TW202033636A - Polyimide-based resin film, substrate for display device, and optical device - Google Patents

Abstract

The present disclosure relates to a polyimide-based resin film which is synthesized by the reaction of an acid anhydride compound and a diamine compound having a specific structure, a substrate for display device, and an optical device using the same.

Description

Polyimide polymer film, display element substrate and optical element using the same

[Cross reference of related applications]

This application claims the Korean patent application No. 10-2019-0013486 filed with the Korean Intellectual Property Office on February 1, 2019, and the Korean patent application filed with the Korean Intellectual Property Office on September 30, 2019 No. 10-2019-0121176, Korean Patent Application No. 10-2019-0121177 filed with the Korean Intellectual Property Office on September 30, 2019, filed with the Korean Intellectual Property Office on September 30, 2019 Korean Patent Application No. 10-2019-0121178, Korean Patent Application No. 10-2019-0161494 filed at the Korean Intellectual Property Office on December 6, 2019, and Korean Intellectual Property on December 6, 2019 The Korean Patent Application No. 10-2019-0161495 filed by the Office has the right of priority, and the disclosure content of the Korean patent application is incorporated into this case for reference.

The present disclosure relates to polyimide resin films, substrates for display elements, and optical elements using the polyimide resin films. The polyimide resin film has high heat resistance and can achieve excellent optical properties and dimensional stability.

Based on flat panel displays (FPD) that are easy to manufacture on a large area and can be reduced in thickness and weight, the display component market is rapidly changing. Such flat panel displays include liquid crystal displays (LCD), organic light emitting displays (OLED), or electrophoretic elements.

According to recent efforts to further expand the applications and uses of flat panel displays, so-called flexible display elements in which flexible substrates are applied to flat panel displays have received special attention. Based on mobile components such as smart phones, the application of such flexible display components has been specifically analyzed, and its application fields have been gradually expanded.

Generally speaking, when manufacturing flexible display devices and lighting devices, thin film transistor (TFT) devices are manufactured by forming multilayer inorganic films such as buffer layers, active layers, and gate insulators on cured polyimide.

However, when light is emitted to the polyimide layer (base layer), the emission efficiency may decrease due to the difference between the refractive index of the multilayer upper layer made of an inorganic film and the refractive index of the polyimide layer.

In addition, when the polyimide material contained in the polyimide layer (base layer) is cured at a high temperature of 400°C or more, optical properties may be reduced due to deterioration of the polyimide.

Therefore, it is necessary to develop a new type of polyimide that can satisfy high heat resistance and excellent optical properties.

[technical problem]

An object of the present disclosure is to provide a polyimide resin film that has high heat resistance and can achieve excellent optical properties and dimensional stability.

Another object of the present disclosure is to provide a substrate for a display device and an optical device using the substrate. [Technical Solution]

在化學式1中，X₁ 為由以下化學式2表示的四價官能基，Y₁ 為具有15或大於15個碳原子的芳族二價官能基，其中至少一個拉電子基團被取代， [化學式2]

在化學式2中，Ar為多環芳族二價官能基， [化學式5]

在化學式5中，X₂ 為由以下化學式6表示的四價官能基中的一者，且Y₂ 為其中至少一個拉電子基團被取代的具有15或大於15個碳原子的芳族二價官能基， [化學式6]

在化學式6中，R₁ 至R₆ 各自獨立地為氫或具有1至6個碳原子的烷基，L為選自由單鍵、-O-、-CO-、-COO-、-S-、-SO-、-SO₂ -、-CR₇ R₈ -、-(CH₂ )_t -、-O(CH₂ )_t O-、-COO(CH₂ )_t OCO-、-CONH-、伸苯基或其組合組成的群組中的任一者，其中R₇ 及R₈ 各自獨立地為氫、具有1至10個碳原子的烷基或具有1至10個碳原子的鹵代烷基中的一者，並且t為1至10的整數。In order to achieve the above objective, one aspect of the present disclosure provides a polyimide-based resin film, the polyimide-based resin film including a polyimide repeating unit represented by the following chemical formula 5 and the following chemical formula 1 The polyimide resin of the polyimide repeating unit shown has a coefficient of thermal expansion in the range of 100°C or more than 100°C and 430°C or less than 430°C of 20 ppm/°C or less than 20 ppm/°C. [Chemical formula 1]

In Chemical Formula 1, X ₁ is a tetravalent functional group represented by the following Chemical Formula 2, Y ₁ is an aromatic divalent functional group having 15 or more carbon atoms, in which at least one electron withdrawing group is substituted, [Chemical Formula 2]

In Chemical Formula 2, Ar is a polycyclic aromatic divalent functional group, [Chemical Formula 5]

In Chemical Formula 5, X ₂ is one of the tetravalent functional groups represented by the following Chemical Formula 6, and Y ₂ is an aromatic divalent having 15 or more carbon atoms in which at least one electron withdrawing group is substituted Functional group, [Chemical formula 6]

In Chemical Formula 6, R ₁ to R ₆ are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms, and L is selected from a single bond, -O-, -CO-, -COO-, -S-, -SO-, -SO ₂ -, -CR ₇ R ₈ -, -(CH ₂ ) _t -, -O(CH ₂ ) _t O-, -COO(CH ₂ ) _t OCO-, -CONH-, benzene Group or a combination thereof, wherein R ₇ and R ₈ are each independently one of hydrogen, an alkyl group having 1 to 10 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms , And t is an integer from 1 to 10.

Another aspect of the present disclosure provides a substrate for a display element including the polyimide-based resin film.

Another aspect of the present disclosure provides an optical element including the polyimide-based resin film. [Beneficial effect]

According to the present disclosure, a polyimide resin film, a substrate for a display element, and an optical element using the same can be provided. The polyimide resin film has low discoloration even during long-term storage and is used in liquid crystal alignment films. It can exhibit excellent light transmittance, and can achieve improved alignment and electrical properties.

Hereinafter, the polyimide-based resin film, the substrate for a display element, and the optical element using the same according to the specific embodiment of the present disclosure will be described in more detail.

Unless otherwise stated throughout this specification, the technical terms used herein are only used to refer to specific embodiments and are not intended to limit the present disclosure.

