Self-lubricating polyimide varnish and polyimide coating produced therefrom

Abstract

The present invention provides a polyimide varnish containing a polyamic acid containing one or more dianhydride monomers and one or more diamine monomers as polymerization units, nanosilica surface-modified with an organic silane, a silicon-based additive represented by the following Chemical Formula 1, and an organic solvent. 【Chemical Formula 1】 TIFF2025521661000009.tif42168

Description

Technical Field

[0001] The present invention relates to a self-lubricating polyimide varnish and a polyimide, a polyimide coating, a polyimide molded article, and a component produced therefrom.

Background Art

[0002] Generally, a polyimide (PI) resin refers to a high heat-resistant resin produced by solution polymerization of an aromatic dianhydride and an aromatic diamine or aromatic diisocyanate to produce a polyamic acid derivative, followed by ring-closing dehydration and imidization at a high temperature. The polyimide resin, as an insoluble and infusible ultra-high heat-resistant resin, has excellent properties such as heat oxidation resistance, heat resistance, radiation resistance, low-temperature properties, and chemical resistance, and is widely used in heat-resistant advanced materials such as automotive materials, aerospace materials, and cosmic ray materials, as well as electronic materials such as insulating coating agents, insulating films, semiconductors, and electrode protection films for TFT-LCDs. Recently, it has also been used in display materials such as optical fibers and liquid crystal alignment films, and in transparent electrode films by containing conductive fillers in the film or coating the surface.

[0003] In particular, in an insulated wire used as a winding for a coil such as a motor, the insulating layer (insulating film) that coats the conductor is required to have excellent insulation, adhesion to the conductor, heat resistance, mechanical strength, etc., and polyimide is used as the resin for forming the insulating layer.

[0004] Specifically, a polyimide varnish is coated as an insulating coating for the winding of an electric vehicle (EV), and after coating, it is processed into the form of a hairpin and inserted into the motor core. However, if the frictional force is high during this process, there is a problem that the processability decreases due to the shape deformation of the winding.

[0005] Therefore, there is a situation where a polyimide varnish for winding / wire coating is required, which has a reduced frictional force, excellent process efficiency, simultaneously satisfies the heat resistance, insulation, and mechanical physical properties of polyimide, and has excellent adhesion to the conductor.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention provides a self-lubricating polyimide varnish with a reduced coefficient of friction.

[0007] The present invention also provides a polyimide produced by imidizing the polyimide varnish.

[0008] The present invention also provides a polyimide coating containing a cured product of the polyimide varnish.

[0009] The present invention also provides a component including a molded body formed from the polyimide varnish.

[0010] The present invention also provides a method for producing the polyimide varnish.

Means for Solving the Problems

[0011] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments are illustrated and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention.

[0012] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates a different meaning. In this application, terms such as "including" or "having" are used to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0013] In this specification, when a quantity, concentration, or other value or parameter is given as a range, a list of preferred ranges or preferred upper and lower limit values, it should be understood that, regardless of whether the range is disclosed separately, all ranges formed by any upper limit value or preferred value of any upper range and any lower limit value or preferred value of any lower range are specifically disclosed.

[0014] When a range of numerical values is mentioned in this specification, unless otherwise specified, the range is intended to be not limited to the specific values mentioned when defining the range, and the scope of the present invention within that range and its endpoints.

[0015] In this specification, "dianhydride" is intended to include its precursors or derivatives, and may also be referred to as "dianhydride acid", "dianhydride", or "acid dianhydride". Although these may not technically be dianhydrides, nevertheless, they react with diamines to form polyamic acids, which can also be converted to polyimides.

[0016] In this specification, "diamine" is intended to include its precursors or derivatives, and although these may not technically be diamines, nevertheless, they react with dianhydride acids to form polyamic acids, which can also be converted to polyimides.

[0017] In the present invention, "C x-y " means having x or more and y or less carbon atoms.

[0018] In the present invention, the term "C 1-20 alkyl" includes, for example, C such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl. 1-20means a linear or branched saturated hydrocarbon. Preferred alkyl groups contain from about 1 to 20 carbon atoms in said chain. Side chains mean those in which one or more lower alkyl groups, such as methyl, ethyl or propyl, are attached to a linear alkyl chain. "Lower alkyl" means a group having from about 1 to about 20 carbon atoms in a chain which may be linear or branched. "Alkyl" may be unsubstituted or may be optionally substituted by one or more substituents which may be the same or different, and each substituent may be halogen, alkyl, aryl, cycloalkyl, cyano, hydroxy, alkoxy, alkylthio, amino, carboxy, etc. Preferably, alkyl may be methyl or ethyl. In the present invention, "methyl (methyl group)" has a structure in which three hydrogen atoms are bonded to one carbon atom and is the smallest alkyl group. This methyl group can exist in three forms: anion, cation and free radical.

[0019] In the present invention, the term "C" 6-20 "aryl" refers to an aromatic hydrocarbon containing 6 to 20 carbon atoms. For example, it can refer to ring systems such as monocyclic (e.g., phenyl); bicyclic (e.g., indenyl, naphthalenyl, tetrahydronaphthyl, tetrahydroindenyl). Preferably, aryl may be a phenyl group having the chemical formula C6H5 and in which 6 carbon atoms are arranged in a cyclic ring structure.

[0020] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application. The specific content for realizing the above invention will be described as follows.

