SELF-LUBRICATING POLYIMIDE VARNISH AND POLYIMIDE COATING PREPARED THEREFROM

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.

Claims

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: ##STR00005## in Chemical Formula 1 above, R.sub.1 to R.sub.10 are each independently a C.sub.1-20 alkyl group or a C.sub.6-20 aryl group; and X.sub.1 to X.sub.3 are each independently a hydrogen atom, a C.sub.1-3 alkyl group, a C.sub.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.sub.1 to X.sub.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. 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. 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. 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. The polyimide varnish of claim 1, wherein the surface-modified nanosilica with organosilane has an average particle diameter of 10 to 200 nm.

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: ##STR00006## in Chemical Formula 2 above, R.sub.1, R.sub.7, and R.sub.10 are each independently a C.sub.1-20 alkyl group; and X.sub.1 to X.sub.3 are each independently a hydrogen atom, a C.sub.1-3 alkyl group, a C.sub.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.sub.1 to X.sub.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. 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. 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. 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. (canceled)

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. 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. 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. 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. 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. 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. (canceled)

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. The polyimide varnish of claim 18, wherein 0 to 1.0 mol % of an aromatic carboxylic acid is further contained.

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.sup.1.

21. A polyimide coating material comprising a cured product of the polyimide varnish according to claim 1.

22. The polyimide coating material of claim 21, wherein the polyimide coating material has a coefficient of friction (PI-SUS) of 0.4 or less.

23. (canceled)

24. (canceled)

25. (canceled)

Description

BEST MODE

[0105] The following exemplary embodiments are presented to help understanding of the present invention. The following Examples are only provided to more easily understand the present invention, but the content of the present invention is not limited by these Examples.

Example

Preparation Example 1. Silicone-Based Additive 1

[0106] 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.), and specific gravity 0.97 g/mL (based on 25 C.)).

Preparation Example 2. Silicone-Based Additive 2

[0107] 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.), and specific gravity 0.98 g/mL (based on 25 C.)).

Preparation Example 3. Silicone-Based Additive 3

[0108] 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.), and specific gravity 1.00 g/mL (based on 25 C.)).

Example 1. Polyimide Varnish

[0109] Into a reaction vessel substituted with nitrogen gas, an organic solvent containing dimethylacetamide and a modifier was introduced, and pyromellitic dianhydride (PMDA) (99.6 mol % to 103.8 mol %) as an dianhydride monomer and surface-modified nanosilica with organosilane (ethylene glycol dispersed silica sol, organosilica sol with silica solid content of 20 wt %, average silica particle diameter of 70-100 nm, viscosity of 20-100 mPa.Math.s, and moisture content of 2% or less) (0.75 wt %) were mixed and stirred at 40 C. for 30 minutes. Then, 4,4-diaminodiphenyl ether (ODA) (100 mol %) as a diamine monomer was added, pyromellitic acid (0 to 0.5 mol %) was added, and a silicone-based additive (0.53 wt %) was added. Then, the resulting mixture was stirred at 40 C. for about 1 hour to polymerize, thereby preparing a polyamic acid solution having a solid content of 15 to 25 wt %.

Comparative Examples 1 to 7. Polyimide Varnish

[0110] Polyimide precursors were prepared in the same manner as in Example 1, except that components and amount ratios of the dianhydride monomer, the diamine monomer, the surface-modified nanosilica with organosilane, and the silicone-based additive were adjusted as shown in Table 1 below.

TABLE-US-00001 TABLE 1 Dianhydride Diamine Silicone monomer monomer Nanosilica additive Classification (mol %) (mol %) (wt %) (wt %) Example 1 PMDA ODA 0.75 Preparation (99.6 mol %) (100 mol %) Example 1 (0.53 wt %) Example 2 PMDA ODA 0.75 Preparation (99.6 mol %) (100 mol %) Example 2 (0.53 wt %) Example 3 PMDA ODA 0.75 Preparation (103.8 mol %) (100 mol %) Example 1 (0.53 wt %) Example 4 PMDA ODA 0.75 Preparation (103.8 mol %) (100 mol %) Example 2 (0.53 wt %) Example 5 PMDA ODA 0.75 Preparation (103.8 mol %) (100 mol %) Example 1 (0.2 wt %) Example 6 PMDA ODA 0.75 Preparation (103.8 mol %) (100 mol %) Example 1 (0.4 wt %) Example 7 PMDA ODA 0.75 Preparation (103.8 mol %) (100 mol %) Example 1 (0.8 wt %) Example 8 PMDA ODA 0.75 Preparation (103.8 mol %) (100 mol %) Example 3 (0.2 wt %) Example 9 PMDA ODA 0.75 Preparation (103.8 mol %) (100 mol %) Example 3 (0.4 wt %) Example 10 PMDA ODA 0.75 Preparation (103.8 mol %) (100 mol %) Example 3 (0.8 wt %) Comparative PMDA ODA Example 1 (99.7 mol %) (100 mol %) Comparative PMDA ODA Example 2 (103.8 mol %) (100 mol %) Comparative PMDA ODA 0.75 Example 3 (103.8 mol %) (100 mol %) Comparative PMDA ODA Preparation Example 4 (99.6 mol %) (100 mol %) Example 1 (0.53 wt %)

Experimental Example

Polyimide Preparation for Measurement of Physical Properties

[0111] Respective polyimide varnishes prepared in Examples and Comparative Examples were subjected to high-speed rotation at 1,500 rpm or higher to remove air bubbles. Then, each de-foamed polyimide varnish was applied to a glass substrate using a spin coater.

[0112] Under a nitrogen atmosphere, the obtained products were heated from room temperature up to 400 C. at a rate of 4 C./min, heat-treated at 400 C. for 60 minutes, and then cooled to 30 C. at a rate of 4 C./min to obtain polyimide films each having a thickness of 201.0 m.

Experimental Example 1. Coefficient of Friction

[0113] Using the QM110CF model of QMESYS, the coefficient of friction was measured by ASTMD1894, D4918 method at a speed of 150 mm/min, a load of 200 g, a displacement of 65 mm, and an atmosphere of 23 C., and results thereof are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Coefficient of friction Classification Initial value Average value Example 1 0.26 0.27 Example 5 0.33 0.34 Example 6 0.34 0.35 Example 7 0.32 0.33 Example 8 0.32 0.34 Example 9 0.29 0.31 Example 10 0.29 0.30 Comparative Example 1 0.46 0.48 Comparative Example 2 0.45 0.46 Comparative Example 3 0.39 0.41 Comparative Example 4 0.43 0.49

[0114] It was found that the polyimide varnishes of the present invention had a low coefficient of friction (PI-SUS) of 0.4 or less.

[0115] In the present specification, the detailed description of the contents capable of being sufficiently recognized and inferred by those skilled in the art of the present disclosure are omitted, and many variations and modification can be made within a range that does not change the technical spirit or essential configuration of the present disclosure in addition to the specific exemplary embodiments described in the present specification. Therefore, the present disclosure may also be practiced in a manner different from that specifically described and illustrated herein, which can be understood by those skilled in the art.