KR102054545B1 - Polyimide precursor solution and method for preparing polyimide film using same - Google Patents

Abstract

In the present invention, by bonding the end group having a specific structure to the end of the polyamic acid, the heat-resistance characteristics of the polyimide, in particular, heat shrinkage characteristics by heating and cooling can be significantly improved by crosslinking of the end groups. In addition, optical properties such as mechanical strength and haze and yellowness characteristics also provide excellent polyimide films. Polyimide film according to the present invention is excellent in mechanical strength and heat resistance, a substrate for a device, a cover substrate for display, an optical film, an integrated circuit (IC) package, an adhesive film, a multilayer FPC (flexible printed circuit), It can be used in various fields such as a tape, a touch panel, a protective film for an optical disk, and the like.

Description

POLYIMIDE PRECURSOR SOLUTION AND METHOD FOR PREPARING POLYIMIDE FILM USING SAME

The present invention relates to a method for producing a polyimide having improved heat resistance and a polyimide precursor solution for producing the same.

Polyimide (PI) is a polymer with relatively low crystallinity or mostly amorphous structure. It is easy to synthesize, can make thin film, and does not need a crosslinker for curing, but also has transparency and rigid chain structure. It is a polymer material with excellent heat resistance, chemical resistance, excellent mechanical properties, electrical properties and dimensional stability. It is widely used in electric and electronic materials such as automotive, aerospace, flexible circuit boards, liquid crystal alignment films for LCD, adhesives and coating agents. have.

However, polyimide does not satisfy the colorless and transparent property, which is a basic requirement for the display field, even though it is a high-performance polymer material with high thermal stability, mechanical properties, chemical resistance, and electrical properties. There is a problem to do. For example, Kapton's coefficient of thermal expansion, sold by DuPont, has a low coefficient of thermal expansion of about 30 ppm / ° C, but this also does not meet the requirements of plastic substrates. Therefore, many studies have been conducted to minimize optical characteristics and thermal hysteresis while maintaining basic characteristics of polyimide.

In general, aromatic polyimides have a unique color of dark brown because of the charge transfer complex (CT-complex) in which π electrons of benzene present in the imide main chain are formed by the interchain linkage. The theory can be explained by the reason that σ electrons, π electrons, and nonbonding non-covalent electron pairs exist in the imide structure, thereby enabling electron excitation.

In general, polyimide absorbs light in the visible range between wavelengths of 400 nm or less and 500 nm, and has a color of yellow to red. Therefore, in order to lower CT-complex, which is a disadvantage of aromatic polyimide, an electronegative element such as trifluoromethyl (-CF ₃ ), sulfone (-SO ₂ ), and ether (-O-) is used in this main chain. There is a method of reducing the resonance effect by limiting the transfer of π electrons by introducing, and also by introducing an olefin-based cycloolefin structure instead of benzene to reduce the density of π electrons in the main chain to form a colorless and transparent polyimide film. There is a method of manufacturing.

On the other hand, polyamideimide has been widely used as an industrial material for electric, electronic, mechanical and aviation fields since it is excellent in heat resistance, mechanical strength, electrical characteristics, and the like. In addition, since the structure itself is different from general polyimide, polyamideimide is known to be soluble in an organic solvent, and is also used for applications in which solution molding is necessary, such as enamel varnish, coating for electrical insulation, and paint.

However, there is a need for the development of polymers for flexible displays having a more optimized coefficient of thermal expansion, high solubility, transparency and thermal stability for use in the display field.

The problem to be solved by the present invention is to provide a polyimide precursor solution for producing a polyimide film with improved heat shrinkage characteristics.

Another object of the present invention is to provide a method for producing a polyimide film prepared from the polyimide precursor solution and a polyimide film prepared therefrom.

The present invention to solve the above technical problem,

Polyamic acid produced by polymerizing a polymerization component comprising at least one tetracarboxylic dianhydride and at least one diamine; And

It provides a polyimide precursor solution containing a compound represented by the following formula (1).

[Formula 1]

In Chemical Formula 1,

Q is selected from an alkyl group having 1 to 10 carbon atoms, a halogen group, a hydroxyl group, a cyano group, an alkoxy group having 1 to 10 carbon atoms and a haloalkyl group having 1 to 10 carbon atoms,

n is an integer of 0-3.

According to one embodiment, the compound of Formula 1 may be included in 0.1 to 0.5 mole parts relative to 100 mole parts of the tetracarboxylic dianhydride.

According to one embodiment, the Q may be selected from a halogen group, a hydroxy group, a haloalkyl group having 1 to 10 carbon atoms.

According to one embodiment, the compound of Formula 1 may be a compound represented by the following formula (1a).

[Formula 1a]

In Formula 1a, Q is the same as defined in Formula 1.

According to one embodiment, the tetracarboxylic dianhydride may be added in excess relative to the content of the diamine so that the terminal of the polyamic acid is an anhydride group.

According to one embodiment, the molar ratio of the tetracarboxylic dianhydride and diamine may be 1: 0.98 to 1: 0.999.

