Polyimide Precursor

Abstract

The present application provides a polyimide precursor capable of realizing an environmentally friendly polyimide having high adhesion, surface flatness, and durability, a method for producing the polyimide precursor, and a polyimide film including a cured product of the polyimide precursor.

Description

[Technical field]

[0001] The present application relates to a polyimide precursor, a method for producing the polyimide precursor, and a polyimide film containing a cured product of the polyimide precursor. [Background technology]

[0002] Generally, polyimide (PI) is a polymer of imide monomer formed by solution polymerization of dianhydride and diamine or diisocyanate, and has excellent mechanical properties such as strength, chemical resistance, weather resistance, and heat resistance due to the chemical stability of the imide ring. In addition, polyimide has been attracting attention as a highly functional polymer material that can be applied to a wide range of industrial fields such as electronics, communications, and optics due to its excellent electrical properties such as insulation properties and low dielectric constant.

[0003] Here, polyimide refers to a highly heat-resistant resin produced by solution-polymerizing a dianhydride monomer and a diamine monomer to produce a polyamic acid, which is then imidized by ring-closing and dehydrating at high temperature. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application provides a polyimide precursor that is environmentally friendly, has high adhesion, excellent surface flatness and durability, and can realize polyimide with a high imidization rate, a method for producing the polyimide precursor, and a polyimide film including a cured product of the polyimide precursor. [Means for solving the problem]

[0005] The present application relates to a polyimide precursor. For example, the polyimide precursor may be a polyimide varnish that is applied to a coating target and then imidized by thermal curing. The polyimide precursor includes the composition described below, and thus can provide an environmentally friendly polyimide having high adhesion, surface flatness, and durability.

[0006] An exemplary polyimide precursor according to the present application includes a polyamic acid including a dianhydride monomer and a diamine monomer as polymerized units, an organic solvent including at least one selected from the group consisting of N,N-diethylacetamide (DEAc), N,N-diethylformamide (DEF), N-ethylpyrrolidone (NEP), dimethylpropionamide (DMPA) and diethylpropionamide (DEPA), a silicon-containing first additive including at least one functional group, and at least one second additive selected from a phosphorus-based additive having an aromatic ring group or an amine-based additive having an aromatic or heteroaromatic ring group.

[0007] The weight average molecular weight of the polyamic acid may be within the range of 40,000 to 100,000 g / mol, 45,000 to 90,000 g / mol, 48,000 to 80,000 g / mol, 50,000 to 75,000 g / mol, or 51,000 to 70,000 g / mol. In the present application, the term weight average molecular weight refers to a value converted to standard polystyrene measured by GPC (Gel Permeation Chromatograph).

[0008] The polyimide precursor according to the present invention may be a polyamic acid solution containing a polyamic acid, an organic solvent, a silicon-containing first additive, and at least one second additive selected from a phosphorus-based additive having an aromatic ring group or an amine-based additive having an aromatic or heteroaromatic ring group. In the present invention, the polyimide precursor, the polyamic acid solution, and the polyimide varnish are interpreted as having the same meaning.

[0009] The polyamic acid may be prepared by polymerization of a dianhydride monomer and a diamine monomer in the presence of the organic solvent, and a silicon-containing additive may be mixed into the polymer. The polyamic acid of the present invention is polymerized in the organic solvent, so that the weight average molecular weight is increased and satisfies the above-mentioned numerical range.

[0010] In the present invention, the silicon-containing first additive may be a silane-based compound or a siloxane-based compound. In addition, the silicon-containing first additive may not be included in the polymerization unit of the polyamic acid by being mixed with the polyamic acid after the polymerization reaction is completed, but may interact with the polyamic acid or polyimide through a functional group to realize a polyimide having high adhesion, surface flatness, and excellent durability. In addition, at least one second additive selected from phosphorus-based additives or amine-based additives may be mixed with the polyamic acid after the polymerization reaction is completed to contribute to increasing the imidization rate and durability of the polyamic acid during curing.

[0011] By mixing with the polyamic acid polymerized in the presence of the organic solvent, a polyimide having high adhesive strength, excellent surface flatness and durability upon curing can be provided.

[0012] In one specific example, the organic solvent may have a negative (-) octanol / water partition coefficient (Log P) calculated by the following formula 1.

[0013] [Number 1] Log P = Log(Kow) Kow=Co / Cw

[0014] In the above equation, Co is the concentration of the solute in octanol, and Cw is the concentration of the solute in water.

[0015] The partition coefficient may be calculated using the ACD / LogP module of ACD / Perceptaplatform from ACD / Labs at a temperature of 25° C., and the ACD / LogP module may use an algorithm based on the QSPR (Quantitative Structure-Property Relationship) methodology using the 2D structure of the molecule. However, since the partition coefficient is an experimental value, it cannot be excluded that it may be measured as a positive (+) value depending on the measurement method or algorithm used.

[0016] Examples of the organic solvent having a negative partition coefficient include N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), and N,N-dimethylpropionamide (DMPA). Considering environmental friendliness, DMPA is preferable.

