Novel diamine compounds and polyimide polymer derived therefrom

Abstract

The present invention relates to a novel diamine compound and a polyimide-based polymer derived therefrom, wherein the diamine compound is represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, A1, A2, A3 and A4 are identical or different from each other and each independently are organic groups comprising one or more substituted or unsubstituted aromatic rings, X is a fluorine or fluorine-substituted alkyl group, and n represents the number of X substituted on the benzene ring.

Description

Technology Field

[0001] The present invention relates to a novel diamine compound and a polyimide-based polymer derived therefrom, and more specifically, to a novel diamine compound, a method for preparing the same, and a polyimide-based polymer capable of producing a film with excellent flexibility and heat resistance obtained by polymerizing the novel diamine compound as a monomer. Background Technology

[0003] Polyimide possesses advantages such as ease of synthesis, the ability to form thin films, and the elimination of the need for crosslinking agents for curing. Consequently, driven by the recent trend toward lighter and more precise electronic products, it is being widely applied as an integration material in semiconductor materials, including Liquid Crystal Displays (LCDs) and Plasma Display Panels (PDPs). Furthermore, significant research is underway to utilize polyimide in flexible plastic display substrates, which possess lightweight and flexible properties.

[0004] A polyimide film is produced by forming the above-mentioned polyimide into a film. Generally, polyimide is manufactured by solution polymerizing an aromatic dianhydride with an aromatic diamine or an aromatic diisocyanate to produce a polyamic acid derivative solution, then coating this solution onto a silicon wafer or glass, and curing it through heat treatment.

[0005] These polyimide-based polymers are prepared by dissolving them in a high-boiling point organic solvent, applying them to a substrate in the form of polyamic acid which is a precursor of polyimide, and then heat-treating them at a temperature of 300°C or higher for a long time to dehydrate and imidize them.

[0006] However, the dehydration and imidization reactions of the aforementioned polyamic acid involve heating at high temperatures for an extended period, which leads to degradation. Furthermore, insufficient heating results in residual polyamic acid within the structure of the manufactured polyimide-based polymer, causing a decline in properties such as moisture resistance and corrosion resistance.

[0007] Accordingly, a method was proposed to produce a polyimide-based polymer film by applying a polyimide-based polymer solution dissolved in an organic solvent to a substrate and then heating to volatilize the solvent [Japanese Patent Publication No. Hei 2-36232]. However, the polyimide-based polymer film produced by the above method had the disadvantage of low solvent resistance.

[0008] In addition, a thermosetting polyimide-based polymer composition [Japanese Patent Publication No. Hei 10-195278] was disclosed for producing a polyimide-based polymer film with excellent adhesion and solvent resistance by heat treatment at a low temperature for a short period of time. However, the above thermosetting resin had the disadvantage of not exhibiting sufficient heat resistance or having low transparency, which limited its fields of application. Prior art literature

[0011] Republic of Korea Publication No. 10-2013-0094738 A The problem to be solved

[0012] In order to solve the aforementioned problems,

[0013] One objective of the present invention is to provide a novel diamine compound.

[0014] One objective of the present invention is to provide a polyimide-based polymer derived from the novel diamine compound.

[0015] One objective of the present invention is to provide a polyimide film prepared from the novel diamine compound having excellent flexibility and heat resistance. means of solving the problem

[0017] A diamine compound according to one embodiment of the present invention is represented by the following chemical formula 1.

[0018] [Chemical Formula 1]

[0019]

[0020] In the above chemical formula 1, A1, A2, A3 and A4 are identical or different from each other and each independently are organic groups comprising one or more substituted or unsubstituted aromatic rings, X is a fluorine or fluorine-substituted alkyl group, and n represents the number of X substituted on the benzene ring.

[0021] A diamine compound according to one embodiment may be a diamine compound represented by the following chemical formula 1-A.

[0022] [Chemical Formula 1-A]

[0023]

[0024] In the above chemical formula 1-A, A1, A2, A3, and A4 are as defined in the above chemical formula 1.

[0025] The diamine compound according to one embodiment may be any one of the compounds represented by the following chemical formulas 1-A-1 to 1-A-6.

[0026] [Chemical Formula 1-A-1]

[0027]

[0028] [Chemical Formula 1-A-2]

[0029]

[0030] [Chemical Formula 1-A-3]

[0031]

[0032] [Chemical Formula 1-A-4]

[0033]

[0034] [Chemical Formula 1-A-5]

[0035]

[0036] [Chemical Formula 1-A-6]

[0037]

[0038] A diamine compound according to one embodiment may be a monomer derived from a polyimide-based polymer.

