Acid anhydride compound, polyamide-imide resin and film using the same

Abstract

To provide an acid anhydride compound having a novel structure, which is a monomer allowing production of a highly heat-resistant, colorless, and transparent polyimide-based film, and a method of producing the same.SOLUTION: There is provided an acid anhydride compound represented by the following Chemical Formula 1. [Chemical Formula 1](In the Formula 1, R1 and R2 are independently of each other hydrogen, (C1 to C20)alkyl, fluoro(C1 to C20)alkyl, (C6 to C20)aryl, or (C3 to C20)heteroaryl, and at least one of the R1 and R2 is fluoro(C1 to C20)alkyl, (C6 to C20)aryl, or (C3 to C20)heteroaryl; and X1 is O or SO2).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an acid anhydride compound having a novel structure, and a polyamideimide resin and a polyamideimide film produced therefrom. [Background technology]

[0002] Recently, as display devices are developed in various forms, emphasis is being placed on making them lighter, slimmer, and more flexible, and attempts are ongoing to replace conventional glass substrates with polyimide films that are lighter, more flexible, and have excellent chemical resistance, etc. However, in order to apply polyimide films to display devices, it is essential to improve their inherent yellowness characteristics and impart colorless and transparent optical properties. In addition, flexible devices require high-temperature processes such as thin film transistors (TFTs) and organic deposition, so they must have excellent thermal dimensional stability to prevent deformation during high-temperature processes and to minimize the difference in expansion and contraction between different materials during high-temperature processes. For example, they must have thermal properties such as a low thermal expansion coefficient of 20 ppm / ℃ or less, which is similar to that of inorganic materials and metals used in TFTs, and a high glass transition temperature of 400℃ or more.

[0003] However, there is a trade-off between the optical properties and heat resistance of polyimide films, and imparting the colorless and transparent optical properties to polyimide films weakens their heat resistance and results in a large thermal expansion coefficient. For this reason, research is ongoing to develop colorless and transparent polyimide films that have high heat resistance and a low thermal expansion coefficient, but there is currently a limit to how much they can satisfy all of these requirements. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Korean Patent Publication No. 10-2014-0085064 (2014.07.07.) Summary of the Invention [Problem to be solved by the invention]

[0005] One aspect of the present invention provides an acid anhydride compound having a novel structure, which is a monomer capable of producing a highly heat-resistant, colorless, transparent polyimide film, and a method for producing the same. Another aspect of the present invention provides a polyamideimide resin and a polyamideimide film containing structural units derived from the novel acid anhydride compound. Another aspect of the present invention provides a flexible display element comprising the polyamideimide film. [Means for solving the problem]

[0006] One aspect of the present invention provides an acid anhydride compound represented by the following chemical formula 1:

[0007] [Chemical formula 1] [ka] (In the above Chemical Formula 1, R 1 and R 2 are each independently hydrogen, (C1-C20) alkyl, fluoro(C1-C20) alkyl, (C6-C20) aryl, or (C3-C20) heteroaryl, 1 and R 2 at least one of is fluoro(C1-C20)alkyl, (C6-20)aryl or (C3-C20)heteroaryl; X 1 is O or SO 2 It is.)

[0008] The acid anhydride compound according to one embodiment may be represented by the following Chemical Formula 2:

[0009] [Chemical formula 2] [ka] (In the above Chemical Formula 2, and n is an integer from 1 to 5.

[0010] According to one embodiment, the acid anhydride compound may be represented by the following Chemical Formula 3:

[0011] [Chemical formula 3] [ka]

[0012] Another aspect of the present invention provides a polyamideimide comprising a structural unit derived from an acid anhydride compound represented by the following Chemical Formula 1 and a structural unit derived from an aromatic diamine:

[0013] [Chemical formula 1] [ka] (In the above Chemical Formula 1, R 1 , R 2 and X 1 is the same as defined above.)

[0014] The polyamideimide according to one embodiment may include a repeating unit represented by the following Chemical Formula 5:

[0015] [Chemical formula 5] [ka] (In the above Chemical Formula 5, R 1 and R 2 are each independently hydrogen, (C1-C20) alkyl, fluoro(C1-C20) alkyl, (C6-C20) aryl, or (C3-C20) heteroaryl, 1 and R 2 at least one of is fluoro(C1-C20)alkyl, (C6-20)aryl, or (C3-C20)heteroaryl; X 1 is O or SO 2 and Ar1 and Ar 2 are each independently [ka] or [ka] and L is a single bond, -O-, -S-, -SO 2 L may be -, (C1-C7)alkylene, (C6-C12)arylene or a combination thereof, wherein the arylene and alkylene of L may be further substituted with one or more selected from (C1-C7)alkyl and halo(C1-C7)alkyl; R 11 ~R 13 are each independently (C1-C7)alkyl, (C1-C7)alkoxy or halo(C1-C7)alkyl; a to c each independently represent an integer of 0 to 2.

