PREPARATION OF PIGMENT DISPERSIONS

• US 20140295338A1
• Filed: 03/29/2013
• Published: 10/02/2014
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: KEOSHKERIAN, Barkev, ALLEN, C. Geoffrey, CHOPRA, Naveen, CHRETIEN, Michelle N., VANBESIEN, Daryl W., ELIYAHU, Jenny
• Granted Patent: US 9,243,148 B2
• Time in Patent Office: Days
• US Class Current: 430/105
• CPC Class Codes: B02C 17/20 Disintegrating members
• CPC Class Codes: C01P 2004/51 Particles with a specific particle size distribution
• CPC Class Codes: C01P 2004/52 highly monodisperse size distribution
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C09B 67/0022 Wet grinding of pigments
• CPC Class Codes: C09B 67/009 polymeric dispersing agent
• CPC Class Codes: C09C 1/3018 Grinding
• CPC Class Codes: C09C 1/56 Treatment of carbon black ; Purification
• CPC Class Codes: C09C 3/041 Grinding
• CPC Class Codes: C09D 11/101 Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
• CPC Class Codes: C09D 11/322 Pigment inks
• CPC Class Codes: C09D 11/34 Hot-melt inks
• CPC Class Codes: C09D 17/00 Pigment pastes, e.g. for mixing in paints artists' paints C09D5/06
• CPC Class Codes: G03G 9/09 Colouring agents for toner particles
• CPC Class Codes: G03G 9/0904 Carbon black
• CPC Class Codes: G03G 9/0926 characterised by physical or chemical properties

Abstract

A method for preparing a pigment dispersion includes milling a starting pigment dispersion containing a pigment and optionally a carrier and a dispersant with milling media having an average particle size of about 100 μm or less, until a final pigment dispersion having at least one of a desired pigment average particle size and a desired pigment particle size distribution is obtained; optionally separating the milling media from the final pigment dispersion; and optionally diluting the final pigment dispersion to obtain a desired pigment particle concentration.

Claims

1. A method for preparing a pigment dispersion, the method comprising:

milling a starting pigment dispersion containing a pigment and optionally a carrier and a dispersant with milling media having an average particle size of about 100 μ

m or less, until a final pigment dispersion having at least one of a desired pigment average particle size and a desired pigment particle size distribution is obtained;

optionally separating the milling media from the final pigment dispersion; and

optionally diluting the final pigment dispersion to obtain a desired pigment particle concentration.

2. The method of claim 1, wherein the starting pigment dispersion comprises pigment particles having an average particle size of greater than about 1 μ

m, and the final pigment dispersion comprises pigment particles having an average particle size of less than about 500 nm.

3. The method of claim 1, wherein the starting pigment dispersion comprises pigment particles having an average particle size of greater than about 1 μ

m, and the final pigment dispersion comprises pigment particles having an average particle size of from about 100 nm to about 400 nm.

4. The method of claim 1, wherein the final pigment dispersion comprises pigment particles having an average particle size of from about 50 to about 500 nm.

5. The method of claim 1, wherein the milling media is selected from the group consisting of diamond dust, silicon carbide, boron carbide, iron oxide, corundum, garnet, aluminum oxide, and mixtures thereof.

6. The method of claim 1, wherein the milling media is selected from the group consisting of diamond dust and iron oxide.

7. The method of claim 1, wherein the milling media is substantially free of zirconium oxide, yttrium oxide, and stainless steel balls.

8. The method of claim 1, wherein the milling media has an average particle size of about 15 nm to about 75 μ

m.

9. The method of claim 1, wherein the milling media comprises iron oxide and has a sub-micron average particle size.

10. The method of claim 1, wherein the milling time is for from about 15 minutes to about four hours.

11. The method of claim 1, wherein the milling media is removed from the final pigment dispersion before or after the final pigment dispersion is diluted to obtain a desired pigment particle concentration.

12. The method of claim 1, wherein the milling media comprises iron oxide, and the milling media is separated from the final pigment dispersion using a magnet.

13. The method of claim 1, wherein the milling media comprises aspherical diamond dust, and the milling media is separated from the final pigment dispersion using filtration.

14. The method of claim 1, comprising separating the milling media from the final pigment dispersion.

15. The method of claim 1, wherein the starting pigment dispersion comprises at least two different pigments.

16. The method of claim 1, wherein the starting pigment dispersion comprises carbon black.

17. A pigment dispersion made by the process of claim 1.

18. A toner composition made from the pigment dispersion of claim 17.

19. A solid ink made from the pigment dispersion of claim 17.

20. A method for preparing a pigment dispersion, the method comprising:

milling a starting pigment dispersion containing a pigment and optionally a carrier and a dispersant with milling media having an average particle size of about 100 μ

m or less, until a final pigment dispersion having at least one of a desired pigment average particle size and a desired pigment particle size distribution is obtained; and

separating the milling media from the final pigment dispersion,

wherein the starting pigment dispersion comprises pigment particles having an average particle size of greater than about 1 μ

m, and the final pigment dispersion comprises pigment particles having an average particle size of less than about 500 nm.