Electrophoretic dispersion

Patent metadata

Field	Value
Publication number	US-9428649-B2
Application number	US-201113287704-A
Country	US
Kind code	B2
Filing date	Nov 2, 2011
Priority date	Nov 5, 2010
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

The present invention is directed to an electrophoretic dispersion comprising pigment particles dispersed in a solvent or solvent mixture, wherein said pigment particles comprises at least one polymer chain comprising a terminal thiocarbonylthio group, attached to the particle surface. The invention also relates to pigment particles suitable for use in an electrophoretic dispersion and methods for their preparation through a RAFT polymerization technique.

First claim

What is claimed is:

1. An electrophoretic dispersion, comprising polymer coated charged pigment particles dispersed in a hydrocarbon solvent, wherein said polymer coated charged pigment particle comprises polymer chains attached to the particle surface and said polymer chain comprises:
(a) an outer polymer layer formed from monomers consisting of first monomers, the outer polymer layer is compatible with the hydrocarbon solvent,
(b) an inner polymer layer formed from monomers consisting of second monomers each comprising a charged functional group to provide charges to the pigment particles, and different from the first monomers, and
(c) a terminal thiocarbonylthio group attached to the outer polymer layer.

2. The dispersion of claim 1 , wherein said first monomer is selected from the group consisting of: lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, n-octadecyl acrylate, and n-octadecyl methacrylate.

3. The dispersion of claim 1 , wherein said second monomer is selected from the group consisting of: vinyl pyridine, 2-hydoxyethyl acrylate, 2-hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, vinylb enzylaminoethylaminopropyl-trimethoxysilane, acrylic acid, methacrylic acid, and vinyl phosphoric acid.

4. The dispersion of claim 1 , wherein said functional group is amine, hydroxy, carboxylate, sulfonate, phosphonate, or phosphate.

5. The dispersion of claim 1 , wherein said charged pigment particles are of the same color.

6. The dispersion of claim 1 , further comprising second pigment particles having a contrasting color from the charged pigment particles of claim 1 .

7. The dispersion of claim 6 , wherein the second pigment particle comprises at least one polymer chain comprising a terminal thiocarbonylthio group, attached to the particle surface.

Assignees

• Li Yu
• Du Hui
• Liu Yayong
• Gu Haiyan
• Zang Hongmei
• E Ink California Llc

Inventors

• Li Yu
• Du Hui
• Liu Yayong
• Gu Haiyan
• Zang Hongmei

Classifications

• C09C1/3692

  Combinations of treatments provided for in groups C09C1/3615 - C09C1/3684 · CPC title

• C09C1/3669 Primary

  Treatment with low-molecular organic compounds · CPC title

• C08F292/00

  Macromolecular compounds obtained by polymerising monomers on to inorganic materials · CPC title

• C08F2438/03

  Use of a di- or tri-thiocarbonylthio compound, e.g. di- or tri-thioester, di- or tri-thiocarbamate, or a xanthate as chain transfer agent, e.g . Reversible Addition Fragmentation chain Transfer [RAFT] or Macromolecular Design via Interchange of Xanthates [MADIX] · CPC title

• C09C1/3676 Primary

  Treatment with macro-molecular organic compounds · CPC title