[0016] The polyamideimide according to one embodiment may include a repeating unit represented by the following formula 6:

[0017] [Chemical formula 6] [ka] (In the above Chemical Formula 6, Ar 1 and Ar 2 are each independently [ka] or [ka] and L is a single bond, -O-, -S- or -CR 14 R 15 - and R 11 ~R 15are each independently (C1-C3)alkyl or fluoro(C1-C3)alkyl; a to c each independently represent an integer of 0 to 2.

[0018] The Ar 1 and Ar 2 may each independently be selected from the following structures: [ka] [ka]

[0019] The polyamideimide according to one embodiment may include a repeating unit represented by the following Formula 7 or Formula 8:

[0020] [Chemical formula 7] [ka]

[0021] [Chemical formula 8] [ka]

[0022] The polyamideimide may have a number average molecular weight of 10,000 to 200,000 g / mol.

[0023] Another aspect of the present invention provides a method for producing polyamideimide, comprising the steps of reacting an acid anhydride compound represented by the following chemical formula 1 with an aromatic diamine represented by the following chemical formula A to produce a dicarboxylic acid compound represented by the following chemical formula 4 by imidization, and reacting the dicarboxylic acid compound represented by the following chemical formula 4 with an aromatic diamine represented by the following chemical formula B to produce a polyamideimide including a repeating unit represented by the following chemical formula 5.

[0024] [Chemical formula 1] [ka]

[0025] [Chemical formula 4] [ka]

[0026] [Chemical formula 5] [ka]

[0027] [Chemical formula A] [ka]

[0028] [Chemical formula B] [ka] (In the above formulas 1, 4, 5, A and B, R 1 , R 2 , X 1 , Ar 1 and Ar 2 is defined as in Chemical Formula 5 above).

[0029] Another aspect of the present invention provides a composition for forming a polyamideimide film, comprising the polyamideimide.

[0030] Another aspect of the present invention provides a polyamideimide film formed from the polyamideimide film-forming composition.

[0031] According to one embodiment, the polyamideimide film has a thickness of 1 to 20 μm and a glass transition temperature (T g ) may be 400° C. or higher.

[0032] The polyamideimide film according to one embodiment may have a coefficient of thermal expansion (CTE) of 20 ppm / ° C. or less, measured in a temperature range of 100 to 450° C. by a thermal deformation analysis (TMA) method.

[0033] The polyamideimide film according to one embodiment may have a yellowness index of 4 or less according to ASTM D1925.

[0034] Another aspect of the present invention provides a flexible display panel comprising the polyamideimide film.

[0035] Another aspect of the present invention provides a dicarboxylic acid compound represented by the following formula 4:

[0036] [Chemical formula 4] [ka] (In the above Chemical Formula 4, R 1 , R 2 , X 1 and Ar 1 is defined as in Chemical Formula 5 above). Effect of the Invention

[0037] The novel acid anhydride compound according to one embodiment can provide a polyamideimide film having excellent thermal and optical properties at the same time. Specifically, the polyamideimide film produced from the novel acid anhydride compound according to one embodiment can be colorless and transparent, as well as have a high glass transition temperature of 400°C or higher and a low thermal expansion coefficient of 20 ppm / °C or lower. That is, the polyamideimide film according to one embodiment is expected to be applicable as a substrate material for flexible display devices that are subjected to high temperature processes. [Brief description of the drawings]

[0038] [Figure 1] 1 is a photograph of the polyamideimide films produced in Examples 1 and 2. [Diagram 2] 1 is a graph showing the transmittance in the ultraviolet-visible light region of the polyamideimide films produced in Examples 1 and 2. [Diagram 3] 1 is a graph showing thermogravimetric analysis of the polyamideimide films produced in Examples 1 and 2 in a nitrogen environment (N2) and an air environment. [Figure 4] 1 is a differential scanning calorimeter analysis graph of the polyamideimide films produced in Examples 1 and 2. [Diagram 5] 1 is a thermomechanical analysis graph of the polyamideimide films produced in Examples 1 and 2. [Figure 6] 1 is a dynamic mechanical analysis graph of the polyamideimide films produced in Examples 1 and 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Unless otherwise defined herein, all technical and scientific terms have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. The terms used in the description of the present specification are for the purpose of effectively describing a particular embodiment and are not intended to limit the present invention.