According to an embodiment, the anhydride group of the polyamic acid and the amino group of Formula 1 may react to include a polyamic acid formed with a terminal group of the formula (10).

[Formula 10]

In Chemical Formula 10,

Q and n are the same as defined in Formula 1,

X is a tetravalent organic group derived from the said tetracarboxylic dianhydride.

According to one embodiment, the polyimide precursor solution may further comprise an alkoxy silane, the residual stress of the support comprising a polyimide prepared by imidizing the polyimide precursor solution is -5 MPa or more and 10 MPa or less, The absorbance at 308 nm of the diethylacetamide (DEAc) solution containing 0.001 mass% of the alkoxy silane compound may be 0.1 or more and 0.5 or less at a measurement thickness of 1 cm.

In order to solve the other problem of the present invention,

Applying a polyimide precursor solution onto the substrate;

It provides a method for producing a polyimide film comprising the step of heat-treating the applied polyimide composition at 300 to 500 ℃.

According to one embodiment, the cross-linking between the polyimide molecules may be formed by the reaction of Scheme 1 in the heat treatment step.

Scheme 1

In the above reaction scheme,

Q and X are the same as defined in the formula (10).

According to one embodiment, in the heat treatment step, the imidization by the ring-closure reaction of the polyamic acid and the reaction of Scheme 1 may occur together.

According to one embodiment, the heat treatment step occurs step by step,

A first heat treatment step in which imidization by a ring closure reaction of the polyamic acid and a dehydration polymerization reaction of Scheme 1 occur;

It may include a second heat treatment step in which intermolecular crosslinking occurs by the decarbonation reaction of Scheme 1.

In addition, the present invention provides a polyimide film produced by the above production method.

According to an embodiment, the polyimide film may have a haze of 1 or less and a yellowness of 15 or less in a range of 8 to 20 μm in thickness.

According to an embodiment, the tensile strength of the polyimide film may be 260 MPa or more at an elongation of 25% or more, and a thermal expansion coefficient of -12 to 15 ppm / ° C.

In addition, the present invention provides a display device including the polyimide film.

In the present invention, by bonding the end group having a specific structure to the end of the polyamic acid, the heat-resistance characteristics of the polyimide, in particular, heat shrinkage characteristics by heating and cooling can be significantly improved by crosslinking of the end groups. In addition, optical properties such as mechanical strength and haze and yellowness characteristics also provide excellent polyimide films. Polyimide film according to the present invention is excellent in mechanical strength and heat resistance, a substrate for a device, a cover substrate for display, an optical film, an integrated circuit (IC) package, an adhesive film, a multilayer FPC (flexible printed circuit), It can be used in various fields such as a tape, a touch panel, a protective film for an optical disk, and the like.

1 is a result of measuring the dimension change (dimension change) in the primary heating and cooling process of the polyimide film according to the Examples and Comparative Examples.

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 the organic group is a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, and a hydroxy group And substituted with a substituent selected from the group consisting of alkoxy groups, carboxylic acid groups, aldehyde groups, epoxy groups, cyano groups, nitro groups, amino groups, sulfonic acid groups and derivatives thereof having 1 to 10 carbon atoms.

In addition, in the present specification, 'combination thereof' unless otherwise specified, a single bond, a double bond, a triple bond, an alkylene group having 1 to 10 carbon atoms (for example, methylene group (-CH _2- ), Ethylene groups (-CH ₂ CH _2- ) and the like, fluoroalkylene groups having 1 to 10 carbon atoms (e.g., fluoromethylene groups (-CF _2- ), perfluoroethylene groups (-CF ₂ CF _2- ); ), Heteroatoms such as N, O, P, S, or Si or functional groups containing the same (e.g., intramolecular carbonyl group (-C = O-), ether group (-O-), ester group ( Or a heteroalkylene group including -COO-), -S-, -NH- or -N = N- or the like) or two or more functional groups are condensed.

Flexible displays have increased market demand due to their light structure, light weight, and thinness. However, flexible devices with high temperature processes require heat resistance at high temperatures, particularly in the case of organic light emitting diode (OLED) devices using oxide TFTs and low temperature polycrytalline silicon (LTPS) processes. It may be close to 500 ° C.

Generally, when polymerizing a polyimide for a substrate, the ratio which makes the diamine which is a monomer and the dianhydride more diamine is used. However, polyimide is advantageous in terms of viscosity and molecular weight stability of various defects such as inorganic film cracking and film lifting by inducing residual stress on the polymerized polymer with excessive diamine. It exhibits shrinkage behavior and may cause problems in high temperature heat treatment processes.

In the present invention, to solve the above problems,

Polyamic acid produced by polymerizing a polymerization component comprising at least one tetracarboxylic dianhydride and at least one diamine; And

It provides a polyimide precursor solution containing a compound represented by the following formula (1).