Unless the context clearly dictates otherwise, the singular forms "一 (a and an)" and "the (the)" used in this article include plural references.

The term "including" or "comprising" as used herein designates specific features, regions, integers, steps, actions, components and/or components, but does not exclude different specific features, regions, integers, steps, The existence or addition of actions, components, parts, and/or groups.

Terms including ordinal numbers such as "first" and "second" are only used for the purpose of distinguishing one component from another, and are not limited by ordinal numbers. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, or similarly, the second component may be referred to as the first component.

In this specification, (co)polymer means to include both polymer and copolymer, polymer means homopolymer composed of a single repeating unit, and copolymer means containing two or more repeating units Of composite polymers.

In this specification, examples of substituents are described below, but not limited to them.

In this specification, the term "substituted" means that other functional groups in the bonding compound replace the hydrogen atom, and the position to be substituted is not limited, as long as the position is the position where the hydrogen atom is substituted (that is, substituted The position where the group may be substituted) is sufficient, and when two or more substituents are substituted, the two or more substituents may be the same or different from each other.

In this specification, the term "substituted or unsubstituted" means unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium; halogen group; cyano group; nitro group; hydroxyl group ；Carbonyl group; Ester group; Amino group; Amino group; Primary amine group; Carboxyl group; Sulfonic acid group; Sulfonamide group; Phosphine oxide group; Alkoxy group; Aryloxy group; Alkylthiooxy group; Aryl group Thiooxy; Alkylsulfonyloxy; Arylsulfonyloxy; Silyl; Boron; Alkyl; Cycloalkyl; Alkenyl; Aryl; Aralkyl; Aralkenyl; Alkylaryl; Alkoxysilylalkyl group; arylphosphine group; or heterocyclic group containing at least one of N atom, O atom and S atom; or unsubstituted or connected with two of the above-exemplified substituents Substituents of one or more substituents are substituted. For example, the "substituent to which two or more substituents are attached" may be biphenyl. That is, the biphenyl group may also be an aryl group, and can be interpreted as a substituent to which two phenyl groups are connected.

或

意指與另一取代基基團連接的鍵，並且直接鍵意指在表示為L的部分中不存在其他原子的情況。In this manual, the symbol

or

It means a bond to another substituent group, and a direct bond means a case where other atoms are not present in the part denoted as L.

In this specification, an aromatic is a property that satisfies the Huckle's Rule, and a compound can be defined as an aromatic if all the following three conditions are met according to the Huckle's Rule.

1) There must be 4n+2 electrons that are completely conjugated by empty p-orbitals, unsaturated bonds, lone electron pairs, etc.

2) 4n+2 electrons must form a planar isomer and form a ring structure.

3) All atoms of the ring must be able to participate in conjugation.

In this specification, an alkyl group is a monovalent functional group derived from an alkane, and may be a straight chain or a branched chain. The number of carbon atoms of the linear alkyl group is not particularly limited, but is preferably 1-20. In addition, the number of carbon atoms of the branched alkyl group is 3-20. Specific examples of alkyl groups include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tertiary butyl, second butyl, 1-methyl-butyl Base, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tertiary pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4 -Methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, octyl, n-octyl, third octyl , 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl -Propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, 2,6-dimethylheptane4-yl, etc., but not limited to these. The alkyl group may be substituted or unsubstituted, and when substituted, examples of the substituent are the same as described above.

In the present specification, a halogenated alkyl group means a functional group in which the aforementioned alkyl group is substituted with a halogen group, and examples of the halogen group are fluorine, chlorine, bromine, or iodine. The haloalkyl group may be substituted or unsubstituted, and when substituted, examples of the substituent are the same as described above.

In this specification, the multivalent functional group is a residue in which a plurality of hydrogen atoms bonded to any compound is removed, and for example, it may be a divalent functional group, a trivalent functional group, and a tetravalent functional group. As an example, the tetravalent functional group derived from cyclobutane means a residue from which any four hydrogen atoms bonded to cyclobutane are removed.

In this specification, the electron withdrawing group may include one or more selected from the group consisting of a haloalkyl group, a halogen group, a cyano group, a nitro group, a sulfonic acid group, a carbonyl group, and a sulfonyl group, and preferably, It may be a halogenated alkyl group such as trifluoromethyl (-CF ₃ ).

In this specification, a direct bond or a single bond means a bond line connected to a bond line where no atom or atomic group is present at the corresponding position. Specifically, it refers to the case where there are no other atoms in the part represented as L ₁ or L ₂ in the chemical formula.

In this specification, the weight average molecular weight refers to the weight average molecular weight based on polystyrene measured by the gel permeation chromatography (GPC) method. In the process of determining the weight average molecular weight based on the polystyrene measured by the GPC method, commonly known analytical elements such as detectors such as a refractive index detector and an analytical column can be used. ). Commonly used temperature conditions, solvent conditions, and flow rate conditions can be used. A specific example of the measurement conditions is as follows: Waters PL-GPC220 instrument with Polymer Laboratories PLgel MIX-B (Polymer Laboratories PLgel MIX-B), using a 300 mm column, and an evaluation temperature of 160 ℃, use 1,2,4-trichlorobenzene as a solvent, a flow rate of 1 ml/min, prepare a sample at a concentration of 10 mg/10 ml, and then feed it in an amount of 200 microliters, and can use polystyrene The calibration curve formed by the polystyrene standard is used to determine the value of Mw. The molecular weights of the polystyrene standards used in this article are 2,000/10,000/30,000/70,000/200,000/700,000/2,000,000/4,000,000/10,000,000 nine types.

Hereinafter, the disclosure will be explained in more detail.

1 , Polyimide film

According to an embodiment of the present disclosure, a polyimide-based resin film can be provided, the polyimide-based resin film including a polyimide repeating unit represented by chemical formula 5 and a polyimide represented by chemical formula 1 A polyimide-based resin with an imine repeating unit, wherein the coefficient of thermal expansion in the range of 100°C or more than 100°C and 430°C or less than 430°C is 20 ppm/°C or less than 20 ppm/°C

The inventors have found through experiments that, as in the polyimide-based resin film of the Examples, the tetravalent functional group derived from the tetracarboxylic dianhydride having the specific structure as shown in the chemical formula 2 and the chemical formula 6 And the divalent functional group with 15 or more carbon atoms in which at least one electron withdrawing group is substituted is contained in the polyimide-based repeating unit structure, and therefore, at a high temperature of 400°C or more The cured polyimide resin film can achieve excellent optical properties and dimensional stability, thereby completing the present disclosure.

