It is selected from the group consisting of fluoroalkyl groups,

R ₁ to R ₅ 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 cyano No group (-CN), a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms.

Preferably, R ₁ to R ₅ are each independently a halogen atom selected from -F, -Cl, -Br and -I, a cyano group (-CN), an alkyl group having 1 to 5 carbon atoms, and a halo having 1 to 4 carbon atoms. It may be at least one selected from a genoalkoxy group and a halogenoalkyl group having 1 to 5 carbon atoms,

n1 to n5 are each independently an integer of 0 to 4.

According to an embodiment, the diamine of Formula 1 may be selected from compounds of Formulas 1-1 to 1-4 below.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

In Formulas 1-1 to 1-4, definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

According to an embodiment, the compound of Formula 1-1 may be selected from the following compounds.

According to an embodiment, the compound of Formula 1-2 may be selected from the following compounds.

According to an embodiment, the compound of Formula 1-3 may be selected from the following compounds.

According to an embodiment, the compound of Formula 1-4 may be selected from the following compounds.

According to a preferred embodiment, the diamine of Formula 1-1 may be prepared by the same reaction as in Reaction Formula 1-1.

[Scheme 1-1]

In Reaction Scheme 1-1, the definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

The diamine of Formula 1-2 may be prepared by the same reaction as in Reaction Formula 2-1.

[Scheme 2-1]

In Reaction Scheme 2-1, definitions of R ₁ to R ₅ and n1 to n5 are the same as those of Formula 1.

The diamine of Formula 1-3 may be prepared by the same reaction as in Reaction Scheme 3-1.

[Reaction Scheme 3-1]

In Reaction Scheme 3-1, the definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

The diamine of Formula 1-4 may be prepared by the same reaction as in Reaction Formula 4-1.

[Reaction Scheme 4-1]

In Reaction Scheme 4-1, the definitions of R ₁ to R ₅ and n1 to n5 are the same as in Formula 1.

According to an embodiment, the weight average molecular weight of the polyimide precursor prepared using the diamine having the above structure 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 decreases due to the decrease in polyimide reactivity, and thus the viscosity is low relative to the solid content, so it may not be easy 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.

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

[Formula 2]

In Chemical Formula 2,

R5 and R6 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.

When the polymerization component containing the structure of Formula 2 is excessively added to the total weight, mechanical properties such as modulus of the polyimide may be deteriorated, and film strength is reduced, such that the film tears 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, and thus, 350°C or more. 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 having a silicone oligomer structure as shown in Formula 2 above 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 decrease.

On the other hand, the polyimide according to the present invention can maintain the Tg at 390°C or higher, despite including the silicone oligomer at 10% by weight or more based on 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, where 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 lowered, for example, the glass transition temperature (Tg) of the prepared polyimide may decrease, or the coefficient of thermal expansion 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, thus maintaining a 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 significantly reduced, making it difficult to use in the process.

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 portion (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 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 the phenomenon of substrate warping after coating-curing as well as thermal and optical properties.

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 the transparency of the film may be deteriorated. 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, 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 formed largely in the molecule, and thus a stress relaxation effect may be effectively exhibited even in 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 one 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 group 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 group, or a structure in which two or more of them are connected by a single bond or a functional group. Alternatively, it may include 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:

[Formula 3a]

[Formula 3b]

[Formula 3c]

[Formula 3d]

[Formula 3e]

In Formulas 3a to 3e, R ₁₁ to R ₁₇ 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 (-NO2), 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,

A ₁₁ and A ₁₂ are each independently a single bond, -O-, -CR'R"- (In this case, R'and R" are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (eg, a 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 (eg, trifluoromethyl group, etc.) , -C(=O)-, -C(=O)O-, -C(=O)NH-, -S-, -SO-, -SO ₂ -, -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 (for example, Cyclohexylene group, etc.), a monocyclic or polycyclic arylene group having 6 to 18 carbon atoms (eg, a phenylene group, a naphthalene group, a fluorenylene group, etc.), and a combination thereof. .

