WO2020130552A1

WO2020130552A1 - Diamine compound, polyimide precursor using same, and polyimide film

Info

Publication number: WO2020130552A1
Application number: PCT/KR2019/017841
Authority: WO
Inventors: 구기철; 김경환
Original assignee: 주식회사 엘지화학
Priority date: 2018-12-18
Filing date: 2019-12-17
Publication date: 2020-06-25
Also published as: TWI754196B; TW202033501A

Abstract

Disclosed is a novel diamine having a structure of comprising an intramolecular imide group, and further comprising aromatic cyclic groups linked by an ester group to both sides of the imide group. When the novel diamine is used as a polymerizable component for preparing a polyimide, a polyimide film having remarkably improved mechanical and thermal properties while maintaining optical properties can be provided.

Description

Diamine compound, polyimide precursor and polyimide film using same

This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0163793 filed on December 18, 2018 and Korean Patent Application No. 10-2019-0167742 filed on December 16, 2019, above All contents disclosed in the patent document are included as part of the present specification.

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

In the display field, weight reduction and miniaturization of products are considered important, and currently used glass substrates are heavy, brittle, and have difficulty in continuous processing. As a substitute for glass substrates, plastic substrates that have the advantage of being lightweight, flexible, and capable of continuous processing Research is being actively conducted to apply the technology to cell phones, notebooks, PDAs, and the like.

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

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

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

In addition, the aromatic polyimide resin exhibits poor processability and brown coloring due to intramolecular interaction and charge transfer complexation (CTC), and to overcome this, an aliphatic chain, a flexible linking group, and a fluorine linker to a monomer used in the production of polyimide Attempts have been made to introduce specialized functional groups. However, the introduction of these substituents caused a problem of deteriorating the mechanical properties, which are the strengths of polyimide.

Accordingly, it is necessary to develop a technique capable of improving mechanical properties while maintaining the properties of polyimide.

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 producing a polyimide film with improved physical properties.

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

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

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

[Formula 1]

In Chemical Formula 1,

Z ₁ to Z ₈ are each independently a carbon atom or a nitrogen atom, Z ₁ to Z ₈ are not nitrogen atoms at the same time, R ₁ , R ₂ , R ₃ , R ₄ are each independently an alkyl group having 1 to 10 carbon atoms, carbon number 1 to 10 haloalkyl group, an alkenyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms, n ₁ , n ₂ , n ₃ , n ₄ are each independently an integer of 0 to 4, X is a single bond, O, S, SS, C(=O), -C(=O)O-, CH(OH), S(=O) ₂ , Si(CH ₃ ) ₂ , CR'R", A functional group selected from the group consisting of C(=O)NH and combinations thereof, wherein R'and R" are each independently from a 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. Can be selected.

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

According to an embodiment, in Formula 1, n1 and n2 are each independently 0, or 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, Z ₁ to Z ₄ may be all carbon atoms.

According to one embodiment, in Formula 1, one of Z ₁ to Z ₄ may be a nitrogen atom or one of Z ₅ to Z ₈ may be a nitrogen atom.

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

According to an embodiment, in Chemical Formula 1, X is a single bond, -O-, -CH ₂ -, -C(CF ₃ )-, -C(CH ₃ ) ₂ -or -SO ₂ -is selected from Can.

According to an embodiment, the diamine of Chemical Formula 1 may be selected from compounds of Chemical Formulas 1-1 to 1-20.

.

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

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

In addition, the present invention provides a polyimide film prepared using the polyimide precursor.

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

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

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

The present invention also

Applying a polyimide precursor composition comprising the polyimide precursor on a carrier substrate;

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

Forming a device on the polyimide film; And

It provides a manufacturing process of a flexible device comprising the step of peeling the polyimide film 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.

Additionally, the present invention provides a method for preparing a diamine having the structure of Formula 1, the method comprising the following steps:

Reacting a compound of formula (i) and formula (ii) to obtain a compound of formula (iii);

Reacting the compound of formula (iii) with the compound of formula (iv) to obtain a compound of formula (v); And

Reducing the compound of Formula v;

(i)

(ii)

(iii)

(iv)

(v)

(One)

In the above formula, Z _a to Z _d are each independently a carbon atom or a nitrogen atom, but Z _a to Z _d are not nitrogen atoms at the same time, and R ₁ , R ₂ and R _a are each independently an alkyl group having 1 to 10 carbon atoms. , A haloalkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms, n ₁ , n ₂ and n are integers from 0 to 4, X is a single bond, O, S, SS, C(=O), -C(=O)O-, CH(OH), S(=O) ₂ , Si(CH ₃ ) ₂ , CR'R", C(=O) NH and combinations thereof. The R'and R" may be 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.