[0017] Considering the environmental friendliness, the organic solvent may be N,N-dimethylpropionamide (DMPA). DMPA is an environmentally friendly organic solvent and can be treated without a separate purification process after polymerization, thereby reducing costs. In addition, the weight average molecular weight of polyamic acid may be adjusted to within the above-mentioned numerical range during polymerization of polyamic acid in the DMPA solvent. Meanwhile, polyamic acid polymerized in the DMPA solvent may show a low imidization rate during curing, but the polyimide precursor according to the present invention has the effect of improving the low imidization rate when it contains a phosphorus-based additive or an amine-based additive.

[0018] Meanwhile, the organic solvent may not contain N-methyl-2-pyrrolidone (NMP). Polyamic acid polymerized in the presence of N-methyl-2-pyrrolidone may not satisfy the weight average molecular weight within the above-mentioned range. In addition, since NMP is classified as a hazardous substance, additional costs are required for purification, and the NMP may cause environmental pollution problems during the treatment process.

[0019] In one embodiment, the content of the silicon-containing first additive may be 0.0001 to 1 wt % based on the entire polyimide precursor, for example, the content of the silicon-containing first additive may be 0.0001 to 0.9 wt %, 0.0001 to 0.8 wt %, 0.0001 to 0.7 wt %, 0.0001 to 0.6 wt %, 0.00001 to 0.5 wt %, 0.0001 to 0.4 wt %, 0.0001 to 0.3 wt %, 0.0001 to 0.2 wt %, 0.0001 to 0.1 wt %, 0.0001 to 0.09 wt %, 0.0001 to 0.08 wt %, or the like, based on the entire polyimide precursor. Amount%, 0.0001~0.07wt%, 0.0001~0.06wt%, 0.0001~0.05wt%, 0.0001~0.04wt%, 0.0001~0.03wt%, 0.0001~0.02wt%, 0.0 001~0.01wt%, 0.001~0.9wt%, 0.001~0.8wt%, 0.001~0.7wt%, 0.001~0.6wt%, 0.001~0.5wt%, 0.001~0.4wt%, 0.001~ 0.3% by weight, 0.001~0.2% by weight, 0.001~0.1% by weight, 0.001~0.09% by weight, 0.001~0.08% by weight, 0.001~0.07% by weight, 0.001~0.06% by weight, 0.001~0 .05% by weight, 0.001~0.04% by weight, 0.001~0.03% by weight, 0.001~0.02% by weight, 0.001~0.01% by weight, 0.01~0.9% by weight, 0.01~0.8% by weight, 0.01~0.7% by weight The silicon-containing first additive may be in the range of 0.01 to 0.6% by weight, 0.01 to 0.5% by weight, 0.01 to 0.4% by weight, 0.01 to 0.3% by weight, 0.01 to 0.2% by weight, 0.01 to 0.1% by weight, 0.01 to 0.09% by weight, 0.01 to 0.08% by weight, 0.01 to 0.07% by weight, 0.01 to 0.06% by weight, 0.01 to 0.05% by weight, 0.01 to 0.04% by weight, 0.01 to 0.03% by weight, or 0.01 to 0.02% by weight. The silicon-containing first additive having a content within the range may be mixed with the polymerized polyamic acid to provide a polyimide having high adhesion, excellent surface flatness, and excellent durability when cured.

[0020] The functional group of the silicon-containing first additive may be amine group, carboxyl group, alcohol, alkoxy group, mercapto, epoxy group, or isocyanate.The silicon-containing additive is a monomer or polymer that contains at least one of the functional groups, and may be, for example, the compound of the following formula 1.

[0021] [C1] R1R2R3Si-R-R4

[0022] In the above Chemical Formula 1, At least one of R1 to R3 is an alkoxy group, and the rest are organic groups; R is a single bond or a divalent organic group, R4 is an organic group having at least one functional group selected from an amine group, a carboxyl group, an alcohol, an alkoxy group, a mercapto group, an epoxy group, or an isocyanate group.

[0023] When the functional group is an amine group, examples of the functional group include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethylsilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-(N-phenylamino)propyltrimethoxysilane, γ-(N-phenylamino)propylmethyldimethoxysilane, γ-(N-methylamino)propyltrimethoxysilane, γ-(N-methylamino)propylmethyldimethoxysilane, γ-(N-ethylamino)propyltrimethoxysilane, γ-(N-ethylamino)propylmethyldimethoxysilane, and N-[3-(trimethoxysilyl)propyl]aniline.

[0024] When the functional group is mercapto, examples include γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane.

[0025] When the functional group is an epoxy group, examples of the functional group include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-(2,3-epoxycyclohexyl)propyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane.

[0026] An example of the silicon-containing first additive in which the functional group is an epoxy group and which is a polymer is X-12-984S (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0027] Furthermore, examples of the silicon-containing additive that is a monomer and has an isocyanate functional group include 3-isocyanatepropyltriethoxysilane.

[0028] In yet another example, the polyimide precursor may include at least one second additive selected from a phosphorus-based additive having an aromatic ring group or an amine-based additive having an aromatic or heteroaromatic ring group.