Specifically, since the polyimide-based resin contains tetracarboxylic dianhydride containing the structure represented by Chemical Formula 2, tetracarboxylic dianhydride containing the structure represented by Chemical Formula 6, and at least one electron withdrawing group in it is The reaction product obtained by the imidization reaction of substituted aromatic diamines having 15 or more carbon atoms, therefore, it is believed that the new structure of the acid anhydride monomer and the aromatic diamine monomer is based on the physical and chemical effects Achieved high heat resistance and excellent optical properties and dimensional stability.

Specifically, polyimide-based resins synthesized from aromatic diamine monomers with 15 or more carbon atoms in which at least one electron withdrawing group is substituted improve the ordering and orientation properties between molecules, And even in the polyimide film obtained by high temperature curing, sufficient heat resistance is ensured, and when it is used as a plastic substrate, it can prevent the plastic substrate from being heat-treated when the metal layer formed on the plastic substrate is heat treated. Thermal damage, and can also suppress the warpage of the metal film formed on the plastic substrate.

In addition, a trifluoromethyl group (-CF ₃ ) capable of imparting an electron withdrawing effect is introduced as a substituent into the diamine monomer compound used to synthesize the polyimide resin, thereby suppressing the formation of the presence in the imine chain The charge transfer complex (CTC) of π (Pi) electrons can ensure transparency and achieve excellent optical properties.

Specifically, the polyimide film according to the present disclosure can increase the refractive index, can be used as a base layer in a flexible display device, and can reduce the refractive index difference with each layer constituting the device, thereby reducing internal dissipation The amount of light, and can effectively increase the efficiency of bottom emission.

In addition, the polyimide film according to the present disclosure has properties capable of reducing optical properties and reducing a high strain value (thermal expansion coefficient) due to deterioration that occurs when cured at a high temperature of 400°C or more.

The polyimide-based resin is intended to include both polyimine and its precursor polymer (for example, polyamide acid or polyamide ester). That is, the polyimide-based polymer may include one or more selected from the group consisting of polyimide repeating units, polyimide repeating units, and polyimide repeating units. That is, the polyimide-based polymer may include one type of polyimide repeating unit, one type of polyimide repeating unit, one type of polyimide repeating unit, or a mixture thereof A copolymer of the two or more types of repeating units.

One or more repeating units selected from the group consisting of polyimide repeating units, polyimide repeating units and polyimide repeating units can form the main chain of the polyimide-based polymer .

Specifically, the polyimide-based resin may include a polyimine repeating unit represented by Chemical Formula 1 and a polyimine repeating unit represented by Chemical Formula 5.

In Chemical Formula 1, X ₁ is a tetravalent functional group represented by Chemical Formula 2, and X ₁ is a functional group derived from a tetracarboxylic dianhydride compound used to synthesize a polyimide-based resin.

In Chemical Formula 2, Ar is a polycyclic aromatic divalent functional group. The polycyclic aromatic divalent functional group is a divalent functional group derived from a polycyclic aromatic hydrocarbon compound or a derivative compound thereof, and may include a fluorenene group. Derivative compounds include all compounds in which one or more substituents are introduced or carbon atoms are replaced by heteroatoms.

More specifically, in the Ar of Chemical Formula 2, the polycyclic aromatic divalent functional group may include a condensed cyclic divalent functional group containing at least two or more aromatic cyclic compounds. That is, the polycyclic aromatic divalent functional group may include at least two or more aromatic ring compounds in the functional group structure, and the functional group may also have a condensed ring structure.

The aromatic cyclic compound may include an aromatic compound containing one or more benzene rings, or a heteroaromatic compound in which a carbon atom in the aromatic compound is replaced by a heteroatom.

The aromatic cyclic compound may contain at least two or more in the polycyclic aromatic divalent functional group, and each of the two or more aromatic cyclic compounds may directly form a condensed ring, or may pass through another A ring structure forms a fused ring. As an example, when two benzene rings are each fused with a cycloalkyl ring structure, it can be defined as two benzene rings forming a fused ring via each cycloalkyl ring.

Condensed cyclic divalent functional groups containing at least two or more aromatic cyclic compounds are divalent functional groups derived from condensed cyclic compounds containing at least two or more aromatic cyclic compounds or derivatives thereof Groups, and derivative compounds include all compounds in which one or more substituents are introduced or carbon atoms are replaced by heteroatoms.

Examples of the polycyclic aromatic divalent functional group are not particularly limited, but as an example, a fluorenene group can be mentioned.

Examples of the tetravalent functional group represented by Chemical Formula 2 include functional groups represented by the following Chemical Formula 2-1. [Chemical formula 2-1]

In chemical formula 1, Y ₁ is an aromatic divalent functional group with 15 or more carbon atoms in which at least one electron withdrawing group is substituted, and Y ₁ may be derived from the synthesis of polyamide acid and polyamide A functional group of a diamine compound of acid ester or polyimide.

In Y ₁ , the aromatic divalent functional group having 15 or more carbon atoms may include three or more aromatic cyclic compounds. Since three or more aromatic cyclic compounds are contained in this manner, the polyimide-based resin has improved ordering properties and orientation properties between molecules, and therefore, even in the polyimide obtained by high-temperature curing Sufficient heat resistance can also be ensured in the imine film.

The aromatic divalent functional group having 15 or more carbon atoms may include one or more selected from the group consisting of bis-terrylene, bis-tetraphenylene, and bis-pentaphenylene.

The electron withdrawing group may include one or more selected from the group consisting of a halogenated alkyl group, a halogen group, a cyano group, a nitro group, a sulfonic acid group, a carbonyl group, and a sulfonyl group.

When electron withdrawing substituents with high electronegativity (for example, trifluoromethyl (-CF ₃ )) are substituted, the formation of charge transfer complexes of π (Pi) electrons existing in the polyimide resin chain is inhibited The effect of (CTC) is increased to ensure improved transparency. That is, it can reduce the packing in the polyimide structure or between the chains, and due to steric hindrance and electrical effects, it can weaken the electrical interaction between the chromophores and improve High transparency is shown in the visible light area.