The present invention discloses a novel diamine having a structure including an intramolecular imide group and further comprising an aromatic ring group connected by an ester group to both sides of the imide group, and the novel diamine is used as a polymerization component to produce polyimide. When used, it is possible to provide a polyimide film that maintains optical properties while also significantly improving mechanical and thermal properties.

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

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

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

To solve this problem, for the development of an optically transparent PI film having a high glass transition temperature (Tg), functional groups are introduced, bulky pendant groups, fluorinated functional groups, etc. are introduced into the polymer backbone, or flexible Methods of introducing units (-S-, -O-, -CH ₂ -, etc.) have been studied. However, the introduction of these substituents may cause a problem of deteriorating the mechanical properties that are strengths of the polyimide.

Thus, the present invention provides a diamine represented by the following formula (1) as a polymerization component capable of producing a polyimide with improved mechanical properties.

[Formula 1]

In Chemical Formula 1,

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

R ₁ , R ₂ , R ₃ , R ₄ are each independently selected from an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms. , n ₁ , n ₂ , n ₃ , n ₄ are each independently an integer from 0 to 4,

X is a single bond, O, S, SS, C(=O), -C(=O)O-, CH(OH), S(=O) ₂ , Si(CH ₃ ) ₂ , CR'R", A functional group selected from the group consisting of C(=O)NH and combinations thereof, wherein R'and R" are each independently from a 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. Can be selected.

The diamine according to the present invention has a charge transfer complexing (CTC) effect through an increase in the interaction of intermolecular pi-pi electrons between diamine repeat units containing an imide group during polyimide polymerization including a diamine containing an intramolecular imide group. As a result, the mechanical properties are improved and the intermolecular distance is increased, thereby increasing the probability of the polymerization reaction, thereby increasing the molecular weight. In addition, as the aromatic ring having an ester group substituted on both sides of the imide group has a more bonded structure, and the aromatic structures are continuously connected, the elevated CTC effect is reduced to increase the processability, and enables the intermolecular hydrogen bonding to mechanically The properties can be further improved. That is, it is possible to suppress the CTC effect again by the ester group while improving the mechanical properties by increasing the CTC effect by increasing the imidation rate.

According to another embodiment, one of Z ₁ to Z ₄ may be a nitrogen atom or one of Z ₅ to Z ₈ may be a nitrogen atom, and according to another embodiment, one of Z ₁ to Z ₄ is a nitrogen atom, Z _{One of 5} to Z ₈ may be a nitrogen atom.

According to one embodiment, the diamine of Formula 1 may be prepared from the same reaction as in Scheme 1 below.

[Scheme 1]

In the above formula, Z _a to Z _d are each independently a carbon atom or a nitrogen atom, but Z _a to Z _d are not nitrogen atoms at the same time,

R ₁ , R ₂ and R _a are each independently selected from an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms, and n ₁ , n ₂ and n are integers from 0 to 4,

The definition of X is the same as in Chemical Formula 1.

In step (1) of Scheme 1, the compound of Formula i and the compound of Formula ii are reacted to obtain the compound of Formula iii.

In this case, the compound of Formula i and the compound of Formula ii may be used in a molar ratio of 1:0.3 to 1:1, such as a molar ratio of 1:0.3 to 1:0.7.

In the reaction of step (1), tetrahydrofuran (THF), ethyl acetate (EA), or the like may be used as an organic solvent, and propylene oxide may be added as a catalyst to increase reactivity.

In addition, the reaction is advantageously performed at 0°C to reduce the violent reaction due to high reactivity, and the reaction time may be 1 to 5 hours, such as 1 to 3 hours.

In step (2) of Scheme 1, the compound of Formula iii and the compound of Formula iv are reacted to obtain a compound of Formula v.

At this time, the compound of Formula iii and the compound of Formula iv may be used in a molar ratio of 1:0.3 to 1:1, such as a molar ratio of 1:0.3 to 1:0.7.