[0021] Self-lubricating polyimide varnish of the present invention The present invention relates to a self-lubricating polyimide varnish with a reduced coefficient of friction and usable for conductor coating applications.

[0022] In one aspect of the present invention, a polyamic acid containing one or more dianhydride monomers and one or more diamine monomers as polymerization units, nanosilica surface-modified with an organic silane, a silicon-based additive represented by the following Chemical Formula 1, and an organic solvent are provided to form a polyimide varnish.

[0023]

Chemical formula

[0024] In the above Chemical Formula 1, R1 to R 10 are each independently a C 1-20 alkyl group or a C 6-20 aryl group, X1 to X3 are each independently a hydrogen atom, a C 1-3 alkyl group, a C 6-10 aryl group, a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group or a polyether group, wherein at least one of X1 to X3 is a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group or a polyether group, m and n are each independently an integer from 0 to 50, where m + n is 1 or more.

[0025] Polyamic acid In the present invention, the dianhydride monomer can be one or more selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), benzophenonetetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (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, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylenebis(trimeric monoester acid anhydride), p-biphenylenebis(trimeric monoester acid anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene 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.

[0026] Specifically, the dianhydride monomer can include one or more selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), and benzophenone tetracarboxylic dianhydride (BTDA), and preferably, pyromellitic dianhydride (PMDA) can be used.

[0027] In addition, the diamine monomer is 1,4-diaminobenzene (PPD), 4,4'-diaminodiphenyl ether (ODA), 2,2-bisaminophenoxyphenyl propane (BAPP), metaphenylenediamine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane (MDA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenyl methane, 3,3'-dicarboxy-4,4'-diaminodiphenyl methane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenyl methane, bis(4-aminophenyl) sulfide, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-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'-diaminodiphenyl methane, 3,4'-diaminodiphenyl methane, 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, 4,4'-diaminodiphenyl sulfoxide, 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 (TPE-R), 1,4-bis(3-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenylphenoxy)benzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone, 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, 1,4-bis[2-(4-aminophenyl)isopropyl]benzene, 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]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[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, and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, etc. can be used.,

[0028] Specifically, the diamine monomer can include one or more selected from the group consisting of 1,4-diaminobenzene (PPD), 4,4'-diaminodiphenyl ether (ODA), and 2,2-bis(aminophenoxy)phenyl propane (BAPP). Preferably, 4,4'-diaminodiphenyl ether (ODA) can be used.

[0029] In the present invention, among the total amount of dianhydride monomers, pyromellitic dianhydride (PMDA) can be included at a ratio of 50 mol% or more. Specifically, it can be included at a ratio of 60 mol% or more, 70 mol% or more, 75 mol% or more, 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, 99 mol% or more, or 100 mol% or more.

[0030] Also, among the total amount of diamine monomers, 4,4'-diaminodiphenyl ether (ODA) can be included at a ratio of 50 mol% or more. Specifically, it can be included at a ratio of 60 mol% or more, 70 mol% or more, 75 mol% or more, 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, 99 mol% or more, or 100 mol% or more.

[0031] The polyamic acid of the present invention may have the dianhydride monomer at 95 to 105 mol% with respect to 100 mol% of the diamine monomer. For example, the lower limit may be 95.5 mol% or more, 96 mol% or more, 96.5 mol% or more, 97 mol% or more, 97.5 mol% or more, 98 mol% or more, 98.5 mol% or more, 99 mol% or more, or 99.5 mol% or more, and the upper limit may be 105 mol% or less, 104.5 mol% or less, or 104 mol% or less.

[0032] Also, the molar ratio of dianhydride monomer (mol%) / diamine monomer (mol%) may be 95 to 105, specifically 97.5 to 102.5. More specifically, it may be 99 to 101, and even more specifically 99.4 to 99.9. In one embodiment, the molar ratio of dianhydride monomer (mol%) / diamine monomer (mol%) is 99.6, 99.7, 103.8.

[0033] In addition, the polyimide varnish of the present invention can further contain an aromatic carboxylic acid. The aromatic carboxylic acid may be further added to form an optimal molar ratio.

[0034] The aromatic carboxylic acid can include one or more selected from the group consisting of pyromellitic acid (PMA), 3,3’,4,4'-biphenyltetracarboxylic acid (BPTA), 1,2,3,4-benzenetetracarboxylic acid, benzophenone-3,3’,4,4'-tetracarboxylic acid, pyrazinetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, and naphthalene-1,4,5,8-tetracarboxylic acid. In one embodiment, pyromellitic acid (PMA) is used.

[0035] In addition, the content of the aromatic carboxylic acid that can be further contained can be 0 to 1.0 mol%, specifically 0 to 0.8 mol%, more preferably 0.1 to 0.6 mol%. Here, 0 mol% may mean that the aromatic carboxylic acid is not contained in the polyimide varnish.

[0036] Nanosilica surface-modified with an organic silane The polyimide varnish of the present invention can contain inorganic particles in order to improve physical properties such as the coefficient of friction. The inorganic particles are nanosilica which are nanosized silicon dioxide (SiO2) fine particles having an average particle diameter of 1000 nm or less. In the present invention, the nanosilica is nanosilica surface-modified with an organic silane, and its form and shape are not particularly limited.