在化學式3中，T₁ 至T₃ 彼此相同或不同，並且各自獨立地為拉電子基團，m1至m3彼此相同或不同，m1至m3中的至少一者為1至4的整數，其餘為0至4的整數，並且n為1至10的整數。More specifically, the aromatic divalent functional group having 15 or more carbon atoms in which at least one electron withdrawing functional group of Y ₁ is substituted may include a functional group represented by the following Chemical Formula 3. [Chemical formula 3]

In Chemical Formula 3, T ₁ to T ₃ are the same or different from each other, and are each independently an electron withdrawing group, m1 to m3 are the same or different from each other, at least one of m1 to m3 is an integer of 1 to 4, and the rest are An integer from 0 to 4, and n is an integer from 1 to 10.

The aromatic divalent functional group having 15 or more carbon atoms in which at least one electron withdrawing group of Y ₁ is substituted may include a functional group represented by the following Chemical Formula 3-1. [Chemical formula 3-1]

在化學式4中，Ar'為多環芳族二價官能基。多環芳族二價官能基為衍生自多環芳族烴化合物或其衍生化合物的二價官能基，並且可包括伸芴基。衍生化合物包括其中引入一或多個取代基或碳原子被雜原子替代的所有化合物。The polyimide-based resin may include a combination of a tetracarboxylic dianhydride represented by the following Chemical Formula 4 and an aromatic diamine having 15 or more carbon atoms in which at least one electron withdrawing group is substituted. [Chemical formula 4]

In Chemical Formula 4, Ar' is a polycyclic aromatic divalent functional group. The polycyclic aromatic divalent functional group is a divalent functional group derived from a polycyclic aromatic hydrocarbon compound or a derivative compound thereof, and may include a fluorenene group. Derivative compounds include all compounds in which one or more substituents are introduced or carbon atoms are replaced by heteroatoms.

Specific examples of the tetracarboxylic dianhydride represented by Chemical Formula 4 include 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, BPAF) .

The aromatic diamine with 15 or more carbon atoms in which at least one electron withdrawing group is substituted is one in which an amine group (-NH ₂ ) is bonded to at least one of the above electron withdrawing groups is substituted. Compounds at both ends of an aromatic divalent functional group with 15 or more carbon atoms. The details of the aromatic divalent functional group having 15 or more carbon atoms in which at least one of the electron withdrawing groups is substituted is the same as the above.

Specific examples of aromatic diamines having 15 or more carbon atoms in which at least one electron withdrawing group is substituted may include diamines represented by the following chemical formula a. [Chemical formula a]

More specifically, in the polyimide-based resin, the bond between the nitrogen atom of the amine group and the carbon atom of the acid anhydride group can be achieved by the terminal acid anhydride group of the tetracarboxylic dianhydride represented by Chemical Formula 4 (- OC-O-CO-) and the terminal amine group (-NH ₂ ) of an aromatic diamine with 15 or more carbon atoms in which at least one electron withdrawing group is substituted.

在化學式5中，X₂ 為由以下化學式6表示的四價官能基中的一者，並且Y₂ 為其中至少一個拉電子基團被取代的具有15或大於15個碳原子的芳族二價官能基， [化學式6]

在化學式6中，R₁ 至R₆ 各自獨立地為氫或具有1至6個碳原子的烷基，L為選自由單鍵、-O-、-CO-、-COO-、-S-、-SO-、-SO₂ -、-CR₇ R₈ -、-(CH₂ )_t -、-O(CH₂ )_t O-、-COO(CH₂ )_t OCO-、-CONH-、伸苯基或其組合組成的群組中的任一者，其中R₇ 及R₈ 各自獨立地為氫、具有1至10個碳原子的烷基或具有1至10個碳原子的鹵代烷基中的一者，並且t為1至10的整數。In addition, the polyimide-based resin may further include a polyimide repeating unit represented by the following Chemical Formula 5. [Chemical formula 5]

In Chemical Formula 5, X ₂ is one of the tetravalent functional groups represented by the following Chemical Formula 6, and Y ₂ is an aromatic divalent aromatic having 15 or more carbon atoms in which at least one electron withdrawing group is substituted Functional group, [Chemical formula 6]

In Chemical Formula 6, R ₁ to R ₆ are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms, and L is selected from a single bond, -O-, -CO-, -COO-, -S-, -SO-, -SO ₂ -, -CR ₇ R ₈ -, -(CH ₂ ) _t -, -O(CH ₂ ) _t O-, -COO(CH ₂ ) _t OCO-, -CONH-, benzene Group or a combination thereof, wherein R ₇ and R ₈ are each independently one of hydrogen, an alkyl group having 1 to 10 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms , And t is an integer from 1 to 10.

[化學式6-2]

Specific examples of the functional group represented by Chemical Formula 6 include a functional group represented by the following Chemical Formula 6-1, or a functional group represented by the following Chemical Formula 6-2. [Chemical formula 6-1]

[Chemical formula 6-2]

Specifically, when the functional group represented by the chemical formula 6-1 or the functional group represented by the chemical formula 6-2 is included, the polyimide-based polymer exhibits excellent optical properties, and such optical properties are improving the yellow index (YI) and enhancing the transmittance is technically advantageous.

That is, the polyimide-based polymer may include: a first repeating unit containing a repeating unit represented by Chemical Formula 1, wherein the repeating unit derived from tetracarboxylic dianhydride is a functional group represented by Chemical Formula 2; And a second repeating unit containing a repeating unit represented by Chemical Formula 5, wherein the repeating unit derived from tetracarboxylic dianhydride is a functional group represented by Chemical Formula 6. The first repeating unit and the second repeating unit can be randomly arranged in the polyimide-based polymer to form a random copolymer, or by forming a block of the first repeating unit and the second repeating unit Blocks to form block copolymers.

The polyimide-based polymer including the repeating unit represented by Chemical Formula 1 and the repeating unit represented by Chemical Formula 5 can be prepared by reacting two or more different tetracarboxylic dianhydride compounds with diamine compounds And two types of tetracarboxylic dianhydrides can be added at the same time to synthesize random copolymers, or two types of tetracarboxylic dianhydrides can be added sequentially to synthesize block copolymers.

