Copper powder, and copper paste, electrically conductive coating material and electrically conductive sheet each produced using said copper powder

Patent metadata

Field	Value
Publication number	US-2017152386-A1
Application number	US-201515320333-A
Country	US
Kind code	A1
Filing date	Mar 26, 2015
Priority date	Jun 25, 2014
Publication date	Jun 1, 2017
Grant date	—

Abstract

Provided is a copper powder in which the number of contact points between copper powder particles is increased to allow excellent electric conductivity to be achieved, and which can be used suitably in use applications including an electrically conductive paste and an electromagnetic wave shield. The copper powder according to the present invention has a dendritic shape composed of a main stem that is grown linearly and multiple branches that are branched from the main stem, wherein the main stem and the branches are composed of a flat-plate-like cupper particle having a cross section with an average thickness of 0.2 to 1.0 μm, and the average particle diameter (D50) of the copper powder is 5.0 to 30 μm. A copper paste having excellent electric conductivity can be produced by mixing the dendritic copper powder with a resin.

First claim

1 . A copper powder having a dendritic shape having a linearly grown main stem and a plurality of branches separated from the main stem, wherein
the main stem and the branches include flat plate-shaped copper particles having a cross sectional average thickness of from 0.2 μm to 1.0 μm, and an average particle diameter (D50) of the copper powder is from 5.0 μm to 30 μm.

2 . The copper powder according to claim 1 , wherein a ratio obtained by dividing a cross sectional average thickness of the flat plate-shaped copper particles by an average particle diameter (D50) of the copper powder is in a range of from 0.01 to 0.1, and
a bulk density of the copper powder is in a range of from 0.3 g/cm 3 to 5.0 g/cm 3 .

3 . The 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.

4 . A metal filler comprising the copper powder according to claim 1 at a proportion of 20% by mass or more to the entire metal filler.

5 . A copper paste comprising the metal filler according to claim 4 mixed with a resin.

6 . An electrically conductive coating material for electromagnetic wave shielding comprising the metal filler according to claim 4 .

7 . An electrically conductive sheet for electromagnetic wave shielding comprising the metal filler according to claim 4 .

Assignees

• Sumitomo Metal Mining Co

Inventors

• Okada Hiroshi
• Yamashita Yu

Classifications

• B22F1/0553

  Complex form nanoparticles, e.g. prism, pyramid, octahedron · CPC title

• B22F1/06

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

• B22F1/052

  characterised by a mixture of particles of different sizes or by the particle size distribution · CPC title

• B22F1/0551

  Flake form nanoparticles · CPC title

• B22F1/068

  Flake-like particles · CPC title