[0029] The second additive can contribute to increasing the imidization rate and durability of the polyimide precursor.

[0030] In one embodiment, the content of the second additive may be 0.001 to 2 wt % based on the entire polyimide precursor. For example, the content of the second additive may be 0.001 to 1.9 wt %, 0.001 to 1.8 wt %, 0.001 to 1.7 wt %, 0.001 to 1.6 wt %, 0.001 to 1.5 wt %, 0.001 to 1.4 wt %, 0.001 to 1.3 wt %, 0.001 to 1.2 wt %, 0.001 to 1. 1% by weight, 0.001~1% by weight, 0.001~0.9% by weight, 0.001~0.8% by weight, 0.001~0.7% by weight, 0.001~0.6% by weight, 0.00 1~0.5wt%, 0.01~1.9wt%, 0.01~1.8wt%, 0.01~1.7wt%, 0.01~1.6wt%, 0.01~1.5wt%, 0.01 ~1.4wt%, 0.01~1.3wt%, 0.01~1.2wt%, 0.01~1.1wt%, 0.01~1wt%, 0.01~0.9wt%, 0.01~0 .8% by weight, 0.01~0.7% by weight, 0.01~0.6% by weight, 0.01~0.5% by weight, 0.1~1.9% by weight, 0.1~1.8% by weight, 0.1~1.7% by weight The second additive may be in the range of 0.1-1.6 wt%, 0.1-1.5 wt%, 0.1-1.4 wt%, 0.1-1.3 wt%, 0.1-1.2 wt%, 0.1-1.1 wt%, 0.1-1 wt%, 0.1-0.9 wt%, 0.1-0.8 wt%, 0.1-0.7 wt%, 0.1-0.6 wt%, or 0.1-0.5 wt%. The second additive having a content within the above range may be mixed with the polyamic acid polymerized with the silicon-containing additive to realize a high imidization rate during curing, as well as contribute to improving durability.

[0031] In one example, the phosphorus additive may have an aromatic ring group. For example, the phosphorus additive may have one or more, two or more, or three or more aromatic ring groups, preferably have three aromatic ring groups, and more preferably, the phosphorus additive may be triphenyl phosphate or triphenyl phosphine.

[0032] In one example, the amine additive may have a benzene ring group or a heteroaromatic ring group containing a nitrogen element, for example, the amine additive may be isoquinoline, β-picoline, 1,2-dimethylimidazole, benzimidazole, triphenylamine or 2-phenylimidazole, preferably triphenylamine.

[0033] In one embodiment, the dianhydride monomer may be an aromatic tetracarboxylic dianhydride. For example, the dianhydride monomer may include at least one compound represented by the following formula 2:

[0034] [ka]

[0035] In the above formula 2, X is a tetravalent aliphatic ring group, a tetravalent heteroaliphatic ring group, a tetravalent aromatic ring group, or a tetravalent heteroaromatic ring group, and a carbon atom of the carbonyl group in the formula 2 is bonded to a ring-constituting atom of the aliphatic ring group, the heteroaliphatic ring group, the aromatic ring group, or the heteroaromatic ring group;

[0036] The aliphatic ring group, the heteroaliphatic ring group, the aromatic ring group, or the heteroaromatic ring group is

[0037] Is it a single ring?

[0038] joined together to form a polycyclic ring, or

[0039] They are linked by a linking group containing at least one divalent substituent selected from the group consisting of a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylidene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted alkynylene group, a substituted or unsubstituted arylene group, -O-, -S-, -C(=O)-, -S(=O)2-, and -Si(Rb)2-, where Rb is hydrogen or an alkyl group.

[0040] Preferably, X is phenyl, biphenyl, [ka] or an aliphatic cyclic group,

[0041] The M includes at least one selected from the group including a single bond, an alkylene group, an alkylidene group, -O-, -S-, -C(=O)-, and -S(=O)2-.

[0042] In this specification, unless otherwise specified, the term "aliphatic cyclic group" refers to an aliphatic cyclic group having 3 to 30 carbon atoms, 4 to 25 carbon atoms, 5 to 20 carbon atoms, or 6 to 16 carbon atoms. Specific examples of tetravalent aliphatic cyclic groups include groups in which four hydrogen atoms have been removed from a ring such as a cyclohexane ring, a cycloheptane ring, a cyclodecane ring, a cyclododecane ring, a norbornane ring, an isobornane ring, an adamantane ring, a cyclododecane ring, or a dicyclopentane ring.

[0043] In this specification, the term "aromatic ring group" means an aromatic ring group having 4 to 30 carbon atoms, 5 to 25 carbon atoms, 6 to 20 carbon atoms, or 6 to 16 carbon atoms, unless otherwise specified. The aromatic ring may be a monocyclic ring or a condensed ring. Examples of the tetravalent aromatic hydrocarbon ring group include groups in which four hydrogen atoms have been removed from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, or a pyrene ring.

[0044] As used herein, the term "arylene group" refers to a divalent organic group derived from the above aromatic ring group.

