Metallic ink

• US 8,404,160 B2
• Filed: 03/31/2009
• Issued: 03/26/2013
• 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: Li, Yunjun, Roundhill, David Max, Li, Xueping, Laxton, Peter B., Arimura, Hidetoshi, Yaniv, Zvi
• Primary Examiner(s): Nguyen, Khanh Tuan
• Application Number:
  US12/415,761
• Publication Number:
  US 20090274833A1
• Time in Patent Office: 1,456 Days
• Field of Search: 252/500, 252/511, 252/512, 252/513, 252/514, 252/519.33, 427/58, 427/123, 106/31.13, 106/31.92, 257/773, 523/160, 977/810
• US Class Current: 252/519.33
• 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, wherein the ink does not comprise a binder.

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 is substantially free of nanoparticle agglomerates larger than about 10 μ

m in diameter.

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

16. The ink of claim 1, wherein the medium length chain aliphatic alcohol is not a polyol.

17. The ink of claim 1, wherein the two or more oxygenated organic compounds each comprise a carbonyl group.

18. The ink of claim 1, wherein the two or more oxygenated organic compounds each comprise an ether acetate.

19. The ink of claim 1, wherein a concentration of the medium length chain aliphatic alcohol within the conductive metal ink is configured to achieve a monolayer coverage of the copper nanoparticles by head groups of the medium length chain aliphatic alcohol.

20. The ink of claim 1, wherein the medium length chain aliphatic alcohol has a head group that is chemically compatible with the copper nanoparticles and a tail group that is chemically compatible with the vehicle.

21. The ink of claim 1, wherein at least some plurality of the copper nanoparticles have a copper oxide layer that is hydrogen bonded to the medium length chain aliphatic alcohol.

22. The ink of claim 1, wherein the alcohol is 2-octanol.

23. The ink of claim 1, wherein the vehicle has a composition that is configured to interact with the copper nanoparticles and the alcohol so that it evaporates from the conductive metal ink when cured.

24. The ink of claim 23, wherein a boiling point of the vehicle is less than 150°

C.