Electrophoretic core-shell particles having an organic pigment core and a shell with a thin metal oxide layer and a silane layer

Patent metadata

Field	Value
Publication number	US-12025901-B2
Application number	US-202117156911-A
Country	US
Kind code	B2
Filing date	Jan 25, 2021
Priority date	Feb 6, 2020
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

An electrophoretic medium comprises a plurality of core-shell particles and a non-polar fluid. The core-shell particles comprise an organic pigment particles core and a shell comprising a metal oxide layer and a silane layer. The metal oxide layer may have a thickness of 0.4 to 2 nm. It may be formed using a fluidized bed reactor by inserting the organic pigment into the reactor as a powder bed, contacting the powder bed with a gaseous stream comprising a metal oxide precursor and an inert gas, and contacting the powder bed with a gaseous stream of a reagent and an inert gas. The silane layer is formed from a silane compound comprising a first functional group, wherein the first functional group reacts with the metal oxide.

First claim

What is claimed is:

1. An electrophoretic medium comprising a plurality of a first type of core-shell particles and a non-polar fluid, wherein each of the plurality of the first type of the core-shell particles comprises:
a core comprising an organic pigment;
a shell comprising a metal oxide layer and a silane layer;
wherein the metal oxide layer is formed on the surface of the organic pigment using a fluidized bed reactor by inserting the organic pigment into the reactor as a powder bed, contacting the powder bed with a gaseous stream comprising an inert gas and a metal oxide precursor, and contacting the powder bed with a gaseous stream of an inert gas and a reagent that reacts with the metal oxide precursor to form a metal oxide; and
wherein the silane layer is formed from a silane compound comprising a first functional group and a second functional group, wherein the first functional group reacts with the metal oxide, and the second functional group is selected from the group consisting of a carboxy group, a sulfate group, a sulfonate group, a phosphate group, and a phosphonic group.

2. The electrophoretic medium according to claim 1 , wherein the shell further comprises a polymer stabilizer layer, wherein the polymer stabilizer layer is formed from the reaction of the silane layer and a monomer or macromonomer, wherein the silane compound comprises a third functional group, wherein the monomer or macromonomer comprises a fourth functional group, and wherein the third functional group of the silane compound reacts with the fourth functional group of the monomer or macromonomer.

3. The electrophoretic medium according to claim 2 , wherein the third functional group of the silane compound is selected from the group consisting of epoxy, vinyl, styrene, acryloyl, methacryloyl, methacryloxyalkyl, amino, hydroxy, carboxy, alkoxy group, and chloride.

4. The electrophoretic medium according to claim 1 , wherein the fourth functional group of the monomer or macromonomer is selected from the group consisting of vinyl, styrene, acryloyl, methacryloyl, methacryloxyalkyl, epoxy, amino, hydroxy, carboxy, and chloride.

5. The electrophoretic medium according to claim 1 , wherein the metal oxide layer comprises aluminum oxide, silica, titanium dioxide, zirconium oxide, zinc oxide or mixtures thereof.

6. The electrophoretic medium according to claim 1 , wherein the first functional group is selected from the group consisting of alkoxy, alkylamino, halide, hydrogen, and hydroxy.

7. The electrophoretic medium according to claim 1 , wherein the metal oxide precursor is selected from the group consisting of trimethylaluminum, triethylaluminum, dimethylaluminum chloride, diethylaluminum chloride, trimethoxyaluminum, triethoxyaluminum, dimethylaluminum propoxide, aluminum triisopopoxide, tributoxy aluminum, tris(dimethylamino) aluminum, tris(diethylamino) aluminum, tris(propylamino) aluminum, aluminum trichloride, trichlorosilane, hexachlorodisilane, silicon tetrachloride, tetramethoxysilane, tetraethoxysilane, tris(tert-pentoxy)silanol, tetraisocyanatesilane, silicon tertrachoride, tris(methylamino)silane, tris(ethylamino)silane, titanium tetrachloride, titanium tetraiodide, tetramethoxy titanium, tetraethoxy titanium, titanium isopropoxide, tetrakis(methylamino) titanium, tetrakis(ethylamino) titanium, dimethyl zinc, diethyl zinc, methyl zinc isopropoxide, zirconium tetrachloride, zirconium tetraiodide, tetramethoxy zirconium, tetraethoxy zirconium, tetraisopropoxy zirconium, tetrabutoxy zirconium, tetrakis(methylamino) zirconium, tetrakis(ethylamino) zirconium, and mixtures thereof.

8. The electrophoretic medium according to claim 1 , wherein the reagent is selected from the group consisting of water, oxygen, ozone, and mixture thereof.

9. The electrophoretic medium according to claim 1 , wherein the metal oxide layer has thickness of from about 0.5 nm to about 2 nm.

10. The electrophoretic medium according to claim 1 , wherein the organic pigment is selected from the group consisting of an azo pigment, a phthalocyanine pigment, a quinacridone pigment, a perylene pigment, a diketopyrrolopyrrole pigment, a benzimidazolone pigment, an isoindoline pigment, an anthranone pigment, an indanthrone pigment, a carbon black pigment, a rhodamine pigment, a benzinamine pigment, a carbon black pigments, and mixtures therein.

11. The electrophoretic medium according to claim 1 , wherein the organic pigment is selected from the group consisting of C.I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4 15:6, 60, and 79; Pigment Red 2, 4, 5, 9, 12, 14, 38, 48:2, 48:3, 48:4, 52:2, 53:1, 57:1, 81, 112, 122, 144, 146, 147, 149, 168, 170, 176, 177, 179, 184, 185, 187, 188, 208, 209, 210, 214, 242, 254, 255, 257, 262, 264, 282, and 285; C.I. Pigment Violet 1, 19, 23, and 32; C.I. Pigment Yellow 1, 3, 12, 13, 14, 15, 16, 17, 73, 74, 81, 83, 97, 109, 110, 111, 120, 126, 127, 137, 138, 139, 150, 151, 154, 155, 174, 175, 176, 180, 181, 184, 191, 194, 213 and 214; C.I. Pigment Green 7, and 36; C.I. Pigment Black 1, and 7; C.I. Pigment Brown 25, 32, 41; Pigment Orange 5, 13, 34, 36, 38, 43, 61, 62, 64, 68,67, 72, 73, and 74, and mixtures thereof.

12. An electrophoretic device comprising
a first light-transmissive electrode layer;
an electro-optic material layer comprising encapsulated electrophoretic medium; and
a second electrode layer;
wherein the electrophoretic medium is the electrophoretic medium of claim 1 .

13. An electrophoretic assembly comprising in order:
a first light-transmissive electrode layer;
an electro-optic material layer comprising encapsulated electrophoretic medium;
an adhesive layer; and
a release sheet;
wherein the electrophoretic medium is the electrophoretic medium of claim 1 .

14. An electrophoretic assembly comprising in order:
a first release sheet;
a first adhesive layer;
an electro-optic material layer comprising encapsulated electrophoretic medium;
an adhesive layer;
a second adhesive layer; and
a second release sheet;
wherein the electrophoretic medium is the electrophoretic medium of claim 1 .

Assignees

• E Ink Corp

Inventors

• Anseth Jay William
• Macdonald Brandon
• Breen Craig Alan

Classifications

• C09B67/0007

  with inorganic coatings · CPC title

• G02F2202/28

  Adhesive materials or arrangements · CPC title

• G02F2001/1678

  characterised by the composition or particle type · CPC title

• G02F2202/022

  polymeric · CPC title

• G02F1/167

  by electrophoresis · CPC title