[0045] As used herein, the term "heterocyclic group" includes heteroaliphatic and heteroaromatic ring groups.

[0046] As used herein, the term "heteroaliphatic cyclic group" refers to a cyclic group in which at least one carbon atom of the aliphatic cyclic group is replaced with at least one heteroatom selected from the group consisting of nitrogen, oxygen, sulfur, and phosphorus.

[0047] In this specification, the term "heteroaromatic ring group" means a ring group in which at least one of the carbon atoms of the aromatic ring is replaced with at least one heteroatom selected from the group consisting of nitrogen, oxygen, sulfur and phosphorus, unless otherwise specified. The heteroaromatic ring group may be a single ring or a condensed ring.

[0048] The aliphatic ring group, the heteroaliphatic ring group, the aromatic ring group, and the heteroaromatic ring group may each be independently substituted with at least one substituent selected from the group consisting of a halogen, a hydroxy group, a carboxy group, an alkyl group having 1 to 4 carbon atoms which is unsubstituted or substituted with a halogen, and an alkoxy group having 1 to 4 carbon atoms.

[0049] As used herein, the term "single bond" refers to a bond that connects both atoms without any atom. For example, in the above formula 2, X is [ka] where, when M is a single bond, both aromatic rings may be directly linked to each other.

[0050] In this specification, the term "alkyl group" means an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, unless otherwise specified. The alkyl group may have a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include polar functional groups such as at least one substituent consisting of halogen, hydroxyl group, alkoxy group, thiol group, or thioether group.

[0051] In this specification, the term "alkenyl group" refers to an alkenyl group having 2 to 30 carbon atoms, 2 to 25 carbon atoms, 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms, unless otherwise specified. The alkenyl group may have a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include polar functional groups such as at least one substituent consisting of halogen, hydroxyl group, alkoxy group, thiol group, or thioether group.

[0052] In this specification, the term "alkynyl group" refers to an alkynyl group having 2 to 30 carbon atoms, 2 to 25 carbon atoms, 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms, unless otherwise specified. The alkynyl group may have a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include polar functional groups such as at least one substituent consisting of halogen, hydroxyl group, alkoxy group, thiol group, or thioether group.

[0053] In this specification, the term "alkylene group" refers to an alkylene group having 2 to 30 carbon atoms, 2 to 25 carbon atoms, 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 10 carbon atoms, or 2 to 8 carbon atoms, unless otherwise specified. The alkylene group may have a linear, branched, or cyclic structure as a divalent organic group in which two hydrogen atoms have been removed from different carbon atoms, and may be optionally substituted with at least one substituent. Examples of the substituent include polar functional groups such as at least one substituent consisting of a halogen, a hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0054] In the specification, the term "alkylidene group" refers to an alkylidene group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, or 1 to 8 carbon atoms, unless otherwise specified. The alkylidene group may have a linear, branched, or cyclic structure as a divalent organic group in which two hydrogen atoms have been removed from one carbon atom, and may be optionally substituted with at least one substituent. Examples of the substituent include polar functional groups such as at least one substituent consisting of a halogen, a hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0055] In this specification, the term "alkoxy group" refers to an alkoxy group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, unless otherwise specified. The alkoxy group may have an alkyl group having a linear, branched, or cyclic structure, and the alkyl group may be optionally substituted with at least one substituent. Examples of the substituent include at least one substituent consisting of a halogen, a hydroxy group, an alkoxy group, a thiol group, or a thioether group.

