Silver paste, and conductive molded article obtained using same

Patent metadata

Field	Value
Publication number	US-10696852-B2
Application number	US-201515534385-A
Country	US
Kind code	B2
Filing date	Dec 8, 2015
Priority date	Dec 11, 2014
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

A problem is to provide a silver paste which can produce, without variation in resistivity value, a conductive silver coating film exhibiting resistivity substantially equivalent to the resistance value of bulk silver in low-temperature sintering. The problem is solved by providing a silver paste including a silver nanoparticle aqueous dispersion prepared by using a compound having a polyethyleneimine skeleton as a protective agent, a compound having a functional group reactable with nitrogen atoms in the polyethyleneimine, and at least one compound selected from the group consisting of a compound having an amine functional group and a compound having an amide functional group.

First claim

The invention claimed is:

1. A silver paste comprising:
an aqueous dispersion of a silver-containing structure containing, as main constituent components,
at least one compound (X) selected from the group consisting of
a compound (x1) containing polyethyleneimine (a) having a number-average molecular weight of 500 to 50,000 and an amino group to which polyethylene glycol (b) having a number-average molecular weight of 500 to 5,000 is bonded,
a compound (x2) containing polyethyleneimine (a) having a number-average molecular weight of 500 to 50,000 and an amino group to which a linear epoxy resin (c) is bonded, and
a compound (x3) containing polyethyleneimine (a) having a number-average molecular weight of 500 to 50,000 and an amino group to which polyethylene glycol (b) having a number-average molecular weight of 500 to 5,000 and a linear epoxy resin (c) are bonded, and
silver nanoparticles (Y);
a compound (Z) having a functional group reactable with a nitrogen atom in the polyethyleneimine (a); and
at least one compound (W) selected from the group consisting of a compound (w1) having an amine functional group and a compound (w2) having an amide functional group,
wherein the compound (W) is used in an amount of 1.0% to 9.0% by weight relative to a silver solid content in the aqueous dispersion.

2. The silver paste according to claim 1 , wherein the fusion temperature in a dry state of the silver paste is within a range of 100° C. to 150° C.

3. The silver paste according to claim 1 , wherein the compound (Z) is at least one compound selected from the group consisting of an aldehyde compound, an epoxy compound, an acid anhydride, a carboxylic acid, and an inorganic acid.

4. The silver paste according to claim 1 , wherein the compound (Z) is an inorganic acid.

5. The silver paste according to claim 1 , wherein the compound (W) is at least one compound selected from the group consisting of a water-soluble amine compound, a water-soluble alcoholamine compound, and a water-soluble amide compound.

6. An electrically conductive product comprising a coating film provided on a solid substrate and having a fusion temperature of 100° C. to 150° C., the coating film containing:
at least one compound (X) selected from the group consisting of
a compound (x1) containing polyethyleneimine (a) having a number-average molecular weight of 500 to 50,000 and an amino group to which polyethylene glycol (b) having a number-average molecular weight of 500 to 5,000 is bonded,
a compound (x2) containing polyethyleneimine (a) having a number-average molecular weight of 500 to 50,000 and an amino group to which a linear epoxy resin (c) is bonded, and
a compound (x3) containing polyethyleneimine (a) having a number-average molecular weight of 500 to 50,000 and an amino group to which polyethylene glycol (b) having a number-average molecular weight of 500 to 5,000 and a linear epoxy resin (c) are bonded; and
silver nanoparticles (Y);
a compound (Z) having a functional group reactable with a nitrogen atom in the polyethyleneimine (a); and
at least one compound (W) selected from the group consisting of a compound (w1) having an amine functional group and a compound (w2) having an amide functional group,
wherein the compound (W) is contained in an amount of 1.0% to 9.0% by weight relative to a silver solid content in the aqueous dispersion.

7. The electrically conductive product according to claim 6 , wherein the compound (Z) is at least one compound selected from the group consisting of an aldehyde compound, an epoxy compound, an acid anhydride, a carboxylic acid, and an inorganic acid.

8. The electrically conductive product according to claim 6 , wherein the compound (Z) is an inorganic acid.

9. The electrically conductive product according to claim 6 , wherein the compound (W) is at least one compound selected from the group consisting of a water-soluble amine compound, a water-soluble alcoholamine compound, and a water-soluble amide compound.

10. The electrically conductive product according to claim 6 , wherein the glass transition temperature of the solid substrate is 180° C. or less.

Assignees

• Dainippon Ink & Chemicals

Inventors

• Kawamura Kaori
• Moriwaki Masayuki
• Sano Yoshiyuki

Classifications

• B22F1/103

  containing an organic binding agent comprising a mixture of, or obtained by reaction of, two or more components other than a solvent or a lubricating agent · CPC title

• B22F1/10

  Metallic powder containing lubricating or binding agents; Metallic powder containing organic material · CPC title

• B22F1/0545

  Dispersions or suspensions of nanosized particles · CPC title

• B22F1/054

  Nanosized particles · CPC title

• B22F1/102

  Metallic powder coated with organic material · CPC title