KR20200021411A - A composition for preparing polyimide, and polyimide film and flexible device prepared by using same - Google Patents

Abstract

The present invention provides a polyimide precursor composition comprising a polymerized product of a diamine component, comprising diaminodiphenyl sulfone (DDS) and an amine-terminated methylphenylsiloxane oligomer, and a dianhydride component, comprising two or more kinds of tetracarboxylic dianhydride, wherein the polymerized product is obtained by conducting a reaction of the dianhydride component and the diamine component at an equivalence ratio of 1 : 1.01 to 1.05. By using the polyimide precursor composition, a transparent polyimide film having excellent high-temperature resistance and low haze can be manufactured.

Description

A polyimide precursor composition, a polyimide film and a flexible device manufactured using the same, a polyimide precursor composition and a polyimide film manufactured using the same.

This application is August 20, 2018. Claiming the benefit of priority based on Korean Patent Application No. 10-2018-0096804 filed, all contents disclosed in the documents of the Korean Patent Application is incorporated as part of this specification.

The present invention relates to a polyimide precursor composition for producing a polyimide film having excellent thermal stability, and to a polyimide film and a flexible device manufactured using the same.

In recent years, weight reduction and miniaturization of products have become important in the display field. In the case of glass substrates, there is a limitation that heavy, easily broken and continuous processes are difficult. Therefore, research is being actively conducted to apply plastic substrates having advantages of being lightweight, flexible, and continuous processes to mobile phones, laptops, PDAs, and the like.

In particular, since polyimide (PI) resins are easy to synthesize, can make thin film, and do not need a crosslinker for curing, they have recently been integrated into semiconductor materials such as LCD and PDP due to the light weight and precision of electronic products. It is applied a lot. In addition, research is being actively conducted to use PI resin in a flexible plastic display board having light and flexible properties.

A polyimide (PI) film prepared by filming a polyimide resin is generally a polyimide film. In general, a polyimide film is prepared by solution polymerization of an aromatic dianhydride and an aromatic diamine or an aromatic diisocyanate to prepare a polyamic acid solution. It is prepared by coating on glass or the like and curing (imidization) by heat treatment.

The process of manufacturing a flexible device involving a high temperature process involves a high temperature process. In particular, an organic light emitting diode (OLED) device using a low temperature polysilicon (LTPS) process may have a process temperature close to 500 ° C. However, at this temperature, even if it is a polyimide excellent in heat resistance, thermal decomposition by hydrolysis tends to occur. Accordingly, in order to manufacture a flexible device using a polyimide film, development of a transparent polyimide film having low haze while maintaining excellent heat resistance and mechanical strength is required.

The problem to be solved by the present invention is to provide a composition for polyimide precursor that can produce a polyimide film with improved heat resistance at high temperature.

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

Another object of the present invention is to provide a flexible device including the polyimide film and a manufacturing process thereof.

In order to solve the problem of the present invention,

A diamine component comprising a diamine of Formula 1 and an amine-terminated methylphenyl siloxane oligomer; And

A polymerization product of a polymerized component comprising a dianhydride component comprising two or more tetracarboxylic dianhydrides, wherein the polymerized component comprises the dianhydride component and the diamine component in a 1: 1.01 to 1.05 equivalent ratio It provides a composition for producing phosphorus polyimide.

[Formula 1]

.

.

According to one embodiment, the amine terminal methylphenylsiloxane oligomer may have a structure of formula (2).

[Formula 2]

In the above formula, p and q are mole fractions, where p is 70 to 90 and q is 10 to 30 when p + q = 100.

According to one embodiment, the dianhydride component may include biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA).

According to an embodiment, the dianhydride component may include BPDA and PMDA in a molar ratio of 4: 6 to 8: 2.

According to an embodiment, the amine-terminated methylphenylsiloxane oligomer may be included in an amount of 5 to 30 wt% based on the total weight of the entire polymerization component.

According to one embodiment, the polyimide precursor composition comprises a solvent, the viscosity may be 2000 cP or more.

According to one embodiment, the solvent may be an organic solvent having a partition coefficient of 25 ° C LogP 0.01 ~ 3.

This invention also provides the polyimide film containing the imidation product of the polyimide precursor composition mentioned above.

According to one embodiment, the haze of the polyimide film may be 1 or less.

According to an embodiment, the modulus of the polyimide film may be 2.2 GPa or less, phosphorus strength of 80 MPa or less, and elongation of 28% or more.

According to one embodiment, the glass transition temperature of the polyimide film is 380 to 410 ℃, the weight loss rate after maintaining for 60 minutes at 350 ℃ is less than 0.037%, the weight loss rate after maintaining for 60 minutes at 380 ℃ It may be 0.12% or less.

According to one embodiment, the residual stress of the polyimide film is 25 MPa or less, whip may be 25 ㎛ or less.

In order to solve another problem of the present invention,

Applying the composition for polyimide onto a carrier substrate;

Forming a polyimide film by imidating the composition for polyimide;

Forming an element on the polyimide film; And

It provides a process for manufacturing 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 one or more processes selected from a LTPS thin film manufacturing process, an ITO thin film manufacturing process, and an oxide thin film manufacturing process.

