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US-20260125577-A1 - SELF-LUBRICATING POLYIMIDE VARNISH AND POLYIMIDE COATING PREPARED THEREFROM

US20260125577A1US 20260125577 A1US20260125577 A1US 20260125577A1US-20260125577-A1

Abstract

The present invention provides polyimide varnish comprising: polyamic acid comprising, as a polymerization unit, at least one dianhydride monomer and at least one diamine monomer; nano silica surface-modified with an organosilane; a silicone-based additive represented by Chemical Formula 1; and an organic solvent.

Inventors

  • Gyeong Hyeon Ro
  • Gyeong Min MOON
  • Se Jong Kim
  • Ik Sang LEE

Assignees

  • PI ADVANCED MATERIALS CO., LTD.

Dates

Publication Date
20260507
Application Date
20230627
Priority Date
20220629

Claims (20)

  1. 1 . A polyimide varnish comprising: polyamic acid comprising, as a polymerization unit, at least one dianhydride monomer and at least one diamine monomer; surface-modified nanosilica with organosilane; a silicone-based additive represented by the following Chemical Formula 1; and an organic solvent: in Chemical Formula 1 above, R 1 to R 10 are each independently a C 1-20 alkyl group or a C 6-20 aryl group; and X 1 to X 3 are each independently a hydrogen atom, a C 1-3 alkyl group, a C 6-10 aryl group, a hydroxyl group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacryl group, a mercapto group, or a polyether group, wherein at least one of X 1 to X 3 is a hydroxyl group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacryl group, a mercapto group, an alkoxy group, a silanol group or a polyether group, and m and n are each independently an integer from 0 to 50, where m+n is 1 or more.
  2. 2 . The polyimide varnish of claim 1 , wherein the dianhydride monomer comprises at least one selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyl tetracarboxylic dianhydride (BPDA), benzophenone tetracarboxylic dianhydride (BTDA), oxidiphthalic 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′-benzophenone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylenebis(trimelytic monoester acid anhydride), p-biphenylenebis(trimelytic 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-naphthalene tetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, and 4,4′-(2,2-hexafluoroisopropylidene)diphthalic acid dianhydride.
  3. 3 . The polyimide varnish of claim 1 , wherein the diamine monomer comprises at least one selected from the group consisting of 1,4-diaminobenzene (PPD), 4,4′-diaminodiphenyl ether (ODA), 2,2-bisaminophenoxyphenylpropane (BAPP), metaphenylenediamine, 3,3′-dimethylbenzidine, 2,2′-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 4,4′-diamino diphenyl 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′-diaminodiphenyl methane, 3,3′-dicarboxy-4,4′-diaminodiphenylmethane, 3,3′,5,5′-tetramethyl-4,4′-diamino diphenylmethane, 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-aminophenyl sulfide)benzene, 1,3-bis(4-aminophenyl sulfide)benzene, 1,4-bis(4-aminophenyl sulfide)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.
  4. 4 . The polyimide varnish of claim 1 , wherein the organosilane of the surface-modified nanosilica with organosilane comprises at least one 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, vinylmethyldiacetoxysilane, vinyldimethylethoxysilane, vinylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri-t-butoxysilane, vinyltris(isobutoxy)silane, vinyltriisopropenoxysilane, vinyltris(2-methoxyethoxy)silane, glycidoxypropyl trimethoxysilane (GPTMS), 3-aminopropyltrimethoxy-silane (APTMS), phenyltrimethoxysilane (PTMS), and N-phenyl-3-aminopropyltrimethoxysilane (PAPTES).
  5. 5 . The polyimide varnish of claim 1 , wherein the surface-modified nanosilica with organosilane has an average particle diameter of 10 to 200 nm.
  6. 6 . The polyimide varnish of claim 1 , wherein the silicone-based additive represented by Chemical Formula 1 is a silicone-based additive represented by the following Chemical Formula 2: in Chemical Formula 2 above, R 1 , R 7 , and R 10 are each independently a C 1-20 alkyl group; and X 1 to X 3 are each independently a hydrogen atom, a C 1-3 alkyl group, a C 6-10 aryl group, a hydroxyl group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacryl group, a mercapto group, an alkoxy group, a silanol group, or a polyether group, wherein at least one of X 1 to X 3 is a hydroxyl group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacryl group, a mercapto group, or a polyether group, and m and n are each independently an integer from 0 to 50, where m+n is 1 or more.
  7. 7 . The polyimide varnish of claim 1 , wherein the silicone-based additive has a refractive index of 1.40 to 1.50 (based on 25° C.), a functional group equivalent of 100 to 10,000 g/mol, and a viscosity of 10 to 20,000 cP (based on 25° C.), wherein the functional group is a hydroxyl group, an amino group, an epoxy group, an acrylic group, an acid anhydride group, a carboxyl group, a methacryl group, a mercapto group, an alkoxy group, a silanol group, or a polyether group.
  8. 8 . The polyimide varnish of claim 1 , wherein the organic solvent is at least one 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, gammabutyrolactone (GBL), Diglyme, and naphthalene.
  9. 9 . The polyimide varnish of claim 8 , wherein the organic solvent further comprises a modifier containing a hydroxyl group (OH) or an amine group (NH)); and wherein the modifier containing a hydroxyl group (OH) or an amine group (NH) is at least one 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.
  10. 10 . (canceled)
  11. 11 . The polyimide varnish of claim 1 , wherein a polyimide solid content contains in an amount of 10 to 30 parts by weight based on 100 parts by weight of the total polyimide varnish.
  12. 12 . The polyimide varnish of claim 1 , wherein the surface-modified nanosilica with organosilane contains in an amount of 0.3 to 7 parts by weight based on 100 parts by weight of the total polyimide varnish.
  13. 13 . The polyimide varnish of claim 1 , wherein the silicone-based additive contains in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the total polyimide varnish.
  14. 14 . The polyimide varnish of claim 1 , wherein pyromellitic dianhydride (PMDA) contains in a ratio of 50 mol % or more among the total dianhydride monomers.
  15. 15 . The polyimide varnish of claim 1 , wherein 4,4′-diaminodiphenyl ether (ODA) contains in a ratio of 50 mol % or more among the total diamine monomers.
  16. 16 . The polyimide varnish of claim 1 , further comprising an aromatic carboxylic acid; and wherein the aromatic carboxylic acid comprises at least one 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.
  17. 17 . (canceled)
  18. 18 . The polyimide varnish of claim 1 , wherein the dianhydride monomer contains in an amount of 95 to 105 mol % based on 100 mol % of the diamine monomer.
  19. 19 . The polyimide varnish of claim 18 , wherein 0 to 1.0 mol % of an aromatic carboxylic acid is further contained.
  20. 20 . The polyimide varnish of claim 1 , wherein the polyimide varnish has a viscosity of 500 to 20,000 cP measured at a temperature of 30° C. and a shear rate of 1 s −1 .

