| abstract |
Copper microparticles that are fine and contain substantially none of agglomerated particles. For example, there are provided copper microparticles of 0.005 to 2.0 μm average particle diameter (D) as measured by an electron microscope, 0.005 to 2.0 μm average particle diameter (d) as measured by a dynamic light scattering particle size distribution measuring apparatus and 0.7 to 2 d/D ratio. There is provided a process comprising mixing a divalent copper oxide with a reducing agent in the presence of a complexing agent and a protective colloid in a liquid medium to thereby produce copper microparticles without formation of a univalent copper oxide from the divalent copper oxide. Further, there is provided a process comprising reducing a divalent copper oxide in the presence of a complexing agent and a protective colloid, such as a protein, to thereby form metallic copper microparticles, adding a protective colloid scavenger, such as a protease, to thereby remove the protective colloid and effect agglomeration of metallic copper microparticles, and filtering the mixture by means of a pressure filter, a vacuum filter, a suction filter, etc. |