The present invention relates to a total tetracarboxylic dianhydride comprising a diamine component comprising a diaminodiphenyl sulfone (DDS) and an amine-terminated methylphenylsiloxane oligomer and a dianhydride component including two or more tetracarboxylic dianhydrides as a polymerized component. The polymerization degree is increased by reacting the total diamine with a ratio of 1: 1.01 to 1.05, thereby providing a transparent polyimide film having excellent heat resistance and low haze.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

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

The present invention, a diamine comprising a diamine of the general formula (1) and an amine terminal methylphenylsiloxane oligomer; And

A polyimide precursor composition comprising a polymerization product of a polymerization component comprising a dianhydride component comprising two or more tetracarboxylic dianhydrides, wherein the polymerization component comprises an acid dianhydride component and a diamine component in a 1: 1.01 to 1.05 equivalent ratio It provides a polyimide precursor composition.

[Formula 1]

.

.

The compound of Formula 1 may be, for example, 4,4- (diaminodiphenyl) sulfone (hereinafter, 4,4-DDS), 3,4- (diaminodiphenyl) sulfone (hereinafter, 3,4-DDS) ) And 3,3- (diaminodiphenyl) sulfone (hereinafter, 3,3-DDS).

The present invention is to prepare a polyamic acid which is a polymerization product by reacting a diamine component including a diamine of formula (1) and an amine-terminated methylphenylsiloxane oligomer with a dianhydride component including two or more tetracarboxylic dianhydrides. The degree of polymerization of the polyamic acid can be increased by reacting the equivalent ratio of the diamine component with a ratio of 1: 1.01 to 1.05, preferably 1: 1.01 to 1.03. As a result, the thermal stability can be improved than the polyimide film made of the polyamic acid obtained by having an equivalent ratio of the dianhydride component and the diamine component being the same or having the dianhydride component reacted in excess of the diamine component.

In the equivalent conditions, the degree of polymerization of the polyamic acid may be further improved, which may be confirmed by an increase in the viscosity of the polymerization solution. For example, the viscosity of the composition containing the polymerization solution of the polyimide precursor composition may be 2,000 cP or more, more preferably 2,400 cP or more. In addition, the viscosity of the composition of the polyimide precursor solution is preferably adjusted to have a viscosity of 15,000 cP or less, preferably 12,000 cP or less, more preferably 10,000 cP or less. When the viscosity of the polyimide precursor composition is too high, the efficiency of degassing during processing of the polyimide film is lowered, so that not only the efficiency of the process but also the produced film may have poor surface roughness due to foaming, which may lower electrical, optical, and mechanical properties. have.

In addition, the polyimide precursor composition according to the present invention shows little haze (white turbidity) in the solution state containing the polymerization solution, and the haze of the polyimide film prepared therefrom is very low, preferably 1 or less. It is possible to provide a transparent polyimide film having a haze value of 0.5 or less.

When manufacturing a polyimide film using a siloxane oligomer as a diamine component, there is a problem that pores occur. Such pores may cause cracks in an inorganic film formed on the polyimide film in a display manufacturing process. Can be.

The present invention provides a pore that may occur when preparing a polyimide film including a siloxane oligomer structure by using a diamine component of DDS (diaminodiphenyl sulfone) of Formula 1 together with an amine-terminated methylphenylsiloxane oligomer as a polymerization component in preparing a polyamic acid ( pore) can be significantly reduced.

When the polyimide film is manufactured using the amine-terminated siloxane oligomer structure as the diamine component, breakage and rearrangement of the siloxane oligomer chain may occur in a high temperature curing process, and pores may occur in the polyimide film by this process. . In this case, in a polyimide having a high modulus structure, that is, a polyimide having a rigid structure, the porosity generated at the high temperature due to its low mobility does not escape to the outside and remains inside the film, leaving pores in the film. The ratio of becomes high.

In the polyimide film according to the present invention, by using a diamine including a flexible structure such as DDS (diaminodiphenyl sulfone) together, the generated pores can be escaped to the outside during the film formation process due to high mobility at high temperature, As a result, the proportion of pores present in the film may be significantly reduced.

In this case, the pore distribution ratio may be measured as follows.

The polyimide film was fixed with 100 mm x 80 mm in a 100,000 magnification image measured by Focused Ion Beam Scanning Electron Microscopes (FIB-SEM), and then subdivided the area by 2 mm x 2 mm to reveal pores based on a total of 2000 areas. The area | region was made into ratio the distribution ratio.

For example, when there are two areas in which pores exist (2ea), the pore distribution ratio is calculated as follows.

% Porosity distribution = 2/2000 x 100 = 0.1%

According to one embodiment, the amine terminal methylphenylsiloxane oligomer may have a structure of the formula (2).

[Formula 2]

In the above formula, p and q are mole fractions, where p is 70 to 90 and q is 10 to 30 when p + q = 100.