[0039] A diamine compound according to one embodiment may include repeating units represented by the following chemical formula 2.

[0040] [Chemical Formula 2]

[0041]

[0042] In the above chemical formula 2, A1, A2, A3, A4, X, and n are as defined in the above chemical formula 1, and Y is a tetravalent organic group.

[0043] A diamine compound according to one embodiment may include a repeating unit represented by the following chemical formula 2-A.

[0044] [Chemical Formula 2-A]

[0045]

[0046] In the above chemical formula 2-A, A1, A2, A3, A4, and Y are as defined in the above chemical formula 2.

[0047] A polyimide film according to one embodiment may include the polyimide-based polymer.

[0048] A device according to one embodiment may include the polyimide film. Effects of the invention

[0050] When a diamine compound of the novel structure according to the present invention is used as a monomer, there is an advantage in that a polyimide film with excellent flexibility and heat resistance can be manufactured.

[0051] Accordingly, the polyimide film according to the present invention is useful for color filters in semiconductor devices, protective films for light-emitting diodes and laser diodes, liquid crystal alignment films, liquid crystal display devices, flexible substrates for optical devices, and other fields of electronics and optics. Specific details for implementing the invention

[0053] Expressions such as "comprising" as used in this specification should be understood as open-ended terms implying the possibility of including other configurations.

[0054] As used herein, "preferably" and "preferably" refer to embodiments of the invention that can provide certain advantages under certain conditions, and are not intended to exclude other embodiments from the scope of the invention.

[0055] The singular form used in this specification is intended to include the plural form unless specifically indicated otherwise in the context.

[0057] A diamine compound according to one embodiment is represented by the following chemical formula 1.

[0058] [Chemical Formula 1]

[0059]

[0060] In the above chemical formula 1, A1, A2, A3 and A4 are identical or different from each other and are each independently organic groups comprising one or more substituted or unsubstituted aromatic rings.

[0061] Here, 'aromatic ring' refers to an aromatic organic compound composed of a conjugated planar ring, which may be a monocyclic aromatic ring such as a benzene ring, or a polycyclic aromatic ring such as a naphthalene ring, anthracene ring, phenanthrene ring, or chrysen ring.

[0062] In addition, the above 'aromatic ring' may be a heteroaromatic ring containing a non-carbon atom, for example, oxygen, nitrogen, or sulfur, in the aromatic ring. In this case, examples may include furan, benzofuran, isobenzofuran, pyrrole, indole, isoindole, thiophene, benzothiophene, imidazole, benzimidazole, purine, pyrazol, indazole, oxazole, benzoxazole, isooxazole, benzisooxazole, thiazole, benzothiazole, pyridine, quinoline, isoquinoline, pyrazine, quinoxaline, acridine, pyrimidine, quinazolin, pyridazine, cinnoline, phthalazine, triazine, azonine, etc.

[0063] Here, the meaning that A1, A2, A3 and / or A4 'contains' an aromatic ring is that the aforementioned aromatic ring exists alone or is connected to other organic functional groups within the chemical structure.

[0064] As an example, A1, A2, A3 and / or A4 may include only one aromatic ring. For example, they may include the following organic groups.

[0065]

[0066] As an example, A1, A2, A3 and / or A4 may comprise a structure in which two or more aromatic rings are directly bonded. For example, they may comprise the following organic groups.

[0067] , ,

[0068] Additionally, in one embodiment, A1, A2, A3 and / or A4 may comprise a structure in which two or more aromatic rings are connected through an organic group. For example, two benzene rings may be connected to an ether group, a straight-chain, branched-chain, or cyclic-chain substituted or unsubstituted alkylene group, -CO group, -SO group, or -SO2 group, etc. For example, they may comprise the following organic groups.

[0069] , , ,

[0070] , , ,

[0071] , ,

[0072] , , ,

[0073] In this specification, the meaning of ‘substituted or unsubstituted’ is that it is substituted or unsubstituted with one or more substituents selected from the group consisting of deuterium; halogen; nitrile group; nitro group; hydroxyl group; carbonyl group; ester group; imide group; amine group; amino group; phosphine oxide group; alkoxy group; aryloxy group; alkylthioxy group; arylthioxy group; alkyl sulfoxy group; aryl sulfoxy group; silyl group; boron group; alkyl group; cycloalkyl group; alkenyl group; aryl group; aralkyl group; aralkenyl group; alkylaryl group; alkylamine group; aralkylamine group; heteroarylamine group; arylamine group; arylphosphine group; or heterocyclic group, or that it is substituted or unsubstituted with two or more of the exemplified substituents connected together.

