Method of Manufacturing Transparent Conductive Film Containing Carbon Nanotubes And Binder, And Transparent Conductive Film Manufactured Thereby

• US 20080286559A1
• Filed: 12/04/2007
• Published: 11/20/2008
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: Korea Electrotechnology Research Institute
• Original Assignee: Korea Electrotechnology Research Institute
• Inventors: Woo, Jong Seok, Kim, Sun Young, Lee, Geon-Woong, Han, Joong Tak
• Granted Patent: US 8,637,122 B2
• Time in Patent Office: Days
• US Class Current: 428/323
• CPC Class Codes: C08K 3/041 Carbon nanotubes
• CPC Class Codes: C09D 163/00 Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
• CPC Class Codes: C09D 163/10 Epoxy resins modified by unsaturated compounds
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Abstract

This invention relates to a method of manufacturing a transparent conductive film containing carbon nanotubes and a binder, in which the carbon nanotubes are subjected to acid treatment, dispersion in a solvent, mixing with the binder, and application on the substrate, and to a transparent conductive film manufactured thereby. The method includes subjecting carbon nanotubes having an outer diameter of less than 15 nm to acid treatment to thus purify and surface functionalize them, followed by dispersing the treated carbon nanotubes in a solvent along with the binder, or mixing a carbon nanotube solution using a polar or nonpolar solvent with a binder solution, and applying the mixture on the substrate. Through the application of the mixture of treated carbon nanotubes and binder on the substrate, the transparent conductive film has improved transparency, electrical conductivity, dispersibility, substrate adhesiveness, chemical stability, durability and scratch resistance, and can be applied to various substrates, including hard or flexible substrates, thanks to high substrate adhesiveness and applicability. A solution in which the surface functionalized carbon nanotubes are well dispersed is prepared, thus facilitating the manufacture of the film using various materials and generating economic benefits.

Claims

1. A method of manufacturing a transparent conductive film containing carbon nanotubes and a binder, comprising subjecting carbon nanotubes to acid treatment, to dispersion in a solvent, to mixing with a binder, and then to application on an upper surface of a substrate.

2. The method as set forth in claim 1, wherein the carbon nanotubes comprise one selected from among single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, and mixtures thereof.

3. The method as set forth in claim 1, wherein the solvent comprises one or more selected from among acetone, methylethylketone, methylalcohol, ethylalcohol, isopropylalcohol, butylalcohol, ethyleneglycol, polyethyleneglycol, tetrahydrofuran, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, hexane, cyclohexanone, toluene, chloroform, distilled water, dichlorobenzene, dimethylbenzene, trimethylbenzene, pyridine, methylnaphthalene, nitromethane, acrylonitrile, octadecylamine, aniline, and dimethylsulfoxide.

4. The method as set forth in claim 1, wherein the binder is added in an amount of 15˜

85 parts by weight, based on 100 parts by weight of a mixture of carbon nanotubes and binder, and comprises one selected from among organic materials, including material selected from among thermoplastic resins, thermosetting resins, light curable resins, silane compounds, polymeric copolymers, self-assembled resins, and combinations thereof.

5. The method as set forth in claim 1, wherein the substrate comprises one selected from among glass, crystal, glass wafers, silicon wafers, and plastics.

6. The method as set forth in claim 1, wherein the application on the upper surface of the substrate is conducted through any one selected from among spraying, dip coating, spin coating, screen coating, ink-jet printing, pad printing, knife coating, kiss coating, and gravure coating.

7. The method as set forth in claim 1, wherein the acid treatment is conducted using an acid solution comprising one selected from among nitric acid, hydrochloric acid, sulfuric acid, hydrogen peroxide and mixtures thereof.

8. The method as set forth in claim 1, wherein the carbon nanotubes have an outer diameter of less than 15 nm.

9. A method of manufacturing a transparent conductive film containing carbon nanotubes and a binder, comprising:

1) mixing the carbon nanotubes with an acid solution, thus purifying the carbon nanotubes;

2) dispersing the purified carbon nanotubes in a polar solvent or a nonpolar solvent, thus preparing a carbon nanotube solution;

3) mixing the carbon nanotube solution with the binder, thus preparing a carbon nanotube/binder coating solution;

4) applying the carbon nanotube/binder coating solution on an upper surface of a substrate; and

5) conducting drying to remove the solvent and to solidify the binder.