[Formula 1]

In Chemical Formula 1,

Q is an alkyl group having 1 to 10 carbon atoms, a halogen group (-F, -Cl, -Br, -I), a hydroxy group (-OH), a cyano group (-CN), an alkoxy group having 1 to 10 carbon atoms and a 1 to 10 carbon atoms It is selected from haloalkyl group of, preferably may be selected from a halogen group, a hydroxy group, a cyano group and a haloalkyl group having 1 to 5 carbon atoms,

n is an integer of 0-3.

According to an embodiment, the compound of Formula 1 may be a compound represented by Formula 1a, and Formula 1a may be suitable for obtaining higher reactivity and higher mechanical strength by crosslinking.

[Formula 1a]

In Formula 1a, Q is the same as defined in Formula 1.

According to one embodiment the tetracarboxylic dianhydride may be one or more compounds selected from compounds comprising the structure of Formula 2,

[Formula 2]

In Chemical Formula 2,

X may be a tetravalent organic group including an aliphatic ring having 3 to 24 carbon atoms or an aromatic ring having 6 to 30 carbon atoms. Specifically, the aromatic ring or aliphatic structure may be a single ring structure, and each ring may be It may be a tetravalent organic group including a structure bonded by a single bond or a heterocyclic structure in which each ring is directly connected, or a structure in which each ring is connected to each other through a crosslinking structure, for example, of Formulas 2a to 2n The tetravalent organic group may be selected from, but is not limited thereto, and preferably, may be a tetravalent organic group including a wholly aromatic structure.

At least one hydrogen atom in the tetravalent organic group of Formulas 2a to 2i may be an alkyl group having 1 to 10 carbon atoms (eg, methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, pentyl group, hexyl group, etc.), Fluoroalkyl groups having 1 to 10 carbon atoms (e.g., fluoromethyl groups, perfluoroethyl groups, trifluoromethyl groups, etc.), aryl groups having 6 to 12 carbon atoms (e.g., phenyl groups, naphthalenyl groups, etc.), It may be substituted with a substituent selected from the group consisting of a sulfonic acid group and a carboxylic acid group, preferably substituted with a fluoroalkyl group having 1 to 10 carbon atoms.

According to one embodiment, the diamine compound may be at least one compound selected from compounds comprising a structure comprising the following formula (3),

[Formula 3]

In Chemical Formula 3,

Y is each independently an aliphatic, alicyclic or aromatic divalent organic group having 4 to 30 carbon atoms, or a combination thereof, and an aliphatic, alicyclic or aromatic divalent organic group is directly connected, or It is a structure selected from divalent organic groups connected to each other via a crosslinked structure. For example, the Y may be a monocyclic or polycyclic aromatic having 6 to 30 carbon atoms, a monocyclic or polycyclic alicyclic having 6 to 30 carbon atoms, or a structure in which two or more thereof are connected by a single bond or a crosslinking bond, Or a divalent organic group including a heterocyclic structure in which each ring is directly connected, and preferably a diamine including a wholly aromatic structure. For example, it may be a divalent organic group represented by Chemical Formulas 3a to 3i, but is not limited thereto.

According to one embodiment of the invention, in the synthesis reaction of the tetracarboxylic dianhydride and diamine, the tetracarboxylic dianhydride may be reacted in excess compared to the content of the diamine, for example, the tetracar The acid dianhydride and the diamine may be reacted in a molar ratio of 1: 0.98 to 1: 0.999, preferably a molar ratio of 1: 0.99 to 1: 0.999, more preferably a molar ratio of 1: 0.995 to 1: 0.999. Can be reacted with.

According to one embodiment, the polyimide precursor solution may further comprise an alkoxy silane compound, the alkoxy silane compound may be selected from those represented by the following formula (4a) to 4d.

[Formula 4a]

 [Formula 4b]

[Formula 4c]

[Formula 4d]

According to an embodiment, the absorbance at 308 nm of a DEAc solution having a residual stress of a support including a polyimide prepared by imidating the polyimide precursor is -5 MPa or more and 10 MPa or less and 0.001 mass% of the alkoxy silane compound. The solution thickness may be 0.1 or more and 0.5 or less at 1 cm. The absorbance of the alkoxy silane compound 0.001% by mass DEAc solution may be filled into a quartz cell having a measurement thickness of 1 cm, and measured by UV-1600 (manufactured by Shimadzu Corporation).

The alkoxy silane compound,

It can be synthesized by reacting with an acid dianhydride and a trialkoxy silane compound, a reaction with an acid anhydride and a trialkoxy silane compound, or a reaction with an amino compound and an isocyanate trialkoxy silane compound. It may be preferred that the acid anhydrides, anhydrides and amino compounds each have an aromatic ring (especially a benzene ring).

The content of the alkoxy silane compound may be appropriately adjusted in a range in which sufficient adhesiveness and peeling performance are expressed, and preferably, the alkoxy silane compound may be included in an amount of 0.01 to 20% by weight based on 100% by weight of the polyimide. The resin film obtained in the range whose content of the alkoxy silane compound with respect to 100 weight% of polyimides is 0.01 mass% or more can acquire the outstanding adhesive force with a support body. In addition, it may be preferable from the viewpoint of the storage stability of the resin composition that the content of the alkoxy silane compound is 20% by weight or less. The content of the alkoxy silane compound may be 0.02 to 15% by weight, preferably 0.05 to 10% by weight, more preferably 0 0.1 to 8% by weight relative to the polyimide.

