METHOD FOR ENCAPSULATING SOLDER METAL POWDERS AND SOLDER METAL POWDERS PRODUCED ACCORDING TO THIS METHOD

摘要

The aim of the invention is to improve a method for encapsulating solder metal powders and the microencapsulated solder in such a way that the metal powder is reliably protected from external oxidising influences and the capsule only releases the metal powder as a result of the influence of temperature, without the influence of soldering flux. To this end, the method comprises the following steps: a) producing a suspension consisting of powder and a hydrophobic liquid; b) producing a hydrophobic surface layer on each metal particle by adding a cationic tenside; c) stirring the mixture obtained in steps a) and b) until a viscous, homogeneous mass is formed; d) mixing a radically polymerisable monomer into the mass obtained in step c); e) adding an organic initiator to start an interfacial polymerisation reaction; f) introducing the mass obtained in step e) into an aqueous substance, constantly stirring and controlling the polymerisation reaction by tempering to 50 to 90.degree.C, and maintaining this temperature for at least 120 minutes and g) cooling, washing and separating the encapsulated solder powde r.