Electrophoretic particle, electrophoretic particle dispersion liquid, display medium, and display device

• US 10,031,394 B2
• Filed: 12/19/2012
• Issued: 07/24/2018
• Est. Priority Date: 02/27/2012
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Nakayama, Daisuke, Yamamoto, Yasuo, Hiji, Naoki, Seki, Mieko, Mizutani, Ryota, Manabe, Chikara, Jun, Cao, Aoshima, Toshihide
• Primary Examiner(s): Choi, Ling Siu
• Assistant Examiner(s): Nguyen, Thuy-Ai N
• Application Number:
  US13/719,587
• Publication Number:
  US 20130222887A1
• Time in Patent Office: 2,043 Days
• Field of Search: 252581
• CPC Class Codes: C08F 2/44 Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
• CPC Class Codes: C08F 220/06 Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• CPC Class Codes: C08F 220/14 Methyl esters , e.g. methyl (meth)acrylate
• CPC Class Codes: C08F 220/18 with acrylic or methacrylic acids
• CPC Class Codes: C08F 220/20 of polyhydric alcohols or phenols , e.g. 2-hydroxyethyl (meth)acrylate or glycerol mono-(meth)acrylate
• CPC Class Codes: C08F 220/34 Esters containing nitrogen , e.g. N,N-dimethylaminoethyl (meth)acrylate
• CPC Class Codes: C08F 220/343 in the form of urethane links
• CPC Class Codes: C08F 228/02 by a bond to sulfur
• CPC Class Codes: C09B 61/00 Dyes of natural origin prepared from natural sources , e.g. vegetable sources
• CPC Class Codes: C09B 67/009 polymeric dispersing agent
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 2001/1678 characterised by the composition or particle type

Abstract

There is provided an electrophoretic particle which contains a core material particle formed of a composition containing a resin, a nitrogen-containing heterocyclic compound having any one of an imino group, a methylol group and an alkoxymethyl group in the molecule and a heterocyclic ring having a nitrogen atom, and a coloring agent.

Claims

1. An electrophoretic particle containing:

a core material particle formed of a composition containing a resin, a nitrogen-containing heterocyclic compound having an imino group, a methylol group, or an alkoxymethyl group in the molecule, and a coloring agent, wherein the nitrogen containing heterocyclic compound crosslinks the resin; and

a covering layer on a surface of the core material particle,

wherein the covering layer is formed of a composition containing a resin of a copolymer comprising at least a polymerization component having a silicone chain.

2. The electrophoretic particle according to claim 1,

wherein the nitrogen-containing heterocyclic compound is selected from the group consisting of a melamine compound and a guanamine compound each having any one of an imino group, a methylol group and an alkoxymethyl group in the molecule.

3. The electrophoretic particle according to claim 1, wherein the covering layer is formed of a composition containing a resin having a dispersion medium-philic part soluble in a dispersion medium, wherein the electrophoretic particle is dispersed and a dispersion medium-phobic part insoluble in a dispersion medium wherein the electrophoretic particle is dispersed.

4. The electrophoretic particle according to claim 1, wherein the content of the nitrogen-containing heterocyclic compound is about 0.5% by mass or more and about 50% by mass or less based on the total of the core material particle.

5. The electrophoretic particle according to claim 3, wherein the covering layer is a covering layer composed of a resinous crosslinked product of the composition containing the resin.

6. An electrophoretic particle dispersion liquid comprising:

a dispersion medium and an electrophoretic particle dispersed in the dispersion medium, wherein the electrophoretic particle is the electrophoretic particle according to claim 1.

7. The electrophoretic particle dispersion liquid according to claim 6, wherein the dispersion medium contains a solvent having a low dielectric constant.

8. A display medium comprising:

a pair of substrates at least either one of which has light-transmitting property, and the electrophoretic particle dispersion liquid according to claim 6, which is enclosed between the pair of substrates.

9. A display medium comprising:

a pair of electrodes at least either one of which has light-transmitting property, and an area having the electrophoretic particle dispersion liquid according to claim 6, which is enclosed between the pair of electrodes.

10. A display device comprising:

the display medium according to claim 8 and a voltage-applying unit that applies a voltage between the pair of substrates of the display medium.

11. A display device comprising:

the display medium according to claim 9 and a voltage-applying unit that applies a voltage between the pair of electrodes of the display medium.

14. The electrophoretic particle of claim 1, wherein the electrophoretic particle is heated to at least at 130°

C. for at least one hour to cause the nitrogen containing heterocyclic compound to crosslink the resin.

12. An electrophoretic particle comprising a core formed of a resinous crosslinked product including:

a resin;

a melamine compound having an imino group, a methylol group or an alkoxymethyl group wherein the melamine compound crosslinks the resin; and

a coloring agent.

15. The electrophoretic particle of claim 12, wherein the melamine compound is of Formula (B)

16. The electrophoretic particle of claim 12, wherein the electrophoretic particle is heated to at least at 130°

C. for at least one hour to cause the melamine compound to crosslink the resin.

13. An electrophoretic particle comprising a core formed of a resinous cross linked product including:

a resin;

a guanamine compound having an imino group, a methylol group or an alkoxymethyl group wherein the guanamine compound crosslinks the resin; and

a coloring agent.

17. The electrophoretic particle of claim 13, wherein the guanamine compound is of Formula (A)

18. The electrophoretic particle of claim 13, wherein the electrophoretic particle is heated at least at 130°

C. for at least one hour to cause the guanamine compound to crosslink the resin.