[0037] In the present invention, the organosilane of the nano-silica surface-modified with an organosilane can include one or more selected from the group consisting of methyltrimethoxysilane, hexamethyldisiloxane, n-octyltrimethoxysilane, n-octyltriethoxysilane, isooctyltrimethoxysilane, dodecyltrimethoxysilane, octadecyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-(methacryloxy)propyltriethoxysilane, 3-(methacryloxy)propylmethyldimethoxysilane, 3-(acryloxypropyl)methyldimethoxysilane, 3-(methacryloxy)propyldimethylethoxysilane, styrylethyltrimethoxysilane, phenyltriethoxysilane, p-tolyltriethoxysilane, vinyldimethyldiacetoxysilane, vinyldimethylethoxysilane, vinylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri-t-butoxysilane, vinyltris(isobutoxy)silane, vinyltriisopropenoxysilane, vinyltris(2-methoxyethoxy)silane, glycidoxypropyltrimethoxysilane (glycidoxypropyl trimethoxysilane: GPTMS), aminopropyltrimethoxysilane ((3-Aminopropyl)trimethoxy-silane: APTMS), phenyltrimethoxysilane (Phenyltrimethoxysilane: PTMS), and phenylaminopropyltrimethoxysilane (N-Phenyl-3-aminopropyltrimethoxysilane: PAPTES). Specifically, it can include one or more selected from methyltrimethoxysilane, hexamethyldisiloxane, phenyltrimethoxysilane, hexyltrimethoxysilane, aminopropyltrimethoxysilane, and phenylaminopropyltrimethoxysilane.In one embodiment, the organosilane may include methyltrimethoxysilane or hexamethyldisiloxane.

[0038] Further, the nanosilica surface-modified with the organosilane may have a compound containing at least one phenyl group at the terminal of the nanosilica surface and a compound containing at least one amine group, hydroxy group, thiol group or epoxide group bonded thereto. Specifically, the compound containing at least one phenyl group at the terminal may be phenyltrimethoxysilane (PTMS) or N-phenyl-3-aminopropyltrimethoxysilane (PAPTES). Also, the compound containing at least one amine group, hydroxy group, thiol group or epoxide group at the terminal may be glycidoxypropyl trimethoxysilane (GPTMS) or (3-aminopropyl)trimethoxy-silane (APTMS).

[0039] The nanosilica surface-modified with the organosilane can be produced by subjecting the nanosilica to a surface treatment with the organosilane. For example, the organosilane is heated under acidic or basic conditions, and surface-modified nanosilica can be obtained by performing a surface treatment for about 1 to 24 hours. Further, the surface modification can be achieved by other known methods. For example, after mixing the organosilane with a solvent, surface-modified nanosilica can be obtained by reacting at a temperature of 10 to 100 ° C or 20 to 60 ° C for 1 to 10 hours or 1 to 5 hours. In order to bond two or more compounds to the surface of the nanosilica, the above methods can be performed respectively.

[0040] By using the nanosilica surface-modified with the organosilane of the present invention, aggregation of inorganic particles in the polyimide varnish can be prevented, and the interaction with the solid content (polyamic acid) can be enhanced by the functional groups of the compound, thereby improving the organic-inorganic hybridization.

[0041] In addition, the surface-modified nano-silica with the organic silane may have an average particle size of 10 to 200 nm. For example, the average particle size may be 10 to 190 nm, 20 to 180 nm, 30 to 170 nm, 40 to 160 nm, or 50 to 150 nm.

[0042] In addition, the content of the surface-modified nano-silica with the organic silane can be 0.3 to 7.0 parts by weight based on 100 parts by weight of the total polyimide varnish. For example, the content of the surface-modified nano-silica with the organic silane, for example, the lower limit may be 0.35 parts by weight or more, 0.40 parts by weight or more, 0.45 parts by weight or more, 0.50 parts by weight or more, 0.55 parts by weight or more, or 0.35 parts by weight or more. Also, for example, the upper limit may be 6 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1.5 parts by weight or less, 1.25 parts by weight or less, 1.20 parts by weight or less, 1.15 parts by weight or less, 1.10 parts by weight or less, 1.05 parts by weight or less, 1.0 parts by weight or less, 0.95 parts by weight or less, 0.9 parts by weight or less, 0.85 parts by weight or less, 0.8 parts by weight or less, 0.79 parts by weight or less, 0.78 parts by weight or less, 0.77 parts by weight or less, or 0.76 parts by weight or less. When the content of the surface-modified nano-silica with the organic silane is less than 0.3 parts by weight, it is not effective for improving the properties. When it exceeds 7 parts by weight, haze and deterioration of physical properties may appear due to aggregation and deterioration of usability.

[0043] Silicon-based additive The polyimide varnish of the present invention reduces the coefficient of friction by containing a silicon-based additive. The silicon-based additive of the present invention is a modified silicone oil, which has a linear siloxane skeleton and means having a functional group other than a hydrogen or hydrocarbon group in the molecular structure.

[0044] Specifically, the silicon-based additive represented by the chemical formula 1 may be the silicon-based additive represented by the following chemical formula 2.

[0045]

Chemical formula

[0046] In the formula (2), R1, R7 and R 10 are each independently a C 1-20 alkyl group, X1 to X3 are each independently a hydrogen atom, a C 1-3 alkyl group, a C 6-10 aryl group, a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group or a polyether group, wherein at least one of X1 to X3 is a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group or a polyether group, m and n are each independently an integer from 0 to 50, where m + n is 1 or more.

