Methods for conductive adhesives based on graphene and applications thereof

Patent metadata

Field	Value
Publication number	US-2019169472-A1
Application number	US-201816203694-A
Country	US
Kind code	A1
Filing date	Nov 29, 2018
Priority date	Dec 1, 2017
Publication date	Jun 6, 2019
Grant date	—

Abstract

The present disclosure relates to conductive adhesives and inks. The disclosed conductive adhesives include glues and epoxies, based on graphene and graphene/carbon composites and the methods of manufacture thereof, such conductive adhesives exhibiting excellent conductivity, thermal properties, durability, low curing temperatures, mechanical flexibility, and reduced environmental impact. Further, adhesives with conductive additives such as silver nanowires and the methods of production thereof are disclosed herein.

First claim

1 . A conductive adhesive comprising:
(a) a conductive additive comprising at least one of:
(i) a carbon-based additive comprising two or more of graphene nanoparticles, graphene nanosheets, and graphene microparticles; and
(ii) a silver-based additive comprising silver nanowires, silver nanoparticles, or both, wherein each of the silver nanowires and/or silver nanoparticles has a diameter of less than 0.5 μm; and
(b) an adhesive agent.

2 . The conductive adhesive of claim 1 , having a percolation threshold when dried of at most about 15%.

3 . The conductive adhesive of claim 1 , wherein the silver nanowires have a length of at least 10 μm.

4 . The conductive adhesive of claim 1 , wherein the adhesive agent comprises a hardener and a resin.

5 . The conductive adhesive of claim 4 , wherein at least a portion of the conductive additive is incorporated into the hardener, the resin, or both.

6 . The conductive adhesive of claim 1 , further comprising a thinner.

7 . The conductive adhesive of claim 1 , having a sheet resistance of about 5 ohm/sq to about 500 ohm/sq when dried.

8 . The conductive adhesive of claim 1 , having a sheet resistivity of about 0.3 ohm/sq/mil to about 2 ohm/sq/mil when dried.

9 . The conductive adhesive of claim 1 , having a conductivity of about 0.15 S/m to about 60 S/m when dried.

10 . The conductive adhesive of claim 1 , further comprising a pigment, a silver metallic pigment, a colorant, a silver metallic colorant, a dye, or any combination thereof.

11 . A conductive ink comprising:
(a) a conductive additive comprising at least one of:
(i) a carbon-based additive comprising two or more of graphene nanoparticles, graphene nanosheets, and graphene microparticles; and
(ii) a silver-based additive comprising silver nanowires, silver nanoparticles, or both, wherein each of the silver nanowires and/or silver nanoparticles has a diameter of less than 0.5 μm; and
(b) a solvent.

12 . The conductive ink of claim 11 , having a percolation threshold when dried of at most about 15%.

13 . The conductive ink of claim 11 , wherein each of the silver nanowires has a length of at least 10 μm.

14 . The conductive ink of claim 11 , wherein the proportion by weight of the conductive additive in the conductive ink is 0.25% to about 20%.

15 . The conductive ink of claim 11 , having a viscosity of at most about 40 centipoise.

16 . The conductive ink of claim 11 , having a sheet resistance when dried of less than 0.8 ohm/sq/mil.

17 . The conductive ink of claim 11 , having a conductivity of greater than 10 S/cm when dried.

18 . The conductive ink of claim 11 , further comprising at least one of a binder, a surfactant, and a defoamer.

19 . The conductive ink of claim 11 , further comprising a pigment, a silver metallic pigment, a colorant, a silver metallic colorant, a dye, or any combination thereof.

20 . A method of forming silver nanowires comprising:
(a) heating a solvent; (b) adding a catalyst solution and a polymer solution to the solvent to form a first solution; (c) injecting a silver-based solution into the first solution to form a second solution; (d) centrifuging the second solution; and (e) washing the second solution with a washing solution to extract the silver nanowires.

Assignees

• Univ California
• Nanotech Energy Inc

Inventors

• El-Kady Maher F
• Mohamed Nahla
• Kavanaugh Jack
• Kaner Richard B

Classifications

• C09J9/02 Primary

  Electrically-conducting adhesives · CPC title

• C09J11/04

  inorganic · CPC title

• C09D11/037

  characterised by the pigment · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C09D11/52

  Electrically conductive inks · CPC title