[0040] As used herein, the singular forms "a," "an," and "the" can be intended to include the plural forms as well, unless the context indicates otherwise.

[0041] Additionally, numerical ranges used herein include lower and upper limits and all values ​​within that range, increments that are logically derived from the shape and width of the ranges defined, all doubly limited values, and all possible combinations of upper and lower limits of numerical ranges that are differently limited. Unless otherwise specified herein, values ​​outside the numerical ranges that may occur due to experimental error or rounding of values ​​are also included in the defined numerical ranges.

[0042] As used herein, the term "comprising" is an open-ended term having the same meaning as terms such as "comprising," "containing," "having," or "characterized by," and does not exclude further unrecited elements, materials, or processes.

[0043] As used herein, the term "alkyl" refers to an organic radical derived from an aliphatic hydrocarbon by removal of one hydrogen, and may include both linear and condensed forms. The alkyl may have 1-20 carbon atoms, specifically 1-15 carbon atoms, specifically 1-10 carbon atoms, specifically 1-7 carbon atoms, specifically 1-5 carbon atoms. The alkyl includes, by way of example only, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, ethylhexyl, and the like.

[0044] As used herein, the term "fluoroalkyl" may refer to an alkyl group in which at least one hydrogen atom has been replaced with a fluoro group (-F).

[0045] As used herein, the term "aryl" refers to an organic radical derived from an aromatic hydrocarbon by removal of one hydrogen, and includes single or fused ring systems containing from 4 to 7, preferably 5 or 6, ring atoms in each ring, as appropriate, and may include multiple aryls linked by single bonds. Examples include, but are not limited to, phenyl, naphthyl, biphenyl, terphenyl, and the like.

[0046] The term "heteroaryl" as used herein means a divalent organic radical derived by removing one hydrogen atom from a heteroaryl. The "heteroaryl" means an aryl group containing at least one heteroatom selected from N, O, S and Se as an aromatic ring skeletal atom, and the remaining aromatic ring skeletal atoms are carbon, and includes 5-6 membered monocyclic heteroaryls and polycyclic heteroaryls condensed with one or more benzene rings, which may be partially saturated. In addition, the heteroaryl in the present invention also includes a form in which one or more heteroaryls are linked by a single bond. Specific examples include monocyclic heteroaryls such as purine, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, isothiazolyl, isoxazolyl, oxazolyl, triazinyl, pyridyl, pyrazinyl, pyrimidinyl, and pyridazinyl; polycyclic heteroaryls such as benzofuranyl, benzothiophenyl, isobenzofuranyl, benzoimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, quinolyl, isoquinolyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, and benzocarbazolyl; and the like, but are not limited thereto.

[0047] The present invention will be specifically described below.

[0048] One aspect of the present invention provides an acid anhydride compound having a novel structure, which is a monomer capable of producing a highly heat-resistant, colorless, transparent polyimide film.

[0049] Specifically, the acid anhydride compound according to one embodiment can be represented by the following Chemical Formula 1.

[0050] [Chemical formula 1] [ka] (In the above Chemical Formula 1, R 1 and R 2are each independently hydrogen, (C1-C20) alkyl, fluoro(C1-C20) alkyl, (C6-C20) aryl, or (C3-C20) heteroaryl, 1 and R 2 at least one of is fluoro(C1-C20)alkyl, (C6-20)aryl, or (C3-C20)heteroaryl; X 1 O or SO 2 Yes.)

[0051] As an example, in the above formula 1, R 1 and R 2 are each independently hydrogen, (C1-C7) alkyl, fluoro(C1-C7) alkyl, (C6-C12) aryl, or (C3-C12) heteroaryl, 1 and R 2 At least one of may be fluoro(C1-C7)alkyl, (C6-12)aryl or (C3-C12)heteroaryl.

[0052] As an example, in the above Chemical Formula 1, R 1 and R 2 are the same as each other and may be fluoro(C1-C20)alkyl, specifically, perfluoro(C1-C20)alkyl, or perfluoro(C1-C7)alkyl.