[0047] Also, the silicon-based additive represented by the formula (1) may be a silicon-based additive represented by the following formula (3).

[0048] [Chemical formula]

[0049] In the formula (3), R7 is a C 1-20 alkyl group, X2 is a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group or a polyether group, m and n are each independently an integer from 0 to 50, where m + n is 1 or more.

[0050] Preferably, in the formula (3), X2 may be an amino group.

[0051] Further, the silicon-based additive represented by the chemical formula 1 may be a silicon-based additive represented by the following chemical formula 4.

[0052] [Chemical formula]

[0053] In the chemical formula 4, the definitions of R1, R 10 , X1, X3, m and n are as described above.

[0054] R1 and R 10 are each independently a C 1-20 alkyl group, X1 and X3 are each independently a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group or a polyether group, and m and n are each independently an integer of 0 to 50, where m + n is 1 or more.

[0055] Preferably, in the chemical formula 4, X1 and X3 may each independently be an amino group.

[0056] Further, the silicon-based additive has a refractive index of 1.40 to 1.50 (based on 25 °C), a functional group equivalent weight of 100 to 10,000 g / mol, a viscosity of 10 to 20,000 cP (based on 25 °C), and the functional group may be a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group or a polyether group.

[0057] In the present invention, the functional group equivalent weight means the mass of the main skeleton bonded per functional group, and is a value obtained by dividing the weight average molecular weight of the silicon-based additive by the number of functional groups per molecule. That is, the functional group equivalent weight of the present invention means the value represented by the following formula.

[0058] [Formula] Functional group equivalent (g / mol) = Weight average molecular weight (g / mol) / Number of functional groups

[0059] For example, when a silicon-based additive with an overall molecular weight of 1,000 g / mol contains 2 functional groups in the molecule, the functional group equivalent is 500 g / mol.

[0060] Preferably, the refractive index is 1.40 - 1.45 (based on 25°C), the functional group equivalent is 200 - 9,000 g / mol, the viscosity is 10 - 1,000 cP (based on 25°C), and the functional group may be a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group, or a polyether group.

[0061] More preferably, the refractive index is 1.40 - 1.42 (based on 25°C), the functional group equivalent is 300 - 8,000 g / mol, the viscosity is 10 - 800 cP (based on 25°C), and the functional group may be a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group, or a polyether group.

[0062] Even more preferably, the refractive index is 1.40 - 1.42 (based on 25°C), the functional group equivalent is 400 - 6,000 g / mol, the viscosity is 10 - 500 cP (based on 25°C), and the functional group may be an amino group.

[0063] In one embodiment, as the side-chain amino-modified silicon, a silicon-based additive with a refractive index of 1.405 (based on 25°C), an amino group equivalent of 5,000 g / mol, and a viscosity of 110 cP (based on 25°C) can be used.

[0064] In one embodiment, as the side-chain amino-modified silicon, a silicon-based additive with a refractive index of 1.408 (based on 25°C), an amino group equivalent of 1,600 g / mol, and a viscosity of 1,000 cP (based on 25°C) can be used.

[0065] In one embodiment, a silicone-based additive with a refractive index of 1.418 (based on 25 °C), an amino group equivalent of 400 g / mol, and a viscosity of 12 cP (based on 25 °C) can be used as the both-terminal amino-modified silicone.

[0066] In the present invention, the silicone-based additive can be contained in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the total polyimide varnish. Specifically, for example, the lower limit may be 0.2 parts by weight or more, 0.06 parts by weight or more, 0.07 parts by weight or more, 0.08 parts by weight or more, 0.09 parts by weight or more, 0.1 parts by weight or more, 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or 0.5 parts by weight or more, and the upper limit may be 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1.8 parts by weight or less, 1.6 parts by weight or less, 1.4 parts by weight or less, 1.2 parts by weight or less, 1.0 parts by weight or less, 0.8 parts by weight or less, or 0.6 parts by weight or less.

[0067] When the content of the silicone-based additive exceeds 5 parts by weight, the mechanical properties of the produced polyimide coating may deteriorate. During the heat treatment for imidization, the silicone-based additive decomposes at high temperature, which may instead reduce the adhesion between the polyimide coating and the conductor or increase the haze, which is not preferable. On the other hand, when the content of the silicone-based additive is less than 0.05 parts by weight, it does not show an effect of improving the friction coefficient, which is not preferable.

[0068] Organic solvent In the present invention, the organic solvent may include one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), N,N'-dimethylformamide (DMF), N,N'-diethylformamide (DEF), N,N'-dimethylacetamide (DMAc), dimethylpropanamide (DMPA), N,N-diethylacetamide (DEAc), dimethyl sulfoxide (DMSO), 3-methoxy-N,N-dimethylpropanamide (KJCMPA), p-chlorophenol, o-chlorophenol, γ-butyrolactone (GBL), diglyme, and naphthalene. Preferably, N-methyl-pyrrolidone (NMP), N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), etc. can be used.

