Cationic modified self-dispersing pigment dispersions and inkjet inks thereof

Patent metadata

Field	Value
Publication number	US-10370549-B2
Application number	US-201615570421-A
Country	US
Kind code	B2
Filing date	Apr 27, 2016
Priority date	Apr 30, 2015
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

This invention pertains to aqueous inkjet inks containing self-dispersing pigments. The self-dispersing pigments are modified with multivalent cations.

First claim

What is claimed is:

1. An aqueous pigment dispersion comprising:
a self-dispersing pigment having at least one type of hydrophilic functional group bonded onto a surface of the self-dispersing pigment, said at least one type of hydrophilic functional group comprising a carboxyl group; and
a multivalent cation selected from the group consisting of Mg 2+ , Ca 2+ , Cu 2+ , Al 3+ , Fe 3+ , and mixtures thereof, wherein said multivalent cation is adsorbed onto said self-dispersing pigment via ionic bonds between the multivalent cation and surface acid group on the self-dispersing pigment displacing monovalent cation(s) associating with the carboxyl group on the surface of the self-dispersing pigment, the displaced monovalent cation(s) are removed from the pigment dispersion.

2. The pigment dispersion of claim 1 , wherein said multivalent cation is present at a level of at least 2 ppm.

3. The pigment dispersion of claim 1 , wherein said multivalent cation is Mg 2+ .

4. The pigment dispersion of claim 1 , wherein said multivalent cation is Cu 2+ .

5. The pigment dispersion of claim 1 , wherein said multivalent cation is Ca 2+ .

6. The pigment dispersion of claim 1 , wherein said multivalent cation is Al 3+ .

7. A process for making an aqueous inkjet ink comprising the step of:
(a) preparing an aqueous vehicle;
(b) adding the aqueous vehicle to an aqueous pigment dispersion, wherein said pigment dispersion comprising a self-dispersing pigment having at least one type of hydrophilic functional group bonded onto a surface of said self-dispersing pigment, said at least one type of hydrophilic functional group comprising a carboxyl group; and a multivalent cation selected from the group consisting of Mg 2+ , Ca 2+ , Cu 2+ , Al 3+ , Fe 3+ , and mixtures thereof, wherein said cation is adsorbed onto said self-dispersing pigment via ionic bonds between the cation and surface acid group on said self-dispersing pigment displacing monovalent cation(s) associating with the carboxyl group on the surface of the self-dispersing pigment; and
(c) removing the monovalent cation(s) displaced by the multivalent cation.

8. The process of claim 7 , wherein said multivalent cation is present at a level of at least 2 ppm.

9. The process of claim 7 , wherein said multivalent cation is Mg 2+ .

10. The process of claim 7 , wherein said multivalent cation is Cu 2+ .

11. The process of claim 7 , wherein said multivalent cation is Ca 2+ .

12. The process of claim 7 , wherein said multivalent cation is Al 3+ .

13. An inkjet ink comprising an aqueous vehicle and an aqueous pigment dispersion, wherein said pigment dispersion comprising a self-dispersing pigment having at least one type of hydrophilic functional group bonded onto a surface of said self-dispersing pigment, said at least one type of hydrophilic functional group comprising a carboxyl group; and a multivalent cation selected from the group consisting of Mg 2+ , Ca 2+ , Cu 2+ , Al 3+ , Fe 3+ , and mixtures thereof, wherein said multivalent cation is adsorbed onto said self-dispersing pigment via ionic bonds between the multivalent cation and surface acid group on said self-dispersing pigment displacing monovalent cation(s) associating with the carboxyl group on the surface of the self-dispersing pigment, the displaced monovalent cation(s) are removed from the pigment dispersion.

14. The ink of claim 13 , wherein said multivalent cation is present at a level of at least 2 ppm.

15. The ink of claim 13 , wherein said multivalent cation is Mg 2+ .

16. The ink of claim 13 , wherein said multivalent cation is Cu 2+ .

17. The ink of claim 13 , wherein said multivalent cation is Ca 2+ .

18. The ink of claim 13 , wherein said multivalent cation is Al 3+ .

Assignees

• Du Pont

Inventors

• Wolfe Michael Stephen
• Eiseman Michael J
• Tam Loretta L
• Kirkpatrick Cullen

Classifications

• C09D17/005

  Carbon black · CPC title

• C09D11/324 Primary

  containing carbon black · CPC title

• C09D17/003

  containing an organic pigment (process features in the making of dye stuff preparations C09B67/00) · CPC title

• C09D11/38

  characterised by non-macromolecular additives other than solvents, pigments or dyes · CPC title

• C09D17/001

  in aqueous medium (C09D17/003, C09D17/004 take precedence) · CPC title