Inkjet inks

Patent metadata

Field	Value
Publication number	US-10947400-B2
Application number	US-201616069087-A
Country	US
Kind code	B2
Filing date	Mar 29, 2016
Priority date	Mar 29, 2016
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

An inkjet ink can include an ink vehicle and ink solids carried by the ink vehicle. The ink solids can include a pigment, 5 wt % to 40 wt % polymeric binder, and 0.3 wt % to 3 wt % wax. The wax can have a melting point of from 90° C. to 115° C. and an average particle size of from 0.1 μm to 0.5 μm. Further, the wax can include wax particles having a particle size greater than 1 μm but which are present at a quantity no greater than 0.1% of the total number of wax particles based on particle count.

First claim

What is claimed is:

1. An inkjet ink, comprising:
an ink vehicle; and
ink solids carried by the ink vehicle, said ink solids comprising:
a pigment;
0.5 wt % to 15 wt % polymeric binder; and
0.3 wt % to 3 wt % wax having a melting point of from 90° C. to 115° C., an average particle size of from 0.1 μm to 0.5 μm, and comprising wax particles having a particle size greater than 1 μm in a quantity no greater than 0.1% of the total number of wax particles, wherein the wax is obtained from a centrifuged wax emulsion.

2. The inkjet ink of claim 1 , wherein the polymeric binder is selected from the group consisting of a polyurethane polymer, an acrylic polymer, and combinations thereof.

3. The inkjet ink of claim 1 , wherein the ink vehicle comprises a glycol ether solvent.

4. The inkjet ink of claim 1 , wherein the wax has a melting point of from 95° C. to 110° C.

5. The inkjet ink of claim 1 , wherein the ink has a solids content of from 30 wt % to 50 wt %.

6. The inkjet ink of claim 1 , wherein the inkjet ink has from 0.5 wt % to 2 wt % wax.

7. The inkjet ink of claim 1 , wherein the wax is a low density polyethylene wax.

8. The inkjet ink of claim 1 , wherein the wax emulsion comprises a low density polyethylene wax having a melting point of from 100° C. to 110° C., wherein wax solids have an average particle size of from 0.1 μm to 0.5 μm, said wax solids comprising wax particles having a particle size greater than 1 μm in a quantity no greater than 0.1% of the total number of wax particles based on particle count.

9. The inkjet ink of claim 1 , wherein the wax is obtained by batch centrifugation of the wax emulsion at from 2000 rpm to 8000 rpm for a period of from 10 minutes to 180 minutes.

10. The inkjet ink of claim 1 , wherein the wax is obtained by continuous centrifugation of the wax emulsion at from 2000 rpm to 10000 rpm.

11. The inkjet ink of claim 1 , wherein the wax is obtained by centrifuging the wax emulsion to selectively settle particles to form a gradient wax emulsion having a low-average-particle-size fraction and a high-average-particle-size fraction, and wherein the wax is obtained by filtering the low-average-particle-size fraction.

12. A method of preparing an inkjet ink, comprising:
preparing a wax emulsion;
centrifuging the wax emulsion to selectively settle particles to form a gradient wax emulsion having a low-average-particle-size fraction and a high-average-particle-size fraction; and
formulating an inkjet ink, comprising:
an ink vehicle;
a pigment;
a polymeric binder; and
wax solids obtained from the low-average-particle-size fraction of the gradient wax emulsion to provide a wax solids content of from 0.3 wt % to 3 wt % in the inkjet ink.

13. The method of claim 12 , wherein the wax emulsion comprises a low density, polyethylene wax having a melting point of from 100° C. to 110° C., wherein the wax solids have an average particle size of from 0.1 μm to 0.5 μm, said wax solids comprising wax particles having a particle size greater than 1 μm in a quantity no greater than 0.1% of the total number of wax particles based on particle count.

14. The method of claim 12 , wherein centrifuging comprises batch centrifugation of the wax emulsion at from 2000 rpm to 8000 rpm for a period of from 10 minutes to 180 minutes.

15. The method of claim 12 , wherein centrifuging comprises continuous centrifugation of the wax emulsion at from 2000 rpm to 10000 rpm.

16. The method of claim 12 , further comprising filtering the low-average-particle-size fraction.

17. The method of claim 12 , wherein:
the polymeric binder is selected from the group consisting of a polyurethane polymer, an acrylic polymer, and combinations thereof;
the ink vehicle comprises a glycol ether solvent; or
both.

18. The method of claim 12 , wherein the inkjet ink has:
a solids content of from 30 wt % to 50 wt %;
from 0.5 wt % to 2 wt % wax solids; or
both.

19. The method of claim 12 , wherein the wax in the wax solids:
has as a melting point of from 95° C. to 110° C.;
includes a low density polyethylene wax; or
both.

20. A printed article, comprising:
a print medium; and
a printed feature applied on top of the print medium with the inkjet ink of claim 1 .

Assignees

• Hewlett Packard Development Co

Inventors

• Yen Max
• Brandstein Or

Classifications

• C09D11/38

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

• C09D11/12

  based on waxes or bitumen · CPC title

• C09D11/102

  containing macromolecular compounds obtained by reactions other than those only involving unsaturated carbon-to-carbon bonds · CPC title

• C09D11/106

  containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C09D11/322 Primary

  Pigment inks · CPC title