In the reaction of step (2), acetic acid, propionic acid or the like may be used to disperse the reaction compounds, and the reaction temperature may be raised to about 100° C. for 3 to 5 hours, such as 4 hours.

Subsequently, after lowering the reaction temperature to room temperature, alcohols such as ethanol and isopropanol may be added to obtain a solid.

In step (3) of scheme 1, the compound of formula 1 is finally obtained by reducing the compound of formula v.

The reduction reaction of step (3) may be carried out in a hydrogen atmosphere in the presence of a palladium/complex (Pd/C) catalyst for 12 to 18 hours, such as 16 hours. At this time, N-methylpyrrolidone, tetrahydrofuran, etc. may be used as the dispersion medium.

According to one embodiment, the weight average molecular weight of the polyimide precursor prepared using the diamine having the above structure may exceed 50,000 g/mol to improve mechanical properties. For example, it may have a weight average molecular weight of 51,000 to 65,000 g/mol. When the molecular weight is 50,000 g/mol or less, the viscosity of the solution is lowered due to the decrease in polyimide reactivity, and the viscosity compared to the solid content is low, so it may not be easy to control the film thickness during the solution coating process and the final curing process. In addition, if the molecular weight is low, mechanical properties may be lowered, resulting in a problem that the film strength is lowered.

According to one embodiment, by including a nitrogen atom in the aromatic ring connected to the ester group, it is possible to reduce the CTC effect to further improve the optical properties.

According to an embodiment, the diamine of Chemical Formula 1 may be a compound of Chemical Formulas 1-1 to 1-20.

.

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

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

[Formula 2]

In Chemical Formula 2,

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

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

[Formula 2-1]

In Chemical Formula 2-1,

R are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 24 carbon atoms,

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

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

When the polymerization component including the structure of Formula 2 is excessively added with respect to the total weight, mechanical properties such as modulus of the polyimide may be deteriorated, and film strength may be reduced, resulting in tearing of the film in the process. Physical damage may occur. In addition, when the diamine having the structure of Formula 2 is excessively added, Tg derived from the polymer having the siloxane structure may appear, 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 containing a silicone oligomer structure as shown in Chemical Formula 2, the effect of reducing the residual stress may be increased, and Tg is 390 in a composition higher than 50% by weight. It may be lower than ℃ and the heat resistance may be lowered.

On the other hand, the polyimide according to the present invention can maintain a Tg of 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 the residual stress due to the silicone oligomer structure can also be obtained.

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

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

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

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

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

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

According to an embodiment, as the acid dianhydride used to polymerize the polyimide precursor, a tetracarboxylic dianhydride may be used, 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 an aliphatic, alicyclic or aromatic tetravalent organic group is connected to each other through a crosslinked structure can 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. Or, a tetracarboxylic acid containing a tetravalent organic group having a rigid structure, such as a heterocyclic ring structure in which a ring structure such as aromatic or cycloaliphatic is single or fused, or a structure connected by a single bond. It may contain dianhydride.

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

[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, hydroxyl group (-OH), thiol group (-SH), nitro group (-NO ₂ ), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms,

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

A ₁₁ and A ₁₂ are each independently a single bond, -O-, -CR'R"- (where R'and R" are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (for example, a methyl group, Ethyl groups, propyl groups, isopropyl groups, n-butyl groups, tert-butyl groups, pentyl groups, etc.) and haloalkyl groups having 1 to 10 carbon atoms (for example, those selected from trifluoromethyl groups, etc.) , -C(=O)-, -C(=O)O-, -C(=O)NH-, -S-, -SO-, -SO ₂ -, -O[CH ₂ CH ₂ O]y -(y is an integer from 1 to 44), -NH(C=O)NH-, -NH(C=O)O-, monocyclic or polycyclic cycloalkylene group having 6 to 18 carbon atoms (for example, A cyclohexylene group, etc.), a monocyclic or polycyclic arylene group having 6 to 18 carbon atoms (for example, a phenylene group, a naphthalene group, a fluorenylene group, etc.), and combinations thereof. ,

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

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

Alternatively, 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. It may be one containing a tetravalent organic group containing a heterocyclic structure directly connected.

