Polyamic acid composition

Abstract

Provided are: a polyamic acid composition which has excellent storage stability and is capable of simultaneously achieving a low dielectric constant, heat resistance, insulating properties, and mechanical properties under harsh conditions such as high temperature; a polyimide which is a cured product of the composition; a coated object which includes the polyimide; and an electronic device which includes the coated object.

Description

Technical Field

[0001] The present application relates to a polyamic acid composition, a polyimide as a cured product of the composition, a coating including the polyimide, and an electronic device including the coating. Background Art

[0002] The insulating layer (insulating coating) covering the conductor needs to have excellent insulation performance, adhesion to the conductor, heat resistance, mechanical strength, etc.

[0003] Furthermore, in electrical devices to which high voltage is applied, such as motors used at high voltage, high voltage is applied to insulated wires constituting the electrical devices, whereby partial discharge (corona discharge) is easily generated on the insulating coating surface thereof.

[0004] The occurrence of corona discharge may cause a local temperature increase or generate ozone or ions, resulting in degradation of the insulating coating of the insulated wire, thereby causing early dielectric breakdown and shortening the life of the electrical device.

[0005] For the above reasons, it is necessary to increase the corona discharge inception voltage of an insulated electric wire used at a high voltage, and for this purpose, it is known that lowering the dielectric constant of the insulating layer is effective.

[0006] Examples of the resin that can be used for the insulating layer include polyimide resin, polyamideimide resin, polyesterimide resin, or the like.

[0007] Among them, in particular, polyimide resin is a material having excellent heat resistance and insulation, which has excellent properties for use as a material for coating a conductor.

[0008] Polyimide resin refers to a high heat-resistant resin prepared by preparing a polyamic acid derivative through solution polymerization of aromatic dianhydride and aromatic diamine or aromatic diisocyanate, followed by ring-closing dehydration and imidization at high temperature.

[0009] As a method of forming an insulating coating using such a polyimide resin, for example, a method can be used in which a polyimide varnish as a precursor of a polyimide resin is applied or coated around an electric wire made of a conductor, and then the polyimide varnish is imidized using a curing furnace capable of performing heat treatment at a predetermined temperature.

[0010] However, although general polyimide resins have excellent physical properties, they have poor storage stability and poor adhesion to conductors, and therefore, when forming an insulating coating, appearance defects may occur due to a floating phenomenon between the conductor and the coating.

[0011] Therefore, it is necessary to produce a polyimide varnish for conductor coating that satisfies storage stability, heat resistance, insulation, low dielectric constant, adhesion, and mechanical properties at the same time. Summary of the invention

[0012] Technical issues

[0013] The present application provides a polyamic acid composition having excellent storage stability and capable of simultaneously achieving low dielectric constant, heat resistance, insulation and mechanical properties under harsh conditions such as high temperature, a polyimide as a cured product of the composition, a coating comprising the polyimide and an electronic device comprising the coating.

[0014] Solutions to the problem

[0015] The present application relates to a polyamic acid composition. The polyamic acid composition according to the present invention may be a polyimide varnish capable of providing polyimide that can simultaneously satisfy flexibility, light resistance, heat resistance, insulation, adhesion and high-temperature mechanical properties after curing.

[0016] The polyamic acid composition comprises a dianhydride monomer and a diamine monomer as polymerization units, and the viscosity change rate at 23°C (ΔV 23℃ ) meets -25% to +25%.

[0017] [General formula 1]

[0018] △V 23℃ = (V2 - V1) / V1 × 100

[0019] In the above general formula 1, ΔV 23℃ It shows the change rate of the viscosity (V2) of the polyamic acid composition stored in a sealed storage container for one week at a temperature of 23° C. relative to the viscosity (V1) of the polyamic acid composition before storage.

[0020] For example, the above 23°C viscosity change rate (△V 23℃ ) can satisfy -25% to +25%, -22% to +22%, -20% to +20%, -19% to +19%, -18% to +18%, -16% to +16%, -14% to +14%, -12% to +12% or -10% to +10%. The viscosity (V1, V2) of the above general formula 1 can be measured using Rheostress 600 of Haake Company, and can be measured under the conditions of a shear rate of 1 / s, a temperature of 30°C and a plate gap of 1mm. The above storage container can use various known materials without limitation, for example, an aluminum can or a PP material bottle can be used.

[0021] Since the polyamic acid composition according to the present application satisfies the above General Formula 1, it is excellent in storage stability at 23°C.

[0022] According to the following general formula 2 of the polyamic acid composition of the present application, the 30°C viscosity change rate (ΔV 30℃ ) can meet -30% to +30%.

[0023] [General formula 2]

[0024] △V 30℃ = (V4 - V3) / V3 × 100

[0025] In the above general formula 2, ΔV 30℃ It shows the change rate of the viscosity (V4) of the polyamic acid composition stored in a sealed storage container at a temperature of 30° C. for one week relative to the viscosity (V3) of the polyamic acid composition before storage.

[0026] For example, the above 30℃ viscosity change rate (△V 30℃ ) can meet -30% to +30%, -25% to +25%, -22% to +22%, -20% to +20%, -19% to +19%, -18% to +18%, -16% to +16%, -14% to +14%, -12% to +12% or -10% to +10%.