Relative to the total repeating units contained in the polyimide resin, the content of the polyimine repeating unit represented by the chemical formula 5 may be 1 mol% or more than 1 mol% and 99 mol% or less 99 mol%.

With respect to the total repeating units contained in the polyimide-based resin, the content of the polyimine repeating unit represented by Chemical Formula 1 and the polyimine repeating unit represented by Chemical Formula 5 may be 70 mol% Or greater than 70 mol%, or 80 mol% or greater than 80 mol%, or 90 mol% or greater than 90 mol%, or 70 mol% or greater than 70 mol% and 100 mol% or less than 100 Mole%, 80 Mole% or more than 80 Mole% and 100 Mole% or less than 100 Mole%, 70 Mole% or more than 70 Mole% and 90 Mole% or less than 90 Mole%, 70 Mole% Ear% or more than 70 mol% and 99 mol% or less than 99 mol%, 80 mol% or more than 80 mol% and 99 mol% or less than 99 mol%, 90 mol% or more than 90 mol% Ear% and 99 mol% or less than 99 mol%.

That is, the polyimide-based resin is composed of only the polyimide repeating unit represented by the chemical formula 1 and the polyimine repeating unit represented by the chemical formula 5, or most of it may be composed of the polyimide repeating unit represented by the chemical formula 1. The imine repeating unit and the polyimine repeating unit represented by Chemical Formula 5 are composed.

More specifically, in addition to diamines with aromatic divalent functional groups with 15 or more carbon atoms in which at least one electron withdrawing group is substituted, polyimide-based resins may not be combined with other diamines. Amine is mixed, or it can be mixed in very small amounts of less than 1 mol%.

在化學式5-1中，X₃ 為由化學式6-1表示的四價官能基，並且Y₃ 為其中至少一個拉電子基團被取代的具有15或大於15個碳原子的芳族二價官能基， [化學式5-2]

在化學式5-2中，X₄ 為由化學式6-2表示的四價官能基，並且Y₄ 為其中至少一個拉電子基團被取代的具有15或大於15個碳原子的芳族二價官能基。More specifically, the polyimide repeating unit represented by Chemical Formula 5 may include one or more repeating units selected from the group consisting of: a polyimide repeating unit represented by the following Chemical Formula 5-1 The unit and the polyimide repeating unit represented by the following chemical formula 5-2. [Chemical formula 5-1]

In Chemical Formula 5-1, X ₃ is a tetravalent functional group represented by Chemical Formula 6-1, and Y ₃ is an aromatic divalent functional group having 15 or more carbon atoms in which at least one electron withdrawing group is substituted Radical, [Chemical formula 5-2]

In Chemical Formula 5-2, X ₄ is a tetravalent functional group represented by Chemical Formula 6-2, and Y ₄ is an aromatic divalent functional group having 15 or more carbon atoms in which at least one electron withdrawing group is substituted base.

The weight average molecular weight of the polyimide resin (measured by GPC) is not particularly limited, but may be, for example, 1000 g/mol or more than 1000 g/mol and 200,000 g/mol or less than 200,000 g/mol. Ears, or 10,000 g/mol or more than 10,000 g/mol and 200,000 g/mol or less than 200,000 g/mol.

Since the polyimide-based resin according to the present disclosure can exhibit excellent colorless and transparent properties, while maintaining properties such as heat resistance and mechanical strength due to the rigid structure, it can be used for element substrates, display covering substrates, optical Films, integrated circuit (IC) packaging, adhesive films, multilayer flexible printed circuits (FRC), tapes, touch panels, protective polymer films for optical discs, etc. Specifically, it can be applied to a display cover substrate.

Meanwhile, the polyimide-based resin film of one embodiment may include a cured product in which the polyimide-based resin is cured at a temperature of 400°C or more. The cured product means a material obtained by a curing step of a resin composition containing a polyimide-based resin, and the curing process can be at 400°C or more, or 400°C or more than 400°C and 500°C or less than 500°C Execute at the temperature.

More specifically, an example of a method of synthesizing a polyimide-based resin film is not particularly limited, and for example, a method of manufacturing a film including the following steps: a resin composition containing a polyimide-based resin The step of coating on a substrate to form a coating film (step 1); the step of drying the coating film (step 2); and the step of heat-treating and curing the dried coating film (step 3).

Step 1 is a step of applying a resin composition containing the above-mentioned polyimide-based resin to a substrate to form a coating film. The method of coating the resin composition containing the polyimide-based resin onto the substrate is not particularly limited, and for example, screen printing, offset printing, flexographic printing, inkjet, etc. can be used. method.

In addition, the resin composition containing the polyimide-based resin may be dissolved or dispersed in an organic solvent. In the case of having such a form, for example, when the polyimide-based resin is synthesized in an organic solvent, the solution may be the reaction solution thus obtained by itself or by diluting the reaction solution with another solvent. Solution. In addition, when the polyimide-based resin is obtained as a powder, the solution may be a solution obtained by dissolving the powder in an organic solvent.

Specific examples of organic solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactone, 2- Pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethyl sulfide, tetramethylurea, pyridine, dimethyl sulfide, hexamethyl sulfide, γ-butyrolactone, 3-Methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide , 1,3-Dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, carbonic acid Ethylene glycol, propylene carbonate, diglyme, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol mono Ethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monoisopropyl ether acetate, ethylene glycol Monobutyl ether, ethylene glycol monobutyl ether acetate, etc. These organic solvents can be used alone or in combination of two or more.

The resin composition containing the polyimide-based resin can include solids in an amount that takes into consideration processability (for example, coating performance during the film forming process) so that the solution has an appropriate viscosity. For example, the content of the composition can be adjusted so that the total content of the resin is 5 wt% or more than 5 wt% and 25 wt% or less than 25 wt%, or can be adjusted to 5 wt% or more than 5 wt% and 20 wt% % Or less than 20% by weight, or 5% by weight or more than 5% by weight and 15% by weight or less than 15% by weight.

