Polymer formulations for use with electro-optic media

Patent metadata

Field	Value
Publication number	US-9777201-B2
Application number	US-201615217206-A
Country	US
Kind code	B2
Filing date	Jul 22, 2016
Priority date	Jul 23, 2015
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

Polymer formulations including urethane acrylates, adhesion promoters, and conductive monomers. By selecting suitable conductive monomers, it is possible to achieve formulations having a volume resistivity from 10 6 to 10 10 Ohm·cm after being conditioned for one week at 25° C. and 50% relative humidity. Such formulations are suitable for incorporation into electro-optic materials, such as electro-optic displays or variable transmission films, e.g., for architectural applications. In other embodiments, the formulations additionally include metal oxide nanoparticles to alter the refractive index and/or conductivity. The addition of certain metal nanoparticles additionally facilitates non-destructive measurement of layer thickness using X-ray fluorescence spectroscopy.

First claim

The invention claimed is:

1. A composition comprising:
a urethane acrylate;
an adhesion promoter;
a conductive monomer comprises alkoxylated acrylate; and
an ionic liquid, wherein the composition has a volume resistivity from 10 6 to 10 10 Ohm.cm after being conditioned for one week at 25° C. and 50% relative humidity.

2. The composition of claim 1 , further comprising a photoinitator.

3. The composition of claim 1 , further comprising cross-linkers.

4. The composition of claim 1 , further comprising metal oxide particles.

5. The composition of claim 4 , wherein the metal oxide particles have an average particle size of 100 nm or less.

6. The composition of claim 4 , wherein the metal oxide particles comprise a metal with an atomic number greater than 18.

7. The composition of claim 6 , wherein the metal is selected from the group consisting of titanium, copper, indium, zinc, nickel, tin, lanthanum, cerium, and zirconium.

8. The composition of claim 1 , wherein the composition contains less than 1% metal.

9. The composition of claim 1 , wherein the molecular weight of the conductive monomer is less than 1000 g/mol.

10. The composition of claim 1 , further comprising a nonconductive monomer that has a volume resistivity of greater than 10 10 Ohm·cm when cured as a homopolymer.

11. The composition of claim 1 , wherein the volume resistivity of the composition is 10 7 to 10 9 Ohm·cm after being conditioned for one week at 25° C. and 50% relative humidity.

12. The composition of claim 11 , wherein the volume resistivity of the composition is 10 8 to 10 9 Ohm·cm when cured at 25° C. for one week.

13. The composition of claim 1 , wherein the composition has a glass transition temperature (T g ) of less than −25° C.

14. The composition of claim 1 , wherein the composition has an index of refraction of 1.0 to 2.0 for visible light.

15. The composition of claim 1 , wherein the ionic liquid is present at less than 0.1 wt % based on a total wt. of the composition.

16. The composition of claim 1 , wherein the ionic liquid comprises a phosphate, borate, sulfonamide, or a cyanamide salt.

17. An active material comprising:
an electro-optic medium;
a light-transmissive electrode; and
a composition of claim 1 .

18. The active material of claim 17 , further comprising a second light-transmissive electrode.

19. A method for fabricating an electro-optic display comprising:
providing an electro-optic medium;
contacting the electro-optic medium with a composition of claim 1 ; and
curing the coating, thereby creating a smooth surface.

20. A method for determining the thickness of a layer of an electro-optic display, the method comprising:
providing an electro-optic display including:
an electro-optic medium,
a light-transmissive electrode, and
a layer comprising a composition including a urethane acrylate, an adhesion promoter, metal oxide particles, a conductive monomer comprises alkoxylated acrylate, and an ionic liquid, wherein the composition has a volume resistivity from 10 6 to 10 10 Ohm.cm after being conditioned for one week at 25° C. and 50% relative humidity;

measuring an intensity of an X-ray fluorescence signal corresponding to the metal oxide; and
determining the thickness of the layer of the electro-optic display.

21. The method of claim 20 , wherein the metal oxide particles comprise zirconium oxide.

Assignees

• E Ink Corp

Inventors

• Widger Peter Carsten Bailey
• Mccullough Lynne A
• Dewitte Russell J
• Paolini Jr Richard J
• Fauvell Thomas
• Nguyen Jonathan Kim

Classifications

• C09J175/16

  having terminal carbon-to-carbon unsaturated bonds · CPC title

• G01N23/223

  by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence · CPC title

• G02F1/167

  by electrophoresis · CPC title

• G02F2202/28

  Adhesive materials or arrangements · CPC title

• G01N2223/633

  thickness, density, surface weight (unit area) · CPC title