[0027] Since the polyamic acid composition according to the present application satisfies the above General Formula 2, it is excellent in storage stability at 30°C.

[0028] The viscosity (V3, V4) of the general formula 2 can be measured using Rheostress 600 of Haake Company, and can be measured under the conditions of a shear rate of 1 / s, a temperature of 30° C., and a plate gap of 1 mm.

[0029] The polyamic acid composition according to the present application may further include a modifying monomer represented by Chemical Formula 1 below.

[0030] [Chemical formula 1]

[0031]

[0032] In the above Chemical Formula 1, A1 to A4 are each independently selected from a hydroxyl group (-OH), an amine group (-NH2), an alkoxy group, and an oxygen anion (-O -), in the above chemical formula 1, X is a tetravalent aliphatic cyclic group, a tetravalent heteroaliphatic cyclic group, a tetravalent aromatic cyclic group or a tetravalent heteroaromatic cyclic group, the carbon atom of the carbonyl group in Chemical Formula 1 is connected to the atoms constituting the ring of the above aliphatic cyclic group, the above heteroaliphatic cyclic group, the above aromatic cyclic group or the above heteroaromatic cyclic group, the above aliphatic cyclic group, the above heteroaliphatic cyclic group, the above aromatic cyclic group or the above heteroaromatic cyclic group is a monocyclic ring; or is bonded to form a polycyclic ring; or is selected from 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 b ) 2-comprising a connecting group including at least one divalent substituent, wherein R b is hydrogen or alkyl.

[0033] Preferably, X in the above chemical formula 1 is phenyl, biphenyl, or an aliphatic cyclic group,

[0034] The M includes at least one selected from the group consisting of a single bond, an alkylene group, an alkylidene group, -O-, -S-, -C(=O)-, and -S(=O)2-.

[0035] The modified monomer represented by the above chemical formula 1 can be derived from a dianhydride monomer as a polymerization unit of polyamic acid. As the molar number of the above modified monomer increases, the elongation of the polyimide as a cured product tends to decrease. When coating a conductor, the elongation of the coating film can be induced to be consistent with the elongation of the conductor coating winding by adjusting the molar number of the modified monomer, thereby suppressing the floating phenomenon between the winding and the coating film.

[0036] In one example, the content of the modifying monomer represented by the above Chemical Formula 1 may be in the range of 6 mol % to 15 mol % based on 100 mol % of the diamine monomer of the polyamic acid. Based on 100 mol % of the diamine monomer of the polyamic acid, the content of the above-mentioned modifying monomer can be in the range of 6 mol % to 14 mol %, in the range of 6 mol % to 13 mol %, in the range of 6 mol % to 12 mol %, in the range of 6 mol % to 11 mol %, in the range of 6 mol % to 10 mol %, in the range of 6.5 mol % to 15 mol %, in the range of 6.5 mol % to 14 mol %, in the range of 6.5 mol % to 13 mol %, in the range of 6.5 mol % to 12 mol %, in the range of 6.5 mol % to 11 mol %, in the range of 6.5 mol % to 10 mol %, in the range of 7 mol % to 15 mol %, in the range of 7 mol % to 14 mol %, in the range of 7 mol % to 13 mol %, in the range of 7 mol % to 12 mol %, in the range of 7 mol % to 11 mol %, or in the range of 7 mol % to 10 mol %. When the molar ratio of the modified monomer is adjusted within the above range, excellent storage stability may be achieved, elongation may be improved during curing, and excellent thermal stability, electrical properties, and mechanical stability may be achieved.

[0037] In another example, the molar ratio (A:B) of the dianhydride monomer (A) to the modifying monomer (B) of the polyamic acid may be in the range of 1:0.06 to 1:0.15, in the range of 1:0.06 to 1:0.14, in the range of 1:0.06 to 1:0.13, in the range of 1:0.06 to 1:0.12, in the range of 1:0.06 to 1:0.11, in the range of 1:0.06 to 1:0.1, in the range of 1:0.07 to 1:0.14, in the range of 1:0.07 to 1:0.13, in the range of 1:0.07 to 1:0.12, in the range of 1:0.07 to 1:0.11, or in the range of 1:0.07 to 1:0.1.

[0038] In a specific example, the dianhydride monomer as the polymerization unit of the polyamic acid may include at least one compound represented by the following Chemical Formula 2.

[0039] [Chemical formula 2]

[0040]

[0041] In the above Chemical Formula 2, Y is a tetravalent aliphatic cyclic group, a tetravalent heteroaliphatic cyclic group, a tetravalent aromatic cyclic group or a tetravalent heteroaromatic cyclic group, the carbon atom of the carbonyl group in Chemical Formula 2 is connected to the atom constituting the ring of the above aliphatic cyclic group, the above heteroaliphatic cyclic group, the above aromatic cyclic group or the above heteroaromatic cyclic group, the above aliphatic cyclic group, the above heteroaliphatic cyclic group, the above aromatic cyclic group or the above heteroaromatic cyclic group is a monocyclic ring; or is mutually bonded to form a polycyclic ring; or is connected to the above by 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-comprising a connecting group including at least one divalent substituent, wherein R a is hydrogen or alkyl.

