Polyimide Precursor

Abstract

The present application provides a polyimide precursor that contains a high molecular weight polyamic acid and thereby can simultaneously realize a low dielectric constant and mechanical properties under severe conditions such as light resistance, heat resistance, insulation properties, and high temperatures, a method for producing the polyamic acid, a method for increasing the molecular weight of the polyamic acid, a film containing the precursor, and a display device in which the film is attached to a substrate.

Description

[Technical field]

[0001] The present application relates to a polyimide precursor comprising a polyamic acid, a method for producing the polyamic acid, a method for increasing the molecular weight of the polyamic acid, a film comprising the precursor, and a display device having the film attached to a substrate. [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 includes a high molecular weight polyamic acid and can simultaneously realize a low dielectric constant and mechanical properties under severe conditions such as light resistance, heat resistance, insulation properties, and high temperatures, a method for producing the polyamic acid, a method for increasing the molecular weight of the polyamic acid, a film including the precursor, and a display device in which the film is attached to the lower part of a substrate. [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 may realize excellent insulation properties, adhesion, heat resistance, mechanical strength, light resistance, and flexibility of polyimide, and may be used as a substrate attachment material for displays.

[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, and 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).

[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 and an organic solvent. 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 a polymerization reaction of a dianhydride monomer and a diamine monomer in the presence of the organic solvent. By being polymerized in the organic solvent, the weight average molecular weight of the polyamic acid of the present invention can be increased and can satisfy the above-mentioned numerical range.

[0010] The polyimide precursor according to the present application contains a high molecular weight polyamic acid satisfying the above numerical range, and thus can provide a polyimide having improved mechanical properties and heat resistance upon imidization.

[0011] In one example, the organic solvent may be N,N-dimethylpropionamide (DMPA). 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 numerical range.

[0012] In one specific example, the polydispersity index (PDI) of the polyamic acid may be within a range of 1 to 5. For example, the polydispersity index (PDI) of the polyamic acid may be within a range of 1.1 to 4.9, 1.2 to 4.5, 1.3 to 4.3, 1.4 to 4.0, 1.5 to 3.8, 1.6 to 3.4, 1.7 to 3.2, 1.8 to 3.0, 1.9 to 2.9, 2 to 2.8, or 2.1 to 2.7.

[0013] 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 Chemical Formula 1:

[0014] [ka]

[0015] In the above Chemical Formula 1, 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 a carbonyl group in Chemical Formula 1 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;

[0016] The aliphatic ring group, the heteroaliphatic ring group, the aromatic ring group, or the heteroaromatic ring group is

[0017] Is it a single ring?

[0018] joined together to form a polycyclic ring, or

[0019] 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(R a ) 2 -, wherein R a is hydrogen or an alkyl group.

[0020] Preferably, X is phenyl, biphenyl, [ka] or an aliphatic ring group, wherein M is a single bond, an alkylene group, an alkylidene group, -O-, -S-, -C(=O)-, or -S(=O) 2 - includes at least one selected from the group including:

[0021] 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.

[0022] 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.

[0023] As used herein, the term "arylene group" refers to a divalent organic group derived from the above aromatic ring group.

[0024] As used herein, the term "heterocyclic group" includes heteroaliphatic and heteroaromatic ring groups.

[0025] 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.

[0026] 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 group 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.

[0027] 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.

[0028] As used herein, the term "single bond" refers to a bond that connects both atoms without any atom. For example, in the above formula 1, X is [ka] where, when M is a single bond, both aromatic rings may be directly linked to each other.

[0029] 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.

[0030] In this specification, the term "alkenyl group" refers to an alkenyl 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 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.

[0031] In this specification, the term "alkynyl group" refers to an alkynyl 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 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.

[0032] In this specification, the term "alkylene group" means 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.

[0033] In this 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.

[0034] 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 hydroxyl group, an alkoxy group, a thiol group, or a thioether group.

[0035] As used herein, the term "alkylamine group" refers to a monoalkylamine (-NHR) or dialkylamine (-NR 2 ), where R each independently represents 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.

[0036] As used herein, the term "alkylamide" refers to a monoalkylamide (-C(O)NHR) or dialkylamide (-C(O)NR) unless otherwise specified. 2 ), where R each independently represents 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.

[0037] In this specification, the term "thioether group" or "sulfide" means -SR, unless otherwise specified, where 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.

[0038] 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.

[0039] In the present specification, unless otherwise specified, the term "carbonyl" includes -C(O)R, 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.

[0040] 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.

[0041] The aliphatic tetracarboxylic dianhydride satisfying the above Chemical Formula 1 is 1,2,4,5-cyclohexanetetracarboxylic dianhydride (i.e., 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 2:3,5:6-dianhydride (CHMDA), to-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 acid dianhydride Anhydride (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 (SBIDA), 4,4,4',4'-tetramethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[furo[3,4-g]chromene]-6,6',8,8'-tetraone (SBCDA), 9,10-difluoro-9,10-bis(trifluoromethyl)-9,10-dihydroanthracene-2,3,6,7-tetracarboxylic dianhydride (6FDA), and the like. .

