Black polymer particles

Patent metadata

Field	Value
Publication number	US-9822232-B2
Application number	US-201415100390-A
Country	US
Kind code	B2
Filing date	Nov 18, 2014
Priority date	Dec 2, 2013
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

This invention relates to a process for the preparation of a dispersion comprising black polymer particles, such black polymer particles prepared by the process, the use of the dispersion and the black polymer particles in electrophoretic fluids, and electrophoretic display devices comprising such fluids.

First claim

The invention claimed is:

1. A process for the preparation of black polymer particles dispersed in at least one non-polar fluorinated solvent for use in electrophoretic devices, the process comprising the steps of
a) forming a reverse emulsion comprising at least one polymer selected from poly(vinyl pyrrolidone) or poly(acrylic acid), at least one carbon black pigment, at least one polar solvent, at least one non-polar fluorinated solvent, at least one fluorinated surfactant, and a blue and/or black dye, wherein the reverse emulsion comprises perfluoro(tributlylamine) as a non-polar phase, and
b) removing the polar solvent or solvents by evaporative methods, wherein the non-polar, fluorinated solvent or solvents are not removed.

2. The process according to claim 1 , wherein the reverse emulsion of step a) is prepared by a process comprising; a1) forming a polar phase by mixing at least one polymer, at least one carbon black pigment, and at least one polar solvent, a2) forming a non-polar phase by mixing at least one non-polar, fluorinated solvent, and at least one surfactant, a3) combining the polar phase and the non-polar phase, and a4) homogenizing the combined phases to form the reverse emulsion.

3. The process according to claim 1 , wherein the polymer of step a) is insoluble in the non-polar fluorinated solvent, and the polymer is produced from at least one monomer that is insoluble in the non-polar fluorinated solvent, or from at least one monomer that is soluble in the non-polar fluorinated solvent.

4. The process according to claim 1 , wherein the non-polar fluorinated solvent used in step a) is a perfluorinated hydrocarbon having a refractive index of ≦1.3, a dielectric constant ≦10, and a boiling point ≧80 ° C., and has a refractive index and a density similar to that of the polymer used in step a).

5. The process according to claim 1 , wherein the polar solvent used in step a) is selected from water, low molecular weight alcohols, methyl ethyl ketone, acetonitrile, DMSO, DMF or mixtures thereof.

6. The process according to claim 1 , wherein a polar phase comprises one or more of water, ethanol, methanol, methyl ethyl ketone, or industrial methylated spirits.

7. The process according to claim 1 , further comprising step c) concentrating the non-polar fluorinated solvent or solvents.

8. The process according to claim 1 , further comprising step c′) removing the non-polar fluorinated solvent or solvents.

9. A dispersion comprising black particles prepared according to claim 8 .

10. A mono, bi or polychromal electrophoretic device comprising the dispersion according to claim 9 .

11. A Total Internal Reflection (TIR) device comprising the dispersion according to claim 9 .

12. An electrophoretic display device comprising the dispersion according to claim 9 .

13. A dispersion prepared by a process according to claim 1 .

14. The process according to claim 1 , wherein the blue and/or black dye is selected from the group consisting of Solvent Blue 35, Solvent Black 27, Solvent Black 29, Solvent Black 34, Acid Black 52, Acid Black 107, Acid Black 132, Acid Black 172, Acid Black 194, Acid Black 211, Acid Black 222, Direct Black 19, Direct Black 22, Direct Black 51, Direct Black 80, and Direct Black 112.

15. The process according to claim 1 , wherein the blue and/or black dye comprises a stabilizer selected from the group consisting of 1,2,2,6,6-pentamethylpiperidine, 1,2,2,6,6-pentamethyl-4-piperidinol, and bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[(3,5-bis(1 ,1 -di methyl)-4-hydroxyphenyl]methylbutylmalonate.

16. A dispersion comprising a non-polar, fluorinated solvent, and black particles, wherein the black particles comprise carbon black, a polymer selected from poly(vinyl pyrrolidone) or poly(acrylic acid), a fluorinated surfactant, and a blue and/or black dye, and wherein the dispersion comprises perfluoro(tributylamine) as a non-polar phase.

17. The dispersion according to claim 16 , comprising perfluoro(tributylamine), and the black particles consist of the carbon black, poly(vinyl pyrrolidone) and/or poly(acrylic acid), and a poly(hexafluoropropylene oxide) polymeric surfactant with a monofunctional carboxylic acid end group, and a weight-average molecular weight Mw between 5000 and 8000.

18. An electronic device comprising a dispersion of claim 16 , wherein the electronic device is selected from the group consisting of an electrooptical device, electrochemical device, electrophotographic device, electrowetting device, electro-osmotic device, electrohydrodynamic device, and electrophoretic device.

19. The device according to claim 18 , the device selected from the group consisting of a dynamic keypad, e-paper watch, dynamic pricing and advertising device, e-reader, rollable display, smart card media, product packaging, mobile phone, lab top, display card, digital signage and shelf edge label.

20. The device according to claim 18 , wherein the dispersion is applied to the device by a technique selected from inkjet printing, slot die spraying, nozzle spraying, and flexographic printing.

Assignees

• Merck Patent Gmbh
• The Queen'S Univ Of Belfast

Inventors

• Farrand Louise D
• Norman Sarah

Classifications

• C09B67/0097

  Dye preparations of special physical nature; Tablets, films, extrusion, microcapsules, sheets, pads, bags with dyes · CPC title

• C09B67/009

  polymeric dispersing agent · CPC title

• C08J2339/06

  Homopolymers or copolymers of N-vinyl-pyrrolidones · CPC title

• C08L39/06

  Homopolymers or copolymers of N-vinyl-pyrrolidones · CPC title

• C08L33/04

  Homopolymers or copolymers of esters {(C08L43/04 takes precedence)} · CPC title