A process for preparing a bimodal mixture of copper nanoparticles and microparticles with a polymeric protective layer, bimodal mixture of copper nanoparticles and microparticles with a polymeric protective layer prepared by this process and a printing preparation containing this bimodal mixture

摘要

The invention relates to a method for preparing a bimodal mixture of copper nanoparticles and microparticles with a polymeric protective layer, in which a reaction mixture is prepared in the first step, the at least one starting material of copper, an aqueous solution of at least one monohydric and / or polyhydric alcohol and at least one organic polymer in a weight ratio starting material (s) of copper: alcohol (s): organic polymer (s) of 1: 5-500: 0.05-0.5, and in the second step at least one organic Reductant is added quantitatively to this reaction mixture with vigorous stirring, wherein the weight ratio of starting material (s) of copper: organic (s) reducing agent 1: 1-20, which simultaneously reduced and precipitated from the reaction mixture under constant intensive stirring copper nanoparticles and copper microparticles in which a protective layer of an organic polymer (a Mixture of organic polymers) is provided. The invention also relates to a bimodal mixture of copper nanoparticles and microparticles prepared by this process with a protective layer of polymer and a printing preparation for printing electrically conductive layers containing 55 to 85% by weight of this mixture.