[0056] In the present specification, the term "alkylamine group" includes monoalkylamine (-NHR) or dialkylamine (-NR2), unless otherwise specified, where R each independently means an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Here, the alkyl group may have a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include at least one substituent consisting of a halogen, a hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0057] In the present specification, the term "alkylamide" includes monoalkylamide (-C(O)NHR) or dialkylamide (-C(O)NR2), unless otherwise specified, where each R independently means an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Here, the alkyl group may have a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include at least one substituent consisting of a halogen, a hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0058] In this specification, the term "thioether group" or "sulfide" means -SR, unless otherwise specified, where each R is independently an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Here, the alkyl group may have a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include at least one substituent consisting of a halogen, a hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0059] In this specification, the term "sulfoxide" means -S(O)R, unless otherwise specified, where each R is independently an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Here, the alkyl group may have a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include at least one substituent consisting of a halogen, a hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0060] In this specification, the term "carbonyl" includes -C(O)R, unless otherwise specified, where each R independently means an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Here, the alkyl group may have an alkyl group of a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include at least one substituent consisting of a halogen, a hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0061] In the present specification, unless otherwise specified, the term "ester" includes -C(O)OR or -OC(O)R, where R each independently means an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Here, the alkyl group may have an alkyl group of a linear, branched, or cyclic structure, and may be optionally substituted with at least one substituent. Examples of the substituent include at least one substituent consisting of a halogen, a hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0062] The aliphatic tetracarboxylic dianhydride satisfying the above formula 2 is 1,2,4,5-cyclohexanetetracarboxylic dianhydride (or HPMDA), bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic 2:3,5:6-dianhydride (BODA), 1,2,3,4-cyclohexanetetracarboxylic dianhydride (CHMDA), bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic 2:3,5:6-dianhydride (BHDA), butane-1,2,3,4-tetracarboxylic dianhydride (BTD), bicyclo-[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride (BTD), -7-ene-2-exo,3-exo,5-exo,6-exo-2,3:5,6-dianhydride (BTA), 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), bicyclo[4.2.0]octane-3,4,7,8-tetracarboxylic dianhydride (OTD), norbornane-2-spiro-α-cyclohexanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (ChODA), cyclopentanone bis-spironorbornanetetracarboxylic dianhydride (CpODA), bicyclo[2.2.1]Heptane-2,3,5-tricarboxyl-5-acetic dianhydride (BSDA), dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride (DCDA), dicyclohexyl-2,3',3,4'-tetracarboxylic dianhydride (HBPDA), 5,5'-oxybis(hexahydro-1,3-isobenzofurandione) (HODPA), 5,5'-methylenebis(hexahydro-1,3-isobenzofurandione) (HMDPA), 3,3'-(1,4-piperazinediyl)bis[dihydro-2,5-furandione] (PDSA), 5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride (DOCDA), 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride (TDA), 3,4-dicarboxy-1,2,3,4-tetrahydro-6-methyl-1-naphthalene succinic dianhydride (MTDA), 3,4-dicarboxy-1,2,3,4-tetrahydro-6-fluoro-1-naphthalene succinic dianhydride (FTDA), 3,3,3',3'-tetramethyl-1,1'-spirobisindan-5,5',6,6'-tetracarboxylic anhydride (S BIDA), 4,4,4',4'-tetramethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[furo[3,4-g]chromene]-6,6',8,8'-tetraone (SBCDA), or 9,10-difluoro-9,10-bis(trifluoromethyl)-9,10-dihydroanthracene-2,3,6,7-tetracarboxylic dianhydride (6FDA).

[0063] The aromatic tetracarboxylic dianhydride satisfying the above formula 2 is pyromellitic dianhydride (or PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (or BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (or a-BPDA), oxydiphthalic dianhydride (or ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (or DSDA), bis(3,4-dicarboxyphenyl)sulfide dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,3',4'-benzophenonetetracarboxylic dianhydride, 3,3,3',4'-benzophenonetetracarboxylic dianhydride (or BTDA), bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)methane dianhydride, )propane dianhydride, p-phenylene bis(trimellitic acid monoester anhydride), p-biphenylene bis(trimellitic acid monoester anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene Examples of suitable benzene dianhydride include benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride (6-FDA).

[0064] The compound represented by Chemical Formula 2 is preferably an aromatic tetracarboxylic dianhydride, and may particularly include 3,3',4,4'-biphenyltetracarboxylic dianhydride (or BPDA) or 2,3,3',4'-biphenyltetracarboxylic dianhydride (or a-BPDA).

[0065] As an example, the diamine monomer may include at least one compound represented by the following formula 3.

[0066] [ka]

[0067] In the above formula 3, any one of B1 to B5 is an amino group, and the rest represents hydrogen, a halogen, a hydroxyl group, a carboxyl group, or an alkyl group which is unsubstituted or substituted with a halogen.

[0068] The diamine monomers that may be used in the preparation of the polyamic acid solution are aromatic diamines, and examples thereof can be classified as follows:

[0069] 1) Diamines having a relatively rigid structure, such as 1,4-diaminobenzene (or paraphenylenediamine, PPD), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, or 3,5-diaminobenzoic acid (or DABA), which have one benzene nucleus in their structure;

[0070] 2) Diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether (or oxydianiline, ODA), 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane (methylenediamine), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenyl nylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4-aminophenyl)sulfide, 4,4'-diaminobenzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (or o-tolidine), 2,2'-dimethylbenzidine (or m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'- Diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, diamines having two benzene nuclei in their structure, such as 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, or 4,4'-diaminodiphenyl sulfoxide;

[0071] 3) 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-amino)phenyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene (or TPE-Q), 1,4-bis(4-aminophenoxy)benzene (or TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone diamines having three benzene nuclei in their structure, such as 1,3-bis(3-aminophenylsulfide)benzene, 1,3-bis(4-aminophenylsulfide)benzene, 1,4-bis(4-aminophenylsulfide)benzene, 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis(4-aminophenylsulfone)benzene, 1,4-bis(4-aminophenylsulfone)benzene, 1,3-bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene, or 1,4-bis[2-(4-aminophenyl)isopropyl]benzene;

[0072] 4) 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl]ether, bis[3-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, bis[3-(3-aminophenoxy)phenyl]ketone, bis[3-(4-aminophenoxy)phenyl] bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[3-(3-aminophenoxy)phenyl]sulfide, bis[3-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl bis[4-(4-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, Diamines that have four benzene nuclei in their structure, such as 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, or 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane.

[0073] The diamine monomer may be used alone or in combination of two or more kinds as necessary, and may include, for example, 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene, or 4,4'-methylenediamine (MDA). Preferably, the compound represented by Chemical Formula 2 may include 1,4-diaminobenzene (PPD).