Polyimide chains comprising siloxane structures, such as amine-terminated methylphenylsiloxane oligomers, may exhibit polarity, and phase separation may occur due to polarity differences with polyimide chains that do not include siloxane structures, thereby causing the siloxane structure to be a polyimide matrix Can be unevenly distributed. In this case, it is difficult to exhibit physical properties such as strength improvement and stress relaxation effect of the polyimide due to the siloxane structure, and the haze may increase due to phase separation, thereby decreasing transparency of the film. In particular, when the diamine containing the siloxane oligomer structure has a high molecular weight, the polyimide chain prepared therefrom has a more pronounced polarity, and the phase separation between the polyimide chains may be more pronounced. In order to avoid such a problem, when a low molecular weight siloxane oligomer is used, a large amount of siloxane oligomer must be added to obtain a stress relieving effect. In this case, a problem such as occurrence of Tg at a low temperature occurs. The physical properties of the mid film may be degraded.

Thus, the present invention can be more evenly distributed siloxane oligomer structure without phase separation in the polyimide matrix by using the diamine of the formula (1) with the amine terminal methylphenylsiloxane oligomer.

The molecular weight of the amine-terminated methylphenylsiloxane oligomer used to prepare the composition according to the present invention may be at least 4000 g / mol. According to one embodiment, the molecular weight may be 5000 g / mol or less, or 4500 g / mol or less. Molecular weight means a weight average molecular weight here, and molecular weight calculation can use the conventional method of calculating an amine equivalent using NMR analysis or an acidic acid titration method.

When the molecular weight of the amine-terminated methylphenylsiloxane oligomer is less than 4000 g / mol, heat resistance may decrease, and as a result, the glass transition temperature (Tg) of the manufactured polyimide film may decrease or the coefficient of thermal expansion may increase excessively. .

According to one embodiment, the amine terminated methylphenylsiloxane oligomer may be from 5 to 30% by weight, preferably from 10 to 25% by weight, based on the total weight of the polymerization product or the polymer component (diamine component and acid dianhydride component), More preferably, it may be added in 10 to 20% by weight.

Excessive addition of amine-terminated methylphenylsiloxane oligomers can lead to a decrease in mechanical properties such as modulus of the resulting polyimide film, and a decrease in film strength, thereby avoiding physical damage such as film tearing in the process. May occur. In addition, when the amine-terminated methylphenylsiloxane oligomer is excessively added, Tg derived from the polymer having the siloxane structure appears at a low temperature of 350 ° C. or lower, and the film is caused by the flow phenomenon of the polymer during the inorganic film deposition process of 350 ° C. or higher. Wrinkles may occur on the surface, and as a result, cracks may occur in the inorganic film formed on the polyimide film.

According to one embodiment, the amine terminal methylphenylsiloxane oligomer may be included in 1 to 20 mol%, preferably 1 to 10 mol% or 1 to 5 mol% based on the total diamine component.

According to the present invention, since the domain size of the amine-terminated methylphenylsiloxane oligomer distributed in the polyimide matrix has a continuous phase as a nano size, for example, 1 nm to 50 nm, or 5 nm to 40 nm, or 10 nm to 30 nm, heat resistance and mechanical properties Residual stress can be minimized while maintaining 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 a flexible display manufacturing process. It is preferable that the portion (domain) containing the amine-terminated methylphenylsiloxane oligomer is connected in a continuous phase in the polyimide matrix, where the continuous phase means a shape in which nano-sized domains are uniformly distributed.

The domain of the amine terminated methylphenylsiloxane oligomer herein refers to the region in which the amine terminated methylphenylsiloxane oligomer is distributed, the size of which refers to the maximum diameter of the circle surrounding the region.

According to the present invention, despite the use of a high molecular weight amine-terminated methylphenylsiloxane oligomer, it can be uniformly distributed in a continuous phase without phase separation in the polyimide matrix to reduce the haze properties to obtain a polyimide film having more transparent properties Not only can it be obtained, but also the mechanical strength and stress relaxation effect of a polyimide film can be improved more efficiently. From these properties, the composition according to the invention can provide not only thermal and optical properties, but also flat polyimide films with reduced substrate warpage after coating-curing.

The polyimide precursor composition according to the present invention comprises two or more tetracarboxylic dianhydrides as a dianhydride component, wherein the tetracarboxylic dianhydride is used together with biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA). It may be desirable to be present. It may also be desirable to include BPDA and PMDA in a molar ratio of 4: 6 to 8: 2 or 5: 5 to 7: 3.

According to another embodiment, the acid dianhydride component may further include other tetracarboxylic dianhydride in addition to BPDA and PMDA. For example, tetracarboxylic dianhydride including a tetravalent organic group selected from the following Chemical Formulas 3a to 3h may be further included.