[0042] Preferably, Y in the above chemical formula 2 is phenyl, biphenyl, or an aliphatic cyclic group,

[0043] The M includes at least one selected from the group consisting of a single bond, an alkylene group, an alkylidene group, -O-, -S-, -C(=O)-, and -S(=O)2-.

[0044] In the present specification, unless otherwise specifically specified, the term "aliphatic cyclic group" may refer to an aliphatic cyclic group having 3 to 30 carbon atoms, 4 to 25 carbon atoms, 5 to 20 carbon atoms, and 6 to 16 carbon atoms. For example, specific examples of the tetravalent aliphatic cyclic group include groups obtained by removing 4 hydrogen atoms from a ring of a cyclohexane ring, a cycloheptane ring, a cyclodecane ring, a cyclododecane ring, a norbornane ring, an isobornane ring, an adamantane ring, a cyclododecane ring, a bicyclopentane ring, and the like.

[0045] In this specification, unless otherwise specified, the term "aromatic ring group" may refer to an aromatic ring group having 4 to 30 carbon atoms, 5 to 25 carbon atoms, 6 to 20 carbon atoms and 6 to 16 carbon atoms. The above aromatic ring group may be a monocyclic ring or a condensed ring. For example, examples of tetravalent aromatic hydrocarbon ring groups include groups obtained by removing 4 hydrogen atoms from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring or a pyrene ring.

[0046] In the present specification, the term "arylene group" may refer to a divalent organic group derived from the above-mentioned aromatic ring group.

[0047] In the present specification, the term "heterocyclic group" includes a heteroaliphatic ring group and a heteroaromatic ring group.

[0048] As used herein, the term "heteroaliphatic cyclic group" may refer to a cyclic group in which at least one of the carbon atoms of the above-mentioned aliphatic cyclic group is substituted with at least one heteroatom selected from the group consisting of nitrogen, oxygen, sulfur and phosphorus.

[0049] In the present specification, unless otherwise specified, the term "heteroaromatic ring group" may refer to a ring group in which at least one carbon atom of the above aromatic ring group is substituted by at least one heteroatom selected from the group consisting of nitrogen, oxygen, sulfur and phosphorus. The above heteroaromatic ring group may be a monocyclic ring or a condensed ring.

[0050] The above-mentioned aliphatic cyclic group, the above-mentioned heteroaliphatic cyclic group, the above-mentioned aromatic cyclic group or the above-mentioned heteroaromatic cyclic group may be substituted by at least one substituent selected from the group consisting of halogen, hydroxyl, carboxyl, alkyl having 1 to 4 carbon atoms which may be substituted or unsubstituted by halogen, and alkoxy having 1 to 4 carbon atoms.

[0051] In this specification, the term "single bond" may refer to a bond connecting two atoms in the absence of any atom. For example, if X in the above chemical formula 1 or Y in the above chemical formula 2 is , where M is a single bond, the two aromatic rings can be directly connected to each other.

[0052] In this specification, unless otherwise specified, the term "alkyl" may refer to 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. The above-mentioned alkyl group may have a straight chain, a branched chain or a cyclic structure, and may be optionally substituted by one or more substituents. For example, the above-mentioned substituent may be a polar functional group such as at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0053] In this specification, unless otherwise specified, the term "alkenyl" may refer 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. The alkenyl group may have a straight chain, a branched chain or a cyclic structure, and may be optionally substituted with one or more substituents. For example, the substituent may be a polar functional group such as at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0054] In this specification, unless otherwise specified, the term "alkynyl" may refer to an alkynyl 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. The above-mentioned alkynyl group may have a straight chain, a branched chain or a cyclic structure, and may be optionally substituted by one or more substituents. For example, the above-mentioned substituent may be a polar functional group such as at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0055] In this specification, unless otherwise specified, the term "alkylene" may refer 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. The above-mentioned alkylene group is a divalent organic group from which two hydrogen atoms are removed from different carbon atoms, and may have a straight chain, a branched chain or a cyclic structure, and may be optionally substituted with one or more substituents. For example, the above-mentioned substituent may be a polar functional group such as at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0056] In this specification, unless otherwise specified, the term "alkylidene" may refer to an alkylidene 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. The above-mentioned alkylidene is a divalent organic group from which two hydrogen atoms are removed from a carbon atom, and may have a straight chain, a branched chain or a cyclic structure, and may be optionally substituted by one or more substituents. For example, the above-mentioned substituent may be a polar functional group such as at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0057] In this specification, unless otherwise specified, the term "alkoxy" may refer 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. The above-mentioned alkoxy group may include an alkyl group having a straight chain, a branched chain or a cyclic structure, and the above-mentioned alkyl group may be optionally substituted with one or more substituents. For example, the above-mentioned substituent group may be at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether groups, etc.