[0074] In one example, the dianhydride monomer may be included in the range of 90 to 102 mol% relative to 100 mol% of the diamine monomer. For example, the dianhydride monomer may be included in the range of 91 to 102 mol%, 92 to 102 mol%, 93 to 102 mol%, 94 to 102 mol%, 95 to 102 mol%, 96 to 102 mol%, 97 to 102 mol%, 98 to 102 mol%, 90 to 101 mol%, 90 to 100 mol%, or 90 to 99 mol% relative to 100 mol% of the diamine monomer.

[0075] In one embodiment, the polyimide precursor may contain 5 to 40 wt%, 10 to 30 wt%, or 15 to 20 wt% of solid content based on the total weight. By adjusting the solid content of the polyimide precursor, the present application can prevent an increase in viscosity and prevent an increase in manufacturing cost and process time that would be required to remove a large amount of solvent during the curing process.

[0076] The polyimide precursor of the present application may include a polyamic acid having a high molecular weight and may have low viscosity characteristics. 1The viscosity measured under the shear rate condition may be 50,000 cP or less, 40,000 cP or less, 30,000 cP or less, 20,000 cP or less, 10,000 cP or less, 9,000 cP or less, 5,000 cP or less, 4,000 cP or less, or 3,000 cP or less. The lower limit is not particularly limited, but may be 500 cP or more or 1000 cP or more. In one specific example, the polyimide precursor of the present application may be in the range of 500 to 10,000 cp. The viscosity may be measured, for example, using MARS40 of Haake Co., Ltd. at a temperature of 23°C. The present application may provide a polyimide precursor having excellent processability and easy application to products by adjusting the viscosity range.

[0077] The present application relates to a method for producing polyamic acid, which can provide a polyamic acid having a high weight average molecular weight by polymerizing polyamic acid in a specific solvent, and can provide an environmentally friendly polyimide having high adhesion, excellent surface flatness and durability, and a high imidization rate by mixing the polymerized polyamic acid with a silicon-containing first additive and a second additive containing at least one of a phosphorus-based additive and an amine-based additive.

[0078] Specifically, the method includes a polymerization step of polymerizing a dianhydride monomer and a diamine monomer in an organic solvent containing at least one selected from the group consisting of N,N-diethylacetamide (DEAc), N,N-diethylformamide (DEF), N-ethylpyrrolidone (NEP), dimethylpropionamide (DMPA) and diethylpropionamide (DEPA) to produce a polyamic acid, and a production step of mixing the polyamic acid produced with a silicon-containing first additive containing at least one functional group and at least one second additive selected from a phosphorus-based additive having an aromatic ring group or an amine-based additive having an aromatic or heteroaromatic ring group to produce a polyimide precursor.

[0079] The second additive can contribute to increasing the imidization rate during curing by being mixed with the polyamic acid after the polymerization reaction has been completed.

[0080] Detailed explanations of each of the above configurations will be omitted below since they overlap with the above contents.

[0081] The present application further relates to a polyimide film containing a cured product of the polyimide precursor. The polyimide film may be a film produced by imidizing the polyimide precursor through thermal curing. The thermal curing conditions are not particularly limited, but may be within a temperature range of 100 to 400°C. The polyimide film may be attached to the lower part of a substrate of a display device.

[0082] Therefore, the thickness of the film may be formed to be thin enough to be suitable for attachment to a product, and for example, the thickness may be within the range of 1 to 100 μm, 5 to 90 μm, 5 to 80 μm, 5 to 70 μm, 10 to 100 μm, 10 to 90 μm, 10 to 80 μm, 10 to 70 μm, 10 to 60 μm, or 10 to 50 μm.

[0083] In addition, the film can have various physical properties controlled within the following numerical ranges by adjusting the materials and content ratios of the polyimide precursor composition.

[0084] For example, the polyimide film is UTM (Universal Testing The elongation, as measured using a Flexural Strength Machine, may be 100% or less, 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less or 25% or less; the tensile strength may be 700Mpa or less, 650Mpa or less, 600Mpa or less, 550Mpa or less, 500Mpa or less, 450Mpa or less, 400Mpa or less, 350Mpa or less, 300Mpa or less, 250Mpa or less, 200Mpa or less or 150Mpa or less; and the modulus may be 12Gpa or less, 11Gpa or less, 10Gpa or less, 9Gpa or less, 8Gpa or less, 7Gpa or less, 6Gpa or less, 5Gpa or less, 4Gpa or less, or 3Gpa or less. The measurements may be performed using a UTM device under the following conditions: width 20 mm, grip distance 50 mm, and crosshead speed 20 min / min.

[0085] The polyimide film may have a 1% thermal decomposition temperature (td) measured using a TGA (Thermo Gravimetric analysis) device within a range of 300 to 600° C., 350 to 600° C., 400 to 600° C., 450 to 600° C., 500 to 600° C., 540 to 600° C., 560 to 600° C., or 570 to 600° C. The 1% thermal decomposition temperature (td) may be measured by removing moisture in the film at a temperature of 150° C. using a TGA device, and then heating the film to 600° C. at a heating rate of 10° C. / min.