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 ( -NO2), 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 includes a fluoromethyl group, a perfluoroethyl group, and a trifluoro The alkyl group may be selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, a pentyl group, and a hexyl group, and the aryl group may be selected from a phenyl group and a naphthalenyl group. It may be, and more preferably a substituent including 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 one containing a tetravalent organic group containing a heterocyclic structure directly connected.

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 by a single bond or a functional group, , Or, selected from a divalent organic group 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 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, a hydroxyl group (-OH), a thiol group (-SH), a nitro group (-NO ₂ ), and cyano 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.

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 (eg, a 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 (eg, trifluoromethyl group, etc.) , -C(=O)-, -C(=O)O-, -C(=O)NH-, -S-, -SO-, -SO ₂ -, -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 (for example, 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 a combination thereof. ,

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.

For example, the diamine may include a divalent organic group selected from the following formulas 6a to 6p.

Alternatively, the diamine may include a divalent organic group having an aromatic ring or an aliphatic structure forming 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.

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, and preferably, for improving reactivity and improving fairness, 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 an embodiment of the present invention, it may be preferable that the molar ratio of the total content of the tetracarboxylic dianhydride and the content of diamine is 1:0.98 to 0.98:1, preferably 1:0.99 to 0.99:1. have.

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 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 an embodiment, as an organic solvent for polymerizing the polymerization component, a solvent having a partition coefficient LogP of 25°C 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 also a method of mixing 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 problem such as a phase separation problem may not be completely improved, so that the 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 with 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 described above, it is possible to control the edge back phenomenon of the solution without using an additive that controls 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 not only can the quality and process problems such as the low molecular weight substances contained in the final product be eliminated, but also the effect of forming a polyimide film having uniform properties more efficiently. 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 conditions of leaving the coating liquid under a humidity condition. The edge-back phenomenon of the coating solution can cause 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, if a hydrophobic solvent with a positive log P is used, the occurrence of thickness change due to cracking of the coating may be 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 the following Equation 1.

[Equation 1]

Edge white rate (%) = [(A-B)/A]×100

In Formula 1,

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

B: This is 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 and leaving it in a humidity condition for 10 minutes or more, such as 10 minutes or more, such as 40 minutes or more, the edge white rate of the coated resin composition solution 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 The edge white rate may be 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. In the humidity condition of 40% or more, more specifically, in the humidity condition in the range of 40% to 80%, that is, 40%, 50%, 60%, 70%, 80%, for example, 50% The edge-back ratio of the cured polyimide film after leaving it for 10 to 50 minutes in a humidity condition may be 0.1% or less, that is, hardly or no edge-back phenomenon may occur even in the curing process by heat treatment, specifically, 0.05% , More preferably, an edge rate close to 0% may be exhibited.

By solving such an edge back phenomenon, the polyimide precursor composition according to the present invention can obtain a polyimide film having more uniform properties, 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 (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 QSPR (Quantitative Structure-Property Relationship) methodology using the 2D structure of the molecule. Use.

Further, aromatic hydrocarbons such as xylene and toluene may be further used, and 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 order to promote dissolution of the polymer.

In addition, in the case of synthesizing polyamic acid or polyimide, in order to inactivate excess polyamino group or acid anhydride group, the molecular end is reacted with dicarboxylic acid anhydride or monoamine, so that a terminal sealing agent that seals the end of the polyimide is further added. I can.

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

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 ℃. 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 that the polyamic acid solution prepared according to the above-described manufacturing method contains solid content in an amount to allow the composition to have an appropriate viscosity in consideration of processability such as coating property 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 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 the reaction solution may be diluted with another solvent. Moreover, when a polyimide precursor was obtained as a solid powder, you may melt|dissolve this in an organic solvent and make it a solution.