[0042] The aromatic tetracarboxylic dianhydride satisfying the above Chemical Formula 1 includes pyromellitic dianhydride (i.e. PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (i.e. BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (i.e. a-BPDA), oxydiphthalic dianhydride (i.e. ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (i.e. 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',4,4'-benzophenonetetracarboxylic dianhydride (i.e. BTDA), bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2- ... Phenyl)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) Examples of the 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).

[0043] The compound represented by Chemical Formula 1 is preferably an aromatic tetracarboxylic dianhydride, and may particularly include 3,3',4,4'-biphenyltetracarboxylic dianhydride (i.e., BPDA) or 2,3,3',4'-biphenyltetracarboxylic dianhydride (i.e., a-BPDA).

[0044] For example, the diamine monomer may include at least one compound represented by the following Formula 2:

[0045] [ka]

[0046] In the above formula 2, 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.

[0047] 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:

[0048] 1) Diamines having a relatively rigid structure, such as 1,4-diaminobenzene (i.e., paraphenylenediamine, PPD), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, or 3,5-diaminobenzoic acid (i.e., DABA), which have one benzene nucleus in their structure;

[0049] 2) Diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether (i.e. 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 phenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4-aminophenyl)sulfide, 4,4'-diaminobenzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (i.e. o-tolidine), 2,2'-dimethylbenzidine (i.e. 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 benzene, 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, and 4,4'-diaminodiphenyl sulfoxide;

[0050] 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 (i.e. TPE-Q), 1,4-bis(4-aminophenoxy)benzene (i.e. TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzof diamines having three benzene nuclei in their structure, such as phenol, 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, and 1,4-bis[2-(4-aminophenyl)isopropyl]benzene;

[0051] 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[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]sulfone 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-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-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, 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 (BAPP), 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, and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane.

[0052] The diamine monomer may be used alone or in combination of two or more kinds as necessary. In the present application, taking into consideration their bond dissociation energies, for example, 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene, or 4,4′-methylenediamine (MDA) may be included. Preferably, the compound represented by Chemical Formula 2 may include 1,4-diaminobenzene (PPD).

[0053] 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 control 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.

[0054] In one specific example, the polyamic acid may be in the range of 1 to 50% by weight based on the total solid content. For example, the range may be 3 to 40% by weight, 5 to 30% by weight, or 10 to 20% by weight. If it is less than 1% by weight, the consistency of the varnish coating layer decreases, and conversely, if it exceeds 40% by weight, the storage stability decreases.

[0055] 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.

[0056] The present application relates to a method for producing a polyamic acid. The method can provide a polyamic acid having a high weight average molecular weight by polymerizing the polyamic acid in a specific solvent. Hereinafter, detailed description that overlaps with the above content will be omitted.

[0057] Specifically, the method may include polymerizing a dianhydride monomer and a diamine monomer using 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).

[0058] The present application further relates to a method for increasing the molecular weight of a polyamic acid. Specifically, the present application relates to a method for increasing the molecular weight of a polyamic acid comprising polymerized units derived from a dianhydride monomer and a diamine monomer, using an organic solvent containing at least one of the aforementioned compounds.

[0059] By polymerizing the polyamic acid in the presence of the organic solvent, the weight average molecular weight of the polyamic acid is increased. Specifically, the weight average molecular weight is increased in an environmentally friendly manner compared to the case where NMP is used as the organic solvent. As a result, a polyimide having improved mechanical properties and heat resistance during imidization can be provided.

[0060] More specifically, the weight average molecular weight of the polyamic acid may be in the range of 40,000 g / mol to 100,000 g / mol.

[0061] The present application further relates to a film comprising the aforementioned polyimide precursor, said film being capable of being attached to a substrate of a display device.

[0062] 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, 10 to 50 μm, 20 to 100 μm, 20 to 90 μm, 20 to 80 μm, or 20 to 70 μm, 20 to 60 μm, or 20 to 50 μm.

[0063] In addition, the film can have various physical properties controlled within the following numerical ranges by adjusting the composition materials and content ratio of the polyimide precursor.

[0064] For example, the 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 taken on a UTM machine with a width of 20 mm, a grip distance of 50 mm, and a crosshead speed of 20 min / min.

[0065] The film may have a coefficient of thermal expansion (CTE) measured using a TMA (Thermo Mechanical Analysis) device within a range of 0.1 ppm / °C to 50 ppm / °C, 0.5 ppm / °C to 50 ppm / °C, 1 ppm / °C to 50 ppm / °C, 5 ppm / °C to 50 ppm / °C, 10 ppm / °C to 45 ppm / °C, 15 ppm / °C to 40 ppm / °C, 20 ppm / °C to 40 ppm / °C, 25 ppm / °C to 40 ppm / °C, or 25 ppm / °C to 35 ppm / °C. The measurement may be performed using the TMA device at a temperature rise rate of 10°C / min in a temperature range of 50 to 200°C while applying a load of 0.02 N.