[0058] In this specification, unless otherwise specified, the term "alkylamine" includes monoalkylamine (-NHR) or dialkylamine (-NR2), wherein R may each independently refer to 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. The alkyl group may include an alkyl group having a linear, branched or cyclic structure, and may be optionally substituted with one or more substituents. For example, the substituent may be at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0059] In this specification, unless otherwise specifically provided, the term "alkylamide" includes monoalkylamide (-C(O)NHR) or dialkylamide (-C(O)NR2), wherein R may each independently refer to 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. The above-mentioned alkyl group may include an alkyl group having a linear, branched or cyclic structure, and may be optionally substituted with one or more substituents. For example, the above-mentioned substituent may be at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0060] In this specification, unless otherwise specified, the term "thiol ether group" or "sulfide" may refer to -SR, wherein R may each independently refer to 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. Wherein, the above-mentioned alkyl group may include an alkyl group having a straight chain, a branched chain or a cyclic structure, and may be optionally substituted with one or more substituents. For example, the above-mentioned substituent may be at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0061] In the present specification, unless otherwise specifically provided, the term "sulfoxide" may refer to -S(O)R, wherein R may each independently refer to 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. The alkyl group may include an alkyl group having a linear, branched or cyclic structure, and may be optionally substituted with one or more substituents. For example, the substituent may be at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0062] In the present specification, unless otherwise specifically provided, the term "carbonyl" may include -C(O)R, wherein R may each independently refer to 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. The above-mentioned alkyl group may include an alkyl group having a linear, branched or cyclic structure, and may be optionally substituted with one or more substituents. For example, the above-mentioned substituent may be at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0063] In this specification, unless otherwise specifically provided, the term "ester" may include -C(O)OR or -OC(O)R, wherein R may each independently refer to 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. The above-mentioned alkyl group may include an alkyl group having a linear, branched or cyclic structure, and may be optionally substituted with one or more substituents. For example, the above-mentioned substituent may be at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, thiol or thiol ether.

[0064] Examples of the aliphatic tetracarboxylic dianhydride satisfying the above Chemical Formula 2 may include 1,2,4,5-cyclohexanetetracarboxylic dianhydride (or HPMDA), bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride 2:3,5:6-dianhydride (BODA), 1,2,3,4-cyclohexanetetracarboxylic dianhydride (CHMDA), bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride 2:3,5:6-dianhydride (BHDA), butane-1,2,3,4-tetracarboxylic dianhydride (BTD), bicyclo-[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride 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-spiro norbornane tetracarboxylic dianhydride (CpODA), bicyclo[2.2.1]heptane-2,3,5-tricarboxylic-5-acetic dianhydride (BSDA), dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride (DCDA), dicyclohexyl-2,3'3,4'-tetracarboxylic dianhydride anhydride (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-naphthalene succinic anhydride (TDA), 3,4-dicarboxy-1,2,3,4-tetrahydro-6-methyl-1-naphthalene butyric acid MTDA, 3,4-dicarboxy-1,2,3,4-tetrahydro-6-fluoro-1-naphthalenesuccinic acid dianhydride (FTDA), 3,3,3',3'-tetramethyl-1,1'-spirobiindane-5,5',6,6'-tetracarboxylic acid anhydride (SBIDA), 4,4,4',4'-tetramethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[furan[3,4-g]chromene]-6,6',8,8'-tetraone (SBCDA) and 9,10-difluoro-9,10-bis(trifluoromethyl)-9,10-dihydroanthracene-2,3,6,7-tetracarboxylic acid dianhydride (6FDA), etc.

[0065] Examples of the aromatic tetracarboxylic dianhydride satisfying the above Chemical Formula 2 may include 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), diphenyl sulfone-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',4,4'-benzophenonetetracarboxylic dianhydride (or BTDA), bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2 -Bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylene bis(trimellitic acid monoester anhydride), p-biphenylene bis(trimellitic acid monoester anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic acid dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic acid dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic 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 or 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride (6-FDA), etc.

[0066] In one embodiment, preferably, the dianhydride monomer may be an aromatic tetracarboxylic dianhydride, for example, may be at least one selected from PDMA, BPDA, a-BPDA, ODPA, DSDA and BTDA.

[0067] In one embodiment, the diamine monomer may include at least one compound represented by the following Chemical Formula 3.

[0068] [Chemical formula 3]

[0069]

[0070] In the above Chemical Formula 3, at least one of B1 to B5 is an amino group, and the rest are hydrogen; halogen; hydroxyl; carboxyl; or alkyl which may be substituted with halogen.

[0071] As an example, the above-mentioned diamine monomer is an aromatic diamine, which can be classified and exemplified as follows.

[0072] 1) A diamine having a benzene nucleus in the structure, such as 1,4-diaminobenzene (or p-phenylenediamine, PPD), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene or 3,5-diaminobenzoic acid (or DABA), has a relatively rigid structure;

[0073] 2) Diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether (or oxydiphenylamine, ODA) and 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'-diamino 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4-aminophenyl) sulfide, 4,4'-diaminobenzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (or o-benzidine), 2,2'-dimethylbenzidine (or m-toluidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether Phenyl 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'-diamino diamines having two benzene nuclei in the structure, such as 2,4'-diaminodiphenylmethane, 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;

[0074] 3) Such as 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-aminophenyl)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'- A diamine having three benzene nuclei in its structure, such as bis(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenylene sulfide)benzene, 1,3-bis(4-aminophenylene sulfide)benzene, 1,4-bis(4-aminophenylene sulfide)benzene, 1,3-bis(3-aminophenyl sulfone)benzene, 1,3-bis(4-aminophenyl sulfone)benzene, 1,4-bis(4-aminophenyl sulfone)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;

[0075] 4) Such as 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] ketone, 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] 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, 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, A diamine having four benzene nuclei in its 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.