[0069] Further, the organic solvent may further include a modifier containing a hydroxy group (OH) or an amine group (NH). Examples of the modifier containing a hydroxy group (OH) or an amine group (NH) include ethylamine, triethanolamine, dimethylamine, trimethylamine, diethylenetriamine, ethylenediamine, tributylamine, pyridine, pyrrolidine, methanol, ethanol, propanol, isopropanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, hexanol, octanol, capryl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, allyl alcohol, crotyl alcohol, propargyl alcohol, ethylene glycol, propylene glycol, benzyl alcohol, phenol, etc. The modifier can react with the dianhydride monomer to control the reactivity.

[0070] The organic solvent can be used for synthesizing polyamic acid by polymerizing the dianhydride monomer and the diamine monomer. The organic solvent can be contained in an amount of 50 to 80 parts by weight, preferably 60 to 75 parts by weight, based on 100 parts by weight of the total polyimide varnish.

[0071] Also, the polyimide solid content can be included in an amount of 10 to 30 parts by weight based on 100 parts by weight of the total polyimide varnish. Specifically, for example, the lower limit may be 12 parts by weight, 15 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, or 25 parts by weight or more, and the upper limit may be 30 parts by weight, 29 parts by weight, 28 parts by weight, or 27 parts by weight or less. By adjusting the solid content of the polyimide varnish, an increase in viscosity can be controlled, and the process time can be shortened during the curing process.

[0072] Polyimide varnish and its cured product The viscosity of the polyimide varnish measured under the conditions of a temperature of 30°C and a shear rate of 1 s -1 may be in the range of 500 to 20,000 cP. For example, the upper limit may be 20,000 cP, 15,000 cP, or 10,000 cP or less. The lower limit is not particularly limited, but may be 1,000 cP, 1,500 cP, 2,000 cP, or 2,500 cP or more. In one embodiment, the viscosity may be measured using a Rheostress 600 manufactured by Haake, or may be measured under the conditions of a shear rate of 1 / s, a temperature of 30°C, and a plate gap of 1 mm. The present invention can provide a polyimide varnish having excellent processability by adjusting the viscosity within the above range.

[0073] The polyimide varnish according to the present invention can have a coefficient of thermal expansion (CTE) after curing in the range of 60 ppm / °C or less. For example, the upper limit of the CTE may be 55 ppm / °C or less, 50 ppm / °C, 45 ppm / °C or less, 40 ppm / °C or less, 38 ppm / °C or less, 36 ppm / °C or less, 35 ppm / °C or less, or 30 ppm / °C or less, and the lower limit may be, for example, 0.1 ppm / °C, 1 ppm / °C, 2.0 ppm / °C, 2.6 ppm / °C, 2.8 ppm / °C, 3.5 ppm / °C, or 4 ppm / °C or more. In one example, the coefficient of thermal expansion may be measured at 100 to 350°C. In one embodiment, the CTE can be measured using a thermomechanical analyzer Q400 model manufactured by TA Instruments. After the polyimide is formed into a film and cut into a width of 2 mm and a length of 10 mm, the temperature is raised from room temperature to 350°C at a rate of 10°C / min while applying a tension of 0.02 N in a nitrogen atmosphere, and the gradient in the section from 100°C to 250°C can be measured.

[0074] In one exemplary embodiment, the polyimide varnish according to the present invention can have a glass transition temperature (Tg) after curing in the range of 250°C to 450°C. For example, the lower limit of the glass transition temperature may be 250°C or more, 255°C or more, 260°C or more, 270°C or more, or 300°C or more, and the upper limit may be 445°C or less, 440°C or less, 435°C or less, 430°C or less, 425°C or less, 420°C or less, 415°C or less, 410°C or less, or 400°C or less. In one embodiment, the glass transition temperature can be measured for the polyimide produced by curing the polyimide varnish using TMA under the condition of 10°C / min.

[0075] The polyimide varnish according to the present application may have a 5% by weight thermal decomposition temperature (Td) of 450 °C or higher after curing. The thermal decomposition temperature can be measured using a thermogravimetric analysis Q50 model manufactured by TA Instruments. In a specific example, the polyimide obtained by curing the polyimide varnish is heated to 150 °C at a rate of 10 °C / min in a nitrogen atmosphere, and then held isothermally for 30 minutes to remove moisture. Next, it is heated to 600 °C at a rate of 10 °C / min, and the temperature at which a 1% weight loss occurs can be measured. The lower limit of the thermal decomposition temperature may be, for example, 450 °C or higher, 460 °C or higher, 470 °C or higher, or 480 °C or higher. The upper limit may be, for example, 800 °C or lower or 600 °C or lower.

[0076] Also, the polyimide obtained by curing the polyimide varnish may have an elongation of 60% or higher, for example, 60%, 62%, 64%, and 66% or higher. The upper limit is not particularly limited, but it may be 80% or lower. In one embodiment, the elongation can be measured by the ASTM D-882 method using an Instron5564 UTM instrument manufactured by Instron after curing the polyimide varnish into a polyimide film and cutting it into a width of 10 mm and a length of 40 mm.

[0077] Also, the polyimide obtained by curing the polyimide varnish has a dielectric constant (Dk) of 4 or lower, specifically, it may be 3.8 or lower, 3.6 or lower, or 3.5 or lower. The lower limit is not particularly limited, but it may be 2.0 or higher.

[0078] In another aspect of the present invention, there is provided a polyimide produced by imidizing the polyimide varnish, and the polyimide may be in the form of a film.

[0079] In another aspect of the present invention, there is provided a polyimide coating containing a cured product of the polyimide varnish.