[0066] The 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., or 540 to 600° C. The measurement may be performed using a TGA device at a temperature of 150° C. preheated and a heating rate of 10° C. / min for 30 minutes.

[0067] The present application further relates to a display device. For example, the device includes a substrate and the above-mentioned film attached to 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 because the above-mentioned film is attached to the lower part of the substrate. Effect of the Invention

[0068] The present application provides a polyimide precursor that contains a high molecular weight polyamic acid and thereby can simultaneously realize a low dielectric constant and mechanical properties under severe conditions such as light resistance, heat resistance, insulation properties, and high temperature, etc.; a method for producing the polyamic acid; a method for increasing the molecular weight of the polyamic acid; a film containing the precursor; and a display device in which the film is attached to a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0069] 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.

[0070] Working Example Into a 500 mL glass reaction vessel equipped with a stirrer, nitrogen gas inlet and outlet pipes, 417 g of N,N-dimethylpropionamide (DMPA), 21.7 g (0.2 mol) of 1,4-diaminobenzene (PPD), and 59.1 g (0.2 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) were added, and a polymerization reaction was carried out at 25°C to produce a polyamic acid solution with a solid content concentration of 15%.

[0071] Comparative Example In a 500 mL glass reaction vessel equipped with a stirrer, nitrogen gas inlet and outlet pipes, 417 g of N-methyl-2-pyrrolidone (NMP), 21.7 g (0.2 mol) of 1,4-diaminobenzene (PPD), and 59.1 g (0.2 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) were added and polymerized at 25°C to produce a polyamic acid solution (polyimide precursor) with a solid content of 15%.

[0072] 1. Viscosity measurement The viscosity of the polyamic acid solutions prepared in the Examples and Comparative Examples was measured at 23° C. using a MARS40 manufactured by Haake Co., Ltd., and the results are shown in Table 1 below.

[0073] [Table 1]

[0074] 2. Measurement of weight average molecular weight (Mw) The polyamic acid solutions of the Examples and Comparative Examples were repeatedly produced to produce four samples each (Examples: Samples 1 to 4, Comparative Examples: Samples 5 to 8).

[0075] The weight average molecular weight of the polyamic acid in each sample was measured using GPC, and the results are shown in Table 2 below.

[0076] [Table 2]

[0077] As shown in Table 2, it was confirmed that the Examples using DMPA as a solvent had a higher weight average molecular weight than the Comparative Examples using NMP as a solvent.

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); Including, The polyimide precursor, wherein the weight average molecular weight of the polyamic acid is within a range of 40,000 g / mol to 100,000 g / mol.

2. The polyimide precursor of claim 1, wherein the polyamic acid has a polydispersity index (PDI) in the range of 1 to 5.

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

4. The polyimide precursor according to claim 1 , wherein the dianhydride monomer comprises at least one compound represented by the following Chemical Formula 1: 【Chemistry 1】 In the formula 1, 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 a carbonyl group in the formula 1 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(R ａ ) ２ -, wherein R ａ is hydrogen or an alkyl group.

5. 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 4, comprising at least one selected from the group consisting of

6. The polyimide precursor of claim 4, wherein the compound represented by Formula 1 comprises 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA).

7. The polyimide precursor according to claim 1 , wherein the diamine monomer comprises at least one compound represented by the following formula 2: 【Chemistry 3】 In the above formula 2, B １ ~B ５ is an amino group, and the remainder represents hydrogen, a halogen, a hydroxyl group, a carboxyl group, or an alkyl group which is unsubstituted or substituted with a halogen.

8. The polyimide precursor according to claim 1, wherein the compound represented by Formula 2 comprises 1,4-diaminobenzene (PPD).

9. 2. The polyimide precursor according to claim 1, wherein the polyamic acid is in the range of 1 to 50% by weight based on the total solid content.

10. Temperature of 23° C. and 1s －１ 2. The polyimide precursor according to claim 1, wherein the viscosity measured under a shear rate condition is within a range of 500 to 10,000 cp.

11. A method for producing a polyamic acid, comprising the step of polymerizing a dianhydride monomer and a diamine monomer using 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).

12. A method for increasing the molecular weight of a polyamic acid containing polymerization units derived from a dianhydride monomer and a diamine monomer, using 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).

13. 13. The method for increasing the molecular weight of a polyamic acid according to claim 12, wherein the weight average molecular weight of the polyamic acid is in the range of 40,000 g / mol to 100,000 g / mol.

14. A film comprising the polyimide precursor of claim 1.

15. The film of claim 14, having a thickness in the range of 1 to 100 μm.

16. 15. The film of claim 14, having an elongation of 100% or less, a tensile strength of 700 Mpa or less, and a modulus of 12 Gpa or less.

17. 15. The film of claim 14, having a coefficient of thermal expansion (CTE) in the range of 0.1 ppm / °C to 50 ppm / °C.

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

19. A substrate; A film according to claim 14 attached to the substrate; A display device comprising:

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