[0076] As required, the above-mentioned diamine monomers can be used alone or in combination of two or more. In the present application, considering the bond dissociation energy, two or more diamine monomers with different structural characteristics can be used in combination. For example, a diamine having one benzene nucleus in its structure and a diamine having two or more benzene nuclei in its structure can be used in combination.

[0077] In one embodiment, the diamine monomer may include at least two of 1,4-diaminobenzene (PPD), 4,4'-diaminodiphenyl ether (or oxydiphenylamine, ODA), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene and 4,4'-methylenediamine (MDA), for example, 1,4-diaminobenzene (PPD) and 4,4'-diaminodiphenyl ether (or oxydiphenylamine, ODA).

[0078] In a specific example, based on the total weight, the above-mentioned polyamic acid composition can include a solid content of 5% to 40% by weight, 5% to 35% by weight, 10% to 40% by weight, 10% to 35% by weight, 10% to 30% by weight, 15% to 40% by weight or 15% to 35% by weight, preferably, a solid content of 15% to 30% by weight can be included. The application controls the viscosity increase by adjusting the solid content of the polyamic acid composition, and prevents the increase of the manufacturing cost and process time required to remove a large amount of solvent during the curing process.

[0079] In a specific example, the weight average molecular weight of the polyamic acid of the present application can be in the range of 10000 g / mol to 100000 g / mol, 15000 g / mol to 80000 g / mol, 18000 g / mol to 70000 g / mol, 20000 g / mol to 60000 g / mol, 25000 g / mol to 55000 g / mol or 30000 g / mol to 50000 g / mol. In the present application, the term weight average molecular weight refers to the converted value relative to the standard polystyrene measured by gel permeation chromatography (Gel permeation Chromatograph, GPC).

[0080] In the present application, based on the total solid content, the content of the polyamic acid can be 1 wt % to 50 wt %, 1 wt % to 45 wt %, 1 wt % to 40 wt %, 1 wt % to 30 wt %, 5 wt % to 50 wt %, 5 wt % to 45 wt %, 5 wt % to 40 wt %, 5 wt % to 30 wt %, 5 wt % to 25 wt %, 5 wt % to 20 wt %, 10 wt % to 20 wt %, or 15 wt % to 20 wt %.

[0081] The polyamic acid composition of the present application may have a low viscosity characteristic. The polyamic acid composition of the present application is heated to 23°C for 1 second. -1The viscosity measured under the shear rate conditions can be 50000cp, 40000cp, 30000cp, 20000cp, 10000cP or less or 9000cP or less. The lower limit is not particularly limited, but can be more than 500cP or more than 1000cP. Preferably, the above viscosity can be in the range of 1000cP to 30000cP. For example, the above viscosity can be measured using Rheostress 600 of Haake Company, and can be measured under the conditions of a shear rate of 1 / s, a temperature of 23°C and a plate gap of 1mm. The present application can provide a polyamic acid composition with excellent processability and convenient product application by adjusting the above viscosity range.

[0082] In the present application, the polyamic acid composition may include an organic solvent. The organic solvent is not particularly limited as long as it is a solvent capable of dissolving the polyamic acid, but the organic solvent may be, for example, an aprotic polar solvent.

[0083] Non-limiting examples of the above-mentioned aprotic polar solvents may include: amide solvents such as N,N'-dimethylformamide (DMF), N,N'-diethylformamide (DEF), N,N'-dimethylacetamide (DMAc) or dimethylpropionamide (DMPA); phenol solvents such as p-chlorophenol, o-chlorophenol, etc.; N-methyl-pyrrolidone (NMP); γ-butyrolactone (GBL) or diethylene glycol dimethyl ether (Diglyme), etc., which can be used alone or in combination of two or more.

[0084] In the present application, in some cases, the solubility of the polyamic acid can be adjusted by using an auxiliary solvent such as toluene, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, ethanol or water.

[0085] In one example, for example, the organic solvent may be N-methylpyrrolidone (NMP).

[0086] The polyamic acid may be formed by polymerizing a diamine monomer and a dianhydride monomer in an inert atmosphere at a temperature ranging from 20°C to 60°C.

[0087] The present application also relates to a polyimide which is a cured product of the polyamic acid composition. Since the polyimide is cured from the polyamic acid composition, it can simultaneously meet the requirements of flexibility, light resistance, heat resistance, insulation, adhesion and high-temperature mechanical properties.

[0088] The polyimide may be formed by thermal curing of polyamic acid. For example, the thermal curing may be performed at a temperature ranging from 100°C to 600°C.

[0089] By adjusting the materials and content ratio of the polyamic acid composition, various physical properties of the polyimide can be controlled within the following numerical ranges.