In addition, the resin composition containing the polyimide-based resin may further include other components in addition to the organic solvent. In a non-limiting example, when coating a resin composition containing a polyimide resin, it may further include the ability to improve the uniformity of the film thickness and surface smoothness, or improve the adhesion to the substrate, or change the dielectric Constant and conductivity, or increase the density (denseness) additives. Examples of these additives include surfactants, silane-based compounds, dielectrics, or cross-linking compounds.

Step 2 is a step of drying a coating film formed by coating a resin composition containing a polyimide-based resin on a substrate.

The step of drying the coating film can be performed by heating tools such as hot plates, hot air circulation furnaces, infrared furnaces, etc., and the drying can be performed at 50°C or more than 50°C and 150°C or less than 150°C, or 50°C Or execute at a temperature greater than 50°C and 100°C or less than 100°C.

Step 3 is a step of heat-treating and curing the dried coating film. In this case, the heat treatment can be performed by heating tools such as hot plates, hot air circulation furnaces, infrared furnaces, etc., and the heat treatment can be performed at 400°C or more, or 400°C or more than 400°C and 500°C Or execute at a temperature less than 500°C.

The thickness of the polyimide-based resin film is not particularly limited, but for example, the thickness can be freely adjusted within a range of 0.01 micrometers or more and 1000 micrometers or less. If the thickness of the polyimide resin film is increased or decreased by a specific value, the physical properties measured in the polyimide resin film may also change to a certain value.

Polyimide resin film can have 20 ppm/°C or less than 20 ppm/°C, or 0.1 ppm/°C or greater than 0.1 ppm/°C and 20 at 100°C or greater and 430°C or less than 430°C. ppm/℃ or less than 20 ppm/℃, or 1 ppm/℃ or more than 1 ppm/℃ and 20 ppm/℃ or less than 20 ppm/℃ thermal expansion coefficient. The range of 100°C or greater than 100°C and 430°C or less than 430°C may refer to the temperature range of 100°C or greater than 100°C and 430°C or less than 430°C.

The coefficient of thermal expansion is obtained by the following method: When the tensile force of the polyimide resin film sample is set to 0.01 Newton or more than 0.01 Newton and 0.1 Newton or less than 0.1 Newton, or 0.01 Newton or more than 0.01 Newton and 0.05 Newton or less 0.05 Newton, 1°C/min to 10°C/min, or 4°C/min or greater than 4°C/min and 6°C/min or less in the temperature range of 100°C or greater than 100°C and 430°C or less than 430°C Perform the primary heating step at a heating rate of 6°C/min, and then perform the primary heating step at a temperature range of 430°C to 100°C at 1°C/min or more than 1°C/min and 10°C/min or less than 10°C/ When cooling at a cooling rate of 3°C/min or greater than 3°C/min and 5°C/min or less than 5°C/min, use TMA (Q400, TA Instruments) to measure thermal expansion changes .

The coefficient of thermal expansion can be measured from a polyimide film sample with a thickness of 10±2 microns. When the thickness of the polyimide film increases or decreases by a specific value, the physical properties measured from the polyimide film can also change a certain value.

Since the polyimide-based resin film satisfies a thermal expansion coefficient of 20 ppm/°C or less than 20 ppm/°C in the range of 100°C or more than 100°C and 430°C or less than 430°C, it can be cured even at high temperatures. The polyimide film can also ensure sufficient heat resistance, and when it is used as a plastic substrate, it can prevent the plastic substrate from being thermally damaged when the metal layer formed on the plastic substrate is heat-treated, and can also prevent The metal film formed on the plastic substrate warps.

In addition, a trifluoromethyl group (-CF ₃ ) capable of imparting an electron withdrawing effect is introduced as a substituent into the diamine monomer compound used to synthesize the polyimide resin, thereby suppressing the formation of the presence in the imine chain The charge transfer complex (CTC) of π (Pi) electrons can ensure transparency and achieve excellent optical properties.

Specifically, the polyimide-based resin film may have a haze value of 2% or less than 2%, or 0.1% or more than 0.1%, and 2% or less than 2%. In addition, the polyimide-based resin film may have a yellow index value of 15 or less, or 1 or more than 1, and 15 or less.

The haze can be measured from a polyimide film sample with a thickness of 10±2 microns. When the thickness of the polyimide film increases or decreases by a specific value, the physical properties measured in the polyimide film can also change a certain value.

In addition, the polyimide-based resin film can have 60% or more than 60%, or 60% or more than 60% and 99% in the wavelength range of 380 nanometers or more and 780 nanometers or less than 780 nanometers. Or less than 99% average transmittance. In addition, the polyimide-based resin film may have a transmittance of 80% or more than 80%, or 80% or more than 80%, and 99% or less than 99% at a wavelength of 550 nanometers.

The transmittance can be measured from a polyimide film sample with a thickness of 10±2 microns. When the thickness of the polyimide film increases or decreases by a specific value, the physical properties measured in the polyimide film can also change a certain value.

2 、Substrate for display element

Meanwhile, according to another embodiment of the present disclosure, it is possible to provide a substrate for a display element including the polyimide resin film of other embodiments. The details of the polyimide-based resin film may include all the contents described above in one embodiment.

The display element including the substrate may include a liquid crystal display element (LCD), an organic light emitting diode (OLED), a flexible display, a rollable display, or a foldable display, etc.

The display element may have various structures according to application fields and specific shapes, and may include, for example, plastic covering windows, touch panels, polarizers, barrier films, light-emitting elements (for example, OLED elements), transparent substrates, and the like.

The polyimide-based resin film of another embodiment described above can be used in various applications, such as substrates, external protective films, or cover windows in such various display elements, and more specifically, can be applied to substrates.

For example, the display device substrate may have a structure in which a device protection layer, a transparent electrode layer, a silicon oxide layer, a polyimide resin film, a silicon oxide layer, and a hard coat layer are sequentially stacked.

The transparent polyimide substrate can further include a silicon oxide layer formed between the transparent polyimide resin film and the cured layer to further improve its solvent resistance, water permeability and optical properties, and can be cured by curing the polysilicon Nitrane to produce the silicon oxide layer.

Specifically, before forming a coating on at least one surface of the transparent polyimide-based resin film, the oxidation can be formed by curing the applied polysilazane after coating and drying a solution containing polysilazane. Silicon layer.