[0086] In one example, the polyimide film may have an adhesive strength to a polyimide substrate within a range of 0.05 to 0.5 N / cm, 0.05 to 0.45 N / cm, 0.05 to 0.4 N / cm, 0.05 to 0.35 N / cm, 0.05 to 0.3 N / cm, 0.05 to 0.25 N / cm, 0.05 to 0.2 N / cm, or 0.05 to 0.15 N / cm. The adhesive strength was measured using a 100×10 mm polyimide substrate and polyimide film using an INSTRON UTM5546 model under conditions of 90° Peel mode and Cross Head Speed ​​50 mm / min.

[0087] The present application further relates to a display device. For example, the device includes a substrate and the polyimide film attached to the lower part of the substrate. The type of the display device is not particularly limited, and can be applied to various types without limitation. The display device has excellent heat resistance, light resistance, and electrical properties due to the polyimide film attached to the lower part of the substrate. Effect of the Invention

[0088] The present application provides a polyimide precursor capable of realizing an environmentally friendly polyimide having high adhesive strength, excellent surface flatness and durability, a method for manufacturing the polyimide precursor, a polyimide film including a cured product of the polyimide precursor, and a display device in which the polyimide film is attached to the lower part of a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0089] The present application will be described in detail through the following examples, but the scope of the present application is not limited to the following examples.

[0090] Example 1 In a 500mL glass reaction vessel equipped with a stirrer, nitrogen gas inlet and outlet pipes, N,N-dimethylpropionamide (DMPA) was added as an organic solvent, 100 mol% of 1,4-diaminobenzene (PPD) and 100 mol% of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) were added. Then, a polymerization reaction was carried out at 25°C to produce a polyamic acid solution with a solid content concentration of 15%, and 0.01 wt% of glycidoxypropyltrimethoxysilane (silicon-containing additive) and 0.1 wt% of triphenylamine (TPA) (amine-based additive) were added to the entire polyamic acid solution produced, and the mixture was stirred at room temperature for 12 hours to produce a polyimide precursor.

[0091] The polyimide precursor was thermally cured from 100° C. to 460° C. at a temperature increase rate of 5° C. / min to produce a polyimide film having a thickness of 10 μm.

[0092] Examples 2 to 7 A polyimide precursor was prepared in the same manner as in Example 1, except that the composition was as shown in Table 1 below.

[0093] Comparative Examples 1 to 5 A polyamic acid solution was prepared in the same manner as in Example 1, except that the composition was as shown in Table 1 below.

[0094] For reference, triphenyl phosphate (TPP) was used as the phosphorus-based additive in Table 1, and the phosphorus-based additive was added to the polyamic acid solution after polymerization was completed. Also, the content of the phosphorus-based additive was shown based on the entire polyamic acid solution.

[0095] [Table 1]

[0096] Experimental example 1 - Surface flatness The surfaces of the polyimide films produced in the Examples and Comparative Examples were visually observed to check for the presence or absence of bubbles and to evaluate the surface flatness. The results are shown in Table 2 according to the following criteria.

[0097] O: No bubbles (excellent surface flatness) △: Few bubbles are generated (normal surface flatness) ×: Many air bubbles are generated (surface flatness is poor)

[0098] Experimental Example 2 - 1% Thermal Decomposition Temperature (1%Td) Using a TA Thermogravimetric Analysis (Q50 model), the polyimide film was heated to 150°C at a rate of 10°C / min under nitrogen atmosphere, and then maintained at isothermal temperature for 30 minutes to remove moisture.Then, the film was heated to 600°C at a rate of 10°C / min to measure the temperature at which a 1% weight loss occurred, and the results are shown in Table 2 below.

[0099] Experimental Example 3 - Adhesion The adhesion strength of the polyimide films prepared in the Examples and Comparative Examples to the polyimide-coated substrate was measured.

[0100] The adhesive strength was measured for a polyimide substrate and a polyimide film having a size of 100×10 mm using an INSTRON UTM5546 model under conditions of 90° Peel mode and a cross head speed of 50 mm / min.

[0101] [Table 2]

[0102] As shown in Table 2 above, the examples containing a silicon-containing additive and a phosphorus-based additive or an amine-based additive were confirmed to have no air bubbles, excellent appearance (excellent surface flatness), and high adhesive strength.

[0103] On the other hand, since the NMP of Comparative Example 1 is classified as a hazardous substance, additional costs are required for purification, and there is a problem that it causes environmental pollution during the treatment process.

[0104] In addition, it was confirmed that Comparative Examples 2 to 4, which used DMPA as an organic solvent but did not contain a silicon-containing additive, had poor appearances due to the generation of bubbles (average or poor surface flatness), and that the adhesive strength was also lower than that of the Examples containing a silicon-containing additive. In addition, it was confirmed that Comparative Example 5, which contained only a silicon-containing additive and did not contain either a phosphorus-based additive or an amine-based additive, had excellent adhesive strength, but had a 1% lower thermal decomposition temperature than the Examples due to a low imidization rate.