[0053] Specifically, the acid anhydride compound according to one embodiment can be represented by the following Chemical Formula 2.

[0054] [Chemical formula 2] [ka] (In the above Chemical Formula 2, where n is an integer from 1 to 5.

[0055] For example, in the above Chemical Formula 2, n is an integer of 1 to 3, and may be 1 or 2.

[0056] More specifically, the acid anhydride compound according to one embodiment may be represented by the following Chemical Formula 3, but is not limited thereto.

[0057] [Chemical formula 3] [ka]

[0058] Another aspect of the present invention provides a polyamideimide comprising a structural unit derived from an acid anhydride compound represented by the following Chemical Formula 1:

[0059] [Chemical formula 1] [ka] (In the above Chemical Formula 1, R 1 , R 2 and X 1 is defined above).

[0060] That is, the acid anhydride compound according to one embodiment can be used as a monomer for producing a polyamideimide polymer, and can synthesize a polyamideimide by reacting with a diamine compound.

[0061] Specifically, the polyamideimide according to one embodiment may include a structural unit derived from an acid anhydride compound represented by Chemical Formula 1 and a structural unit derived from an aromatic diamine adjacent to each other, for example, may include a repeating unit represented by Chemical Formula 5 below.

[0062] [Chemical formula 5] [ka] (In the above Chemical Formula 5, R 1 and R 2 are each independently hydrogen, (C1-C20) alkyl, fluoro(C1-C20) alkyl, (C6-C20) aryl, or (C3-C20) heteroaryl, 1 and R2 at least one of is fluoro(C1-C20)alkyl, (C6-20)aryl or (C3-C20)heteroaryl; X 1 is O or SO 2 and Ar 1 and Ar 2 are each independently [ka] or [ka] and L is a single bond, -O-, -S-, -SO 2 L may be -, (C1-C7)alkylene, (C6-C12)arylene or a combination thereof, wherein the arylene and alkylene of L may be further substituted with one or more selected from (C1-C7)alkyl and halo(C1-C7)alkyl; R 11 ~R 13 are each independently (C1-C7)alkyl, (C1-C7)alkoxy or halo(C1-C7)alkyl; a to c each independently represent an integer of 0 to 2.

[0063] As an example, in the formula 5, R 1 and R 2 are each independently hydrogen, (C1-C7) alkyl, fluoro(C1-C7) alkyl, (C6-C12) aryl, or (C3-C12) heteroaryl, 1 and R 2 At least one of can be fluoro(C1-C7)alkyl, (C6-12)aryl, or (C3-C12)heteroaryl.

[0064] As an example, in the formula 5, 1 and R 2are the same as each other and may be fluoro(C1-C20)alkyl, specifically, perfluoro(C1-C20)alkyl, or perfluoro(C1-C7)alkyl.

[0065] Specifically, the polyamideimide according to one embodiment may contain a repeating unit represented by the following chemical formula 5-1.

[0066] [Chemical formula 5-1] [ka] (In the above Chemical Formula 5-1, n is an integer from 1 to 5; Ar 1 and Ar 2 is defined as in Chemical Formula 5 above).

[0067] For example, in the above Chemical Formula 5, n is an integer of 1 to 3, and may be 1 or 2.

[0068] Specifically, the polyamideimide according to one embodiment may include a repeating unit represented by the following chemical formula 6.

[0069] [Chemical formula 6] [ka] (In the above Chemical Formula 6, Ar 1 and Ar 2 are each independently [ka] or [ka] and L is a single bond, -O-, -S- or -CR 14 R 15 - and R 11 ~R 15are each independently (C1-C3)alkyl or fluoro(C1-C3)alkyl; a to c each independently represent an integer of 0 to 2.

[0070] As an example, the Ar 1 and Ar 2 can be independently selected from the following structures: [ka] [ka]

[0071] As an example, the polyamideimide according to one embodiment may include a repeating unit represented by the following Formula 7 or Formula 8, but is not limited thereto.

[0072] [Chemical formula 7] [ka]

[0073] [Chemical formula 8] [ka]

[0074] The number average molecular weight of the polyamideimide according to one embodiment may be 10,000 to 200,000 g / mol, or 50,000 to 200,000 g / mol, or 80,000 to 200,000 g / mol.

[0075] Hereinafter, a method for producing the polyamideimide according to one embodiment will be described. The organic solvent used therein is not limited, and the reaction time and temperature can be changed without departing from the spirit of the present invention.