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

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

[Formula 5a]

[Formula 5b]

[Formula 5c]

[Formula 5d]

[Formula 5e]

In the above formulas 5a to 5e,

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

b1 is an integer from 0 to 4, b2 is an integer from 0 to 6, b3 is an integer from 0 to 3, b4 and b5 are each independently integers from 0 to 4, 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.

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

According to an embodiment of the present invention, the acid dianhydride and diamine may be reacted in a molar ratio of 1:1.1 to 1.1:1. The reaction molar ratio may be changed according to intended reactivity and fairness.

According to an embodiment of the present invention, the molar ratio of the acid dianhydride and diamine may be 1:0.98 to 0.98:1, preferably 1:0.99 to 0.99:1.

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

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

According to one embodiment, as the organic solvent for polymerizing the polymerization component, a solvent having a positive distribution coefficient of 25°C LogP may be used. By using an organic solvent in which LogP is a positive number, Tg can be maintained at a high temperature of 390°C or higher even in a composition in which methylphenylsilicone oligomer is contained in an amount of 10 wt% or more.

In addition, the organic solvent having a positive partition coefficient as described above may reduce turbidity caused by phase separation due to a 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. However, the whitening phenomenon can be reduced by using only the organic solvents described above, so that a more transparent polyimide film can be produced.

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

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

When the distribution coefficient value is positive, it means that the polarity of the solvent is hydrophobic. According to the research of the present inventors, it can be seen that when the polyimide precursor composition is prepared using a specific solvent having a positive distribution coefficient value, the edge back phenomenon is improved. there was. In addition, the present invention can control the edge back phenomenon of the solution without using additives that control the surface tension of the material such as a leveling agent and the smoothness of the coating film by using a solvent in which Log P is positive as described above, which is an additive Since no additional additives such as are used, it is possible to remove quality and process problems such as the low-molecular substance content in the final product, as well as more efficiently to form a polyimide film having uniform properties. .

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

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

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

[Equation 1]

Edge percentage (%) = [(A-B)/A]Х100

In the above formula 1,

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

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

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

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

The edge percentage as described above is maintained even after curing, for example, after coating the polyimide precursor composition on the substrate for 10 minutes or more, for example, at a temperature of 20 to 30° C., a humidity condition of 40% or more, more specifically Is cured after being left for 10 to 50 minutes at a humidity condition in the range of 40% to 80%, that is, at a humidity condition of 40%, 50%, 60%, 70%, 80%, for example, at a humidity condition of 50%. The polyimide film may have an edge percentage of 0.1% or less, that is, an edge back phenomenon may or may not occur even in a curing process by heat treatment, and specifically, an edge close to 0.05%, more preferably almost 0%. It can indicate the percentage.

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

In addition, the density of the solvent according to the present invention may be 1 g/cm ³ or less, as measured by the standard measurement method of ASTM D1475, and when the density has a value of 1 g/cm ³ or more, the relative viscosity may be increased, so the process Phase efficiency can be reduced.

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

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

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

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

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

The method for 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 diamine is dissolved in an organic solvent, it can be prepared by adding a tetracarboxylic dianhydride to the resulting mixed solution to polymerize it.

The polymerization reaction may be carried out 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 becomes high and the molecular weight may increase, and the viscosity of the precursor composition increases, which may be disadvantageous in the process.

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

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

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

Alternatively, the polyimide precursor composition may be adjusted to have a viscosity of 3,000 cP or more at a solid content concentration of 20% by weight or less, and the viscosity of the polyimide precursor composition is 10,000 cP or less, preferably 9,000 cP or less, more preferably It is preferable to adjust to have a viscosity of 8,000 cP or less. When the viscosity of the polyimide precursor composition exceeds 10,000 cP, the efficiency of defoaming decreases during processing of the polyimide film, and thus, not only the process efficiency, but also the prepared film has poor surface roughness due to the generation of bubbles, resulting in poor electrical, optical, and mechanical properties. It may degrade.

Subsequently, a transparent polyimide film 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 one embodiment, the step of applying a polyimide precursor composition on a carrier substrate; And

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

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

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

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

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

The drying process may be carried out 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 It can also be carried out in a multi-stage heat treatment within the range. The heat treatment process may be performed for 20 minutes to 70 minutes, and preferably 20 minutes to 60 minutes.

