Silver-coated copper powder, and conductive paste, conductive coating material and conductive sheet, each of which uses said silver-coated copper powder

Patent metadata

Field	Value
Publication number	US-2017253750-A1
Application number	US-201515509273-A
Country	US
Kind code	A1
Filing date	Mar 26, 2015
Priority date	Sep 12, 2014
Publication date	Sep 7, 2017
Grant date	—

Abstract

Provided is a dendritic silver-coated copper powder which is prevented from agglomeration, while ensuring excellent electrical conductivity by increasing contact points in cases where silver-coated dendritic copper powder particles are in contact with each other. This dendritic silver-coated copper powder is suitable for use in conductive pastes, electromagnetic shielding materials and the like. A dendritic silver-coated copper powder 1 according to the present invention has a dendritic form which comprises a linearly grown main trunk 2 and a plurality of branches 3 arising from the main trunk 2. The main trunk 2 and the branches 3 are configured of copper particles which have plate-like shapes having an average cross-sectional thickness of 0.2-1.0 μm, and the surfaces of which are coated with silver. This dendritic silver-coated copper powder 1 has an average particle diameter (D50) of 5.0-30 μm as determined by a laser diffraction/scattering particle size distribution measuring method.

First claim

1 . A dendritic silver-coated copper powder, wherein
the dendritic silver-coated copper powder has a dendritic shape having a linearly grown main stem and a plurality of branches separated from the main stem, the main stem and the branches include copper particles which have a flat plate shape having a cross sectional average thickness of from 0.2 μm to 1.0 μm and a surface coated with silver, and an average particle diameter (D50) of the dendritic silver-coated copper powder measured by a method for laser diffraction and scattering type particle size distribution measurement is from 5.0 μm to 30 μm.

2 . The dendritic silver-coated copper powder according to claim 1 , wherein
a ratio obtained by dividing a cross sectional average thickness of the copper particles coated with silver by an average particle diameter (D50) of the dendritic silver-coated copper powder is in a range of from 0.01 to 0.1, and a bulk density of the dendritic silver-coated copper powder is in a range of from 0.5 g/cm 3 to 5.0 g/cm 3 .

3 . The dendritic silver-coated copper powder according to claim 1 , wherein an amount of silver coated is from 1% by mass to 50% by mass with respect to 100% by mass of the entire silver-coated copper powder coated with silver.

4 . The dendritic silver-coated copper powder according to claim 1 , wherein a BET specific surface area value is from 0.2 m 2 /g to 3.0 m 2 /g.

5 . The dendritic silver-coated copper powder according to claim 1 , wherein
a crystallite diameter in the Miller index of a (111) plane by X-ray diffraction is in a range of from 800 Å to 2000 Å.

6 . A metal filler comprising the dendritic silver-coated copper powder according to claim 1 at a proportion of 25% by mass or more to the entire metal filler.

7 . The metal filler according to claim 6 , comprising a spherical copper powder having an average particle diameter (D50) of from 0.5 μm to 10 μm.

8 . The metal filler according to claim 7 , wherein
the spherical copper powder is a spherical silver-coated copper powder having a surface coated with silver, and an amount of silver coated on the spherical silver-coated copper powder is from 1% by mass to 50% by mass with respect to 100% by mass of the entire spherical silver-coated copper powder coated with silver.

9 . An electrically conductive paste comprising the metal filler according to claim 6 mixed with a resin.

10 . An electrically conductive coating material for electromagnetic wave shielding comprising the metal filler according to claim 6 .

11 . An electrically conductive sheet for electromagnetic wave shielding comprising the metal filler according to claim 6 .

Assignees

• Sumitomo Metal Mining Co

Inventors

• Okada Hiroshi
• Yamashita Hideyuki

Classifications

• B22F1/068

  Flake-like particles · CPC title

• 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

• B22F1/06

  Metallic powder characterised by the shape of the particles (nanosized particles B22F1/054) · CPC title

• B22F1/10

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

• B22F1/17

  Metallic particles coated with metal · CPC title