[0074] In the above chemical formula 1, X is fluorine or a fluorine-substituted alkyl group. An example of a fluorine-substituted alkyl group may be a fluormethyl group as the fluorine-substituted alkyl group.

[0075] In the above chemical formula 1, n represents the number of X substituted on the benzene ring, and n is a natural number from 1 to 4. For the sake of understanding, for example, if n is 4, it means that 4 X are substituted on the benzene ring.

[0076] In one embodiment, the two -O-substituents bonded to the benzene ring may be bonded to each other at the ortho, meta, or para positions, and more preferably at the para position.

[0077] In one embodiment, the diamine compound can be represented by the following chemical formula 1-1.

[0078] [Chemical Formula 1-1]

[0079]

[0080] In the above Chemical Formula 1-1, A1, A2, A3, and A4 are as defined in Chemical Formula 1. In this case, X is a fluorine group.

[0081] A diamine compound according to one embodiment may be a diamine compound represented by the following chemical formula 1-A.

[0082] [Chemical Formula 1-A]

[0083]

[0084] In the above chemical formula 1-A, A1, A2, A3, and A4 are as defined in the above chemical formula 1.

[0085] The diamine compound according to one embodiment may be any one of the compounds represented by the following chemical formulas 1-A-1 to 1-A-6.

[0086] [Chemical Formula 1-A-1]

[0087]

[0088] [Chemical Formula 1-A-2]

[0089]

[0090] [Chemical Formula 1-A-3]

[0091]

[0092] [Chemical Formula 1-A-4]

[0093]

[0094] [Chemical Formula 1-A-5]

[0095]

[0096] [Chemical Formula 1-A-6]

[0097]

[0098] A novel diamine compound according to one embodiment can be prepared by various manufacturing methods.

[0099] A diamine compound according to one embodiment may be a monomer derived from a polyimide-based polymer.

[0100] In this case, the meaning of a monomer derived from a polyimide-based polymer is that the above-mentioned diamine compound is used as a monomer for synthesizing a polyimide-based polymer.

[0101] Here, the term "polyimide-based polymer" means one that includes polyimide, polyimide precursors (i.e., polyamic acid or polyamic acid esters), and polyamide.

[0102] In addition, the above diamine compound may be used for manufacturing a polyimide film. The above diamine compound is used as a monomer for synthesizing a polyimide-based polymer, and can be used to manufacture a polyimide film containing the polyimide-based polymer synthesized thereby.

[0103] In addition, as a more preferred embodiment, the polyimide-based polymer can be prepared through a polymerization reaction of a diamine compound and an acid dianhydride.

[0104] In this case, the polyimide-based polymer may further include repeating units derived from acid dianhydride in addition to repeating units derived from the diamine compound.

[0105] As a more desirable example, a tetracarboxylic acid dianhydride may be used as the acid dianhydride polymerized with the diamine compound.

[0106] It is preferable to use a tetracarboxylic acid dianhydride that is uncolored or one that is difficult to form charge transfer complexes known as the cause of coloration. Additionally, an aliphatic tetracarboxylic acid dianhydride or alicyclic tetracarboxylic acid dianhydride is preferred due to its excellent transparency, but an aromatic tetracarboxylic acid dianhydride with better heat resistance may also be used within the range of uncolored.

[0107] For example, aliphatic tetracarboxylic acid dianhydrides include, for example, butane-1,2,3,4-tetracarboxylic acid dianhydride or pentane-1,2,4,5-tetracarboxylic acid dianhydride, and alicyclic tetracarboxylic acid dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, cyclohexane-1,2,4,5-tetracarboxylic acid dianhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic acid dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic acid dianhydride, etc.

[0108] Examples of aromatic tetracarboxylic acid dianhydrides include pyromellitic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic acid dianhydride, 4,4'-hexafluoropropylidene bisphthalic acid dianhydride, and 3,3',4,4'-diphenylsulfone tetracarboxylic acid dianhydride.

[0109] In addition, aliphatic tetracarboxylic acid dianhydrides having an aromatic ring, such as 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione and 1,3,3a,4,5,9b-hexahydro-5-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, may also be used.

[0110] In one embodiment, such tetracarboxylic acid dianhydrides can be used alone or in combination of two or more types.