According to an embodiment, the content of the composition can be adjusted by adding an organic solvent so 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. 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 decreases during processing of the polyimide film, so that not only the process efficiency, but also the produced film has poor surface roughness due to the generation of air 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, 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. Among these, 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, 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 on a 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 the thickness is 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 be in the range of 300 to 500°C, preferably 320 to 480°C, and the temperature Within the range, it may be carried out in multi-stage heat treatment. 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. 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.

Further, 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.

In addition, the refractive index in the plane direction at 532 nm of the polyimide film may be 1.73 or more, preferably 1.74 or more, and the refractive index in the thickness direction may be 1.53 or more, preferably 1.54 or more.

The polyimide film may have high heat resistance, and for example, a thermal decomposition temperature (Td_1%) at which a mass reduction of 1% occurs may be 500°C or higher.

The polyimide film may have a modulus of 3 to 6 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 6 GPa, the coverlay film has excellent stiffness 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 (here, n is an integer greater than or equal to 0).

For example, the polyimide film according to the present invention may have a CTE value of 12 ppm/℃ or less, and preferably may have a value of 0 to 12 ppm/℃.

Since the polyimide film of the present invention has a low thermal expansion coefficient of 12 ppm/°C or less, expansion and contraction of the film due to temperature change can be minimized, and thus, warpage of the substrate that may be caused by such expansion and contraction By reducing the same phenomenon, problems in the process such as peeling from the glass substrate can be minimized.

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

According to an embodiment, the polyimide film may have an adhesive force 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 formed with the device 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 crystallizing the a-Si thin film with an excimer laser, a flexible device including an LTPS layer can be obtained by peeling a carrier substrate and a polyimide film by laser peeling or the like.

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 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.

<Synthesis Example 1>

A compound of Formula 1-1 was prepared in the same manner as in Scheme 1-1 below.

[Scheme 1-1]

Specifically, a starting material including boronic acid and a starting material including bromine were dissolved in a tetrahydrofuran solvent, and 3 equivalents of potassium carbonate were dissolved in water, followed by heating and stirring. 5 mol% of tetrakispalladium triphenylphosphine was used as a catalyst. The reaction was confirmed through TLC. When the reaction was completed, the organic layer and the aqueous layer were separated, and moisture from the organic layer was removed using anhydrous magnesium sulfate. The solvent was evaporated through a vacuum distillation apparatus and purified through column chromatography to prepare a compound of Formula 1-i.

After dissolving the compound of Formula 1-i including the carboxylic acid in anhydrous toluene solvent, thionyl chloride (SOCl ₂ ) was slowly added dropwise. After heating and stirring until the disappearance of the starting material, the solvent was removed through distillation under reduced pressure to obtain a compound of Formula 1-ii.

The starting material including the compound of Formula 1-ii and the starting material including a hydroxy group and a nitro group were dissolved in a tetrahydrofuran solvent, and 2 equivalents of potassium carbonate were added and heated and stirred to prepare a compound of Formula 1-iii. The reaction is confirmed by TLC, and when the reaction is complete, water is added to remove the salt. The organic layer is dried using anhydrous magnesium sulfate, and the solvent is evaporated through a vacuum distillation apparatus. Purified through column chromatography.

The starting material of Formula 1-iii including a nitro group was added to an ethanol solvent, and 3wt% of Pd/C was added. After that, 10 equivalents of hydrazine was slowly added dropwise and heated. The reaction was confirmed through TLC, and after the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was completely dissolved in a tetrahydrofuran solvent, and then filtered again using Celite to remove the Pd/C used. The solvent was removed through a vacuum distillation apparatus, and the obtained solid was filtered to obtain a compound of Formula 1-1.

<Synthesis Example 2>

A compound of Formula 1-2 was prepared in the same manner as in Scheme 2-1 below.

[Scheme 2-1]

Specifically, a starting material including boronic acid and a starting material including bromine were dissolved in a tetrahydrofuran solvent, and 3 equivalents of potassium carbonate were dissolved in water, followed by heating and stirring. 5 mol% of tetrakispalladium triphenylphosphine was used as a catalyst. The reaction was confirmed through TLC. When the reaction was completed, the organic layer and the aqueous layer were separated, and moisture from the organic layer was removed using anhydrous magnesium sulfate. The solvent was evaporated through a vacuum distillation apparatus and purified through column chromatography to prepare a compound of Formula 2-i.