The method for reacting the tetracarboxylic dianhydride with the diamine can be carried out according to a conventional polyimide precursor polymerization production method such as solution polymerization. Specifically, a polyamic acid can be produced by dissolving diamine in an organic solvent, followed by polymerization by adding tetracarboxylic dianhydride and dicarboxylic acid or dicarboxylic chloride to the resultant mixed solution.

According to the present invention, a polyamic acid having a terminal group represented by the following Chemical Formula 10 may be prepared by further adding a compound of the following Chemical Formula 1 to a polyamic acid in which an excess of tetracarboxylic dianhydride is reacted to form a dianhydride group at an end thereof.

[Formula 10]

In Chemical Formula 10,

Q and n are the same as defined in Formula 1,

X is a tetravalent organic group derived from the said tetracarboxylic dianhydride.

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

In addition, the polymerization temperature may be carried out at -20 to 60 ℃, preferably 0 to 45 ℃. If the reaction temperature is too high, the reactivity may be increased to increase the molecular weight, it may be disadvantageous in the process by increasing the viscosity of the precursor solution.

In addition, as the organic solvent that can be used in the polymerization reaction, specifically, gamma-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy- Ketones such as 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 Acetamide (DMAc), N, N-diethylacetamide, dimethylformamide (DMF), diethylformamide (DEF), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), 1,3-dimethyl-2-imidazolidinone, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, pyridine, dimethyl sulfone, hexamethylphosphoramide, tetramethylurea, N-methylcaprolactam, tetrahydro Furan, m-dioxane, P-dioxane, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- ( 2-methoxyethoxy)] ether, Equamide M100, ethylene Id (Equamide) may be used be selected from B100 and mixtures thereof.

Preferably, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, Acetamide solvents such as N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone, N-ethylpyrrolidone (NEP), and N-vinyl-2-pyrrolidone Phenolic solvents such as phenol, o-, m- or p-cresol, xylenol, halogenated phenol, catechol, or hexamethylphosphoramide, γ-butyrolactone, and the like.

In addition, the number average molecular weight of the polyimide according to the present invention may be 20,000 to 200,000 g / mol, or 20,000 to 100,000 g / mol, or 25,000 to 80,000 g / mol, and the weight average molecular weight is 40,000 to 200,000 g / mol Or 40,000 to 100,000 g / mol, or 50,000 to 100,000 g / mol. When the weight average molecular weight or the number average molecular weight distribution of the polyimide is outside the above range, film formation may be difficult or the characteristics of the polyimide film such as permeability, heat resistance and mechanical properties may be deteriorated.

The polyimide precursor solution 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 may be the reaction solution itself obtained. The reaction solution may be diluted with another solvent. Moreover, when a polyimide precursor is obtained as a solid powder, it may be made to melt | dissolve this in the organic solvent and set it as the solution.

Subsequently, the polyimide precursor obtained as a result of the polymerization reaction is imidated, whereby a transparent polyimide film can be produced. In this case, the imidization process may specifically include a chemical imidization method or a thermal imidization method.

It is preferable that the polyimide precursor solution manufactured by the above-mentioned manufacturing method contains solid content in the quantity which makes the said composition have appropriate viscosity in consideration of processability, such as applicability | paintability in the film formation process. According to one embodiment, the content of the solid content may be adjusted to a content of at least 5% by weight, or at least 8% by weight of the polyimide precursor solution, up to 20% by weight, preferably 18% by weight or less, more preferably It can be adjusted to 16% by weight or less.

Alternatively, the polyimide precursor solution may be adjusted to have a viscosity of 2,000 cP or more, or 3,000 cP or more, preferably 4,000 cP or more, and the viscosity of the polyimide precursor solution may be 15,000 cP or less, preferably 12,000 cP or less, More preferably, it is adjusted to have a viscosity of 10,000 cP or less. When the viscosity of the polyimide precursor solution is high, the efficiency of degassing during the processing of the polyimide film is lowered, so that not only the efficiency of the process but also the produced film may be poor in surface roughness due to bubble generation, thereby deteriorating electrical, optical and mechanical properties. .

The polyimide precursor solution may be applied to a substrate and heat treated on an IR oven, a hot air oven or a hot plate, and the heat treatment temperature may be 300 ° C. to 500 ° C., preferably 300 ° C. to 450 ° C., for example, 300 ° C. It may be in the temperature range to 400 ℃, it may be carried out by a multi-stage heating treatment within the temperature range. The heat treatment process may be performed for 20 minutes to 70 minutes, preferably 20 minutes to 60 minutes or so.

In the polyimide precursor solution according to the present invention, at the same time as the ring-closure reaction of the polyamic acid in the heat treatment process, crosslinking by the terminal of Formula 10 formed on the polyamic acid may be formed.