[0111] A polyimide-based polymer according to one embodiment may include repeating units represented by the following chemical formula 2.

[0112] [Chemical Formula 2]

[0113]

[0114] In the above chemical formula 2, A1, A2, A3, A4, X, and n are as defined in the above chemical formula 1, and Y is a tetravalent organic group.

[0115] In the above chemical formula 2, the organic group of Y refers to a substituent having four bonding positions, and means including all general organic functional groups.

[0116] As an example, it may be an organic group containing an aromatic compound.

[0117] As an example, the above Y is , , or It may be, but is not limited to this.

[0118] The above Y may be derived from an acid anhydride that polymerizes with the above diamine compound.

[0119] In one embodiment, when there are N repeating units represented by the above chemical formula 2, N may be a natural number selected from 10 to 10000, but is not limited thereto.

[0120] In one embodiment, the polyimide-based polymer may include repeating units represented by the following chemical formula 2-1. In this case, X is a fluorine group.

[0121] [Chemical Formula 2-1]

[0122]

[0123] In Chemical Formula 2-1 above, A1, A2, A3, and A4 are as defined in Chemical Formula 1 above. In this case, X is a fluorine group.

[0124] In one embodiment, the polyimide-based polymer may include repeating units represented by the following chemical formula 2-A.

[0125] [Chemical Formula 2-A]

[0126]

[0127] In the above chemical formula 2-A, A1, A2, A3, A4, and Y are as defined in the above chemical formula 2.

[0128] In one embodiment, the polyimide-based polymer may include one or more repeating units represented by the following chemical formulas 2-A-1 to 2-A-6.

[0129] [Chemical Formula 2-A-1]

[0130]

[0131] [Chemical Formula 2-A-2]

[0132]

[0133] [Chemical Formula 2-A-3]

[0134]

[0135] [Chemical Formula 2-A-4]

[0136]

[0137] [Chemical Formula 2-A-5]

[0138]

[0139] [Chemical Formula 2-A-6]

[0140]

[0141] According to one embodiment of the present invention, when polymerizing a polyimide precursor, one or more additional diamine compounds may be mixed and used in addition to the diamine compound. For example, a diamine compound comprising a monocyclic or polycyclic aromatic divalent organic group having 6 to 24 carbon atoms, a monocyclic or polycyclic alicyclic divalent organic group having 6 to 18 carbon atoms, or a structure in which two or more of these are connected by a single bond or a functional group may be additionally used. Alternatively, a diamine compound comprising a ring structure such as aromatic or alicyclic, either alone or fused with a heterocyclic ring structure, or a structure in which two or more of these are connected by a single bond may be additionally used.

[0142] In this case, the polyimide-based polymer may further include repeating units derived from the diamine compound mixed together, in addition to the repeating units derived from the diamine compound.

[0143] In addition, various monomers, additives, etc. required for the synthesis of polyimide-based resins may be applied without limitation as needed, even if not exemplified in this specification.

[0144] Meanwhile, a polyamic acid or a polyamic acid ester may be formed as a precursor compound prior to the formation of the polyimide, wherein the polyimide precursor may include repeating units derived from the diamine compound.

[0145] In addition, as one embodiment, the polyimide precursor may further include repeating units derived from acid dianhydride.

[0146] In addition, as one embodiment, the polyimide precursor may further include repeating units derived from other diamine compounds in addition to repeating units derived from the diamine compound.

[0147] In addition, various monomers, additives, etc. required for the synthesis of polyimide precursors may be applied without limitation as needed, even if not exemplified in this specification.

[0148] A method for preparing a polyimide-based polymer resin according to one embodiment of the present invention may use either a single-stage polymerization method in which the diamine and tetracarboxylic acid dianhydride are polymerized only at a high temperature in the presence of a solvent, or a two-stage polymerization method in which an amic acid is synthesized at a low temperature first and then imidized at a high temperature.

[0149] In one embodiment, the ratio of diamine to tetracarboxylic acid dianhydride can be appropriately adjusted according to the molecular weight of the polyimide-based polymer resin, etc. According to one embodiment, the diamine is preferably in a molar ratio of 0.95 to 1.05, more preferably 0.98 to 1.02.

[0150] In addition, monofunctional raw materials such as phthalic anhydride and aniline may be added to adjust the molecular weight of the polyimide-based polymer resin. In this case, the amount of the added raw material is preferably 2 mol% or less relative to the polyimide-based polymer resin.

