Urea-terminated polyurethane dispersants

• US 8,759,418 B2
• Filed: 05/22/2009
• Issued: 06/24/2014
• Est. Priority Date: 05/23/2008
• Status: Active Grant

• Current Assignee: DuPont Electronics, Inc. (DuPont de Nemours, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Li, Xiaoqing, Lin, Tyau-Jeen, McIntyre, Patrick F.
• Primary Examiner(s): NILAND, PATRICK DENNIS
• Application Number:
  US12/990,959
• Publication Number:
  US 20110065861A1
• Time in Patent Office: 1,859 Days
• Field of Search: 523/160, 523/161, 524/589, 524/590, 524/591, 524/839, 524/840, 347/1, 347/85, 347/95, 347/100
• US Class Current: 523/160
• CPC Class Codes: C08G 18/0823 containing carboxylate salt groups or groups forming them
• CPC Class Codes: C08G 18/2885 containing halogen atoms
• CPC Class Codes: C08G 18/3206 aliphatic
• CPC Class Codes: C08G 18/8041 with compounds of C08G18/3271
• CPC Class Codes: C08G 18/8064 with monohydroxy compounds
• CPC Class Codes: C09D 11/326 characterised by the pigment dispersant
• CPC Class Codes: C09D 17/001 in aqueous medium C09D17/003, C09D17/004 take precedence

Abstract

The present invention relates to urea terminated polyurethane dispersants based on certain diols which have grafted alkyl, aryl or fluoroalkyl substituents, aqueous dispersions of such polyurethanes, the manufacture of the urea terminated polyurethane dispersions and inks containing pigments and/or disperse dyes dispersed with these urea terminated polyurethane dispersants.

Claims

1. An aqueous colorant dispersion comprising a comprising a colorant and a urea terminated polyurethane ionic dispersant in an aqueous vehicle, wherein:

(a) at least some of the ionic dispersant is physically adsorbed to the colorant,

(b) the polymeric ionic dispersant stably disperses the pigment in the aqueous vehicle,

(c) the volume average particle size of the dispersion is less than about 300 nm,

wherein the urea terminated polyurethane dispersant comprises at least one compound of the general Structure (I);

2. The aqueous colorant dispersion of claim 1, where the urea content of the urea terminated polyurethane is at least about 2.5 wt % and at most about 10.5 wt %.

3. The aqueous colorant dispersion of claim 1, where the ionic content of the polyurethane is 10 to 190 milliequivalents per 100 g of polyurethane.

4. The aqueous colorant dispersion of claim 1, where the ionic content of the polyurethane is 20 to 140 milliequivalents per 100 g of polyurethane.

5. The aqueous colorant dispersion of claim 1, where the ionic content of the polyurethane is 25 to 90 milliequivalents per 100 g of polyurethane.

6. The aqueous colorant dispersion of claim 1, where the colorant to urea terminated polyurethane dispersant ratio is from about 0.5 to about 6 on a weight basis.

7. The aqueous colorant dispersion of claim 1, where R₂ comprises at least Z₂, at least one Z₁ or Z₃ and at least one additional diol of the general structure (V)

8. An aqueous colored ink jet ink comprising the aqueous colorant dispersion of claim 1, having from about 0.1 to about 10 wt % pigment based on the total weight of the ink, a weight ratio of colorant to urea terminated polyurethane dispersant of from about 0.5 to about 6, a surface tension in the range of about 20 dyne/cm to about 70 dyne/cm at 25°

C, and a viscosity of lower than about 30 cP at 25°

C.

10. A process for making a dispersed pigment comprising the step of mixing the pigment and a urea terminated polyurethane dispersant of claim 1, in an aqueous carrier medium, then dispersing or deflocculating the pigment.

11. The method of claim 10, wherein the dispersing is accomplished in a process selected from the group consisting of 2-roll milling, media milling, and by passing the mixture through a plurality of nozzles within a liquid jet interaction chamber at a liquid pressure of at least 5,000 psi.

13. The aqueous colorant dispersion of claim 1, where the colorant is a pigment or disperse dye.

14. The aqueous colorant dispersion of claim 1, where the colorant to urea terminated polyurethane dispersant ratio is from about 0.5 to about 6 on a weight basis.

15. The aqueous colorant dispersion of claim 1 where the colorant to urea terminated polyurethane dispersant ratio is from about 0.75 to about 4 on a weight basis.

16. The aqueous colorant dispersion of claim 1 formulated for inkjet printing on textiles.

18. The aqueous colorant dispersion of claim 1 where at least one Z₁ is a dial derived from a polyether trial having a molecular weight of about 260.

19. The aqueous colorant dispersion of claim 18, where R₂ comprises at least Z₂, at least one Z₁ or Z₃ and at least one additional diol of the general structure (V)

20. The aqueous colorant dispersion of claim 1 where Z₁ has a molecular weight of from about 250 to about 650.

9. An inkjet ink composition comprising an aqueous vehicle and colorant particles stabilized by an urea terminated polyurethane dispersant in an aqueous vehicle wherein the urea terminated poiyurethane dispersant comprises at least one compound of the general Structure (I):

17. The inkjet ink composition of claim 9 formulated for inkjet printing on textiles.

12. A process for making a dispersed pigment comprising the steps of a) preparing a urea terminated polyurethane dispersant and then mixing the pigment and the urea terminated polyurethane dispersant in an aqueous carrier medium, then dispersing or deflocculating the pigment where the urea terminated polyurethane (Structure I):