For example, cross-linking by-(C = O) -O- (C = O)-is formed by the dehydration condensation of the carboxylic acid functional group at the end of Chemical Formula 10, and the crosslinking is continued in the subsequent heat treatment. Decarbonation reactions such as a decarbonation reaction and a decarbonation reaction may occur from the groups to form radicals in the terminal groups, and terminal group crosslinks may be formed by the bonding of the radicals.

More specifically, the crosslinking reaction by the heat treatment may be represented by the following Scheme 1.

Scheme 1

According to one embodiment, the heat treatment reaction may occur in stages, for example, the first heat treatment step of the imidization by the ring-closure reaction of the polyamic acid and the dehydration polymerization reaction of Scheme 1;

It may include a secondary heat treatment step in which the intermolecular cross-linking occurs by the de-carbon dioxide and carbon monoxide reaction of Scheme 1, wherein the maximum temperature of the second heat treatment step may be higher than the temperature of the first heat treatment step.

The organic solvent contained in the polyimide precursor solution of the present invention may be the same as the organic solvent used in the synthesis reaction.

As long as this invention is a range which does not impair an effect, you may add a silane coupling agent, a crosslinking | crosslinked compound, the imidation promoter for the purpose of advancing imidation efficiently, etc.

Therefore, in another embodiment of the present invention, an article including the polyimide film is provided.

The molded article may be a film, a fiber, a coating material, an adhesive material, but is not limited thereto. The molded article may be formed by a dry wet method, a dry method, a wet method, etc. using the composite composition of the copolymer and the inorganic particles, but is not limited thereto. Specifically, as described above, the molded article may be an optical film, in which case, the composition comprising the polyimide copolymer is easily applied by a method such as spin coating on a substrate, and then dried and cured. Can be prepared.

The present invention also provides a polyimide film having a high heat shrinkage behavior (negative CTE value) due to cooling during heating and cooling process, thereby forming crosslinks between molecular chains by end groups formed by the compound of Formula 1, By improving the heat resistance of the polyimide film, not only the heat shrinkage behavior can be alleviated, but also the mechanical strength of the film can be enhanced.

For example, the polyamide film according to the present invention may have a coefficient of thermal expansion of −12 to 15 ppm / ° C. after n + 1 heating and cooling steps in a temperature range of 100 ° C. to 450 ° C., preferably Preferably it may be a value of -11 to 12 ppm / ℃, more preferably -10 to 10 ppm / ℃.

In addition, the polyimide film has a modulus of about 5.0 GPa or more, or about 5 to 9 GPa, and the tensile strength may be 260 MPa or more, preferably 270 MPa or more at an elongation of 25% or more.

The polyimide according to the present invention can improve or maintain not only heat resistance as described above, but also mechanical properties due to crosslinking, optical properties such as yellowness and haze characteristics from substituents substituted at terminal groups, and thus, substrates and displays for devices. It can be used in various fields such as cover substrate, optical film, integrated circuit (IC) package, adhesive film, multilayer FPC (flexible printed circuit), tape, touch panel, protective film for optical disk, etc. .

According to another embodiment of the present invention provides a display device including the molded article. Specifically, the display device may include a liquid crystal display device (LCD), an organic light emitting diode (OLED), and the like, and particularly, a low temperature polycrystalline silicon (LTPS) requiring a high temperature process. It may be suitable for OLED devices using the process, but is not limited thereto.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice 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.

The abbreviations indicated below are as follows.

A3BBA: 4-amino-3-bromobenzoic acid

A3HBA: 4-amino-3-hydroxybenzoic acid

A2HBA: 4-amino-2-hydroxybenzoic acid

A2TFMBA: 4-amino-2- (trifluoromethyl) benzoic acid

3,4-BTFMA: 3,4-bis (trifluoromethyl) aniline (3,4-bis (trifluoromethyl) aniline)

DEAc: diethylacetamide (N, N-diethylacetamide)

TFMB: 2,2'-bis (trifluoromethyl) -4,4'-biphenyl diamine (2,2'-bis (trifluoromethyl) -4,4'-biphenyl diamine)

PMDA: Pyromellitic Dianhydride

BPDA: 3,3,4,4'-biphenyltetracarboxylic dianhydride (3,3 ', 4,4' '-Biphenyltetracarboxylic dianhydride)

a-BPDA: 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride (2,3,3', 4'-Biphenyltetracarboxylic dianhydride)

Example 1 a-BPDA (0.1) BPDA (0.2) PMDA (0.7) / TFMB (0.999) + A3BBA (0.002)

After filling 90 g of the organic solvent DEAc in the stirrer through which the nitrogen stream flowed, 16.7 g of TFMB was dissolved while maintaining the temperature of the reactor at 25 ° C. To the TFMB solution, 1.54 g of a-BPDA, 3.08 g of BPDA, and 8.0 g of PMDA were added at the same temperature, followed by stirring for a predetermined time to prepare a polyamic acid. 0.0226 g of A3BBA was added to the polyamic acid solution, followed by stirring for a period of time to obtain a polyimide precursor solution.