The substrate for a display device according to the present disclosure can provide a transparent polyimide with solvent resistance, optical properties, water permeability, and scratch resistance, as well as excellent warpage properties and impact resistance, by including the above-mentioned device protection layer Cover the substrate.

3 ,Optical element

Meanwhile, according to another embodiment of the present disclosure, an optical element including the polyimide resin film of other embodiments can be provided. The details of the polyimide-based resin film may include all the details described above in one embodiment.

The optical element may include all types of elements using properties achieved by light, and may be, for example, a display element. Specific examples of display elements include liquid crystal display elements (LCD), organic light emitting diodes (OLED), flexible displays, rollable displays, or foldable displays, etc., but are not limited to these.

The optical element may have various structures according to application fields and specific shapes, and for example, it may have structures including covering plastic windows, touch panels, polarizers, barrier films, light-emitting elements (such as OLED elements), transparent substrates, and the like.

The polyimide-based resin film of another embodiment described above can be used in various applications, such as substrates, external protective films, or cover windows in various optical elements, and more specifically, can be applied to substrates.

Hereinafter, the embodiments of the disclosure will be described in more detail with examples. However, these examples are provided for illustrative purposes only, and are not intended to limit the scope of the present disclosure.

> Example: Preparation of polyimide resin >

Example 1

(1) Preparation of polyimide precursor composition

[化學式b]

The organic solvent DEAc was filled into the reactor under a nitrogen stream, and then 0.735 mol of diamine represented by the following chemical formula a was added and dissolved at the same temperature while maintaining the temperature of the reactor at 25°C. 0.3675 mol of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) represented by chemical formula b was added to the solution to which the diamine represented by the following chemical formula a was added at the same temperature And 0.3675 mol of 3,3',4,4'-biphenyltetracarboxylic dianhydride (3,3',4,4'-biphenyltetracarboxylic dianhydride, BPDA) as the acid dianhydride, and stirred for 24 hours The polyimide precursor composition is obtained. [Chemical formula a]

[Chemical formula b]

(2) Preparation of polyimide film

The polyimide precursor composition was spin-coated on the glass substrate. The glass substrate coated with the polyimide precursor composition was put into an oven and heated at a rate of 5°C/min, and performed by keeping it at 80°C for 30 minutes and 450°C for 30 minutes The curing process is used to prepare a polyimide film with a thickness of 10 microns.

Instance 2

In addition to using 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6-FDA) as the acid dianhydride instead of 3,3',4,4'-biphenyltetracarboxylic dianhydride ( BPDA), a polyimide film was prepared in the same manner as in Example 1.

> Comparative example: Preparation of polyimide film >

Comparative example 1

(1) Preparation of polyimide precursor composition

The organic solvent DEAc was filled into the reactor under nitrogen flow, and then 0.735 mol 2,2'-bis(trifluoromethyl)benzidine (2,2'-bis(trifluoromethyl)benzidine, TFMB) was added, and Dissolve at the same temperature while maintaining the temperature of the reactor at 25°C. At the same temperature, 0.735 mol 3,3',4,4'-biphenyltetracarboxylic acid was added to the solution containing 2,2'-bis(trifluoromethyl)benzidine (TFMB) Anhydride (BPDA) was used as the acid dianhydride and stirred for 24 hours to obtain a polyimide precursor composition.

(2) Preparation of polyimide film

The polyimide precursor composition was spin-coated on the glass substrate. The glass substrate coated with the polyimide precursor composition was put into an oven and heated at a rate of 5°C/min, and performed by keeping it at 80°C for 30 minutes and 450°C for 30 minutes The curing process is used to prepare a polyimide film with a thickness of 10 microns.

Comparative example 2

In addition to adding 0.3675 mol 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 0.3675 mol 4,4'-(hexafluoroisopropylidene) diphthalic anhydride ( A polyimide film was prepared in the same manner as in Example 1, except that 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 6-FDA) was used as the acid dianhydride.

Comparative example 3

Except for using pyromellitic dianhydride (PMDA) instead of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), a polyamide was prepared in the same manner as in Example 1. Imine film.

> Experimental example: Measure the physical properties of the polyimide film obtained in the example and the comparative example >

The physical properties of the polyimide films obtained in the Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 1 below.

1 ,Thermal expansion coefficient( CTE )

The membrane was prepared in a size of 5×20 mm, and then the sample was loaded using accessories. The length of the film actually measured is made the same 16 mm. The main heating step is performed at a heating rate of 5°C/min within a temperature range of 100°C or more than 100°C and 430°C or less than 430°C with the film tension set to 0.02 Newton, and then at a temperature of 430°C to 100°C When cooling was performed at a cooling rate of 4°C/min within the range, the thermal expansion changes were measured using TMA (Q400, TA instrument). The thermal expansion coefficient was evaluated according to the following criteria. ○: 20 ppm/°C or less than 20 ppm/°C ∆: greater than 20 ppm/°C and less than 30 ppm/°C Χ: 30 ppm/°C or greater than 30 ppm/°C

2 , Yellow index ( YI )

A color meter (Color-Eye 7000A, GRETAGMACBETH) was used to measure the yellow index of the polyimide film and evaluated according to the following standards. ○: 15 or less ∆: greater than 15 and less than 25 Χ: 25 or greater than 25

2 , Haze

The haze value of the polyimide film was measured with a haze meter (NDH-5000) and evaluated according to the following standards. ○: 2% or less than 2% ∆: greater than 2% and less than 3% Χ: 3% or more than 3%

4 ,Transmittance

(1) The average transmittance in the wavelength range of 380nm or more and 780nm or less than 780nm

Measured with a transmittance meter (model name: HR-100, manufactured by Murakami Color Research Laboratory) based on Japanese Industrial Standard (JIS) K 7105 at 380 nm or greater than 380 nm and 780 The average transmittance in the wavelength range of nanometers or less than 780 nanometers, and was evaluated according to the following standards. ○: 60% or more than 60% ∆: greater than 50% and less than 60% Χ: 50% or less than 50%

