Dispersant in non-polar solvent

• US 6,562,889 B2
• Filed: 04/18/2001
• Issued: 05/13/2003
• Est. Priority Date: 04/18/2001
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Rao, Prabhakara Satyauolu
• Primary Examiner(s): Michl, Paul R.
• Application Number:
  US09/837,784
• Publication Number:
  US 20030018111A1
• Time in Patent Office: 755 Days
• Field of Search: 524/462, 524/366, 524/319
• US Class Current: 524/366
• CPC Class Codes: C08J 3/09 in organic liquids
• CPC Class Codes: C09K 23/007 Organic compounds containing halogen
• CPC Class Codes: G02F 1/167 by electrophoresis

Abstract

The present invention provides a stable, non-film-forming dispersion comprising a) dispersed particles, b) a liquid non-polar solvent which is preferably fluorinated, and c) a dispersant selected from the group consisting of highly fluorinated polyethers, having an atomic ratio of carbon to oxygen of between 2 and 4 inclusive, and bearing at least one polar functional group which is preferably an ionizable group such as a carboxylic acid group.

Claims

1. A stable, non-film-forming dispersion comprising a) dispersed particles, b) a liquid, non-polar solvent, and c) a dispersant selected from the group consisting of highly fluorinated polyethers, having an atomic ratio of carbon to oxygen of between 2 and 4 inclusive, and bearing at least one polar functional group.

2. The dispersion according to claim 1 wherein said solvent is a liquid, non-polar hydrocarbon solvent.

3. The dispersion according to claim 1 wherein said solvent is highly fluorinated.

4. The dispersion according to claim 1 wherein said solvent is perfluorinated.

5. The dispersion according to claim 1 wherein said dispersant is perfluorinated.

6. The dispersion according to claim 1 wherein said at least one polar functional group is an end group.

7. The dispersion according to claim 1 wherein said at least one polar functional group is an ionizable functional group.

8. The dispersion according to claim 1 wherein said at least one polar functional group is a carboxylic acid group.

9. The dispersion according to claim 1 wherein said solvent has a dielectric constant equal to or less than 3.0.

10. The dispersion according to claim 1 wherein said solvent comprises a perfluorinated alkane.

11. The dispersion according to claim 1 wherein said dispersed particles comprise acrylic polymer latex particles.

12. The dispersion according to claim 1 wherein said dispersed particles comprise pigment.

13. The dispersion according to claim 1 wherein said dispersed particles have an average particle size of 300 nm or less.

14. The dispersion according to claim 1 wherein said dispersed particles have an average particle size of 250 nm or less.

15. The dispersion according to claim 1 wherein said dispersed particles have an average particle size of 200 nm or less.

16. The dispersion according to claim 1 which contains no charging agent.

17. The dispersion according to claim 16 which has a conductance of 1 picomho/cm or more.

18. The dispersion according to claim 17 which has a conductance of 5 picomho/cm or more.

19. The dispersion according to claim 17 which has a conductance of 40 picomho/cm or more.

20. The dispersion according to claim 17 which has a conductance of 80 picomho/cm or more.

21. An electrophoretic device comprising the dispersion according to claim 1.

22. An electrophoretic display comprising the dispersion according to claim 1, wherein said dispersed particles may be alternately a) removed from dispersion by application of an electric field, and b) redispersed by removal or reversal of said electric field.