[0080] The polyimide coating may have a coefficient of friction (PI-SUS) of 0.4 or less. Specifically, the coefficient of friction may be 0.39 or less, 0.38 or less, 0.36 or less, 0.34 or less, 0.32 or less, 0.30 or less, 0.29 or less, or 0.28 or less. When the coefficient of friction exceeds 0.4, after coating the polyimide varnish as an insulating coating for the windings of an electric vehicle (EV), forming it into the shape of a hairpin, and inserting it into the motor corner, there is a problem that the shape of the winding is deformed and the processability deteriorates.

[0081] In one embodiment, the method for manufacturing the coating may include a step of coating a polyimide varnish on the surface of a conductor and a step of imidizing the polyimide varnish coated on the surface of the conductor.

[0082] The conductor may be a copper wire made of copper or a copper alloy, but conductors made of other metal materials such as silver wires, and various metal-plated wires such as aluminum and tin-plated wires may also be included as conductors. The thickness of the conductor and the coating may conform to the KS C 3107 standard. The diameter of the conductor may be in the range of 0.3 to 3.2 mm, and the standard coating thickness (average value of the maximum coating thickness and the minimum coating thickness) of the coating may be 21 to 194 μm for type 0, 14 to 169 μm for type 1, and 10 to 31 μm for type 2. The cross-sectional shape of the conductor may be a circular wire, a flat wire, a hexagonal wire, etc., but is not limited thereto.

[0083] The polyimide coating according to the present invention may have a voltage endurance characteristic of the time that the insulating material can withstand at a predetermined voltage according to IEC-60851-5 of 170 minutes or more, for example, 180 minutes or more, 200 minutes or more, 220 minutes or more, or 230 minutes or more.

[0084] In another aspect of the present invention, an electric wire including the polyimide coating is provided.

[0085] Specifically, it may be a coated electric wire including a polyimide coating manufactured by coating the surface of an electric wire with the polyamic acid solution and imidizing it. In one specific example, the coated electric wire may include an electric wire and a coating in which the above-described polyimide is coated on the surface of the electric wire and imidized.

[0086] In addition, the present application can provide an electronic device including the coated electric wire. Examples of the electronic device include an electric motor.

[0087] In another aspect of the present invention, a component including a molded body formed from a polyimide varnish is provided.

[0088] Specifically, the component may be an electronic circuit board member, a semiconductor device, a lithium ion battery member, a solar cell member, a fuel cell member, a motor winding, an engine peripheral member, a paint, an optical component, a heat dissipation material, an electromagnetic wave shielding material, a surge component, a dental material, a slide coating, and an electrostatic chuck.

[0089] Method for producing polyimide varnish The method for manufacturing a polyimide varnish according to the present invention includes steps of mixing and heating a dianhydride monomer, a diamine monomer, nanosilica surface-modified with an organic silane, a silicon-based additive, and an organic solvent.

[0090] Specifically, (a) a step of mixing and heating nanosilica surface-modified with an organic silane and a dianhydride monomer in an organic solvent, (b) a step of adding a diamine monomer and reacting it, (c) a step of adding a silicon-based additive and manufacturing a polyimide varnish, and a step of adding an aromatic carboxylic acid can be further performed after step (B) and before step (c).

[0091] The organic solvent, dianhydride monomer, diamine monomer, nanosilica surface-modified with an organic silane, silicon-based additive, etc. are applied in the same manner as the content of the above-described polyimide varnish.

Advantages of the Invention

[0092] The polyimide varnish of the present invention has self-lubricity by reducing the friction coefficient, is excellent in process efficiency, simultaneously satisfies the heat resistance, insulation property and mechanical properties of polyimide, and has excellent adhesion to conductors. Therefore, it has excellent utility as an electric wire coating.

Modes for Carrying Out the Invention

[0093] In order to facilitate the understanding of the present invention, examples are presented. The following examples are provided to more easily understand the present invention, and the content of the present invention is not limited by the examples.

[0094] <Example> Production Example 1. Silicon-based Additive 1 Side-chain amino-modified silicone oil (refractive index 1.405 (based on 25 °C), amino group equivalent 5,000 g / mol, viscosity 110 cP (based on 25 °C), specific gravity 0.97 g / mL (based on 25 °C)).

[0095] Production Example 2. Silicon-based Additive 2 Side-chain amino-modified silicone oil (refractive index 1.408 (based on 25 °C), amino group equivalent 1,600 g / mol, viscosity 1,000 cP (based on 25 °C), specific gravity 0.98 g / mL (based on 25 °C)).

[0096] Production Example 3. Silicon-based Additive 3 Both-end amino-modified silicone oil (refractive index 1.418 (based on 25 °C), amino group equivalent 430 g / mol, viscosity 12 cP (based on 25 °C), specific gravity 1.00 g / mL (based on 25 °C)).

[0097] Example 1. Polyimide Varnish An organic solvent containing dimethylacetamide and a modifier was introduced into a reaction vessel replaced with nitrogen gas. Pyromellitic dianhydride (PMDA) (99.6 mol% - 103.8 mol%) as a dianhydride monomer, nanosilica surface-treated with an organic silane (ethylene glycol-dispersed silica sol, silica solid content concentration 20 wt%, silica average particle size 70 - 100 nm, viscosity 20 - 100 mPa·s, water content 2% or less of organosilica sol) (0.75 wt%) were mixed and stirred at 40°C for 30 minutes. Next, 4,4'-diaminodiphenyl ether (ODA) (100 mol%) was added as a diamine monomer, pyromellitic acid (0 - 0.5 mol%) was introduced, and a silicon-based additive (0.53 wt%) was added. After that, it was stirred at 40°C for 1 hour for polymerization to produce a polyamic acid solution with a solid content of 15 - 25 wt%.