[0090] The following physical properties may be measured after the polyimide is formed into a sample in the form of a thin film having a thickness of 10 μm to 30 μm.

[0091] For example, the elongation of the polyimide measured using a universal testing machine (UTM) may be in the range of 10% to 60%. For example, the upper limit of the elongation may be 58% or less, 55% or less, 53% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, or 25% or less, and the lower limit of the elongation may be 10% or more, 12% or more, 15% or more, 18% or more, or 20% or more.

[0092] The tensile strength of the polyimide measured using a universal testing machine may be 500 MPa or less, for example, 450 MPa or less, 400 MPa or less, 350 MPa or less, 300 MPa or less, 250 MPa or less, 200 MPa or less, 195 MPa or less, 190 MPa or less, or 150 MPa or less, and the elastic modulus may be 15 Gpa or less, 12 Gpa or less, 11 Gpa or less, 10 Gpa or less, 9 Gpa or less, 8 Gpa or less, 7 Gpa or less, 6 Gpa or less, 5 Gpa or less, 4 Gpa or less, or 3 Gpa or less. The above measurement may be performed using a UTM device at a width of 20 mm, a clamping distance of 50 mm, and a crosshead speed of 20 min / min.

[0093] In addition, the thermal expansion coefficient (CTE) of the polyimide measured using a thermomechanical analysis (TMA) device may be in the 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 while applying a load of 0.02 N at a temperature increase rate of 10°C / min in a temperature range of 50°C to 200°C using the TMA device.

[0094] The glass transition temperature of the polyimide measured using a dynamic mechanical analysis (DMA) device may be in the range of 200° C. to 500° C., 250° C. to 450° C., 300° C. to 400° C., or 350° C. to 400° C. The measurement may be performed using the DMA device at a temperature increase rate of 5° C. / min.

[0095] In addition, the 5% thermal decomposition temperature of the polyimide measured using a thermogravimetric analysis (TGA) device may be in the range of 450° C. to 650° C., 450° C. to 600° C., or 450° C. to 580° C. The measurement may be performed by preheating to a temperature of 150° C. and using a TGA device at a temperature increase rate of 10° C. / min for 30 minutes.

[0096] In addition, the dielectric constant (Dk) of the polyimide measured according to ASTM D150 may be in the range of 1 to 5, 1 to 4.5, 1.5 to 4.5, 2 to 4, 2.5 to 4, 3 to 4, or 3.2 to 4.

[0097] The dielectric breakdown voltage (BDV) of the above-mentioned polyimide measured according to ASTM D149 can be in the range of 100kV / mm to 500kV / mm, 120kV / mm to 480kV / mm, 140kV / mm to 450kV / mm, 150kV / mm to 400kV / mm, 170kV / mm to 350kV / mm, 190kV / mm to 320kV / mm, 200kV / mm to 300kV / mm, 210kV / mm to 280kV / mm or 220kV / mm to 250kV / mm. The above-mentioned dielectric breakdown voltage can be measured by methods known in the industry. In one example, the dielectric breakdown voltage can be measured as follows. The above-mentioned polyimide is made into a sample in the form of a film, and all moisture of the film is removed in an oven below 100°C. Then, after cutting the sample into appropriate size, use a dielectric breakdown tester (Automated Test Set for Insulating Materials, equipment suitable for ASTM D149 standard, PHENIX TECHNOLOGIES 6CCE50-5). After placing the sample on the sample stage, increase the voltage from 0 at a constant speed to measure the ultimate dielectric strength of the insulator.

[0098] In addition, the present application relates to a coating. The coating may include a polyimide as a cured product of the polyamic acid composition. The coating may include a substrate; and a polyimide covering the upper portion of the substrate. For example, the polyimide may be coated and cured on the surface of a conductor.

[0099] The substrate may be a conductor. The conductor may be a copper wire made of copper or a copper alloy, but may also include a conductor made of other metal materials (e.g., silver wire, etc.) or various metal-plated wires (e.g., aluminum wire or tinned wire, etc.). The thickness of the conductor and the coating may conform to the KSC 3107 standard. The diameter of the conductor may be in the range of 0.3 mm to 3.2 mm, and as the standard film thickness of the coating (the average value of the maximum film thickness and the minimum film thickness), type 0 is 21 μm to 194 μm, type 1 is 14 μm to 169 μm, and type 2 is 10 μm to 31 μm. The cross-sectional shape of the conductor may be a loop wire, a rectangular wire, a hexagonal wire, etc., but is not limited thereto.

[0100] In one example, the method for preparing the coating may include the following steps: coating a polyamic acid composition on a surface of a conductor; and imidizing the polyamic acid composition coated on the surface of the conductor.

[0101] The present invention may also provide an electronic device comprising the above-mentioned covering.

[0102] Effects of the Invention

[0103] The present application provides a polyamic acid composition having excellent storage stability and capable of simultaneously achieving low dielectric constant, heat resistance, insulation and mechanical properties under harsh conditions such as high temperature, a polyimide as a cured product of the composition, a coating comprising the polyimide, a coated wire comprising the above-mentioned coating, and an electronic device comprising the coated wire. DETAILED DESCRIPTION

[0104] Hereinafter, the present invention will be described in more detail by referring to the examples of the present invention and comparative examples not related to the present invention. However, the scope of the present invention is not limited to the following examples.