[0076] According to one embodiment, the polyamideimide may be prepared by reacting an acid anhydride compound represented by the following formula 1 with an aromatic diamine represented by the following formula A to prepare a dicarboxylic acid compound represented by the following formula 4 through imidization, and reacting the dicarboxylic acid compound represented by the following formula 4 with an aromatic diamine represented by the following formula B to prepare a polyamideimide including a repeating unit represented by the following formula 5.

[0077] [Chemical formula 1] [ka]

[0078] [Chemical formula 4] [ka]

[0079] [Chemical formula 5] [ka]

[0080] [Chemical formula A] [ka]

[0081] [Chemical formula B] [ka] (In the above Chemical Formulas 1, 4, 5, A and B, R 1 , R 2 , X 1 , Ar 1 and Ar 2 is defined as in Chemical Formula 5 above).

[0082] Without intending to be bound by a particular theory, as an example, when the step of preparing the dicarboxylic acid compound represented by the above-mentioned Chemical Formula 4 is not included, the regularity of the monomer sequence in the polymer chain of the polyamideimide (acid anhydride compound-Ar 1 -Acid anhydride compound-Ar 2 ) cannot be ensured, and the thermal stability of the polyamideimide film in the future may decrease, making it difficult to achieve the physical properties aimed at in the present invention.

[0083] Another aspect of the present invention provides a composition for forming a polyamideimide film, comprising the polyamideimide.

[0084] Specifically, the polyamideimide film-forming composition according to one embodiment may contain the polyamideimide and an organic solvent.

[0085] The organic solvent contained in the composition is selected from the group consisting of ketones such as gamma-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, and 4-hydroxy-4-methyl-2-pentanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers (cellosolves) such as 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, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; and ethyl acetate, butyl acetate, and ethylene glycol monoethyl ether. The monomer may be one or a mixture of two or more selected from acetates such as ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, and dipropylene glycol monomethyl ether acetate; alcohols such as methanol, ethanol, propanol, ethylene glycol, propylene glycol, and carbitol; and amides such as N,N-dimethylpropionamide (DMPA), N,N-diethylpropionamide (DEPA), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide (DEAc), N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), and N,N-dimethylmethoxyacetamide, but is not limited thereto.

[0086] The polyamideimide film-forming composition according to one embodiment may have a solids (polyamideimide polymer) content of 5 wt % or more, or 10 wt % or more, based on the total weight of the composition, and specifically, may be 5 wt % to 50 wt %, or 10 wt % to 40 wt %, or 20 wt % to 40 wt %.

[0087] Another aspect of the present invention provides a polyamideimide film formed from the polyamideimide film-forming composition.

[0088] The polyamideimide film according to one embodiment may have a thickness of 1 to 500 μm, or 1 to 100 μm, or 1 to 50 μm, or 1 to 20 μm.

[0089] The polyamide-imide film has a glass transition temperature (T g ) is 400°C or more, and has very excellent thermal stability, and the coefficient of thermal expansion (CTE) measured in the temperature range of 100 to 450°C by thermal deformation analysis method (TMA method) may be 20 ppm / °C or less.

[0090] In other words, the polyamideimide film according to the working mode does not deform even in the high-temperature process required for flexible devices, and the difference in expansion and contraction between different materials in the high-temperature process can be minimized.

[0091] The polyamideimide film according to one embodiment may have a yellowness index according to ASTM D1925 of 5 or less, or 4 or less, or 3 or less.

[0092] That is, the polyamideimide film according to one embodiment can have high heat resistance and a low thermal expansion coefficient while being colorless and transparent, and is expected to be applicable as a substrate material for flexible display elements that are subjected to high temperature steps. EXAMPLES

[0093] The above-mentioned embodiments will be described in more detail with reference to the following examples, which are merely for illustrative purposes and are not intended to limit the scope of the invention.