Description

TECHNICAL FIELD The present invention relates to a self-lubricating polyimide varnish and polyimide, polyimide coating material, polyimide molded body, and components prepared therefrom. BACKGROUND ART Polyimide resin refers to a highly heat-resistant resin obtained by performing solution polymerization on aromatic dianhydride and aromatic diamine or aromatic diisocyanate to prepare a polyamic acid derivative, followed by ring-closure dehydration at high temperature and imidization. The polyimide resin is an insoluble, infusible, ultra-high heat-resistant resin and has excellent properties such as thermal oxidation resistance, heat resistance, radiation resistance, low-temperature characteristics, chemical resistance, and the like, and thus it is used in a wide range of fields, including heat-resistant advanced materials such as automotive materials, aviation materials, and spacecraft materials, etc., and electronic materials such as insulating coatings, insulating films, semiconductors, and electrode protective films of TFT-LCD. Recently, the polyimide resin is also used in display materials such as optical fibers and liquid crystal alignment films, transparent electrode films by containing conductive filler in the films or performing surface coating, etc. In particular, insulated wires used as windings for coils such as motors require a conductor-coating insulation layer (insulating film) that offers excellent insulation, adhesion to the conductor, heat resistance, mechanical strength, etc. Therefore, polyimide is used as a resin to form the insulation layer. Specifically, polyimide varnish is coated as an insulating coating for the windings of electric vehicles (EVs), processed into a hairpin shape, and inserted into the motor core. However, this process has a problem in that the processability is reduced due to the shape deformation of the windings when the friction force is high. Therefore, there is a need for a polyimide varnish for winding/wire coating that has excellent adhesion to a conductor while simultaneously satisfying the heat resistance, insulation, and mechanical properties of polyimide, with excellent process efficiency due to reduced friction. DISCLOSURE Technical Problem An object of the present invention is to provide a self-lubricating polyimide varnish with a low coefficient of friction. Another object of the present invention is to provide a polyimide prepared by imidizing the polyimide varnish. Still another object of the present invention is to provide a polyimide coating material comprising a cured product of the polyimide varnish. Still another object of the present invention is to provide a component comprising a molded body formed from the polyimide varnish. Still another object of the present invention is to provide a method for preparing the polyimide varnish. Technical Solution Various modifications can be made and various embodiments may be implemented in the present disclosure, and specific embodiments are illustrated in the drawings and described in detail. However, it should be understood that this is not intended to limit the present disclosure to specific embodiments, and comprises all modifications, equivalents, and substitutes included in the spirit and scope of the present disclosure. Terms used in the present application are only used to describe specific embodiments and are not intended to limit the present disclosure. Singular expressions shall include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, elements, components, or combinations thereof described in the specification and it should not be understood as precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. When amounts, concentrations, or other values or parameters herein are given as ranges, preferred ranges, or lists of upper desirable values and lower desirable values, it should be understood as specifically disclosing all ranges formed by any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether the scope is separately disclosed. When ranges of numerical values are stated herein, unless otherwise stated, it is intended that the endpoints of the range and the scope of the parent invention within the range are not limited to the specific values stated when defining the range. As used herein, “dianhydride” is intended to include precursors or derivatives thereof, which are also referred to as “dianhydride” or “acid dianhydride”. This product may technically not be dianhydrides, but will nonetheless react with diamine to form a polyamic acid, and the polyamic acid may be converted back into polyimide. As used herein, “diamine” is intended to include precursors or derivatives thereof