[0151] In the case of a single-stage polymerization method, the reaction temperature can be 150°C to 300°C, and the reaction time can be 1 to 15 hours. In addition, in the case of a two-stage polymerization method, polyamic acid synthesis can be performed at a temperature of 0°C to 120°C for 1 to 100 hours, and imidization can be performed at a temperature of 0°C to 300°C for 1 to 15 hours.

[0152] According to one embodiment, it is preferable that the solvent usable during synthesis has compatibility with the raw material diamine, tetracarboxylic acid dianhydride, and the product polyimide-based polymer resin. Specifically, phenols such as phenol, 4-methoxypheno-4-methoxyphenol, 2,6-dimethylphenol, and m-cresol; ethers such as tetrahydrofuran and anisole; ketones such as cyclohexanone, 2-butanone, methylisobutylketone, 2-heptanone, 2-octanone, and acetophenone; esters such as butyl acetate, methyl benzoate, and γ-butyrolactone; cellosolves such as butyl cellosolve acetate and propylene glycol monomethyl ether acetate; and amides such as N,N-dimethylformamide, N,N-dimethylacetoamide, and N-methyl-2-pyrrolidone may be used.

[0153] In addition, when aromatic hydrocarbons such as toluene and xylene are used in combination, the water generated during imidization is easily removed by azeotrope. These solvents may be used alone or in a mixture of two or more.

[0154] In one embodiment, when at least two types of at least one of the diamine and tetracarboxylic acid dianhydride are used, a method of mixing all the raw materials in advance and then polycondensing them together, or a method of reacting the two or more types of aromatic diamines or tetracarboxylic acid dianhydrides used individually and adding them in sequence may be used.

[0155] In addition, a method may be used in which a dehydrating agent and an imidization catalyst are added during the imidization process, and the imidization is carried out by heating as necessary. The dehydrating agent may be an acid anhydride, such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. It is preferable to use such a dehydrating agent in an amount of 1 to 10 moles per mole of diamine.

[0156] The above imidization catalyst may be a tertiary amine such as pyridine, colidine, rutidine, or triethylamine. It is preferable to use such an imidization catalyst in an amount of 0.5 to 10 moles per mole of dehydrating agent.

[0157] Since the polyimide-based polymer resin according to the present invention has excellent solubility, it is possible to dissolve it in an organic solvent and adjust the viscosity to a suitable level so that it can be easily coated on various substrates.

[0158] Organic solvents capable of dissolving the above-mentioned polyimide-based polymer resin may be, for example, general organic solvents used in the synthesis of polyimide-based polymer resins, aromatic hydrocarbon solvents different from those used in synthesis, ketone solvents, etc. Among these, when dissolving in low-boiling point aromatic hydrocarbon solvents or ketone solvents, etc., they may be used when dissolving the purified polyimide resin again by methods such as adding a non-solvent to the prepared polyimide resin solution to re-precipitate it.

[0159] In one embodiment, the substrate on which the polyimide-based polymer resin can be coated may be, for example, a metal such as iron, copper, nickel, or aluminum; an inorganic material such as glass; or an organic resin such as an epoxy resin or an acrylic resin.

[0160] In addition, as one embodiment, the thermosetting properties can be further improved by adding a substance that reacts with phenolic groups to the polyimide-based polymer resin prepared above. Examples of substances that react with phenolic groups include polyfunctional organic compounds such as resins and oligomers containing two or more functional groups capable of reacting with phenolic groups, such as carboxyl groups, amino groups, and epoxy groups.

[0161] The present invention also provides a polyimide film having excellent flexibility and heat resistance, manufactured by curing the polyimide-based polymer resin.

[0162] The above curing can be performed under normal conditions, and specifically, it is preferable to perform it at a temperature of 80°C to 300°C, preferably 100°C to 250°C. If the curing temperature is below 80°C, the curing time is long, resulting in low practicality, and problems with storage stability may arise when selecting equipment used at low temperatures. In addition, unlike conventional polyamic acid solutions, it does not require heating at a high temperature higher than 300°C for a long time after application, so thermal degradation of the substrate can be suppressed.

[0163] The above polyimide film may have a transmittance of 80% or more in the 400 to 700 nm range (visible light) when the film thickness is 10 μm, a temperature at which the weight of the film decreases by 5% is 300°C or higher, and a thermal decomposition initiation temperature of 300°C or higher.

[0164] The present invention provides a device comprising the polyimide film as a substrate, in particular, a flexible device. The flexible device may be, for example, a thin-film transistor, a liquid crystal display (LCD), electronic paper, an organic EL display, a plasma display panel (PDP), an IC card, etc., but is not limited thereto.