[Formula 3a]

[Formula 3b]

[Formula 3c]

[Formula 3d]

[Formula 3e]

[Formula 3f]

[Formula 3g]

[Formula 3h]

In Chemical Formulas 3a to 3h,

R11 to R24 are each independently a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group (-SH), a nitro group (-NO2), a cyan It may be a substituent selected from a furnace group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, 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, and a7 and a8 are each independently an integer of 0 to 3 A10 and a12 are each independently an integer of 0 to 3, a11 is an integer of 0 to 4, a15 and a16 are each independently an integer of 0 to 4, a17 and a18 are each independently an integer of 0 to 4 , a6, a9, a13, a14, a19, a20 are each independently an integer of 0 to 3,

n is an integer of 1 to 3,

A11 to A16 are each independently a single bond, -O-, -CR'R "-, -C (= O)-, -C (= O) O-, -C (= O) NH-, -S- It may be selected from the group consisting of -SO2-, phenylene group and combinations thereof, wherein R 'and R "are each independently a hydrogen atom, an alkyl group of 1 to 10 carbon atoms and a fluoroalkyl group of 1 to 10 carbon atoms It is selected from the group consisting of.

Where * in the formula represents a binding site.

In addition, the polyimide precursor composition according to the present invention may further include other diamines in addition to the diamine and the amine terminal methylphenylsiloxane oligomer of the formula (1) as the diamine component. For example, it may further include a diamine having a structure of the formula (4).

[Formula 4]

In Chemical Formula 4,

R31 and R32 are each independently a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, hydroxyl group (-OH), thiol group (-SH), nitro group (-NO2), A substituent selected from a furnace group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms, and preferably a halogen atom and a halogenoalkyl group. It may be a substituent selected from an alkyl group, an aryl group and a cyano group. For example, the halogen atom may be fluoro (-F), the halogenoalkyl group is a fluoroalkyl group having 1 to 10 carbon atoms, may be selected from fluoromethyl group, perfluoroethyl group, trifluoromethyl group, etc. have. The alkyl group may be selected from methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, pentyl group, hexyl group. The aryl group may be selected from a phenyl group, naphthalenyl group. More preferably, they may be fluoro substituents, such as a fluoro atom and a fluoroalkyl group.

In this case, the "fluoro-based substituent" means not only the "fluoro atom substituent" but also the "substituent containing a fluoro atom".

Q is a single bond, -O-, -CR'R "-, -C (= O)-, -C (= O) O-, -C (= O) NH-, -S-, -SO2-, It may be selected from the group consisting of a phenylene group and combinations thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluoroalkyl group having 1 to 10 carbon atoms It will be.

According to one embodiment, a diamine component comprising a diamine and an amine terminal methylphenylsiloxane oligomer of Formula 1 and a tetracarboxylic dianhydride component including BPDA and PMDA as a polymerization component, and polymerized in an organic solvent to include a polyamic acid A polyimide precursor composition can be prepared.

The polyimide manufacturing composition may further include an adhesion promoter, and the adhesion promoter may be included in an amount of 0.05 to 3 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the polyamic acid, which is a polymerization product.

According to one embodiment, the adhesion promoter may include a structure of Formula 5 or Formula 6.

[Formula 5]

[Formula 6]

In Chemical Formulas 5 and 6,

Q1 is a tetravalent organic group having 1 to 30 carbon atoms or a tetravalent organic group represented by Ra-L-Rb, wherein Ra and Rb are each independently substituted or unsubstituted aliphatic having 4 to 10 carbon atoms, having 6 to 24 carbon atoms. Aromatic, a monovalent organic group selected from cyclic aliphatic having 3 to 24 carbon atoms, L is a single bond, -O-, -CR'R "-, -C (= O)-, -C (= O) O —, —C (═O) NH—, —S—, —SO 2 —, a phenylene group, or a combination thereof, wherein R ′ and R ″ are each independently a hydrogen atom, having 1 to 4 carbon atoms An alkyl group of 10 and a fluoroalkyl group of 1 to 10 carbon atoms, more preferably L may be selected from -SO2-, -CO-, -O-, C (CF3) 2;

Q2 is a divalent organic group having 1 to 30 carbon atoms or a divalent organic group represented by Rc-L-Rd, and each of Rc and Rd is independently substituted or unsubstituted aliphatic having 4 to 10 carbon atoms and having 6 to 24 carbon atoms. Aromatic, a monovalent organic group selected from cyclic aliphatic having 3 to 24 carbon atoms, L is a single bond, -O-, -CR'R "-, -C (= O)-, -C (= O) O —, —C (═O) NH—, —S—, —SO 2 —, a phenylene group, or a combination thereof, wherein R ′ and R ″ are each independently a hydrogen atom, having 1 to 4 carbon atoms An alkyl group of 10 and a fluoroalkyl group of 1 to 10 carbon atoms;

R1 and R3 are each independently an alkyl group having 1 to 5 carbon atoms;

R2 and R4 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, more preferably an ethyl group;

a and b are each independently an integer of 1 to 3.

For example, Q1 may be a tetravalent organic group selected from Chemical Formulas 5a to 5s, but is not limited thereto.

In Chemical Formula 6, Q2 may be a divalent organic group selected from Chemical Formulas 6a to 6s, but is not limited thereto.

