Process for preparing bimodal mixture of copper nanoparticles and microparticles with polymeric protecting layer, the bimodal mixture of copper nanoparticles and microparticles with the polymeric protecting layer prepared thereby and printing formulation comprising such a bimodal mixture

摘要

BACKGROUND OF THE INVENTION The present invention relates to a process for preparing a bimodal mixture of nanoparticles and copper microparticles with a protective polymer layer in which a first reaction mixture comprising at least one copper precursor, an aqueous solution of at least one monohydric and / or polyhydric alcohol and at least one organic polymer in a precursor weight ratio is prepared. (precursors) copper: alcohol (alcohols): organic polymer (s) 1: 5-500: 0.05-05, and in the second phase at least one organic reducing agent is added to the reaction mixture quantitatively under vigorous stirring, the weight ratio copper precursor (s): the organic reducing agent (s) is 1: 1-20, while copper nanoparticles and microparticles which are coated with a protective layer of organic polymer (s) are simultaneously reduced and secreted with intensive mixing from the reaction mixture. . The invention also relates to a bimodal mixture of nanoparticles and copper microparticles with a protective layer, a polymer prepared in this manner, and printing formulations for printing electrically conductive layers comprising 55 to 85% by weight of the composition.