The organic solvent was added to prepare a polyimide precursor solution so that the solid concentration of the polyimide precursor solution prepared from the reaction was 14 to 14.5 wt%.

The viscosity of the polyimide precursor solution was 7,413 cP, and the molecular weight of the prepared polyimide precursor was Mn 30,700 g / mol and Mw 58,700 g / mol.

Example 2 a-BPDA (0.1) BPDA (0.2) PMDA (0.7) / TFMB (0.999) + A3HBA (0.002)

After filling 90 g of the organic solvent DEAc in the stirrer through which the nitrogen stream flowed, 16.7 g of TFMB was dissolved while maintaining the temperature of the reactor at 25 ° C. To the TFMB solution, a-BPDA 1.54, BPDA 3.08 g, and PMDA 8.0 g were added at the same temperature, dissolved for a predetermined time, and stirred to prepare a polyamic acid. 0.013 g of A3HBA was added to the polyamic acid solution, followed by stirring for a period of time to obtain a polyimide precursor solution.

The organic solvent was added to prepare a polyimide precursor solution so that the solid concentration of the polyimide precursor solution prepared from the reaction was 14 to 14.5 wt%. The viscosity of the polyimide precursor solution was 8,800 cP, the molecular weight of the prepared polyimide precursor was Mn 27,200 g / mol, Mw 61,257 g / mol.

Example 3 a-BPDA (0.1) BPDA (0.2) PMDA (0.7) / TFMB (0.999) + A2HBA (0.002)

After filling 90 g of the organic solvent DEAc in the stirrer through which the nitrogen stream flowed, 16.7 g of TFMB was dissolved while maintaining the temperature of the reactor at 25 ° C. To the TFMB solution, a-BPDA 1.54, BPDA 3.08 g, and PMDA 8.0 g were added at the same temperature, dissolved and stirred for a predetermined time to prepare a polyamic acid. 0.012 g of A2HBA was added to the polyamic acid solution, followed by stirring for a predetermined time to obtain a polyimide precursor solution.

The organic solvent was added to prepare a polyimide precursor solution so that the solid concentration of the polyimide precursor solution prepared from the reaction was 14 to 14.5 wt%. The viscosity of the polyimide precursor solution was 7,980 cP, the molecular weight of the prepared polyimide precursor was Mn 34,175 g / mol, Mw 59,954 g / mol.

Example 4 a-BPDA (0.1) BPDA (0.2) PMDA (0.7) / TFMB (0.999) + A2TFMBA (0.002)

After filling 90 g of the organic solvent DEAc in the stirrer through which the nitrogen stream flowed, 16.7 g of TFMB was dissolved while maintaining the temperature of the reactor at 25 ° C. To the TFMB solution, a-BPDA 1.54, BPDA 3.08 g, and PMDA 8.0 g were added at the same temperature, dissolved for a predetermined time, and stirred to prepare a polyamic acid. 0.0215 g of A2TFMBA was added to the polyamic acid solution, followed by stirring for a period of time to obtain a polyimide precursor solution.

The organic solvent was added to prepare a polyimide precursor solution so that the solid concentration of the polyimide precursor solution prepared from the reaction was 14 to 14.5 wt%. The viscosity of the polyimide precursor solution was 6,696 cP, the molecular weight of the prepared polyimide precursor was Mn 30,778 g / mol, Mw 57,220 g / mol.

Comparative Example 1 a-BPDA (0.1) BPDA (0.2) PMDA (0.7mol) / TFMB (0.999mol)

After filling 90 g of the organic solvent DEAc in the stirrer through which the nitrogen stream flowed, 16.7 g of diamine TFMB was dissolved while maintaining the temperature of the reactor at 25 ° C. 1.54 g of dihydrate a-BPDA, 3.08 g of BPDA, and 8.0 g of PMDA were added to the diamine TFMB solution at the same temperature to obtain a polyimide precursor solution after stirring for a predetermined time.

The organic solvent was added to prepare a polyimide precursor solution so that the solid concentration of the polyimide precursor solution prepared from the reaction was 13 to 13.5 wt%. The viscosity of the polyimide precursor solution was 4,500 cP, the molecular weight of the prepared polyimide precursor was Mn 20,892 g / mol, Mw 53,245 g / mol.

Comparative Example 2 a-BPDA (0.1) BPDA (0.2) PMDA (0.7) / TFMB (0.999) + 3,4-BTFMA

After filling 90 g of the organic solvent DEAc in the stirrer through which the nitrogen stream flowed, 16.7 g of diamine TFMB was dissolved while maintaining the temperature of the reactor at 25 ° C. To the diamine TFMB solution, 1.54 g of dihydrate a-BPDA, 3.08 g of BPDA, and 8.0 g of PMDA were added at the same temperature to dissolve and stir for a predetermined time to prepare a polyamic acid. 0.0240 g of 3,4-BTFMA was added to the polyamic acid solution, followed by stirring for a predetermined time to obtain a polyimide precursor solution.

