Conductive thermal transfer ribbon

• US 20080057233A1
• Filed: 08/20/2007
• Published: 03/06/2008
• Est. Priority Date: 08/29/2006
• Status: Abandoned Application

• Current Assignee: International Imaging Materials Inc. (IIMAK Holding Corp.)
• Original Assignee: International Imaging Materials Inc. (IIMAK Holding Corp.)
• Inventors: Berube, Gregory, Balling, Bernard, Harrison, Daniel J., Geddes, Pamela A.
• Application Number:
  US11/894,229
• Publication Number:
  US 20080057233A1
• Time in Patent Office: Days
• US Class Current: 428/32.74
• CPC Class Codes: B41M 5/3825 Electric current carrying heat transfer sheets
• CPC Class Codes: H05K 2203/0528 Patterning during transfer, i.e. without preformed pattern, e.g. by using a die, a programmed tool or a laser
• CPC Class Codes: H05K 2203/1105 Heating or thermal processing not related to soldering, firing, curing or laminating, e.g. for shaping the substrate or during finish plating
• CPC Class Codes: H05K 3/046 by selective transfer or selective detachment of a conductive layer
• CPC Class Codes: H05K 3/207 using a prefabricated paste pattern, ink pattern or powder pattern

Abstract

A thermal transfer ribbon comprised of a support and an ink layer disposed above the support. The ink layer has a thickness of from about 0.1 to about 10 microns; it contains at least 75 weight percent of particulate conductive metal material and from about 1 to about 25 weight percent of binder; and it has a surface resistivity of less than about 1,000,000 ohms per square. When the ink layer is transferred to a substrate, the surface resistivity of the transferred ink is less than 100 ohms per square when printed onto a flexible substrate at a printing speed of 2 centimeters per second and a printing energy of 7.6 joules per square centimeter. The particulate conductive metal preferably contains a noble metal and has a melting point of at least 800 degrees Celsius and a particle size such that least about 95 weight percent of its particles are smaller than 50 microns.

Claims

1. A thermal transfer ribbon comprised of a support and a conductive ink layer disposed above the support, wherein:

(a) said conductive ink layer is comprised of at least 75 weight percent of particulate conductive metal material and from about 1 to about 25 weight percent of binder, and it has a surface resistivity of less than about 1,000,000 ohms per square;

(b) said conductive ink layer has a thickness of from about 0.1 to about 10 microns;

(c) said particulate conductive metal has a particle size such that least about 95 weight percent of its particles have a maximum dimension smaller than 50 microns; and

(d) when said conductive ink layer is thermally printed onto a flexible polyester substrate at a printing speed of 2 centimeters per second and a printing energy of 7.6 joules per square centimeter, its surface resistivity is less than about 100 ohms/square;

2. The thermal transfer ribbon as recited in claim 1, wherein said particulate metal material is comprised of a noble metal.

3. The thermal transfer ribbon as recited in claim 2, wherein said noble metal is selected from the group consisting of silver, gold, platinum, palladium, iridium, rhenium, mercury, ruthenium, osmium, and mixtures thereof.

4. The thermal transfer ribbon as recited in claim 3, wherein said particulate conductive metal has a melting point of at least 800 degrees Celsius.

5. The thermal transfer ribbon as recited in claim 4, wherein said noble metal is selected from the group consisting of silver, gold, and mixtures thereof.

6. The thermal transfer ribbon as recited in claim 5, wherein, when said conductive ink layer is thermally printed onto a flexible polyester substrate at a printing speed of 2 centimeters per second and a printing energy of 7.6 joules per square centimeter and thereafter polished;

said printed and polished conductive ink layer has a surface resistivity is less than about 50 ohm/square;

7. The thermal transfer ribbon as recited in claim 5, wherein said conductive metal particles are comprised of an element that has a reduction potential of at least about 0.5 volts at 25 degrees Celsius and 1 atmosphere pressure;

and wherein said conductive ink layer has a thickness of less than about 8 microns.