[0165] The structure and manufacturing method of the above device are in accordance with known contents.

[0167] The present invention will be described in more detail below through examples. These examples are intended solely to explain the present invention more practically, and it will be obvious to those skilled in the art that the scope of the present invention is not limited by these examples according to the gist of the invention.

[0169] Examples and Comparative Examples

[0170] Manufacturing of polyimide-based polymers

[0171] 0.2 moles of the tetracarboxylic acid dianhydride of Table 1 below and 200 g of dimethylacetylamide (DMA) were added to a flask equipped with a stirrer, thermometer, dropping device, and nitrogen purging device, and dissolved by heating to 50°C and stirring. Subsequently, 0.2 moles of the following aromatic diamine were dissolved in 200 g of dimethylacetylamide (DMA) at room temperature, then added dropwise using a dropping funnel for 1 hour, and stirred at 50°C for 5 hours.

[0172] A portion of the reaction mixture was dissolved in DMSO-d6 solvent, and NMR was measured to confirm that no diamine was present in the reactants. Conversely, IR measurements confirmed the formation of polyamic acid.

[0173] Specifically, the reacted diamine compound and tetracarboxylic acid dianhydride are summarized in Table 1 below.

[0174] division diamine Tetracarboxylic acid dianhydride Example 1 Chemical formula 1-A-1 (0.2 moles) (0.2 moles) Example 2 Chemical formula 1-A-2 (0.2 moles) (0.2 moles) Example 3 Chemical formula 1-A-3 (0.2 moles) (0.2 moles) Comparative Example 1 (0.2 moles) (0.2 moles) Comparative Example 2 (0.2 moles) (0.2 moles)

[0176] Polyimide film manufacturing

[0177] A polyimide-based polymer solution prepared according to the above examples and comparative examples was applied onto a glass substrate and dried in a 100°C hot air dryer for 10 minutes to produce a film with a thickness of 10 μm. To imidize the amic acid remaining in the film, it was further heated in a 300°C oven for 3 hours. Subsequently, the film prepared from the glass substrate was peeled off to produce a polyimide film.

[0179] Experimental Example

[0180] Evaluation of Polyimide Film Characteristics

[0181] The physical properties of the polyimide films according to the above-prepared examples and comparative examples were measured in the following manner, and the results are shown in Table 2 below.

[0183] 1. Flexibility

[0184] The angle at which the polyimide films according to the above examples and comparative examples broke while being bent was measured.

[0185] [Evaluation Criteria]

[0186] ◎: Does not break even when bent 180 degrees

[0187] O: Breaks at 150~180 degrees

[0188] ×: Breaks at 150 degrees or less

[0190] 2. Heat resistance

[0191] The temperature at which the weight of the polyimide film decreased by 5% and the thermal decomposition initiation temperature according to the examples and comparative examples manufactured using the Q50 equipment of TA Instruments were measured and classified as follows.

[0192] [Evaluation Criteria]

[0193] ◎: Temperature at which weight decreases by 5% and thermal decomposition initiation temperature is 320℃ or higher

[0194] O: Temperature at which weight decreases by 5% and pyrolysis initiation temperature are 300℃ or higher but less than 320℃

[0195] ×: Temperature at which weight decreases by 5% and pyrolysis initiation temperature are less than 300℃

[0197] division pliability heat resistance Example 1 ◎ O Example 2 ◎ O Example 3 ◎ O Comparative Example 1 × × Comparative Example 2 × ◎

[0199] As can be seen in Table 2 above, the polyimide films according to the embodiments of the present invention (Examples 1 to 3) are superior in terms of both flexibility and heat resistance compared to the polyimide films according to the comparative examples (Comparative Examples 1 and 2), even though the same acid anhydride was used.

[0201] Foregoing, specific parts of the present invention have been described in detail through various embodiments. It will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the invention. Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

Claims

Claim 1 Polyimide-based polymer comprising a repeating unit derived from any one diamine compound selected from compounds represented by the following chemical formulas 1-A-1 to 1-A-6: [Chemical Formula 1-A-1] [Chemical Formula 1-A-2] [Chemical Formula 1-A-3] [Chemical Formula 1-A-4] [Chemical Formula 1-A-5] [Chemical Formula 1-A-6] . Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 A polyimide film comprising a polyimide-based polymer of claim 1. Claim 8 A device comprising a polyimide film of claim 7.

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