METALLIC INK

• US 20090274833A1
• Filed: 03/31/2009
• Published: 11/05/2009
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: Ishihara Chemical Co., Ltd., Applied Nanotech, Inc. (Nano Magic, Inc.)
• Original Assignee: Ishihara Chemical Co., Ltd., Applied Nanotech Holdings Incorporated (Nano Magic, Inc.)
• Inventors: Laxton, Peter B., Li, Xueping, Yaniv, Zvi, Li, Yunjun, Roundhill, David Max, Arimura, Hidetoshi
• Granted Patent: US 8,404,160 B2
• Time in Patent Office: Days
• US Class Current: 427/123
• CPC Class Codes: B22F 1/0545 Dispersions or suspensions of nanosized particles
• CPC Class Codes: B22F 2301/10 Copper
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C09D 11/037 characterised by the pigment
• CPC Class Codes: C09D 11/322 Pigment inks
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: H01B 1/026 Alloys based on copper
• CPC Class Codes: H05K 1/097 Inks comprising nanoparticles and specially adapted for being sintered at low temperature H05K1/095 takes precedence
• CPC Class Codes: H05K 2203/1131 Sintering, i.e. fusing of metal particles to achieve or improve electrical conductivity

Abstract

A metallic ink including a vehicle, a multiplicity of copper nanoparticles, and an alcohol. The conductive metallic ink may be deposited on a substrate by methods including inkjet printing and draw-down printing. The ink may be pre-cured and cured to form a conductor on the substrate.

Claims

1. A conductive metal ink comprising:

a vehicle comprising two or more oxygenated organic compounds;

copper nanoparticles; and

a medium length chain aliphatic alcohol.

2. The ink of claim 1, wherein the medium length chain aliphatic alcohol has four to twelve carbon atoms, inclusive.

3. The ink of claim 2, wherein the alcohol is isobutanol, 2-octanol, or a combination thereof.

4. The ink of claim 1, wherein the viscosity of the alcohol exceeds the viscosity of the vehicle.

5. The ink of claim 1, wherein the dielectric constant of the alcohol exceeds the dielectric constant of the vehicle.

6. The ink of claim 1, wherein the alcohol is a non-polymeric alcohol.

7. The ink of claim 1, wherein the alcohol comprises between about 30 wt % and about 96 wt % of organic liquids in the ink.

8. The ink of claim 1, further comprising an ionic dispersant.

9. The ink of claim 8, wherein the ionic dispersant comprises between about 0.5 wt % and 20 wt % of the ink.

10. The ink of claim 1, wherein the copper nanoparticles comprise copper oxide.

11. The ink of claim 1, wherein the copper nanoparticles comprise between about 40 wt % and about 60 wt % of the ink.

12. The ink of claim 1, wherein the boiling point of the vehicle is less than 150°

C.

13. The ink of claim 1, wherein the vehicle is hydrophilic.

14. The ink of claim 1, wherein the ink does not comprise a binder.

15. The ink of claim 1, wherein the ink is substantially free of nanoparticle agglomerates larger than about 10 μ

m in diameter.

16. The ink of claim 1, wherein the ink is curable to form a smooth, homogeneous conductor.

17. A method of forming a conductor from a metallic ink, the method comprising:

depositing a metallic ink on a substrate to form a smooth, homogenous layer of ink on the substrate, the ink comprising;

a vehicle comprising two or more oxygenated organic compounds;

copper nanoparticles; and

a medium length chain aliphatic alcohol; and

solidifying the conductive metallic ink to form a conductor on the substrate.

18. The method of claim 17, wherein the ink is substantially free of nanoparticle agglomerates larger than about 110 μ

m in diameter.

19. The method of claim 17, wherein depositing comprises draw-down printing.

20. The method of claim 17, wherein depositing comprises inkjet printing.

21. The method of claim 17, wherein the resistivity of the conductor is less than about 10 μ

Ω

-cm.

22. The method of claim 17, wherein the copper nanoparticles comprise about 40 wt % to about 60 wt % of the ink.