An adhesion promoter comprising the structure of Formula 5 or 6 may not only significantly improve the adhesion to the inorganic layer but also have low reactivity with the polyamic acid. Alkoxy silane-based additives such as ICTEOS and APTEOS, which are general adhesion enhancing additives, have high reactivity with polyamic acid, and may cause an increase in viscosity of the composition due to side reactions of the polyamic acid and the additive. However, the adhesion promoters of Chemical Formulas 5 and 6 may reduce the viscosity increase due to side reaction with the polyamic acid, thereby improving the room temperature storage stability of the composition.

In addition, the highly heat-resistant polyimide used as a conventional flexible display substrate uses a method of applying and forming an adhesion promoter on the glass substrate to increase the adhesion with the glass substrate used as a carrier substrate or the glass substrate on which an inorganic layer is deposited. It was. However, this method has a limitation in that the foreign matter occurs in the application process of the adhesion promoter, or additional coating process is required, so the process economy is low. Moreover, even when an adhesion promoter is added directly to a polyimide precursor composition, there existed a problem that an amino group forms a salt with the carboxylic acid of a polyamic acid, and precipitates, and adhesiveness falls.

In addition, there is also a prior art that can improve the adhesion by synthesizing the adhesion promoter having a structure similar to the formulas 5 and 6 directly to the polyimide precursor, but after curing because it uses an acid anhydride having a relatively rigid structure There is a problem in that the retardation phenomenon occurs in the adhesion promoter portion, resulting in an increase in the retardation value in the thickness direction of the resulting polyimide film. In addition, in the case of using an adhesion promoter including a flexible structure such as ODPA (4,4'-oxydiphthalic anhydride), the retardation value does not increase due to the flexibility of the structure, but the Tg tends to decrease.

According to a preferred embodiment of the present invention, the adhesion promoter has a fluorene skeleton, while maintaining the effect of the adhesion promotion to the maximum, while the intermolecular free volume due to the fluorene skeleton does not affect the packing density isotropic It can represent the characteristics of. In addition, the heat resistance is also excellent due to the structural features containing a lot of aromatics.

That is, even when the adhesion promoter is mixed and used in the polyimide precursor composition, it is not precipitated and the occurrence of foreign matters can be minimized, so that the adhesion with the substrate is excellent, but the phase difference in the thickness direction, which is the optical property of the resulting polyimide film, is excellent. It is possible to provide an isotropic polyimide film without affecting.

In order to obtain the polyimide precursor composition according to the present invention, an organic solvent which can be used when polymerizing the diamine component and the acid dianhydride component is gamma-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl Ketones such as ethyl ketone, cyclohexanone, cyclopentanone, and 4-hydroxy-4-methyl-2-pentanone; Aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; Ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether Glycol ethers (cellosolve) such as dipropylene glycol diethyl ether and triethylene glycol monoethyl ether; Ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethanol, propanol, ethylene glycol, propylene glycol, carbitol, dimethyl Propionamide (dimethylpropionamide, DMPA), diethylpropionamide (DEPA), dimethylacetamide (DMAc), N, N-diethylacetamide, dimethylformamide (DMF), diethylformamide (DEF), N Methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, pyridine, dimethyl sulfone, hexamethylphosphoramide, tetramethylurea, N- Methyl caprolactam, tetrahydrofuran, m-dioxane, P-dioxane, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane , 'S [2- (2-methoxyethoxy)] ether, amide Ek (Equamide) M100, amides Ek (Equamide) and the like B100, there is a singly or as mixtures of two or more thereof may be used of these.

Preferably, the partition coefficient at 25 ° C. (LogP value) may be a positive solvent, the organic solvent may have a boiling point of 300 ° C. or less, and more specifically, the 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 ACD / LogP module of ACD / Percepta platform of ACD / Labs, and ACD / LogP module uses QSPR (Quantitative Structure-Property Relationship) methodology based algorithm using molecular 2D structure. I use it.

The partition coefficient (LogP value) at 25 ° C. of representative solvents is as follows.

The solvent having a distribution coefficient (Log P) is dimethylpropionamide (DMPA), diethylpropionamide (DEPA), N, N-diethylacetamide (N, N-diethylacetamide, DEAc), N, N It may be one or more selected from diethylformamide (N, N-diethylformamide, DEF), N-ethylpyrrolidone (NEP). Preferably it may be an amide solvent.

The method for reacting the tetracarboxylic dianhydride component with the diamine component can be carried out according to a conventional polyimide precursor polymerization method such as solution polymerization. For example, after dissolving a diamine component in an organic solvent, tetracarboxylic dianhydride can be added and polymerization may be carried out. The polymerization can be carried out under inert gas or a stream of nitrogen and can be carried out under anhydrous conditions.

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

The polyimide precursor composition according to the present invention may be in the form of a solution in which a polyamic acid as a polymerization product is dissolved in an organic solvent. For example, when the polymerization component is polymerized in an organic solvent, the composition may be the reaction solution itself or may be diluted by adding another solvent to the reaction solution. In the case where the polymerization product is obtained as a solid powder, the polymer may be dissolved in an organic solvent to form a solution. For example, in the polymerization reaction, an organic solvent having a positive LogP may be used, and an organic solvent having a negative LogP may be used as an organic solvent to be mixed thereafter.