10. The method as set forth in claim 9, wherein the 2) dispersing the purified carbon nanotubes is conducted through ultrasonic dispersion or ball milling.

11. The method as set forth in claim 10, wherein the ultrasonic dispersion is conducted for 1˜

60 hours using a sonicator having power ranging from 50 W to 700 W at a frequency ranging from 20 kHz to 50 kHz.

12. The method as set forth in claim 9, wherein the 3) mixing the carbon nanotube solution with the binder is conducted by preparing a binder solution, including the binder and the polar or nonpolar solvent, which is then mixed with the carbon nanotube solution.

13. The method as set forth in claim 9, further comprising controlling a viscosity of the carbon nanotube/binder coating solution, before the 4) applying the carbon nanotube/binder coating solution.

14. The method as set forth in claim 9, wherein the carbon nanotubes comprise one selected from among single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, and mixtures thereof.

15. The method as set forth in claim 9, wherein the solvent comprises one or more selected from among acetone, methylethylketone, methylalcohol, ethylalcohol, isopropylalcohol, butylalcohol, ethyleneglycol, polyethyleneglycol, tetrahydrofuran, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, hexane, cyclohexanone, toluene, chloroform, distilled water, dichlorobenzene, dimethylbenzene, trimethylbenzene, pyridine, methylnaphthalene, nitromethane, acrylonitrile, octadecylamine, aniline, and dimethylsulfoxide.

16. The method as set forth in claim 9, wherein the binder is added in an amount of 15˜

85 parts by weight, based on 100 parts by weight of a mixture of carbon nanotubes and binder, and comprises one selected from among organic materials, including material selected from among thermoplastic resins, thermosetting resins, light curable resins, silane compounds, polymeric copolymers, self-assembled resins, and combinations thereof.

17. The method as set forth in claim 9, wherein the substrate comprises one selected from among glass, crystal, glass wafers, silicon wafers, and plastics.

18. The method as set forth in claim 9, wherein the applying the carbon nanotube/binder coating solution on the upper surface of the substrate is conducted through any one selected from among spraying, dip coating, spin coating, screen coating, ink-jet printing, pad printing, knife coating, kiss coating, and gravure coating.

19. The method as set forth in claim 9, wherein the acid solution comprises one selected from among nitric acid, hydrochloric acid, sulfuric acid, hydrogen peroxide and mixtures thereof.

20. The method as set forth in claim 9, wherein the carbon nanotubes have an outer diameter of less than 15 nm.

21. A transparent conductive film containing carbon nanotubes and a binder, manufactured by applying a carbon nanotube/binder coating solution, obtained by mixing the carbon nanotubes, subjected to acid treatment, with the binder, on an upper surface of a substrate.

22. The transparent conductive film as set forth in claim 21, wherein the carbon nanotubes comprise one selected from among single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, and mixtures thereof.

23. The transparent conductive film as set forth in claim 21, wherein the carbon nanotubes are dispersed in a solvent, the solvent comprising one or more selected from among acetone, methylethylketone, methylalcohol, ethylalcohol, isopropylalcohol, butylalcohol, ethyleneglycol, polyethyleneglycol, tetrahydrofuran, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, hexane, cyclohexanone, toluene, chloroform, distilled water, dichlorobenzene, dimethylbenzene, trimethylbenzene, pyridine, methylnaphthalene, nitromethane, acrylonitrile, octadecylamine, aniline, and dimethylsulfoxide.

24. The transparent conductive film as set forth in claim 21, wherein the binder is added in an amount of 15˜

85 parts by weight, based on 100 parts by weight of a mixture of carbon nanotubes and binder, and comprises one selected from among organic materials, including material selected from among thermoplastic resins, thermosetting resins, light curable resins, silane compounds, polymeric copolymers, self-assembled resins, and combinations thereof.

25. The transparent conductive film as set forth in claim 21, wherein the substrate comprises one selected from among glass, crystal, glass wafers, silicon wafers, and plastics.

26. The transparent conductive film as set forth in claim 21, wherein an acid solution used for the acid treatment of carbon nanotubes comprises one selected from among nitric acid, hydrochloric acid, sulfuric acid, and mixtures thereof.

27. The transparent conductive film as set forth in claim 21, wherein the carbon nanotubes have an outer diameter of less than 15 nm.