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

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

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

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

The polyimide film prepared as described above may have a modulus of 3 to 6 GPa. If the modulus (elastic modulus) is less than 3Gpa, the film has low stiffness and is easily fragile to external impact, and when the modulus exceeds 6 GPa, the stiffness of the coverlay film is excellent, but sufficient flexibility may not be obtained. have.

In addition, the elongation of the polyimide film is 90% or more, preferably 91% or more, and the tensile strength may be 130 MPa or more, preferably 138 MPa or more.

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

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

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

In addition, the present invention,

Applying the polyimide precursor composition on a carrier substrate;

Forming a device on the polyimide film; And

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

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

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

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

After the LTPS thin film manufacturing process including the step of crystallizing the a-Si thin film with an excimer laser, 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 may be heat treated at a lower temperature than the process using silicon, for example, the heat treatment temperature of the ITO TFT process may be 240°C±50°C, and the heat treatment temperature of the oxide TFT process may be 350°C±50°C. Can be

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

<Production Example 1> Preparation of compound of formula 1-1

After dissolving the compound of formula A (35.0 g, 166.7 mmol) in THF (270 mL) in a nitrogen atmosphere, pyridine (pyr) (26.4 g, 333.4 mmol) was added and then cooled to 0°C. The compound of Formula B (11.6 g, 83.4 mmol) was divided into four equal portions into the solution and added at 10 minute intervals. After 3 hours, hexane (270 mL) was added to produce a solid. The solid obtained after filtration was washed with hexane/ethyl acetate (10/7) to prepare a compound of Formula C (23.8 g, yield 91.3%).

MS[M+H] ⁺ =314

The compound of formula C (20 g, 63.9 mmol) and the compound of formula D (10.2 g, 32.0 mmol) were dispersed in glacial acetic acid (200 mL) and heated to 100°C. After 4 hours, after lowering the temperature to room temperature, 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 (25.9 g, yield 88.8%).

MS[M+H] ⁺ =911

After dispersing the compound of formula E (20g, 22.0 mmol) in N-methylpyrrolidone (NMP) (180 mL), palladium/charcoal (Pd/C) (0.60 g) was added and stirred in a hydrogen atmosphere for 16 hours. . After completion of the reaction, water (180 mL) was added to the filtrate obtained to produce a solid. The solid obtained after filtration was recrystallized from NMP and ethyl acetate to prepare a compound of Formula 1-1 (14.8 g, yield 79.9%).

MS[M+H] ⁺ =851

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

In Preparation Example 1, the compound of Formula G was prepared in the same manner as the method of preparing the compound of Formula C, except that the compound of Formula F was used instead of Formula B.

The compound of Formula H was prepared in the same manner as the method of preparing the compound of Formula E, except that the compound of Formula G was used instead of Formula C. Finally, the compound of Formula 1-2 was prepared in the same manner as the method of preparing the compound of Formula 1-1, except that the compound of Formula H was used instead of Formula E.

MS[M+H] ⁺ =853

<Production Example 3> Preparation of the compound of Formula 1-9

In Preparation Example 1, the compound of Formula J was prepared in the same manner as the method of preparing the compound of Formula E, except that the compound of Formula I was used instead of Formula D.

A compound of Formula 1-9 was prepared in the same manner as the method of preparing a compound of Formula 1-1, except that a compound of Formula J was used instead of Formula E.

MS[M+H] ⁺ =731

<Production Example 4> Preparation of a compound of Formula 1-10

A compound of formula K was prepared in the same manner as the method of preparing a compound of formula E, except that a compound of formula G instead of formula C and a compound of formula I instead of formula D were used. Finally, the compound of Formula 1-10 was prepared in the same manner as the method of preparing the compound of Formula 1-1, except that the compound of Formula K was used instead of Formula E.

MS[M+H] ⁺ =733

<Production Example 5> Preparation of the compound of Formula 1-13

In Preparation Example 1, the compound of Formula M was prepared in the same manner as the method of preparing the compound of Formula C, except that the compound of Formula L was used instead of Formula B.

A compound of formula O was prepared in the same manner as the method of preparing a compound of formula E, except that a compound of formula M instead of formula C and a compound of formula N instead of formula D were used.

Finally, the compound of Formula 1-13 was prepared in the same manner as the method of preparing the compound of Formula 1-1, except that the compound of Formula O was used instead of Formula E.