[0094] [Physical property measurement method] (1) Horizontal bacterial molecular weight Measurements were performed using gel permeation chromatography (GPC). The column was PLgel MIXED-B 10 μm, the standard sample was polystyrene, and the solvent was tetrahydrofuran (THF). The sample was adjusted to a concentration of 5 mg / 10 mL at 30°C and a flow rate of 1.0 mL / min, and then 200 μL of the sample was supplied for measurement. (2) Yellowness Measurements were performed based on the ASTM D1925 standard. (3) Cutoff wavelength The transmittance was measured according to the ASTM D1003 standard, and the wavelength at which the transmittance began to appear was determined as the cutoff wavelength (λ 0 ) was decided. (4) Transmittance Based on the ASTM D1003 standard, the transmittance (T 400nm ) and transmittance for 550 nm wavelength (T 550nm ) were measured. (5) Thermal decomposition temperature (T d、5% ) Thermogravimetric analysis (TA Instruments, TGA Q50) was used. The measurement conditions were room temperature to 800°C, a heating rate of 5°C / min, and a pressure of 1.5 bar / min under nitrogen gas injection. The temperature at which a 5% mass loss occurred was determined as the thermal decomposition temperature (T d、5% ) was decided. (6) Glass transition temperature (T g ) Using isothermal differential scanning calorimetry (TAinstruments, DSC Q20), the temperature was increased and cooled from 0°C to 400°C at a rate of 10°C / min, and the measurement was performed using the value obtained the second time. (7) Coefficient of thermal expansion (CTE) The measurements were taken using a thermomechanical analyzer (Thermomechanical Analyzer, TA instruments, TMA-Q400). The average expansion coefficient was measured under conditions of a load of 0.01 N, a temperature range from room temperature to 450°C, and a heating rate of 5°C / min. (8) Alpha transition temperature (T α ) The measurements were performed using a dynamic mechanical analyzer (Dynamic Mechanical Analyzer, TA instruments, DMAQ800) based on the ASTM D4065 standard. The alpha transition temperature was measured under the conditions of a load of 0.01 N, a temperature range from room temperature to 450°C, a heating rate of 5°C / min, a frequency of 1 Hz, and an amplitude of 15 μm. Since the glass transition temperature was not observed up to 450°C with a differential scanning calorimeter, the alpha transition temperature observed at the same temperature as the glass transition temperature was measured.

[0095] [Production Example 1] Production of acid anhydride compounds [ka]

[0096] In a three-necked round-bottom flask, add 7.88 g of 4-bromo-1,2-dimethylbenzene, 4.00 g of 3-ethylphenol, and iron(III) acetylacetonate (Fe(acac) 3 ) 1.16g, copper iodide (CuI) 0.62g, potassium carbonate (K 2 CO 3 A reaction solution was prepared by adding 9.05 g of dimethylformamide (DMF) and 5 mL of anhydrous dimethylformamide (DMF). The reaction solution was stirred at 135° C. for 12 hours, and then extracted with hexane to obtain compound A-1.

[0097] Compound A-1 was added to a one-neck round-bottom flask together with 26.45 g of hexafluoroacetone trihydrate in a mixed solvent of 34 mL of dichloromethane (DCM) and 34 mL of triflic acid. After stirring at room temperature for 33 hours, the reaction solution was slowly poured into an aqueous solution of sodium hydroxide (NaOH) to neutralize it. The product was then extracted with diethylether to obtain a product, which was then stirred again at room temperature for 20 hours in a mixed solvent of 49.5 mL of dichloromethane (DCM) and 98.9 mL of triflic acid, and the reaction solution was then slowly poured into an aqueous solution of sodium hydroxide (NaOH) in the same manner to neutralize it, and then extracted with hexane to obtain compound A-2.

[0098] Compound A-2 was dissolved in a mixture of sodium hydroxide and potassium permanganate (KMnO 4 ), and then treated with a sulfuric acid aqueous solution of pH 1 to obtain a tricarboxylic acid compound, compound A-3. Compound 1-C was vacuum sublimated at 210°C to obtain an acid anhydride compound A (yield 15%).

[0099] 1 H-NMR (400MHz, Acetone-d 6 ), δ(ppm): 11.93(broad, COOH, 1H), 8.53(s, 1H), 8.17(d, J=8.6Hz, 1H), 8.08(s, 1H), 8.05(dd, J=8.6, 1.9Hz, 1H), 7.99(d, J=1.8Hz, 1H).

[0100] <Production of polyamide-imide resin> [Example 1] Production of dicarboxylic acid compounds [ka]

[0101] In a round-bottom flask, 8.57 g of the compound A, 3.17 g of 2,2'-bis(trifluoromethyl)benzidine, and 50 mL of dimethylacetamide were placed and stirred at room temperature for 12 hours while flowing nitrogen, after which 5.06 g of acetic anhydride and 5.56 g of DABCO were added and stirred for another 14 hours. The reaction solution was poured into a pH 1 aqueous solution, and the precipitate was dried to produce a dicarboxylic acid compound (yield 100%).