8. The thermal transfer ribbon as recited in claim 5, wherein when said conductive ink layer is thermally printed onto a flexible substrate at a printing speed of 2 centimeters per second and a printing energy of 7.6 joules per square centimeter, it has a volume resistivity that is less than about 100 microohm-cm;

13. The thermal transfer ribbon as recited in claim 1, wherein said binder is a thermoplastic binder.

14. The thermal transfer ribbon as recited in claim 13, wherein said conductive ink layer is comprised of from about 1 to about 15 weight percent of said thermoplastic binder.

15. The thermal transfer ribbon as recited in claim 14, wherein said conductive ink layer is comprised of at least about 90 weight percent of said particulate conductive metal material.

16. The thermal transfer ribbon as recited in claim 15, wherein said thermoplastic binder has a softening point of from about 45 to about 150 degrees Celsius.

17. The thermal transfer ribbon as recited in claim 16, wherein said particulate conductive metal material has a particle size such that least about 95 weight percent of its particles have a maximum dimension smaller than 15 microns.

24. The thermal transfer ribbon as recited in claim 5, wherein said particulate metal material is in the form of a flake.

25. The thermal transfer ribbon as recited in claim 24, wherein, when said conductive ink layer is thermally printed onto a flexible substrate at a printing speed of 2 centimeters per second and a printing energy of 7.6 joules/square centimeter and has a volume resistivity is less than about 100 micro ohm-cm;

26. The thermal transfer ribbon as recited in claim 25, wherein at least about 90 weight percent of said particulate conductive material is present in said conductive ink layer;

27. The thermal transfer ribbon as recited in claim 26, wherein said binder is a thermoplastic binder with a softening point of from about 45 to about 150 degrees Celsius;

28. The thermal transfer ribbon as recited in claim 5, wherein said particulate conductive metal material has a particle size such that least about 95 weight percent of its particles have a maximum dimension smaller than 100 nanometers.

9. A thermal transfer ribbon comprised of a support and a conductive ink layer disposed above the support, wherein:

(a) said conductive ink layer is comprised of at least 75 weight percent of particulate conductive metal material and from about 1 to about 25 weight percent of binder, and it has a surface resistivity of less than about 100 ohms per square;

(b) said conductive ink layer has a thickness of from about 0.1 to about 10 microns;

(c) said particulate conductive metal has a particle size such that least about 95 weight percent of its particles have a maximum dimension smaller than 50 microns; and

(d) said particulate metal material is comprised of a noble metal.

10. The thermal transfer ribbon as recited in claim 9, wherein said particulate conductive metal material is in the form of a flake.

11. The thermal transfer ribbon as recited in claim 10, wherein said noble metal is selected from the group consisting of silver, gold, and mixtures thereof.

12. The thermal transfer ribbon as recited in claim 11, wherein, when said conductive ink layer is thermally printed onto a flexible polyester substrate at a printing speed of 2 centimeters per second and a printing energy of 7.6 joules per square centimeter, said printed conductive ink layer has a surface resistivity of less than about 10 ohms/square;

18. The thermal transfer ribbon as recited in claim 10, wherein said particulate conductive material comprises a mixture of a noble metal and a non-noble metal.

19. The thermal transfer ribbon as recited in claim 18, wherein said non-noble metal is copper.

20. The thermal transfer ribbon as recited in claim 19, wherein said noble metal is silver.

21. The thermal transfer ribbon as recited in claim 20, wherein said particulate conductive material is comprised of from about 5 to about 40 weight percent of silver, by total weight of silver and copper.

22. The thermal transfer ribbon as recited in claim 21, wherein said particulate conductive material is comprised of from about 10 to about 20 weight percent of silver, by total weight of silver and copper.

23. The thermal transfer ribbon as recited in claim 22, wherein said silver is coated onto said copper at a coating thickness of from about 0.3 to about 0.7 microns.