The organic solvent was added to prepare a polyimide precursor solution so that the solid concentration of the polyimide precursor solution prepared from the reaction was 14 to 14.5 wt%. The viscosity of the polyimide precursor solution was 10,390 cP, the molecular weight of the prepared polyimide precursor was Mn 37,000 g / mol, Mw 67,000 g / mol.

Experimental Example 1

The polyimide precursor solutions prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were 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 3 ° C./min, and the curing process was performed by maintaining the mixture at 80 ° C. for 10 minutes and 1 hour at 430 ° C. After completion of the curing process, the glass substrate was immersed in water, the film formed on the glass substrate was removed and dried at 100 ° C. in an oven to prepare a film of polyimide.

For each polyimide film prepared above, the transmittance, yellowness, mechanical strength, and the like were measured in the same manner as shown in Table 1 and Table 2.

The transmittance was measured for the wavelengths of 450 nm, 550 nm and 633 nm with a transmittance meter (model name HR-100, manufactured by Murakami Color Research Laboratory) in accordance with JIS K 7105.

Yellowness Index (YI) was measured using a color difference meter (Color Eye 7000A).

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

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

After fabricating three to four types of dumbbell shaped specimens in accordance with ASTM D 412, the modulus (Gpa) and tensile strength (MPa) of each resin film were measured at 50 mm / min using Zwick / Roell Zwick / Z010 model equipment. ) Was measured.

Tg and coefficient of thermal expansion (CTE) were measured using TMA (Q400 from TA).

Specifically, the prepared polyimide film to prepare a size of 5 x 20 mm and then load the sample using the accessories. The length of the film actually measured was made the same at 16 mm. After setting the film pulling force to 0.02N and proceeding the first temperature increase step at a temperature increase rate of 4 ℃ / min in the temperature range of 100 ℃ to 450 ℃, cooling at 4 ℃ / min in the temperature range of 450 ℃ to 100 ℃ The pattern of thermal expansion change when cooling at a rate was measured by TMA (Q400 by TA). The measurement results are shown in Tables 1, 2 and FIG.

Analysis item Example 1
(A3BBA) Example 2
(A3HBA) Example 3
(A2HBA) Example 4
(A2TFMBA) Film thickness (㎛) 10.3 10.3 10.5 10.5 Tg (℃) 355 358 359 360 Td 1% (℃) 542.8 548.3 550.5 551.4 Permeability (%) 450 nm 75.8 77.4 76.1 72.9 550nm 86.1 86.6 86.2 85.4 633 nm 87.5 87.9 87.7 87.3 YI 11.6 13.0 13.3 13.6 Haze (%) 0.48 0.57 0.53 0.47 CTE (ppm / ° C) -9.7 -9.2 -10.1 -10.3 Modulus (GPa) 6.9 7.1 7.2 7.1 Tensile Strength (MPa) 279 285 280 290

Analysis item Comparative Example 1 Comparative Example 2
(3,4-BTFMA) Film thickness (㎛) 10.7 9.6 Tg (℃) 353 349 Td 1% (℃) 541 543.5 Permeability (%) 450 nm 75.5 75.6 550nm 86.2 86.1 633 nm 87.8 87.8 YI 15.4 12.5 Haze (%) 0.76 0.78 CTE (ppm / ° C) -14 -9.9 Modulus (GPa) 7.2 6.8 Tensile Strength (MPa)
@ 25% elongation 240 250

Polyimide film according to the present invention from the results of Table 1 and Table 2 has a terminal group as shown in Formula 1, as shown in Figure 1 shrinkage characteristics by the heating and cooling process compared to the polyimide film of Comparative Example 1 Not only can this be significantly improved, but mechanical strength such as tensile strength can also be improved together. In addition, it can be seen from the result of Comparative Example 2 that the polyimide film having sufficient mechanical strength cannot be obtained from the structure of Comparative Example 2, in which there is no crosslinkable functional group.

The polyimide according to the present invention can provide a polyimide film having improved heat resistance and mechanical strength while maintaining colorless and transparent properties.

Example 5 TFMB (0.98) / PMDA (0.85) _6FDA (0.15) / A2TFMBA (0.002) + alkoxy silane

After filling with 100g of N, N-diethylacetamide (DEAc) in a stirrer with nitrogen stream, TFMB (2,2`-bis (trifluoromethyl) -4,4`-biphenyl diamine) while maintaining the reactor temperature at 25 ℃ 12 g were dissolved. 7 g of pyromellitic dianhydride (PMDA) and 2.5 g of 6FDA (4,4 '-(Hexafluoroisopropylidene) diphthalic anhydride) were added to the TFMB solution at the same temperature to dissolve and stir for a predetermined time to prepare a polyamic acid. A2TFMBA was added to the polyamic acid solution in an amount of 0.002 mol and stirred to prepare a polyimide precursor solution. DEAc was added so that the solid content concentration of the polyimide precursor solution was 10 to 10.5% by weight to prepare a polyimide precursor solution. The viscosity of the polyimide precursor solution was 6,300 cps.