After dissolving the compound of Formula 2-i including the carboxylic acid in anhydrous toluene solvent, thionyl chloride (SOCl ₂ ) was slowly added dropwise. After heating and stirring until the disappearance of the starting material, the solvent was removed through distillation under reduced pressure to obtain a compound of Formula 2-ii.

The starting material including the compound of Formula 2-ii and the starting material including an amine group and a nitro group were dissolved in a tetrahydrofuran solvent, and 2 equivalents of potassium carbonate were added and heated and stirred to prepare a compound of Formula 2-iii. The reaction is confirmed by TLC, and when the reaction is complete, water is added to remove the salt. The organic layer is dried using anhydrous magnesium sulfate, and the solvent is evaporated through a vacuum distillation apparatus. Purified through column chromatography.

The starting material of Formula 2-iii including a nitro group was added to an ethanol solvent, and 3wt% of Pd/C was added. After that, 10 equivalents of hydrazine was slowly added dropwise and heated. The reaction was confirmed through TLC, and after the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was completely dissolved in a tetrahydrofuran solvent, and then filtered again using Celite to remove the Pd/C used. The solvent was removed through a vacuum distillation apparatus, and the obtained solid was filtered to obtain a compound of Formula 1-2.

<Synthesis Example 3>

A compound of Formula 1-3 was prepared in the same manner as in Scheme 3-1 below.

[Reaction Scheme 3-1]

Specifically, a starting material including boronic acid and a starting material including bromine were dissolved in a tetrahydrofuran solvent, and 3 equivalents of potassium carbonate were dissolved in water, followed by heating and stirring. Tetrakis palladium triphenylphosphine 5 mol% was used as a catalyst. The reaction was confirmed through TLC. When the reaction was completed, the organic layer and the aqueous layer were separated, and moisture from the organic layer was removed using anhydrous magnesium sulfate. The solvent was evaporated through a vacuum distillation apparatus and purified through column chromatography to prepare a compound of Formula 3-i.

The starting material including the compound of Formula 3-i and the starting material including carboxylic acid and nitro group were dissolved in a tetrahydrofuran solvent, and 2 equivalents of potassium carbonate were added and heated and stirred to prepare a compound of Formula 3-ii. The reaction is confirmed by TLC, and when the reaction is complete, water is added to remove the salt. The organic layer is dried using anhydrous magnesium sulfate, and the solvent is evaporated through a vacuum distillation apparatus. Purified through column chromatography.

The compound of Formula 3-ii including a nitro group was added to an ethanol solvent, and 3wt% of Pd/C was added. After that, 10 equivalents of hydrazine was slowly added dropwise and heated. The reaction was confirmed through TLC, and after the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was completely dissolved in a tetrahydrofuran solvent, and then filtered again using Celite to remove the Pd/C used. The solvent was removed through a vacuum distillation apparatus, and the obtained solid was filtered to obtain a compound of Formula 1-3.

<Synthesis Example 4>

A compound of Formula 1-4 was prepared in the same manner as in Scheme 4-1 below.

[Reaction Scheme 4-1]

Specifically, a starting material including boronic acid and a starting material including bromine were dissolved in a tetrahydrofuran solvent, and 3 equivalents of potassium carbonate were dissolved in water, followed by heating and stirring. Tetrakis palladium triphenylphosphine 5 mol% was used as a catalyst. The reaction was confirmed through TLC. When the reaction was completed, the organic layer and the aqueous layer were separated, and moisture from the organic layer was removed using anhydrous magnesium sulfate. The solvent was evaporated through a vacuum distillation apparatus and purified through column chromatography to prepare a compound of Formula 4-i.