According to one embodiment, the composition for preparing polyimide may be adjusted by adding a solvent such that the content of the polymerization product (solid content) is 8 to 30% by weight, preferably 10 to 25% by weight, more preferably 10 To 20% by weight.

In addition, it is preferable to adjust the solid content in an amount such that the composition has an appropriate viscosity in consideration of fairness such as coating property in the film forming process to the polyamic acid solution prepared according to the above-described manufacturing method.

According to one embodiment, the viscosity of the polyimide manufacturing composition may be 2,000 cP or more, preferably 2,400 cP or more.

The molecular weight of the polyamic acid or polyimide precursor that is a polymerization product may be one having a weight average molecular weight of 10,000 to 200,000 g / mol, or 20,000 to 100,000 g / mol, or 30,000 to 100,000 g / mol. Moreover, it is preferable that molecular weight distribution (Mw / Mn) is 1.1-2.5. The weight average molecular weight Mw and the number average molecular weight Mn are calculated | required by standard polystyrene conversion using gel permeation chromatography.

When the weight average molecular weight or molecular weight distribution of the polyimide precursor is out of the above range, it may be difficult to form a film, or there is a concern that the properties of the resulting polyimide film, such as permeability, heat resistance and mechanical properties, may be deteriorated.

Subsequently, the polyimide film can be manufactured by imidating the polyimide precursor obtained as a result of the said polymerization reaction.

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

The polyimide film may be prepared by subjecting the applied composition to heat treatment and imidizing the same.

In this case, a glass, a metal substrate or a plastic substrate may be used as the substrate without particular limitation, and among these, the thermal and chemical stability is excellent during the imidization and curing process for the polyimide precursor, and without curing the release agent, It may be desirable for the glass substrate to be able to easily separate the polyimide film formed afterwards without damage.

In addition, the coating process may be carried out 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, dipping method, brushing method and the like can be used. Of these, the continuous process is possible, and it may be more preferable to be carried out by a casting method that can increase the imidation ratio of the polyimide.

The polyimide precursor composition may be applied over the substrate in a thickness range such that the polyimide film to be produced has a thickness suitable for the display substrate. Specifically, it may be applied in an amount such that it becomes a thickness of 10 to 30㎛.

In addition, after the polyimide precursor composition is applied, a drying process for removing the solvent present in the polyimide precursor composition may be optionally further performed before the curing process.

The drying process may be performed according to a conventional method, specifically, may be carried out at a temperature of 140 ℃ or less, or 80 ℃ to 140 ℃. If the implementation temperature of a drying process is less than 80 degreeC, a drying process will become long, and if it exceeds 140 degreeC, imidation will advance and it will be difficult to form polyimide film of uniform thickness.

Following the drying process, the polyimide precursor composition may be applied to the substrate, heat treated at a temperature in the range of 300 to 500 ° C., preferably 320 to 480 ° C., to imidize and cure the polyimide film. The heat treatment process may be a multi-stage heat treatment within the above temperature range, may be performed for 20 to 70 minutes, preferably for a time of about 20 to 60 minutes. Heat treatment may be performed using an IR oven, a hot air oven or a hot plate, but is not limited thereto.

Thereafter, the polyimide film can be produced by peeling the polyimide film formed on the substrate from the substrate according to a conventional method.

The polyimide film prepared as described above may have a modulus (elasticity) of 2.2 GPa or less, for example, 0.1 to 2 Gpa, a tensile strength of 80 MPa or less, preferably 50 to 80 MPa, and an elongation. May be at least 28%. When the modulus is less than 0.1 GPa, the rigidity of the film is easy to be easily broken by external impact, and when the modulus of elasticity exceeds 2.2 GPa, the rigidity may be excellent but sufficient flexibility may not be obtained.

In addition, the residual stress of the polyimide film is 25MPa or less, whip may be 25㎛ or less.

In addition, the polyimide film according to the present invention may have a glass transition temperature (Tg) of 380 to 410 ° C.

 In addition, the polyimide film according to the present invention may be excellent in thermal stability according to the temperature change, for example, the coefficient of thermal expansion after the heating and cooling process n + 1 times in the temperature range of 100 ℃ to 350 ℃ -10 It may have a value of from 100 ppm / ℃, preferably a value of -7 to 70 ppm / ℃, more preferably may be 63 ppm / ℃ or less.

In addition, the polyimide film according to the present invention may be improved in thermal decomposition properties due to temperature rise and heating, for example, the weight loss rate after maintaining for 60 minutes at 350 ℃ is less than 0.037%, 60 minutes at 380 ℃ The weight loss rate after holding for a while may be 0.12% or less.

Further, in the polyimide film according to the present invention, the phase difference in thickness direction Rth has a phase difference value Rth in the thickness direction of 100 nm or less, preferably about -100 to +100 nm, whereby Visibility suitable for display can be expressed in a range.

