PROCESS FOR MAKING CNT/PFA COMPOSITE COATINGS FOR FUSER APPLICATIONS

• US 20100055589A1
• Filed: 08/26/2008
• Published: 03/04/2010
• Est. Priority Date: 08/26/2008
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: ZHANG, Qi, HU, Nan-Xing, QI, Yu
• Granted Patent: US 8,557,345 B2
• Time in Patent Office: Days
• US Class Current: 430/71
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C08K 3/041 Carbon nanotubes
• CPC Class Codes: C08K 3/34 Silicon-containing compounds
• CPC Class Codes: C08L 33/02 Homopolymers or copolymers of acids; Metal or ammonium salts thereof
• CPC Class Codes: C08L 65/00 Compositions of macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain C08L7/00 - C08L57/00, C08L61/00 take precedence; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 79/02 Polyamines
• CPC Class Codes: C09D 127/18 Homopolymers or copolymers of tetrafluoroethene
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C09D 7/65 macromolecular C09D7/41-C09D7/48 take precedence
• CPC Class Codes: C09D 7/70 characterised by shape, e.g. fibres, flakes or microspheres
• CPC Class Codes: G03G 15/2057 relating to the chemical composition of the heat element and layers thereof
• CPC Class Codes: G03G 2215/2048 Surface layer material

Abstract

Exemplary embodiments provide nanotube-containing coating compositions and methods for making and using the coating compositions. In an exemplary embodiment, the coating composition can include a plurality of nanotubes (e.g., carbon nanotubes (CNTs)) dispersed stably and uniformly in a polymer matrix containing fluoropolymers. The coating composition can further include stabilizers to allow a stable and/or uniform dispersion of the plurality of nanotubes in the fluoropolymers. The nanotube coating composition can be coated on an article surface to improve mechanical robustness, and electrical and thermal conductivity of the coated article The coated article can be used as a fuser member, a fixing member, a pressure roller, or a release agent donor member in an electrostatographic printing machine or process.

Claims

1. A method for making a coating composition comprising:

forming a stabilizer solution;

providing a fluoropolymer suspension;

mixing a plurality of nanotubes in a media with the stabilizer solution and the fluoropolymer suspension to form a coating composition, whereby the stabilizer allows a stable dispersion of the plurality of nanotubes in the media and in the fluoropolymer.

2. The method of claim 1, wherein the stabilizer is a material selected from the group consisting of polymeric amines, polymeric acids, conjugated polymers, and natural gum materials.

3. The method of claim 1, wherein the stabilizer is a material selected from the group consisting of polyallylamine, polyethylenimine, poly(diallyldimethylammonium chloride), poly(allylamine hydrochloride), and mixtures thereof.

4. The method of claim 1, wherein the stabilizer is selected from the group consisting of poly(acrylic acid), poly(3,4-ethylenedioxythiophene), poly(3,4-ethylenedioxythiophene) complexes with a polymeric acid, Gum Arobic, chitosan, and mixtures thereof.

5. The method of claim 1, further comprising adjusting a pH value of the stabilizer solution or the mixed coating composition in an aqueous media, wherein the pH value is about 3 to about 10.

6. The method of claim 1, further comprising adding one or more acidic drops in the stabilizer solution or the mixed coating composition to control a pH value, when the stabilizer is polyallylamine having a molecular weight ranging from about 300 to about 100,000.

7. The method of claim 1, further comprising sonicating the stabilizer solution, the fluoropolymer suspension, the plurality of nanotubes in the media or the mixed coating composition.

8. The method of claim 1, wherein each of the plurality of nanotubes comprises one or more of a single wall carbon nanotube (SWCNT) or a multi-wall carbon nanotube (MWCNT).

9. The method of claim 1, wherein each of the plurality of nanotubes has an inside diameter ranging from about 0.5 nanometer to about 20 nanometers as well as an outside diameter ranging from about 1 nanometer to about 80 nanometers, and has an aspect ratio ranging from about 1 to about 10000.

10. The method of claim 1, wherein the media for the plurality of nanotubes is a liquid selected from a group consisting of water, an alcohol, an aliphatic hydrocarbon of from C5 to about C18, an aromatic hydrocarbon of from C6 to C18, an ether, a ketone, an amide, and mixtures thereof.

11. The method of claim 1, wherein the plurality of nanotubes is present in an amount from about 0.01 to about 20 percent by weight of the fluoropolymer.

12. The method of claim 1, wherein the fluoropolymer comprises a monomeric repeat unit that is selected from the group consisting of tetrafluoroethylene, perfluoro(methyl vinyl ether), perfluoro(propyl vinyl ether), perfluoro(ethyl vinyl ether), vinylidene fluoride, hexafluoropropylene, and mixtures thereof.

13. The method of claim 1, wherein the fluoropolymer comprises a fluororesin selected from the group consisting of polytetrafluoroethylene, copolymer of tetrfluoroethylene and hexafluoropropylene, copolymer of tetrafluoroethylene and perfluoro(propyl vinyl ether), copolymer of tetrafluoroethylene and perfluoro(ethyl vinyl ether), and copolymer of tetrafluoroethylene and perfluoro(methyl vinyl ether).

14. The method of claim 1, wherein the fluoropolymer is in a form of a particle suspension, a colloid dispersion or a latex with an average particle size ranging from about 10 nanometers to about 5000 nanometers.

15. The method of claim 1, wherein the fluoropolymer comprises one or more of a small particle with an average particle size ranging from about 50 nanometers to about 500 nanometers and a large particle with an average particle size ranging from about 1 micrometer to about 50 micrometers.

16. The method of claim 1, further comprising forming a filler suspension and mixing the filler suspension with one or more of the stabilizer solution, the fluoropolymer suspension, the plurality of nanotubes in the media or the mixed coating composition.

17. The method of claim 16, wherein the filler suspension further comprises one or more inorganic particles comprising metal oxides, silicon carbide, boron nitride, and graphite, wherein the metal oxides are selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide, zinc oxide, tin oxide, iron oxide, magnesium oxide, manganese oxide, nickel oxide, copper oxide, antimony pentoxide, indium tin oxide, and mixtures thereof.

18. The method of claim 16, further comprising treating each surface of the one or more inorganic particles by a surface treatment agent comprising silane.

19. The method of claim 1, further comprising coating the mixed coating composition onto a surface and drying the coated coating composition.

20. A method for making a coated article comprising:

providing a substrate;

forming a coating composition according to the method of claim 1; and

forming a coated layer by applying the coating composition to the substrate.

21. The method of claim 20, further comprising heating the coated layer at a temperature ranging from about 250°

C. to about 400°

C. following the application of the coating composition.

22. The method of claim 20, wherein the substrate is formed of a material selected from the group consisting of metals, plastics, and ceramics,

wherein the metals are selected from the group consisting of aluminum, anodized aluminum, steel, nickel, copper, and mixtures thereof, and

wherein the plastics are selected from the group consisting of polyimides, polyester, polyetheretherketone (PEEK), poly(arylene ether)s, polyamides and mixtures thereof.

23. The method of claim 20, wherein the substrate is in a form of a cylinder, a belt or a plate.

24. The method of claim 20, further comprising disposing one or more functional layers between the substrate and the coated layer.

25. The method of claim 20, further comprising using the coated article as one or more of a fuser roll, a fixing roll, a pressure roller, and release agent donor roll in an electrostatographic printing process.