[0102] Manufacture of polyamide-imide resin [ka]

[0103] In a three-necked round-bottom flask, 379.52 mg (0.33 mmol) of the dicarboxylic acid compound obtained above and 105.70 mg (0.33 mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) were placed, and calcium chloride (CaCl 2 A reaction solution was prepared by adding 0.3 g of dimethylacetamide, 1 mL of triphenylphosphite (TPP), 1 mL of pyridine, and 5 mL of anhydrous N-methylpyrrolidone. The flask was equipped with a nitrogen inlet, an outlet, and a mechanical stirrer, and the reaction solution was stirred at 100°C for 8 hours. After the reaction was completed, the reaction solution was precipitated in a water:methanol=1:1 volume ratio solution, and the precipitated polymer was filtered, washed several times with methanol, and then dried in a vacuum oven at 80°C. The dried polymer was dissolved again in dimethylacetamide, precipitated in methanol, filtered, and dried in a vacuum oven at 180°C to obtain polyamideimide resin 1 of Example 1 (yield 100%). The number average molecular weight of the polyamideimide resin of Example 1 was 94,400 g / mol.

[0104] 1 H-NMR (DMF-d 7, 400MHz), δ(ppm): 11.31(s, amide, 1H), 10.83(s, amide, 1H), 8.81(s, 2H), 8.44(s, 2H), 8.33-8.21(m, 4 H), 8.28(s, 2H), 8.18-8.16(m, 6H), 8.08(d, J=7.7Hz, 2H), 7.85(d, J=8.6Hz, 2H), 7.47(d, J=8.9Hz, 2H).

[0105] [Example 2] [ka]

[0106] The polyamideimide resin of Example 2 was prepared in the same manner as in Example 1, except that 2,6-bis(trifluoromethyl)benzidine was used instead of 2,2'-bis(trifluoromethyl)benzidine (TFMB) in the preparation of the polyamideimide resin in Example 1 (yield 100%). The 2,6-bis(trifluoromethyl)benzidine was prepared by the method disclosed in Korean Patent Publication No. 10-2014-0085064, and the number average molecular weight of the obtained polyamideimide resin of Example 2 was 104,900 g / mol.

[0107] 1 H-NMR (DMF-d 7 , 400MHz), δ(ppm): 11.31(s, amide, 1H), 10.83(s, amide, 1H), 8.81(s, 2H), 8.44(s, 2H), 8.33-8.21(m, 4 H), 8.28(s, 2H), 8.18-8.16(m, 6H), 8.08(d, J=7.7Hz, 2H), 7.85(d, J=8.6Hz, 2H), 7.47(d, J=8.9Hz, 2H).

[0108] <Production of polyamideimide film> Each of the polyamideimide resins prepared in Example 1 and Example 2 was dissolved in N,N'-dimethylacetamide (DMAc) at 35% by weight to prepare a composition for forming a polyamideimide film. The composition was drop-cast onto a glass substrate, dried at 30°C for 12 hours, heat-treated at 200°C for 6 hours, and then cooled to room temperature. The film formed on the glass substrate was then separated from the substrate to obtain a polyamideimide film having a thickness of about 10 μm. The physical properties of the polyamideimide film were measured according to the methods described in the physical property measurement methods, and the results are shown in Table 1 below.

[0109] [Table 1]

[0110] As shown in Table 1, it was confirmed that the polyamideimide film prepared from the novel acid dianhydride compound according to one embodiment has high transmittance and low yellowness in the visible light region, and transmits light in a wide wavelength region. In addition, the polyamideimide film according to one embodiment has a high thermal decomposition temperature under both nitrogen and air conditions, has excellent thermal stability without affecting the environment, and has a low thermal expansion coefficient of 20 ppm / °C or less. In other words, the polyamideimide film according to one embodiment is not only colorless and transparent, but also does not deform even in high-temperature processes and can minimize the difference in expansion and contraction between different materials, and is expected to be usefully applied as a substrate material for flexible display elements.

[0111] As described above, the present invention has been described using specific details and limited examples, but this is provided to help understand the present invention more completely. The present invention is not limited to the above examples, and various modifications and variations can be made from these descriptions by those having ordinary knowledge in the field to which the present invention pertains.

