Electrophoretic particles and processes for the production thereof

Patent metadata

Field	Value
Publication number	US-10208207-B2
Application number	US-201715600730-A
Country	US
Kind code	B2
Filing date	May 20, 2017
Priority date	Feb 6, 2014
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

Polymer shells similar to those described in U.S. Pat. No. 6,822,782 can be formed on pigment particles by (a) physi-sorping a reagent comprising polymerizable groups on to the pigment particles by treating the particle with a reagent having a polymerizable or polymerization-initiating group, such that the reagent will not desorb from the particle surface when the particle is placed in a hydrocarbon medium; or (b) treating pigment particles bearing nucleophilic groups with a reagent having a polymerizable or polymerization-initiating group, and an electrophilic group, thus attaching the polymerizable or polymerization-initiating groups to the particle surface. The zeta potential of the pigment particles can be varied by a process similar to (b) but using a reagent which does not have a polymerizable or polymerization-initiating group.

First claim

The invention claimed is:

1. A process for treatment of pigment particles, the process comprising physi-sorping a reagent comprising polymerizable groups on to the surfaces of the pigment particles by treating the particle with a solution of a reagent having a polymerizable or polymerization-initiating group, thereby causing the reagent to become physi-sorbed on to the particle surface such that the reagent will not desorb from the particle surface when the particle is placed in a hydrocarbon medium,
wherein the pigment is negatively charged and the reagent contains a quaternary ammonium salt.

2. A process according to claim 1 wherein the pigment particle comprises an inorganic pigment.

3. A process according to claim 1 further comprising reacting the pigment particle with the reagent physi-sorbed thereon with at least one monomer or oligomer under conditions effective to cause reaction between the polymerizable or polymerization-initiating group on the particle and the at least one monomer or oligomer, thereby causing the formation of polymer on the particle.

4. A process according to claim 1 wherein the quaternary ammonium salt comprises at least one of [3-(methacryloyloxy)ethyl]trimethylammonium chloride, [3-(methacryloyloxy)-ethyl]trimethylammonium methyl sulfate, and [3-(methacryloylamino)-propyl]trimethylammonium chloride.

5. An electrophoretic material comprising a plurality of electrically charged particles disposed in a fluid and capable of moving through the fluid under the influence of an electric field, wherein at least one of the charged particles is produced by the process of claim 1 .

6. A process for treatment of pigment particles, the process comprising physi-sorping a reagent comprising polymerizable groups on to the surfaces of the pigment particles by treating the particle with a solution of a reagent having a polymerizable or polymerization-initiating group, thereby causing the reagent to become physi-sorbed on to the particle surface such that the reagent will not desorb from the particle surface when the particle is placed in a hydrocarbon medium,
wherein the pigment is positively charged and the reagent contains an anionic functional group.

7. A process according to claim 6 wherein the reagent comprises at least one of 3-sulfopropyl methacrylate potassium salt and sodium 4-vinylbenzenesulfonate.

8. A process according to claim 6 wherein the pigment particle comprises an inorganic pigment.

9. A process according to claim 6 further comprising reacting the pigment particle with the reagent physi-sorbed thereon with at least one monomer or oligomer under conditions effective to cause reaction between the polymerizable or polymerization-initiating group on the particle and the at least one monomer or oligomer, thereby causing the formation of polymer on the particle.

10. An electrophoretic material comprising a plurality of electrically charged particles disposed in a fluid and capable of moving through the fluid under the influence of an electric field, wherein at least one of the charged particles is produced by the process of claim 6 .

Assignees

• E Ink Corp

Inventors

• Yezek Lee
• Drabek Andrew
• Slominski Luke M
• Morrison Jennifer M
• Telfer Stephen J
• Steinberg Brian

Classifications

• C09B48/00 Primary

  Quinacridones · CPC title

• H01B1/00

  Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors · CPC title

• G02F2001/1678

  characterised by the composition or particle type · CPC title

• G03G17/04

  using photoelectrophoresis · CPC title

• C09B67/0013

  with polymeric coatings · CPC title