Dendritic silver powder

Patent metadata

Field	Value
Publication number	US-10357824-B2
Application number	US-201615776295-A
Country	US
Kind code	B2
Filing date	Oct 14, 2016
Priority date	Dec 3, 2015
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A new dendritic silver powder can be mixed with a synthetic resin to give electroconductive films having sufficient electroconductivity. Even when the films vary in thickness, the electroconductivity of the films can be maintained. The volume-cumulative particle diameter D50 (referred to as “D50D”) determined by adding the silver powder to water containing a dispersant, applying 300-watt ultrasonic waves to the resultant mixture for 3 minutes, and examining the dispersion with a laser diffraction/scattering type particle size analyzer is 1.0-15.0 μm and that the ratio of the volume-cumulative particle diameter D50 (referred to as “D50N”) determined by adding the silver powder to the water containing a dispersant and examining the mixture under the same conditions as for the D50D except that no ultrasonic waves are applied, to the D50D, D50N/D50D, is 1.0-10.0.

First claim

The invention claimed is:

1. A dendritic silver powder comprising silver particles having a shape including a trunk and a plurality of branches that branch off perpendicularly or obliquely from the trunk and that have grown two- or three-dimensionally under observation of an electron microscope at a magnification of 3000 to 10000, the silver particles accounting for 50% by number or more based on all the silver particles being observed, wherein:
D50D of the silver powder is 1.0-15.0 μm,
wherein D50D is defined by a volume cumulative particle diameter D50 of the silver powder, and
wherein D50 is measured by a laser diffraction/scattering particle size distribution measurement apparatus with a pretreatment wherein a dispersion containing the silver powder, a dispersant and water is subjected to irradiation of 300 watts of ultrasonic waves for 3 minutes, and

D50N/D50D of the silver powder is 1.0-10.0,
wherein D50N is defined by a volume cumulative particle diameter D50 of the silver powder, and
wherein D50 is measured by a laser diffraction/scattering particle size distribution measurement apparatus without the irradiation of ultrasonic waves, that is carried out in measuring D50D, to a dispersion containing the silver powder, a dispersant and water.

2. The dendritic silver powder according to claim 1 , wherein a specific surface area measured according to a BET single-point method is 0.2-5.0 m 2 /g.

3. The dendritic silver powder according to claim 1 , wherein a crystallite diameter of the silver particles is 500 Å-3000 Å.

4. The dendritic silver powder according to claim 2 , wherein a crystallite diameter of the silver particles is 500 Å-3000 Å.

Assignees

• Mitsui Mining & Smelting Co

Inventors

• Morinaka Hiroyuki
• Wakimori Yasunari
• Ochi Kentaro

Classifications

• Y10T428/12014

  having metal particles · CPC title

• B22F2304/10

  Micron size particles, i.e. above 1 micrometer up to 500 micrometer · CPC title

• B22F2301/255

  Silver or gold · CPC title

• B22F1/00

  Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties · CPC title

• H01B5/00

  Non-insulated conductors or conductive bodies characterised by their form · CPC title