50 ml of the flask was nitrogen-substituted, 19.5 g of DEAc was added, 2.42 g (7.5 mmol) of BTDA (benzophenone tetracarboxylic anhydride) and 3.321 g of 3-aminopropyl triethoxysilane (trade name: LS-3150, manufactured by Shin-Etsu Chemical Co., Ltd.) (15 mmol) was added and reacted for 5 hours at room temperature to obtain an alkoxy silane compound solution.

At this time, the DEAc solution which makes the said alkoxy silane compound into 0.001 mass% was filled in the quartz cell of measuring thickness 1cm, and the absorbance when measured by UV-1600 (made by Shimadzu Corporation) was 0.13.

10 g of the polyimide precursor solution and the alkoxy silane compound were stirred well in a vessel to prepare a polyimide precursor solution containing an alkoxy silane.

Experimental Example 2

The adhesiveness, laser peeling property, and YI (thickness conversion of 10 micrometers thickness) which measured the polyimide precursor solution containing the alkoxy silane of the said Example 5 by the method described below are shown in Table 3, respectively.

Adhesive
(gf / inch) Laser intensity
(mJ / cm ² ) Particle Generation
YI Example 5 870 220 none 13.8

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 (16)

A polyamic acid produced by polymerizing a polymerization component comprising at least one tetracarboxylic dianhydride and at least one diamine;
A polyimide precursor solution comprising a polyimide precursor obtained by reacting a compound represented by the following Formula 1, wherein the weight average molecular weight of the polyimide precursor is 40,000 to 200,000.
[Formula 1]

In Chemical Formula 1,
Q is selected from a halogen group and a haloalkyl group having 1 to 10 carbon atoms,
n is an integer of 0-3. The method of claim 1,
The compound of Formula 1 is contained in 0.1 to 0.5 mole parts relative to 100 mole parts of the tetracarboxylic dianhydride. The method of claim 1,
The tetracarboxylic dianhydride includes biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, and the diamine is 2,2'-bis (trifluoromethyl) -4,4'-biphenyldiamine Polyimide precursor solution comprising a. The method of claim 1,
The polyimide precursor solution of the compound of Formula 1 is a compound represented by the formula (1a):
[Formula 1a]

In Formula 1a, Q is selected from a halogen group and a haloalkyl group having 1 to 10 carbon atoms. The method of claim 1,
The said tetracarboxylic dianhydride is added in excess compared with diamine so that the terminal of the said polyamic acid is an anhydride group. The method of claim 5,
The molar ratio of the tetracarboxylic dianhydride and diamine is 1: 0.98 to 1: 0.999 polyimide precursor solution. The method of claim 1,
A polyimide precursor solution comprising a polyamic acid in which an anhydride group of the polyamic acid reacts with an amino group of Formula 1 to form a terminal group of Formula 10:
[Formula 10]

In Chemical Formula 10,
Q and n are the same as defined in Formula 1,
X is a tetravalent organic group derived from the said tetracarboxylic dianhydride. The method of claim 1,
As a polyimide precursor solution which further contains an alkoxysilane compound,
The absorbance at 308 nm of the DEAc solution containing 0.001 mass% of the residual stress of the support including the polyimide precursor solution prepared by imidating the polyimide precursor is -5 MPa or more and 10 MPa or less, and the measurement thickness of the solution The polyimide precursor solution which is 0.1 or more and 0.5 or less in 1 cm. Applying a polyimide precursor solution according to any one of claims 1 to 8 on a substrate;
Method of producing a polyimide film comprising the step of heat-treating the applied polyimide composition at 300 to 500 ℃. The method of claim 9,
Method for producing a polyimide film that crosslinking is formed between the polyimide molecules by the reaction of Scheme 1 in the heat treatment step:
Scheme 1

In Reaction Scheme 1,
Q is selected from a halogen group and a haloalkyl group having 1 to 10 carbon atoms,
X is a tetravalent organic group derived from tetracarboxylic dianhydride. The method of claim 9,
In the heat treatment step, the imidation by the ring-closure reaction of the polyamic acid and the reaction of the reaction scheme 1 occurs together. The method of claim 9,
The heat treatment is carried out in stages,
A first heat treatment step in which imidization by a ring closure reaction of the polyamic acid and a dehydration polymerization reaction of Scheme 1 occur;
Method of producing a polyimide film comprising a second heat treatment step in which intermolecular crosslinking occurs by the decarbonation reaction of Scheme 1. Polyimide film prepared by the manufacturing method according to claim 9. The method of claim 13,
The said polyimide film is the range of thickness of 8-20 micrometers, haze is 1 or less, and yellowness is 15 or less polyimide film. The method of claim 13,
The polyimide film has a tensile strength of 260 MPa or more and a thermal expansion coefficient of -12 to 15 ppm / ° C at a elongation of 25% or more. Display device comprising the polyimide film according to claim 13.

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