The compound of Formula 4-i and a starting material including a carboxylic acid and a nitro group were dissolved in a tetrahydrofuran solvent, and 2 equivalents of potassium carbonate were added and heated and stirred to prepare a compound of Formula 4-ii. The reaction is confirmed by TLC, and when the reaction is complete, water is added to remove the salt. The organic layer is dried using anhydrous magnesium sulfate, and the solvent is evaporated through a vacuum distillation apparatus. Purified through column chromatography.

The compound of Formula 4-ii including a nitro group was added to an ethanol solvent, and 3wt% of Pd/C was added. After that, 10 equivalents of hydrazine was slowly added dropwise and heated. The reaction was confirmed through TLC, and after the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was completely dissolved in a tetrahydrofuran solvent, and then filtered again using Celite to remove the Pd/C used. The solvent was removed through a vacuum distillation apparatus, and the obtained solid was filtered to obtain a compound of Formula 1-4.

<Production Example 1>

Diamine of the following compound 1 was prepared by the method of Synthesis Example 1.

HR LC/MS/MS m/z calcd for C ₃₄ H ₂₂ N ₄ O ₄ (M+): 550.1641; found: 550.1644

<Production Example 2>

Diamine of the following compound 2 was prepared by the method of Synthesis Example 1.

HR LC/MS/MS m/z calcd for C ₃₆ H ₃₂ N ₂ O ₄ (M+): 556.2362; found: 556.2364

<Example 3>

Diamine of the following compound 3 was prepared by the method of Synthesis Example 1.

HR LC/MS/MS m/z calcd for C ₃₇ H ₃₁ F ₃ N ₂ O ₄ (M+): 624.2236; found: 624.2240

<Production Example 4>

Diamine of the following compound 4 was prepared by the method of Synthesis Example 1.

HR LC/MS/MS m/z calcd for C ₃₇ H ₂₂ N ₆ O ₄ (M+): 614.1703; found: 614.1705

<Production Example 5>

Diamine of the following compound 5 was prepared by the method of Synthesis Example 2.

HR LC/MS/MS m/z calcd for C ₃₆ H ₃₄ N ₄ O ₂ (M+): 554.2682; found: 554.2683

<Production Example 6>

Diamine of the following compound 6 was prepared by the method of Synthesis Example 2.

HR LC/MS/MS m/z calcd for C ₃₃ H ₂₆ F ₂ N ₄ O ₂ (M+): 548.2024; found: 548.2027

<Production Example 7>

Diamine of the following compound 7 was prepared by the method of Synthesis Example 2.

HR LC/MS/MS m/z calcd for C ₃₆ H ₂₂ F ₁₂ N ₄ O ₂ (M+): 770.1551; found: 770.1554

<Production Example 8>

Diamine of the following compound 8 was prepared by the method of Synthesis Example 2.

HR LC/MS/MS m/z calcd for C ₃₃ H ₂₄ F ₄ N ₄ O ₂ (M+): 584.1835; found: 584.1837

<Production Example 9>

Diamine of the following compound 9 was prepared by the method of Synthesis Example 3.

HR LC/MS/MS m/z calcd for C ₃₂ H ₂₂ F ₂ N ₂ O ₄ (M+): 536.1548; found: 536.1550

<Production Example 10>

Diamine of the following compound 10 was prepared by the method of Synthesis Example 3.

HR LC/MS/MS m/z calcd for C ₃₄ H ₂₁ FN ₄ O ₄ (M+): 568.1547; found: 568.1549

<Production Example 11>

Diamine of the following compound 11 was prepared by the method of Synthesis Example 3.

HR LC/MS/MS m/z calcd for C ₃₆ H ₂₀ F ₁₂ N ₂ O ₄ (M+): 772.1231; found: 772.1234

<Production Example 12>

Diamine of the following compound 12 was prepared by the method of Synthesis Example 3.

HR LC/MS/MS m/z calcd for C ₃₃ H ₂₂ F ₄ N ₂ O ₄ (M+): 586.1516; found: 586.1518

<Production Example 13>

Diamine of the following compound 13 was prepared by the method of Synthesis Example 4.