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

In addition, the present invention,

A composition for producing a polyimide comprising a diamine component comprising a diamine of formula (1) and an amine-terminated methylphenylsiloxane oligomer and a polyimide precursor which is a polymerization product of an acid dianhydride component comprising two or more tetracarboxylic dianhydrides on a carrier substrate Applying;

Forming a polyimide film by heating the composition for producing polyimide coated on the carrier substrate to imidize the polyimide precursor;

Forming an element on the polyimide film; And

It provides a process for manufacturing 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 at least one selected from a low temperature polysilicon (LTPS) thin film manufacturing process, an ITO thin film manufacturing process, and an oxide thin film manufacturing process.

For example, LTPS thin film manufacturing process

Forming a barrier layer comprising SiO 2 on the polyimide film;

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

Dehydrogen annealing step of heat-treating the deposited a-Si thin film at a temperature of 450 ± 50 ℃; And

After the LTPS thin film manufacturing process including crystallizing the a-Si thin film with an excimer laser or the like, the flexible substrate including the LTPS layer may be obtained by peeling the carrier substrate and the 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 200 ° C. ± 50 ° C., and the heat treatment temperature of the oxide TFT process is 320 ° C. ± 50 ° C. Can be.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Example 1 BPDA-PMDA (5: 5) / DDS / DPS-DMS (An: Am = 1: 1.0208)

After filling DEAc (N, N-diethylacetamide) in the reactor with nitrogen stream, 0.13595 mol of 4,4'-DDS (4,4'-diaminodiphenyl sulfone) was kept at the same temperature while maintaining the reactor temperature at 25 ° C. It was added and dissolved. To the solution added with DDS, 0.06798 mol of pyromellitic dianhydride (PMDA) and 0.06798 mol of BPDA (3,3 ', 4,4'-biphenyltetracarboxylic dianhydride) were added at the same temperature and stirred for 24 hours, followed by modification of terminal amine of Chemical Formula 2 0.00283 mol of DPS-DMS (diphenylsiloxane-dimethylsiloxane co-oligomer, weight average molecular weight 4360 g / mol) was added and stirred at 80 ° C. for 4 hours. After that, the oil bath was removed and returned to room temperature to obtain a transparent polyamic acid solution.

Example 2 BPDA-PMDA (5: 5) / DDS / DPS-DMS (An: Am = 1: 1.0158)

A polyamic acid solution was prepared in the same manner as in Example 1, except that the molar ratio of the diamine component and the dianhydride component was adjusted.

Example 3 BPDA-PMDA (5: 5) / DDS / DPS-DMS (An: Am = 1: 1.0107)

A polyamic acid solution was prepared in the same manner as in Example 1, except that the molar ratio of the diamine component and the dianhydride component was adjusted.

Comparative Example 1 BPDA-PMDA (5: 5) / DDS / DPS-DMS (An: Am = 1.0208: 1)

A polyamic acid solution was prepared in the same manner as in Example 1, except that the molar ratio of the diamine component and the dianhydride component was adjusted.

<Comparative Example 2> BPDA-PMDA (5: 5) / DDS / DPS-DMS (An: Am = 1: 1)

A polyamic acid solution was prepared in the same manner as in Example 1, except that the molar ratio of the diamine component and the dianhydride component was adjusted.

Experimental Example 1 Measurement of Viscosity and Haze of a Solution

The viscosity and haze of each polyimide precursor solution prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were measured and shown in Table 1 below.

The viscosity of the solution was measured with a late rheometer (model LVDV-1II Ultra, manufactured by Brookfield) in a container with 5 ml of PAA solution, the spindle was lowered, the rpm was adjusted, and the torque was waited for 1 minute when the torque reached 80. The viscosity value was measured. The spindle used was 52Z and the temperature was 25 ℃.

The haze of the solution was visually observed, O indicates that there was haze, and X indicated that there was no haze.

As can be seen in Table 1, the viscosity of the polyimide precursor compositions prepared in Examples 1 to 3 is higher than 2400 cP, indicating a higher solution viscosity than Comparative Examples 1 and 2, which means that the degree of polymerization of the polyamic acid is high. do. In addition, the polyimide precursor solution according to the present invention showed little haze.

Experimental Example 2

Each of the polyimide precursor solutions prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was spin coated onto 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 polyimide film was prepared by performing a curing process by maintaining 30 minutes at 80 ° C. and 30 minutes at 400 ° C.

The physical properties of each film were measured and shown in Table 2 below.

Yellow (YI)

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

Haze

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

<Permeability>

The transmittance | permeability was measured for the 450 nm, 550 nm, and 633 nm wavelength by the transmittance | permeability meter (model name HR-100, a Murakami Color Research Laboratory) based on JISK7105.

<Thickness direction phase difference (Rth)>

Thickness direction retardation (Rth) was measured using Axoscan. The film was cut to a certain size to measure the thickness, and then the thickness was measured while calibrating in the direction of the C-plate to compensate for the phase difference by measuring the phase difference with Axoscan.