[0098] Comparative Examples 1 - 7. Polyimide varnish As shown in Table 1 below, a polyimide precursor was produced in the same manner as in Example 1, except that the components and content ratios of the dianhydride monomer, diamine monomer, nanosilica surface-treated with an organic silane, and silicon-based additive were adjusted.

[0099]

Table 1

[0100] <Experimental Example> Production of polyimide for physical property measurement For each of the polyimide varnishes produced in the above Examples and Comparative Examples, bubbles were removed by high-speed rotation at 1,500 rpm or more. Next, the degassed polyimide varnish was applied to a glass substrate using a spin coater.

[0101] Under a nitrogen atmosphere, the temperature was raised from room temperature to 400°C at a rate of 4°C / min, heat-treated at 400°C for 60 minutes, then cooled to 30°C at a rate of 4°C / min to obtain a polyimide in the form of a 20 ± 1.0 μm film.

[0102] Experimental Example 1. Coefficient of friction Using the QM110CF model manufactured by QMESYS, the coefficient of friction was measured under the atmospheric conditions of a speed of 150 mm / min, a load of 200 g, a displacement of 65 mm, and 23°C according to the ASTM D 1894 and D4918 methods, and the results are shown in Table 2 below.

[0103]

Table 2

[0104] The polyimide varnish of the present invention has been shown to have a low coefficient of friction (PI-SUS) of 0.4 or less.

[0105] This specification omits the detailed description of the content that can be fully recognized and analogized by those with ordinary knowledge in the technical field of the present invention. Various modifications are possible within the scope of not changing the technical idea and essential configuration of the present invention other than the specific examples described in this specification. Therefore, the present invention can also be implemented in a manner different from that specifically described and exemplified in this specification, which is understandable to those with ordinary knowledge in the technical field of the present invention.

Claims

1. A polyamic acid containing one or more dianhydride monomers and one or more diamine monomers as polymerization units, nanosilica surface-modified with an organic silane, a silicon-based additive represented by the following Chemical Formula 1, and an organic solvent, a polyimide varnish. 【Chemical 1】 In the Chemical Formula 1, R １ to R １０ are each independently a C １－２０ alkyl group or a C ６－２０ aryl group, X １ to X ３ are each independently a hydrogen atom, C １－３ alkyl group, C ６－１０ aryl group, hydroxy group, amino group, epoxy group, acrylic group, acid anhydride group, carboxyl group, methacrylic group, mercapto group, or polyether group, Here, X １ ~X ３ at least one of which is a hydroxy group, amino group, epoxy group, acrylic group, acid anhydride group, carboxyl group, methacrylic group, mercapto group, alkoxy group, silanol group or polyether group, m and n are each independently an integer from 0 to 50, where m + n is 1 or more.

2. The polyimide varnish according to Claim 1, wherein the dianhydride monomer contains one or more selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), benzophenonetetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (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, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylenebis(trimellitic monoester acid anhydride), p-biphenylenebis(trimellitic monoester acid anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene 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.

3. The diamine monomer is 1,4-diaminobenzene (PPD), 4,4'-diaminodiphenyl ether (ODA), 2,2-bisaminophenoxyphenyl propane (BAPP), metaphenylenediamine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane (MDA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4-aminophenyl) sulfide, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-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, 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, 4,4'-diaminodiphenyl sulfoxide, 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 (TPE-R), 1,4-bis(3-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenylphenoxy)benzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone, 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, 1,4-bis[2-(4-aminophenyl)isopropyl]benzene, 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]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[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, and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, the polyimide varnish according to claim 1, comprising one or more selected from the group consisting of.

4. The organic silane of the nano-silica surface-modified with an organic silane is one or more selected from the group consisting of methyltrimethoxysilane, hexamethyldisiloxane, n-octyltrimethoxysilane, n-octyltriethoxysilane, isooctyltrimethoxysilane, dodecyltrimethoxysilane, octadecyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-(methacryloxy)propyltriethoxysilane, 3-(methacryloxy)propylmethyldimethoxysilane, 3-(acryloxypropyl)methyldimethoxysilane, 3-(methacryloxy)propyldimethylethoxysilane, styrylethyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, p-tolyltriethoxysilane, vinyldimethoxyacetoxysilane, vinyldimethylethoxysilane, vinylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri-t-butoxysilane, vinyltris(isobutoxy)silane, vinyltriisopropenoxysilane, vinyltris(2-methoxyethoxy)silane, glycidoxypropyltrimethoxysilane (glycidoxypropyl trimethoxysilane: GPTMS), aminopropyltrimethoxysilane ((3-Aminopropyl)trimethoxy-silane: APTMS), phenyltrimethoxysilane (Phenyltrimethoxysilane: PTMS) and phenylaminopropyltrimethoxysilane (N-Phenyl-3-aminopropyltrimethoxysilane: PAPTES). The polyimide varnish according to claim 1.