MS[M+H] ⁺ =731

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

In Preparation Example 1, the compound of Formula Q was prepared in the same manner as the method of preparing the compound of Formula C, except that the compound of Formula P was used instead of Formula B.

A compound of formula R was prepared in the same manner as the method of preparing a compound of formula E, except that a compound of formula Q instead of formula C and a compound of formula N instead of formula D were used.

Finally, the compound of Formula 1-14 was prepared in the same manner as the method of preparing the compound of Formula 1-1, except that the compound of Formula R was used instead of Formula E.

MS[M+H] ⁺ =733

<Production Example 7> Preparation of the compound of Formula 1-15

The compound of formula T was prepared in the same manner as the method of preparing the compound of formula E, except that the compound of formula M is used instead of the formula C and the compound of formula S is used instead of the formula D.

Finally, the compound of Formula 1-15 was prepared in the same manner as the method of preparing the compound of Formula 1-1, except that the compound of Formula T was used instead of Formula E.

MS[M+H] ⁺ =867

<Production Example 8> Preparation of the compound of Formula 1-16

The compound of formula U was prepared in the same manner as the method of preparing the compound of formula E, except that the compound of formula Q is used instead of the formula C and the compound of formula S is used instead of the formula D.

Finally, 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 U was used instead of Formula E.

MS[M+H] ⁺ =869

<Comparative Example 1> 6-FDA/ TFMB

After filling 130 g of DEAc (Diethylacetamide) in a reactor in which a nitrogen stream flows, 0.0500 mol of TFMB (2,2'-Bis (trifluoromethyl)benzidine) was added at the same temperature and dissolved while maintaining the temperature of the reactor at 25°C. To the solution to which TFMB diamine was added, 0.0500 mol of 6-FDA (4,4'-(Hexafluoroisopropylidene) diphthalic anhydride) was added together with 40 g of DEAc, and reacted for 48 hours to prepare a polyimide precursor solution.

<Example 1> 6-FDA / diamine of formula 1-1

After filling 200 g of DEAc (Diethylacetamide) in a reactor in which a nitrogen stream flowed, 0.0413 mol of diamine of Formula 1-1 prepared in Preparation Example 1 was dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. To the solution to which the diamine of Formula 1-1 was added, 0.0413 mol of 6-FDA (4,4'-(Hexafluoroisopropylidene)diphthalic anhydride) was added with 60 g of DEAc and reacted for 48 hours to prepare a polyimide precursor solution.

<Example 2> 6-FDA/Formula 1-2

After filling 200 g of DEAc (Diethylacetamide) in a reactor in which a nitrogen stream flowed, 0.0413 mol of diamine of Formula 1-2 prepared in Preparation Example 2 was dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. A polyimide precursor solution was prepared by adding 0.0413 mol of 6-FDA (4,4'-(Hexafluoroisopropylidene)diphthalic anhydride) with DEAc 60g to the solution to which the formula 1-2 diamine was added and reacting for 48 hours.

<Example 3> 6-FDA / Formula 1-9

After filling 180 g of DEAc (Diethylacetamide) in a reactor in which a nitrogen stream flowed, 0.0413 mol of diamine of Formula 1-9 prepared in Preparation Example 3 was dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. A polyimide precursor solution was prepared by adding 0.0413 mol of 6-FDA (4,4'-(Hexafluoroisopropylidene)diphthalic anhydride) with DEAc 60g to the solution to which diamine was added to Formula 1-9 for 48 hours.

<Example 4> 6-FDA/Formula 1-10

After filling 180 g of DEAc (Diethylacetamide) in a reactor in which a nitrogen stream flowed, 0.0413 mol of diamine of Formula 1-10 prepared in Preparation Example 4 was dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. A polyimide precursor solution was prepared by adding 0.0413 mol of 6-FDA (4,4'-(Hexafluoroisopropylidene)diphthalic anhydride) with DEAc 60g to the solution to which the diamine 1-10 was added, and reacting for 48 hours.

The viscosity of the polyimide precursor solutions prepared in Examples 1 to 4 and Comparative Example 1 and the molecular weight of the polyamic acid are measured and are shown in Table 1 below.

Viscosity was measured using Viscotek's TDA302.

The molecular weight was measured using GPCmax VE2001 from Viscotek.