Glass Transition Temperature (Tg) and Thermal Expansion Coefficient (CTE)

Prepare the film in 5 x 20 mm size and load the sample using the accessory. The length of the film actually measured was made the same at 16 mm. The film pulling force was set to 0.02N and the first temperature rising step was performed at a temperature rising rate of 5 ° C./min at a temperature range of 100 to 400 ° C., followed by a cooling rate of 4 ° C./min at a temperature range of 400 to 100 ° C. After cooling, a second temperature increase process was performed again at a temperature increase rate of 5 ° C./min in a temperature range of 100 to 450 ° C., and thermal expansion change was measured by TMA (Q400 by TA).

At this time, the inflection point seen in the temperature increase section in the second temperature increase step was set to Tg.

<Pyrolysis temperature (Td1%) and weight loss rate (%)>

The temperature at which the weight loss rate of the polymer was 1% in a nitrogen atmosphere was measured using TGA.

The weight loss rate at the time of holding at 350 degreeC for 60 minutes was measured.

The weight loss rate at 60 minutes at 380 ° C. was measured.

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

A film of 5 mm x 50 mm long and 10 μm thick was stretched at a speed of 10 mm / min using a tensile tester (Instron, Instron: Instron 3342) to measure modulus (GPa), tensile strength (MPa), and elongation (%).

<Residual Stress and Bow Value Measurement>

The resin composition was applied by a spin coater on a 6 inch silicon wafer having a thickness of 525 um in which the [warping amount] of the wafer was measured in advance using a residual stress measuring device (FLX2320 of Tencor). Then, heat curing treatment was performed at 250 ° C. 30 min and 400 ° C. 60 min in a nitrogen atmosphere to prepare a silicon wafer with a resin film having a thickness of 10 μm after curing. The residual stress generated between the silicon wafer and the resin film was measured using the Real Bow value, which measured the amount of warpage of the wafer using a residual stress measuring device.

As can be seen in Table 2, the haze of the polyimide films prepared in Examples 1 to 3 showed significantly lower values than the haze of the films prepared in Comparative Examples 1 and 2. Particularly, in the case of the polyimide film reacted with a 1: 1 equivalent ratio of Comparative Example 2, haze did not appear in the solution and the film.

In addition, the elongation of Examples 1 to 3 was measured to be higher than Comparative Examples 1 and 2, it can be seen that the polyimide film synthesized in the equivalent ratio of Examples 1 to 3 can exhibit more flexible characteristics.

The specific parts of the present invention have been described in detail above, and it is apparent to those skilled in the art that such specific descriptions are merely preferred embodiments, and thus the scope of the present invention is not limited thereto. something to do. Therefore, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (15)

And a polymerization product of a polymerization component comprising a diamine component including a diamine having a structure of Formula 1 and an amine-terminated methylphenylsiloxane oligomer, and an dianhydride component comprising two or more tetracarboxylic dianhydrides, wherein the polymerization Wherein the component comprises a dianhydride component and a diamine component in a ratio of 1: 1.01 to 1.05 equivalents:
[Formula 1]

. The method of claim 1,
The amine terminal methylphenylsiloxane oligomer has a structure for the polyimide film having the structure of formula (2):
[Formula 2]

In the above formula, p and q are mole fractions, where p is 70 to 90 and q is 10 to 30 when p + q = 100. The method of claim 1,
The dianhydride component is a polyimide precursor composition comprising biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA). The method of claim 3,
Wherein said dianhydride component comprises BPDA and PMDA in a molar ratio of 4: 6 to 8: 2. The method of claim 1,
The polyimide precursor composition comprising 5 to 30% by weight of the amine terminal methylphenylsiloxane oligomer based on the total weight of the polymerization component. The method of claim 1,
The polyimide precursor composition comprises a solvent, the viscosity is at least 2000cP polyimide precursor composition. The method of claim 5,
A polyimide precursor composition wherein the solvent is an organic solvent having a 25 ° C. partition coefficient LogP of 0.01 to 3. The polyimide film containing the imide of the polyimide precursor composition of Claims 1-7. The method of claim 8,
The polyimide film whose haze of the said polyimide film is one or less. The method of claim 8,
The polyimide film having a modulus of 2.2 GPa or less, a phosphorus strength of 80 MPa or less, and an elongation of 28% or more. The method of claim 8,
The glass transition temperature of the polyimide film is 380 to 410 ℃, the weight loss rate after holding at 350 ℃ for 60 minutes is less than 0.037%, the weight loss rate after holding at 380 ℃ for 60 minutes is less than 0.12% polyimide film . The method of claim 8,
The polyimide film having a residual stress of 25 MPa or less and a whip degree of 25 µm or less. A flexible device comprising the polyimide film of claim 8 as a substrate. Applying the polyimide precursor composition of claim 1 onto a carrier substrate;
Forming a polyimide film by imidating the polyimide precursor composition;
Forming an element on the polyimide film; And
Peeling the polyimide film formed with the device from the carrier substrate. The method of claim 14,
Wherein said flexible device manufacturing process comprises at least one process from the group consisting of an LTPS thin film manufacturing process, an ITO thin film manufacturing process, and an oxide thin film manufacturing process.