[0105] On the other hand, the examples containing an amine-based additive or a phosphorus-based additive had a high 1% thermal decomposition temperature due to a high imidization rate, and Comparative Examples 3 and 4 containing an amine-based additive or a phosphorus-based additive had a higher 1% thermal decomposition temperature than Comparative Example 2 due to a high imidization rate.

[0106] Since the higher the 1% thermal decomposition temperature, the better the durability. From the above results, it was confirmed that the amine-based additive or phosphorus-based additive has an effect of improving the durability of polyimide.

Claims

1. a polyamic acid containing a dianhydride monomer and a diamine monomer as polymerization units; an organic solvent containing at least one selected from the group consisting of N,N-diethylacetamide (DEAc), N,N-diethylformamide (DEF), N-ethylpyrrolidone (NEP), dimethylpropionamide (DMPA) and diethylpropionamide (DEPA); a silicon-containing first additive comprising at least one functional group; and at least one second additive selected from a phosphorus-based additive having an aromatic ring group, or an amine-based additive having an aromatic or heteroaromatic ring group.

2. The polyimide precursor of claim 1 , wherein the organic solvent is N,N-dimethylpropionamide (DMPA).

3. 2. The polyimide precursor according to claim 1, wherein the content of the silicon-containing first additive is 0.0001 to 1 wt % based on the entire polyimide precursor.

4. 2. The polyimide precursor of claim 1, wherein the functional group of the silicon-containing first additive is an amine group, a carboxyl group, an alcohol, an alkoxy group, a mercapto, an epoxy group, or an isocyanate.

5. The polyimide precursor according to claim 1, wherein the content of the second additive is 0.001 to 2 wt % based on the entire polyimide precursor.

6. The polyimide precursor of claim 1 , wherein the phosphorus-based additive is triphenyl phosphate or triphenyl phosphine.

7. 2. The polyimide precursor according to claim 1, wherein the amine additive is isoquinoline, β-picoline, 1,2-dimethylimidazole, benzimidazole, triphenylamine or 2-phenylimidazole.

8. The polyimide precursor according to claim 1 , wherein the dianhydride monomer comprises at least one compound represented by the following formula 2: 【Chemistry 1】 In the above formula 2, X is a tetravalent aliphatic ring group, a tetravalent heteroaliphatic ring group, a tetravalent aromatic ring group, or a tetravalent heteroaromatic ring group, and a carbon atom of the carbonyl group in the formula 2 is bonded to a ring-constituting atom of the aliphatic ring group, the heteroaliphatic ring group, the aromatic ring group, or the heteroaromatic ring group; The aliphatic ring group, the heteroaliphatic ring group, the aromatic ring group, or the heteroaromatic ring group is Is it a single ring? joined together to form a polycyclic ring, or A single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylidene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted alkynylene group, a substituted or unsubstituted arylene group, -O-, -S-, -C(=O)-, -S(=O) ２ - and -Si(Rb)2-, wherein R ｂ is hydrogen or an alkyl group.

9. X is phenyl, biphenyl, 【Chemistry 2】 or an aliphatic cyclic group, The M is a single bond, an alkylene group, an alkylidene group, -O-, -S-, -C(=O)-, or -S(=O) ２ The polyimide precursor according to claim 8, comprising at least one selected from the group consisting of

10. 9. The polyimide precursor according to claim 8, wherein the compound represented by Chemical Formula 2 comprises 3,3',4,4'-biphenyltetracarboxylic dianhydride (or BPDA).

11. The polyimide precursor according to claim 1 , wherein the diamine monomer comprises at least one compound represented by the following formula 3: 【Chemistry 3】 In the above formula 3, B １ ~B ５ One of the groups is an amino group, and the remaining groups are hydrogen, halogen, a hydroxyl group, a carboxyl group, or an alkyl group which is unsubstituted or substituted with a halogen.

12. The polyimide precursor according to claim 11, wherein the compound represented by Chemical Formula 3 includes 1,4-diaminobenzene (PPD).

13. a polymerization step of polymerizing the dianhydride monomer and the diamine monomer in an organic solvent containing at least one selected from the group consisting of N,N-diethylacetamide (DEAc), N,N-diethylformamide (DEF), N-ethylpyrrolidone (NEP), dimethylpropionamide (DMPA) and diethylpropionamide (DEPA) to prepare a polyamic acid; and a production step of mixing the produced polyamic acid, a silicon-containing first additive containing at least one functional group, and at least one second additive selected from a phosphorus-based additive having an aromatic ring group or an amine-based additive having an aromatic or heteroaromatic ring group to produce a polyimide precursor.

14. A polyimide film comprising a cured product of the polyimide precursor according to claim 1.

15. The polyimide film according to claim 14, which has a thickness in the range of 1 to 100 μm.

16. The polyimide film according to claim 14, having an adhesive strength to a polyimide substrate in the range of 0.05 to 0.5 N / cm.

17. The polyimide film according to claim 14, wherein the 1% thermal decomposition temperature (td) is within the range of 300 to 600° C.

Images