Urea-terminated polyurethane dispersants

• US 9,410,010 B2
• Filed: 12/04/2008
• Issued: 08/09/2016
• Est. Priority Date: 12/10/2007
• 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: Roberts, C. Chad, McIntyre, Patrick F., Wolfe, Michael Stephen, Li, Xiaoqing, Sunkara, Hari Babu
• Primary Examiner(s): NILAND, PATRICK DENNIS
• Application Number:
  US12/328,158
• Publication Number:
  US 20120035317A1
• Time in Patent Office: 2,805 Days
• Field of Search: 347/1, 347/85, 347/95, 347/100, 523/160, 523/161, 524/591, 524/839, 524/840
• US Class Current: 1/1
• CPC Class Codes: C08G 18/0823 containing carboxylate salt groups or groups forming them
• CPC Class Codes: C08G 18/12 using two or more compounds having active hydrogen in the first polymerisation step
• CPC Class Codes: C08G 18/2865 Compounds having only one primary or secondary amino group; Ammonia
• CPC Class Codes: C08G 18/3206 aliphatic
• CPC Class Codes: C08G 18/348 Hydroxycarboxylic acids
• CPC Class Codes: C08G 18/4854 Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
• CPC Class Codes: C08G 18/6692 with compounds of group C08G18/34
• 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 polyurethanes dispersants based on diols and polyether diols, 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. The urea termination can have nonionic hydrophilic substituents.

Claims

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

(a) the ionic dispersant is physically adsorbed to the colorant,

(b) the polymeric ionic dispersant stably disperses the colorant 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 inkjet ink of claim 1 where the urea content of the urea terminated polyurethane is at most about 4 wt. %.

3. The inkjet ink of claim 1 where the polyurethane dispersant has Structure (I), comprising the polyether diol of Structure (II) where p=2 or greater and m is greater than or equal to 3 to about 12.

4. The inkjet ink of claim 1 where the polyurethane dispersant has an ionic content of about 10 to 210 milliequivalents per 100 g of polyurethane.

5. The inkjet ink of claim 3 where the polyurethane dispersant comprises a polyether diol component wherein Z₂ is at least 50 weight percent of the polyether diol.

6. The inkjet ink of claim 3 where the polyurethane dispersant comprises a polyether diol component Z₂ which has a number average molecular weight of 200 to 5000.

7. The inkjet ink of claim 3 where the polyurethane dispersant comprises a polyether diol component Z₂ of Structure (II) where m=3 or 4.

8. The inkjet ink of claim 3 where R₅ and R₆ of the polyurethane dispersant are hydrogen.

9. The inkjet ink of claim 1 having viscosity at 25°

C. of 6 cPs or less wherein the colorant is a pigment.

10. The inkjet ink of claim 3 where Groups R₃ and R₄ of the polyurethane dispersant are alkyl.

11. The inkjet ink of claim 1 where the colorant to urea terminated polyurethane dispersant ratio is from about 0.5 to about 6 on a weight basis.

12. An inkjet ink 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.

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

13. An inkjet ink composition comprising an aqueous vehicle and colorant particles stabilized by an urea terminated polyurethane dispersant dispersion in an aqueous vehicle wherein:

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

14. The inkjet ink of claim 13 where the polyurethane dispersant has Structure (I) comprising the polyether diol of Structure (II) where p=2 or greater and m is greater than or equal to 3 to about 12.

15. 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) is prepared by

(a) providing reactants comprising (i) at least one diol Z₁ ii) at least one polyisocyanate component comprising a diisocyanate, and (iii) at least one hydrophilic reactant comprising at least one isocyanate reactive ingredient containing an ionic group, Z₂;

(b) contacting (i), (ii) and (iii) in the presence of a water-miscible organic solvent to form am isocyanate-functional polyurethane prepolymer;

(c) adding water to form an aqueous dispersion; and

(d) prior to, concurrently with or subsequent to step (c), chain-terminating the isocyanate-functional prepolymer with a primary or secondary amine;

where structure (I) is

16. The urea terminated polyurethane dispersant of claim 15 where the ratio of moles of amine of the chain-terminating primary or secondary amine to the moles of the isocyanate of the isocyanate-functional prepolymer is 1.0:

1 to 1.2;

1.