[0105] Example 1

[0106] Preparation of polyamic acid composition

[0107] N-methylpyrrolidone (NMP) was introduced into a 500 ml reactor equipped with a stirrer and a nitrogen injection / exhaust tube while nitrogen was injected therein, and after the reactor temperature was set to 40°C, 4,4'-diaminodiphenyl ether (or oxydiphenylamine, ODA), pyromellitic dianhydride (PMDA) and modified pyromellitic dianhydride (PMDA*) were also introduced and confirmed to be completely dissolved. Next, 1,4-diaminobenzene (or p-phenylenediamine, PPD) was introduced and a polymerization reaction was carried out in the same manner to prepare a polyamic acid composition.

[0108] The modified pyromellitic dianhydride (PMDA*) is represented by the following Chemical Formula 4.

[0109] [Chemical formula 4]

[0110]

[0111] Preparation of polyimide film

[0112] The polyamic acid composition was cured at 100°C for 20 minutes, 150°C for 20 minutes, 200°C for 20 minutes, 300°C for 20 minutes, 350°C for 20 minutes, and 110°C for 60 minutes to obtain a polyimide film with a thickness of 30 μm.

[0113] Examples 2 to 4 and Comparative Examples 1 to 2

[0114] Polyamic acid compositions and polyimide films of Examples 2 to 4 and Comparative Examples 1 to 2 were prepared in the same manner as in Example 1, except that the monomers and their content ratios were changed as shown in Table 1 below.

[0115] Table 1

[0116]

[0117] Experimental Example 1 - Viscosity Change Rate at 23°C and 30°C

[0118] The polyamic acid compositions of Examples and Comparative Examples were stored in sealed storage containers at 23° C. and 30° C. for 1 week, and the viscosity change rates before and after storage were measured. The results are shown in Table 2 below.

[0119] The viscosity before and after the above storage was measured using a Rheostress 600 from Haake at a shear rate of 1 / s, a temperature of 23°C (or a temperature of 30°C) and a plate gap of 1 mm.

[0120] Experimental Example 2 - Elongation, tensile strength and elastic modulus

[0121] The elongation, tensile strength and elastic modulus of the polyimide films prepared in Examples and Comparative Examples were measured using a universal testing machine. The results are shown in Table 2 below.

[0122] Experimental Example 3-Glass Transition Temperature

[0123] The glass transition temperatures of the polyimide films prepared in Examples and Comparative Examples were measured using a dynamic mechanical analyzer. The results are shown in Table 2 below.

[0124] Experimental Example 4-5% Thermal Decomposition Temperature

[0125] The 5% thermal decomposition temperatures of the polyimide films prepared in Examples and Comparative Examples were measured using a thermogravimetric analyzer. The results are shown in Table 2 below.

[0126] Experimental Example 5 - Coefficient of Thermal Expansion (CTE)

[0127] The thermal expansion coefficients of the polyimide films prepared in Examples and Comparative Examples were measured using a thermomechanical analyzer. The results are shown in Table 2 below.

[0128] Experimental Example 6-Dielectric Constant

[0129] The dielectric constants of the polyimide films prepared in Examples and Comparative Examples were measured according to ASTM D150, and the results are shown in Table 2 below.

[0130] Experimental Example 7-Dielectric Breakdown Voltage

[0131] The polyimide films prepared in the examples and comparative examples were made into samples, and all moisture in the films was removed in an oven below 100°C. Then, after the samples were cut into appropriate sizes, a dielectric breakdown tester (Automated Test Set for Insulating Materials, equipment suitable for ASTM D149 standard, PHENIX TECHNOLOGIES 6CCE50-5) was used. After the samples were placed on the sample stage, the voltage was increased from 0 at a constant speed to measure the ultimate dielectric strength of the insulator, and the results are shown in Table 2 below.

[0132] Table 2

[0133]

[0134] As shown in Table 2, Comparative Example 1 is a sample containing a smaller amount of modified monomers than the examples, and the 23°C viscosity change rate and the 30°C viscosity change rate are 28% and 51%, respectively, showing results exceeding the upper limits of 25% and 30%. In addition, even if the molar ratio of diamine to dianhydride is close to 1:1, the modified monomer is not sufficiently contained, and thus the desired storage stability cannot be ensured, resulting in a result that the viscosity change rate value exceeds the upper limit value.

[0135] In addition, Comparative Example 2 is a sample not containing a modified monomer, and the viscosity change rate values ​​at 23°C and 30°C are 35% and 80%, respectively, showing results exceeding the upper limits of 25% and 30%. Since the molar ratio of diamine to dianhydride is 100:95, which is lower than the general mixing ratio of 1:1 and the molecular weight is low, a film cannot be formed and other physical properties cannot be measured.