HR LC/MS/MS m/z calcd for C ₃₄ H ₂₄ F ₆ N ₄ O ₂ (M+): 634.1803; found: 634.1806

<Production Example 14>

Diamine of the following compound 14 was prepared by the method of Synthesis Example 4.

HR LC/MS/MS m/z calcd for C ₃₃ H ₂₆ Cl ₂ N ₄ O ₂ (M+): 580.1433; found: 580.1434

<Production Example 15>

Diamine of the following compound 15 was prepared by the method of Synthesis Example 4.

HR LC/MS/MS m/z calcd for C ₃₄ H ₂₂ F ₂ N ₆ O ₂ (M+): 584.1772; found: 584.1775

<Production Example 16>

Diamine of the following compound 16 was prepared by the method of Synthesis Example 4.

HR LC/MS/MS m/z calcd for C ₃₅ H ₃₀ Cl ₂ N ₄ O ₂ (M+): 608.1746; found: 608.1749

<Comparative Example 1>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 1.672 mol of TFMB (2,2'-Bis(trifluoromethyl)benzidine) was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. To the solution to which TFMB was added, 1.672 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Comparative Example 2>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 1.537 mol of BAPT was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. To the solution to which BAPB was added, 1.537 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Example 1>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 0.973 mol of diamine of Compound 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 Compound 1 was added, 0.973 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Example 2>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 0.962 mol of diamine of Compound 2 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 Compound 2 was added, 0.962 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Example 3>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 0.965 mol of diamine of Compound 5 was added at the same temperature and dissolved while maintaining the temperature of the reactor at 25°C. To the solution to which the diamine of Compound 5 was added, 0.965 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Example 4>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 0.916 mol of diamine of Compound 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 Compound 8 was added, 0.916 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Example 5>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 0.942 mol of diamine of Compound 10 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 Compound 10 was added, 0.942 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Example 6>

After filling the organic solvent DEAc into a stirrer through which a nitrogen stream flows, 0.693 mol of diamine of Compound 11 was added at the same temperature and dissolved while maintaining the temperature of the reactor at 25°C. To the solution to which the diamine of Compound 11 was added, 0.693 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Example 7>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 0.844 mol of diamine of compound 13 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 Compound 13 was added, 0.844 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Example 8>

After filling the organic solvent DEAc in a stirrer through which a nitrogen stream flows, 0.880 mol of diamine of Compound 16 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 Compound 16 was added, 0.880 mol of BPDA was added at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

<Experimental Example 1>

Each of the polyimide precursor solutions prepared in Examples 1 to 8 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, and the curing process was carried out by holding at 80°C for 30 minutes and 300°C for 30 minutes to prepare a polyimide film.

Table 1 shows the physical properties of each film.

<Transmittance>

The transmittance was measured for a wavelength of 450 nm with a transmittance meter (model name HR-100, manufactured by Murakami Color Research Laboratory) according to JIS K 7105.

<Measurement of refractive index>

The prepared polyimide film was peeled and the refractive indexes in the plane direction and the thickness direction were measured at a wavelength of 532 nm using a prism coupler (SPA-3DR) measuring equipment.

<Glass transition temperature (Tg) and coefficient of thermal expansion (CTE)>

After preparing the film to a size of 5 x 20 mm, the sample is loaded using an accessory. The length of the film actually measured was the same as 16 mm. After setting the film pulling force to 0.02N and performing the first heating process at a heating rate of 5°C/min in a temperature range of 100 to 350°C, a cooling rate of 4°C/min in a temperature range of 350 to 100°C. A cooling process was performed, and the change in thermal expansion was measured with TMA (Q400 manufactured by TA).

<Measurement of pyrolysis temperature (Td_1%)>

Using a thermogravimetric analyzer (TGA, TG-DTA2000), the temperature was measured when the initial weight of the polyimide film decreased by 1% while increasing the temperature at a heating rate of 10°C/min in nitrogen.

