Charge control agents and particle dispersions including the same

Patent metadata

Field	Value
Publication number	US-12454598-B2
Application number	US-202418615274-A
Country	US
Kind code	B2
Filing date	Mar 25, 2024
Priority date	May 10, 2019
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

Mixtures are disclosed containing a plurality of charged pigment particles and one or more charge control agents. At least one of the charge control agents has a chemical structure that includes a cationic head group, such as an ammonium cation or an iminium compound, and a non-ionic, polar functional group, other than an acyclic secondary amide group. The mixtures are useful as dispersions for forming electrophoretic media that may be incorporated into electrophoretic displays. Alternatively, the dispersions may be useful for forming electrophotographic toners and dispersions for other printing applications.

First claim

We claim:

1. An electrophoretic medium comprising a dispersion comprising a non-polar fluid, a plurality of charged particles and a blend of a first charge control agent and a second charge control agent, wherein the first charge control agent comprises a cationic head group and having a chemical structure according to Formula I;

wherein m is 0, 1, 2, or 3;
wherein each R is independently selected from the group consisting of an alkyl group, and an aryl group;
wherein Z is one of a branched alkanediyl group, and an unbranched alkanediyl group;
wherein n is an integer less than or equal to 20;
wherein HT is a hydrophobic moiety;
the second charge control agent being represented by Formula XV, Formula XVI, or Formula XVII;

wherein each R 21 , R 22 , R 23 is independently selected from the group consisting of an alkyl group or an aryl group;
wherein v is an integer of at least 2 and less than or equal to 20;
wherein HT is a hydrophobic moiety;

wherein HT of Formulas XVI and XVII is a hydrophobic moiety comprising a functional group selected from the group consisting of poly(hydroxystearic acid), poly(ricinoleic acid), poly(isobutylene), and an unbranched or a branched alkyl group, wherein the unbranched or the branched alkyl group comprises from about 10 to about 35 carbon atoms,
and wherein the plurality of charged particles are capable of moving through the non-polar fluid upon application of an electric field.

2. The electrophoretic medium of claim 1 , wherein the hydrophobic moiety HT of Formula I comprises a functional group selected from the group consisting of poly(hydroxystearic acid), poly(ricinoleic acid), poly(isobutylene), and an unbranched or a branched alkyl group, wherein the unbranched or the branched alkyl group comprises from about 10 to about 35 carbon atoms.

3. The electrophoretic medium of claim 1 , wherein the first charge control agent has a chemical structure according to Formula VII,

wherein HT is a hydrophobic moiety.

4. The electrophoretic medium of claim 1 , wherein the first charge control agent has a weight average molecular weight greater than or equal to 1000 g/mol.

5. The electrophoretic medium of claim 1 , wherein mis 3.

6. The electrophoretic medium of claim 1 , wherein Formula I comprises a trimethylammonium cationic group or a triethylammonium cationic group.

7. The electrophoretic medium of claim 1 , wherein group (Z) n of Formula I is an unbranched group —(CH 2 ) q — wherein q is from 1 to 20.

8. The electrophoretic medium of claim 1 , wherein each R 21 , R 22 , and R 23 of Formula XV is independently an alkyl group.

9. The electrophoretic medium of claim 1 , wherein the non-polar fluid is a saturated linear or branched hydrocarbon.

10. The electrophoretic medium of claim 1 , wherein the non-polar fluid is a silicone oil.

11. The electrophoretic medium of claim 1 , wherein the non-polar fluid is a halogen-containing polymer.

12. The electrophoretic medium of claim 1 , wherein the non-polar fluid has boiling point higher than 90° C.

13. The electrophoretic medium of claim 1 , wherein the non-polar fluid has water solubility of less than 10 parts per million.

Assignees

• E Ink Corp

Inventors

• BZOWEJ Eugene
• Marshall John L
• Telfer Stephen J
• Macdonald Brandon

Classifications

• C08G69/08

  derived from amino-carboxylic acids · CPC title

• C09B67/009

  polymeric dispersing agent · CPC title

• G02F1/167 Primary

  by electrophoresis · CPC title

• G02F2202/022

  polymeric · CPC title

• G03G9/09758

  comprising a heterocyclic ring · CPC title