Claims

1. A polyamic acid composition, characterized in that The polyamic acid comprises a dianhydride monomer and a diamine monomer as polymerization units. The viscosity change rate ΔV at 23°C of the polyamic acid composition of the following general formula 1 is 23℃ Satisfy -25% to +25%: [General formula 1] <h2 style=";text-align:left;direction:ltr">△V<h2 style=";text-align:left;direction:ltr"> 23℃ <h2 style=";text-align:left;direction:ltr"> =(V2 - V1) / V1×100 In the above general formula 1, ΔV 23℃ It represents the rate of change of the viscosity V2 of the polyamic acid composition stored in a sealed storage container at a temperature of 23° C. for one week relative to the viscosity V1 of the polyamic acid composition before storage.

2. The polyamic acid composition according to claim 1, characterized in that The viscosity change rate ΔV at 30°C of the polyamic acid composition of the following general formula 2 is 30℃ Satisfy -30% to +30%: [General formula 2] △V 30℃ =(V4 - V3) / V3×100 In the above general formula 2, ΔV 30℃ It represents the rate of change of the viscosity V4 of the polyamic acid composition stored in a sealed storage container at a temperature of 30° C. for one week relative to the viscosity V3 of the polyamic acid composition before storage.

3. The polyamic acid composition according to claim 1, characterized in that Further comprising a modified monomer represented by the following Chemical Formula 1: [Chemical formula 1] In the above Chemical Formula 1, A1 to A4 are each independently selected from a hydroxyl group (-OH), an amine group (-NH2), an alkoxy group, and an oxygen anion (-O - ), 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 the carbon atom of the carbonyl group in Chemical Formula 1 is connected to an atom constituting a ring of the above aliphatic ring group, heteroaliphatic ring group, aromatic ring group or heteroaromatic ring group, The above-mentioned aliphatic cyclic group, the above-mentioned heteroaliphatic cyclic group, the above-mentioned aromatic cyclic group or the above-mentioned heteroaromatic cyclic group is a monocyclic ring; or is joined to each other to form a polycyclic ring; or is selected from 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-comprising a connecting group including at least one divalent substituent, wherein R a is hydrogen or alkyl.

4. The polyamic acid composition according to claim 3, characterized in that The content of the modifying monomer represented by the above Chemical Formula 1 is 6 to 15 mol % based on 100 mol % of the diamine monomer of the polyamic acid.

5. The polyamic acid composition according to claim 1, characterized in that The dianhydride monomer includes at least one compound represented by the following Chemical Formula 2: [Chemical formula 2] In the above Chemical Formula 2, Y is a tetravalent aliphatic ring group, a tetravalent heteroaliphatic ring group, a tetravalent aromatic ring group or a tetravalent heteroaromatic ring group, and the carbon atom of the carbonyl group in Chemical Formula 2 is connected to the atoms constituting the ring of the above aliphatic ring group, heteroaliphatic ring group, aromatic ring group or heteroaromatic ring group, The above-mentioned aliphatic cyclic group, the above-mentioned heteroaliphatic cyclic group, the above-mentioned aromatic cyclic group or the above-mentioned heteroaromatic cyclic group is a monocyclic ring; or is joined to each other to form a polycyclic ring; or is selected from 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-comprising a connecting group including at least one divalent substituent, wherein R a is hydrogen or alkyl.

6. The polyamic acid composition according to claim 1, characterized in that The dianhydride monomer includes at least one compound represented by the following Chemical Formula 3: [Chemical formula 3] In the above Chemical Formula 3, at least one of B1 to B5 is an amino group, and the rest are hydrogen; halogen; hydroxyl; carboxyl; or alkyl which may be substituted with halogen.

7. The polyamic acid composition according to claim 3, characterized in that: The molar ratio A:B of the dianhydride monomer A to the modifying monomer B of the polyamic acid is in the range of 1:0.06 to 1:0.

15.

8. The polyamic acid composition according to claim 1, characterized in that: The solid content is in the range of 5 wt % to 40 wt %.

9. The polyamic acid composition according to claim 1, characterized in that: At 30℃ and 1s -1 The viscosity measured under shear rate conditions ranges from 1000 cp to 50000 cp.

10. A polyimide, characterized in that: A cured product of the polyamic acid composition according to claim 1.

11. The polyimide according to claim 10, characterized in that The elongation measured using a universal testing machine ranged from 10% to 60%.

12. The polyimide according to claim 10, characterized in that The thermal expansion coefficient measured using a thermomechanical analysis device is in the range of 0.1 ppm / °C to 50 ppm / °C.

13. The polyimide according to claim 10, characterized in that The glass transition temperature measured using a dynamic mechanical analysis device is in the range of 200°C to 500°C.

14. The polyimide according to claim 10, characterized in that The 5% thermal decomposition temperature measured using a thermogravimetric analysis apparatus is in the range of 450°C to 650°C.

15. The polyimide according to claim 10, characterized in that The dielectric constant measured according to ASTM D150 is in the range of 1 to 5.

16. The polyimide according to claim 10, characterized in that The dielectric breakdown voltage measured according to ASTM D149 is in the range of 100 kV / mm to 500 kV / mm.

17. A covering, characterized in that: include: Base material; and The polyimide according to any one of claims 10 to 16 coated on the above substrate.

18. The covering according to claim 17, characterized in that The substrate is a conductor.

19. An electronic device, characterized in that: Comprising the covering according to claim 17.

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