Each polyimide precursor solution prepared in Examples 1 to 4 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.The curing process was performed by maintaining 30 minutes at 80° C., 30 minutes at 250° C., and 30 to 40 minutes at 400° C. A polyimide film was prepared. Table 1 shows the physical properties of each film.

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

As can be seen from the results of Table 1, the polyimide precursor solution containing the 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 a higher molecular weight than Comparative Example 1 using TFMB It can be seen that a polyamic acid having a 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.

Since the specific parts of the present invention have been described in detail above, for those skilled in the art, this specific technique is only a preferred embodiment, and it is obvious that 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

Diamine having the structure of Formula 1:

[Formula 1]

In Chemical Formula 1,

Z 1 to Z 8 are each independently a carbon atom or a nitrogen atom, Z 1 to Z 8 are not nitrogen atoms at the same time, R 1 , R 2 , R 3 , R 4 are each independently an alkyl group having 1 to 10 carbon atoms, carbon number 1 to 10 haloalkyl group, an alkenyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms, n 1 , n 2 , n 3 , n 4 are each independently an integer of 0 to 4, X is a single bond, O, S, SS, C(=O), -C(=O)O-, CH(OH), S(=O) 2 , Si(CH 3 ) 2 , CR'R", A functional group selected from the group consisting of C(=O)NH and combinations thereof, wherein R'and R" are each independently from a group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluoroalkyl group having 1 to 10 carbon atoms. Is selected.
According to claim 1,

At least one of Z 1 to Z 4 is a carbon atom, and at least one of Z 5 to Z 8 is a carbon atom.
According to claim 1,

n 1 and n 2 are each independently 0, or 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.
According to claim 1,

Diamines in which Z 1 to Z 4 are all carbon atoms.
According to claim 1,

A diamine in which one of Z 1 to Z 4 is a nitrogen atom or one of Z 5 to Z 8 is a nitrogen atom.
According to claim 1,

A diamine in which one of Z 1 to Z 4 is a nitrogen atom and one of Z 5 to Z 8 is a nitrogen atom.
According to claim 1,

Diamine in which X is a single bond, -O-, -CH 2 -, -C(CF 3 )-, -C(CH 3 ) 2 -or -SO 2 -.
According to claim 1,

The diamine of the formula (1) is selected from compounds of the formulas 1-1 to 1-20:

.
A polyimide precursor obtained by polymerizing a polymerization component comprising at least one diamine and at least one acid dianhydride,

A polyimide precursor in which the diamine comprises the diamine of any one of claims 1 to 8.
A polyimide film prepared using the polyimide precursor according to claim 9.
Applying a polyimide precursor composition comprising the polyimide precursor according to claim 9 on a carrier substrate; And

A polyimide film prepared by a method comprising heating and curing the polyimide precursor composition.
A flexible device comprising the polyimide film according to claim 10 as a substrate.
Applying a polyimide precursor composition comprising the polyimide precursor of claim 9 on a carrier substrate;

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

Forming a device on the polyimide film; And

And peeling the polyimide film on which the element is formed from the carrier substrate.
The method of claim 13,

The manufacturing process of a flexible device, wherein the manufacturing process includes an LTPS (low temperature polysilicon) process, an ITO process or an oxide process.
Reacting a compound of formula (i) and formula (ii) to obtain a compound of formula (iii);

Reacting the compound of formula (iii) with the compound of formula (iv) to obtain a compound of formula (v); And

Method for preparing a diamine having the structure of Formula 1 by reducing the compound of Formula v:

(i)

(ii)

(iii)

(iv)

(v)

(One)

In the above formula,

Z a to Z d are each independently a carbon atom or a nitrogen atom, but Z a to Z d are not nitrogen atoms at the same time, and R 1 , R 2 and R a are each independently an alkyl group having 1 to 10 carbon atoms, and 1 to 10 carbon atoms. A haloalkyl group, an alkenyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 18 carbon atoms, n 1 , n 2 and n are each independently an integer of 0 to 4, X is a single bond, O, S, SS, C(=O), -C(=O)O-, CH(OH), S(=O) 2 , Si(CH 3 ) 2 , CR'R", C(=O)NH and It is a functional group selected from the group consisting of a combination of these, and R'and R" are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluoroalkyl group having 1 to 10 carbon atoms.