From the results of Table 1, it can be seen that the polyimide of Examples 1 to 8 containing the diamine according to the present invention has a higher refractive index in the thickness direction and the surface direction than Comparative Examples 1 and 2.

In general, in the case of a high-transmission polyimide film, the refractive index is n=1.65 or less.When light is emitted to the polyimide layer, the difference between the refractive index of the upper layer including the inorganic layer (n=1.8 or more) and the refractive index of the polyimide layer The emission efficiency can be reduced.

The polyimide film containing the diamine according to the present invention can reduce the amount of light dissipated inside by reducing the difference in refractive index from the upper layer by improving the refractive index in the surface direction and the thickness direction while maintaining physical properties such as heat resistance as much as possible. As a result, the efficiency of the bottom emission from the flexible display device to the substrate layer can be increased.

In addition, since the polyimide film of the present invention has a low thermal expansion coefficient of 12 ppm/℃ or less, expansion and contraction of the film due to temperature change can be minimized, thereby minimizing process problems such as peeling from the glass substrate. .

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 (15)

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

In Chemical Formula 1,
Z is O, S, SS, C(=O), -C(=O)O-,-OC(=O)-, CH(OH), S(=O)2, CR'R", -C (=O)NH-, -NHC(=O)-, and a functional group selected from the group consisting of a combination thereof, and R'and R" are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a carbon number of 1 to 10 It is selected from the group consisting of fluoroalkyl groups,
R ₁ to R ₅ 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 cyano A no group (-CN), a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms,
n1 to n5 are each independently an integer of 0 to 4. The method of claim 1,
The diamine of Formula 1 is selected from compounds of Formulas 1-1 to 1-4:
[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

In Formulas 1-1 to 1-4, the definitions of R ₁ to R ₅ and n1 to n5 are the same as those defined for Formula 1. The method of claim 1,
R ₁ to R ₅ are each independently a halogen atom selected from -F, -Cl, -Br and -I, a cyano group (-CN), an alkyl group having 1 to 5 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, One or more diamines selected from halogenoalkyl groups having 1 to 5 carbon atoms. A method of preparing a diamine of Formula 1-1 by a reaction such as the following Scheme 1:
[Scheme 1]

In Reaction Scheme 1, the definitions of R ₁ to R ₅ and n1 to n5 are the same as those defined for Formula 1 in claim 1. A method of preparing a diamine of Formula 1-2 by a reaction such as the following Scheme 2:
[Scheme 2]

In Scheme 2, the definitions of R ₁ to R ₅ and n1 to n5 are the same as those defined for Formula 1 in claim 1. A method of preparing a diamine of Formula 1-3 by a reaction as shown in Scheme 3 below:
[Scheme 3]

In Scheme 3, the definitions of R ₁ to R ₅ and n1 to n5 are the same as those defined for Formula 1 in claim 1. A method of preparing a diamine of the following formula 1-4 by a reaction as shown in Scheme 4:
[Scheme 4]

In Scheme 4, the definitions of R ₁ to R ₅ and n1 to n5 are the same as those defined for Formula 1 in claim 1. As a polyimide precursor obtained by polymerizing a polymerization component containing at least one diamine and at least one acid dianhydride,
The polyimide precursor that the diamine comprises the diamine of any one of claims 1 to 3. A polyimide film prepared using the polyimide precursor according to claim 8. The method of claim 9,
The polyimide film is a polyimide film having a refractive index of 1.73 or more in a surface direction and 1.53 or more in a thickness direction. The method of claim 9,
The polyimide film is a polyimide film having a coefficient of thermal expansion (CTE) of 12 ppm/℃ or less. A flexible device comprising the polyimide film according to claim 9 as a substrate. Applying a polyimide precursor composition including the polyimide precursor according to claim 8 on a carrier substrate; And
A method for producing a polyimide film comprising heating and curing the polyimide precursor composition. 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 14,
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.