5. The nano-silica surface-modified with the organic silane has an average particle size of 10 to 200 nm. The polyimide varnish according to claim 1.

6. The silicon-based additive represented by the chemical formula 1 is the silicon-based additive represented by the following chemical formula 2. The polyimide varnish according to claim 1. [Chemical 2] In the chemical formula 2, R １ 、 R ７ and R １０ are each independently a C １－２０ alkyl group, X １ ~X ３ is, independently of one another, a hydrogen atom, C １－３ alkyl group, C ６－１０ aryl group, hydroxy group, amino group, epoxy group, acrylic group, acid anhydride group, carboxyl group, methacrylic group, mercapto group, alkoxy group, silanol group or polyether group, Here, X １ ~X ３ At least one of which is a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, or a polyether group, m and n are each independently an integer from 0 to 50, where m + n is 1 or more.

7. The silicon-based additive has a refractive index of 1.40 to 1.50 (based on 25 °C), a functional group equivalent weight of 100 to 10,000 g / mol, a viscosity of 10 to 20,000 cP (based on 25 °C), and the functional group is a hydroxy group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacrylic group, a mercapto group, an alkoxy group, a silanol group, or a polyether group. The polyimide varnish according to claim 1.

8. The organic solvent is one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), N,N'-dimethylformamide (DMF), N,N'-diethylformamide (DEF), N,N'-dimethylacetamide (DMAc), dimethylpropanamide (DMPA), N,N-diethylacetamide (DEAc), dimethyl sulfoxide (DMSO), 3-methoxy-N,N-dimethylpropanamide (KJCOMPA), p-chlorophenol, o-chlorophenol, γ-butyrolactone (GBL), diglyme, and naphthalene. The polyimide varnish according to claim 1.

9. The organic solvent further contains a modifier containing a hydroxy group (OH) or an amine group (NH). The polyimide varnish according to claim 8.

10. The modifier containing the hydroxy group (OH) or the amine group (NH) is one or more selected from the group consisting of ethylamine, triethanolamine, dimethylamine, trimethylamine, diethylenetriamine, ethylenediamine, tributylamine, pyridine, pyrrolidine, methanol, ethanol, propanol, isopropanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, hexanol, octanol, capryl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, allyl alcohol, crotyl alcohol, propargyl alcohol, ethylene glycol, propylene glycol, benzyl alcohol, and phenol. The polyimide varnish according to claim 9.

11. The polyimide solid content is 10 to 30 parts by weight based on 100 parts by weight of the entire polyimide varnish, the polyimide varnish according to claim 1.

12. The nano-silica surface-modified with the organic silane is 0.3 to 7 parts by weight based on 100 parts by weight of the entire polyimide varnish, the polyimide varnish according to claim 1.

13. The silicone-based additive is 0.05 to 5 parts by weight based on 100 parts by weight of the entire polyimide varnish, the polyimide varnish according to claim 1.

14. Among the entire dianhydride monomers, pyromellitic dianhydride (PMDA) is contained at a ratio of 50 mol% or more, the polyimide varnish according to claim 1.

15. Among the entire diamine monomers, 4,4'-diaminodiphenyl ether (ODA) is contained at a ratio of 50 mol% or more, the polyimide varnish according to claim 1.

16. The polyimide varnish according to claim 1, further comprising an aromatic carboxylic acid.

17. The aromatic carboxylic acid is pyromellitic acid (PMA), 3,3',4,4'-biphenyltetracarboxylic acid (3,3',4,4'-biphenyltetracarboxylic acid, BPTA), 1,2,3,4-benzenetetracarboxylic acid (1,2,3,4-benzenetetracarboxylic acid), benzophenone-3,3',4,4'-tetracarboxylic acid (benzophenone-3,3',4,4'-tetracarboxylic acid), pyrazinetetracarboxylic acid (pyrazinetetracarboxylic acid), 2,3,6,7-naphthalenetetracarboxylic acid (2,3,6,7-naphthalenetetracarboxylic acid), and naphthalene-1,4,5,8-tetracarboxylic acid (naphthalene-1,4,5,8-tetracarboxylic acid) The polyimide varnish according to claim 16, comprising one or more selected from the group consisting of.

18. The polyimide varnish according to claim 1, wherein the dianhydride monomer is 95 to 105 mol% with respect to 100 mol% of the diamine monomer.

19. The polyimide varnish according to claim 18, further comprising 0 to 1.0 mol% of an aromatic carboxylic acid.

20. The polyimide varnish has a viscosity of 500 to 20,000 cP measured under the conditions of a temperature of 30°C and a shear rate of 1 s －１ The polyimide varnish according to claim 1.

21. A polyimide coating containing a cured product of the polyimide varnish according to any one of claims 1 to 20.

22. The polyimide coating according to claim 21, wherein the friction coefficient (PI-SUS) is 0.4 or less.

23. An electric wire containing the polyimide coating according to claim 21.

24. A component containing a molded body formed from the polyimide varnish according to any one of claims 1 to 20.

25. The component according to claim 24, wherein the component is any one of an electronic circuit board member, a semiconductor device, a lithium ion battery member, a solar cell member, a fuel cell member, a motor winding, an engine peripheral member, a paint, an optical component, a heat dissipation material, an electromagnetic wave shielding material, a surge component, a dental material, a slide coating, and an electrostatic chuck.

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