(2) Transmittance at a single wavelength of 550nm

The transmittance at a wavelength of 550nm was measured with a transmittance meter based on JISK7105 (model name: HR-100, manufactured by Murakami Color Research Laboratory), and evaluated according to the following standards. ○: 80% or more than 80% ∆: greater than 60% and less than 80% Χ: 60% or less than 60%

Table 1

Measured results of experimental examples of examples and comparative examples category CTE (ppm/℃) YI Haze (%) Transmittance (%) @380~780 Transmittance (%)@550 Example 1 ○ ○ ○ ○ ○ Example 2 ○ ○ ○ ○ ○ Comparative example 1 Χ ○ Χ ○ ∆ Comparative example 2 Χ ∆ ∆ ○ ○ Comparative example 3 ○ ∆ ○ ∆ ∆

As shown in Table 1, it was confirmed that the polyimide film obtained in the example not only has a coefficient of thermal expansion (CTE) value of 20 ppm/°C or less than 20 ppm/°C (this is compared with Comparative Example 1 and Comparative Example 2). Is 30 ppm/°C or more than 30 ppm/°C) and therefore has excellent heat resistance, and the polyimide film has a haze value of 2% or less (compared to Comparative Example 1 And in Comparative Example 2, values greater than 2% are low) and therefore have excellent optical properties with improved transparency. On the other hand, it was confirmed that the polyimide film obtained in the example not only has a yellow index (YI) of 15 or less (which is lower than the yellow index of more than 15 and less than 25 in Comparative Example 3), but The polyimide film has a higher value than Comparative Example 3 even in terms of transmittance, thereby having excellent optical properties.

no

no

Claims (17)

A polyimide-based resin film, comprising: a polyimide-based resin including a polyimine repeating unit represented by the following chemical formula 1 and a polyimine repeating unit represented by the following chemical formula 5, wherein The coefficient of thermal expansion in the range of 100°C or greater and 430°C or less than 430°C is 20 ppm/°C or less than 20 ppm/°C: [Chemical formula 1]

In Chemical Formula 1, X ₁ is a tetravalent functional group represented by the following Chemical Formula 2, Y ₁ is an aromatic divalent functional group having 15 or more carbon atoms, in which at least one electron withdrawing group is substituted, [Chemical Formula 2]

In Chemical Formula 2, Ar is a polycyclic aromatic divalent functional group, [Chemical Formula 5]

In Chemical Formula 5, X ₂ is one of the tetravalent functional groups represented by the following Chemical Formula 6, and Y ₂ is an aromatic divalent having 15 or more carbon atoms in which at least one electron withdrawing group is substituted Functional group, [Chemical formula 6]

In Chemical Formula 6, R ₁ to R ₆ are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms, and L is selected from a single bond, -O-, -CO-, -COO-, -S-, -SO-, -SO ₂ -, -CR ₇ R ₈ -, -(CH ₂ ) _t -, -O(CH ₂ ) _t O-, -COO(CH ₂ ) _t OCO-, -CONH-, benzene Group or a combination thereof, wherein R ₇ and R ₈ are each independently one of hydrogen, an alkyl group having 1 to 10 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms , And t is an integer from 1 to 10. The polyimide resin film according to claim 1, The haze value is 2% or less than 2%. The polyimide resin film according to claim 1, The yellow index value is 15 or less. The polyimide resin film according to claim 1, Among them, the average transmittance in the wavelength range of 380 nanometers or more than 380 nanometers and 780 nanometers or less than 780 nanometers is 60% or more than 60%. The polyimide resin film according to claim 1, Among them, the transmittance in the wavelength range of 550 nm is 80% or greater. The polyimide resin film according to claim 1, Wherein in the Ar of Chemical Formula 2, the polycyclic aromatic divalent functional group includes a condensed cyclic divalent functional group containing at least two or more aromatic cyclic compounds. The polyimide resin film according to claim 1, Wherein in the Ar of Chemical Formula 2, the polycyclic aromatic divalent functional group includes a fluorenene group. The polyimide-based resin film according to claim 1, wherein the tetravalent functional group represented by Chemical Formula 2 includes a functional group represented by the following Chemical Formula 2-1: [Chemical Formula 2-1]

. The polyimide-based resin film according to claim ₁ , wherein in the Y ₁ , the aromatic divalent functional group having 15 or more carbon atoms includes three or more aromatic cyclic groups Compound. The polyimide-based resin film according to claim 9, The aromatic divalent functional group having 15 or more carbon atoms includes one or more selected from the group consisting of bis-terrylene, bis-tetraphenylene, and bis-pentaphenylene. The polyimide resin film according to claim 1, Wherein the electron withdrawing group includes one or more selected from the group consisting of haloalkyl, halogen, cyano, nitro, sulfonic acid, carbonyl, and sulfonyl. The polyimide-based resin film according to claim ₁ , wherein the aromatic divalent functional group having 15 or more carbon atoms in which at least one electron withdrawing functional group of the Y ₁ is substituted includes the following The functional group represented by Chemical Formula 3: [Chemical Formula 3]

In Chemical Formula 3, T ₁ to T ₃ are the same or different from each other, and are each independently an electron withdrawing group, m1 to m3 are the same or different from each other, at least one of m1 to m3 is an integer of 1 to 4, and the rest are An integer from 0 to 4, and n is an integer from 1 to 10. The polyimide-based resin film according to claim ₁ , wherein the aromatic divalent functional group having 15 or more carbon atoms in which at least one electron withdrawing functional group of the Y ₁ is substituted includes the following Functional group represented by Chemical Formula 3-1: [Chemical Formula 3-1]

. The polyimide-based resin film according to claim 1, wherein the polyimine-based resin includes a tetracarboxylic dianhydride represented by the following chemical formula 4 and at least one electron withdrawing group substituted with 15 or Combinations of aromatic diamines greater than 15 carbon atoms: [Chemical formula 4]

In Chemical Formula 4, Ar' is a polycyclic aromatic divalent functional group. The polyimide resin film according to claim 1, The content of the polyimine repeating unit represented by Chemical Formula 5 and the polyimine repeating unit represented by Chemical Formula 1 relative to the total repeating unit contained in the polyimide-based resin is 70 mol% or more than 70 mol%. A substrate for a display element includes the polyimide-based resin film according to claim 1. An optical element comprising the polyimide resin film according to claim 1.