[0112] Therefore, the concept of the present invention is not limited to the described embodiments, and all modifications equivalent to or equivalent to the scope of the claims, as well as the scope of the claims described below, fall within the scope of the concept of the present invention.

Claims

1. A polyamideimide comprising a structural unit derived from an acid anhydride compound represented by the following chemical formula 1 and a structural unit derived from an aromatic diamine. [Chemical formula 1] 【Chemistry 48】 (In the above Chemical Formula 1, R １ , R ２ and X １ is the same as defined in the first item of Chemical Formula 1.)

2. The polyamideimide according to claim 1 , comprising a repeating unit represented by the following formula 5: [Chemical formula 5] 【Chemistry 49】 (In the above Chemical Formula 5, R １ and R ２ are each independently hydrogen, (C1-C20) alkyl, fluoro(C1-C20) alkyl, (C6-C20) aryl, or (C3-C20) heteroaryl, １ and R ２ at least one of is fluoro(C1-C20)alkyl, (C6-20)aryl, or (C3-C20)heteroaryl; X １ is O or SO ２ and Ar １ and Ar ２ are each independently 【Chemistry 50】 【Chemistry 51】 L is a single bond, -O-, -S-, or -SO ２ -, (C1-C7) alkylene, (C6-C12) arylene or a combination thereof, wherein the arylene and alkylene of L may be further substituted with one or more selected from (C1-C7) alkyl and halo(C1-C7) alkyl; R １１ ~R １３ each independently is (C1-C7)alkyl, (C1-C7)alkoxy, or halo(C1-C7)alkyl; a to c are each independently an integer of 0 to 2.

3. The polyamideimide according to claim 2 , comprising a repeating unit represented by the following chemical formula 6: [Chemical formula 6] 【Chemistry 52】 (In the above Chemical Formula 6, Ar １ and Ar ２ are each independently 【Chemistry 53】 【Chemical 54】 L is a single bond, -O-, -S- or -CR １４ R １５ - and R １１ ~R １５ are each independently (C1-C3)alkyl or fluoro(C1-C3)alkyl; a to c each independently represents an integer of 0 to 2.

4. The Ar １ and Ar ２ The polyamideimide according to claim 3 , wherein each of the following structures is independently selected: 【Chemistry 55】 【Chemistry 56】

5. The polyamideimide according to claim 4 , comprising a repeating unit represented by the following Chemical Formula 7 or Chemical Formula 8: [Chemical formula 7] 【Chemistry 57】 【Chemistry 58】

6. The polyamideimide according to claim 5, wherein the number average molecular weight of the polyamideimide is 10,000 to 200,000 g / mol.

7. A step of reacting an acid anhydride compound represented by the following formula 1 with an aromatic diamine represented by the following formula A, and imidizing the reacted acid anhydride compound represented by the following formula 4 to prepare a dicarboxylic acid compound represented by the following formula 4: and reacting a dicarboxylic acid compound represented by chemical formula 4 with an aromatic diamine represented by chemical formula B below to produce a polyamideimide containing a repeating unit represented by chemical formula 5. [Chemical formula 1] 【Chemical 59】 【Chemistry 60】 【Chemistry 61】 【Chemistry 62】 【Chemistry 63】 (In the above chemical formulas 1, 4, 5, A and B, R １ , R ２ , X １ , Ar １ and Ar ２ is the same as the definition of Chemical Formula 5 in Claim 2.

8. A composition for forming a polyamideimide film, comprising the polyamideimide according to any one of claims 1 to 6.

9. A polyamideimide film formed from the polyamideimide film forming composition described in claim 8.

10. The polyamideimide film has a thickness of 1 to 20 μm and a glass transition temperature (T ｇ 10. The polyamideimide film according to claim 9, wherein the temperature at which the film is heated is 400° C. or higher.

11. The polyamideimide film according to claim 10, wherein the polyamideimide film has a coefficient of thermal expansion (CTE) of 20 ppm / °C or less, measured in a temperature range of 100 to 450°C by thermal deformation analysis (TMA Method).

12. 12. The polyamideimide film according to claim 11, wherein the polyamideimide film has a yellowness index according to ASTM D1925 of 4 or less.

13. A flexible display panel comprising the polyamideimide film of claim 9.

14. A dicarboxylic acid compound represented by the following chemical formula 4. [Chemical formula 4] 【Chemistry 64】 (In the above Chemical Formula 4, R １ , R ２ , X １ and Ar １ is the same as the definition of Chemical Formula 5 in Claim 2.

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