| abstract |
A solder composition having a lead-free SnZn type alloy and a soldering flux containing at least an epoxy resin and an organic carboxylic acid, characterized in that the organic carboxylic acid is dispersed in a solid state in the solder composition at room temperature (25 ˚C), or in that the organic carboxylic acid has a molecular weight of 100 to 200 g/mol, or in that the organic carboxylic acid or the SnZn type alloy has a microcupsule structure covered by a film comprising a resin selected from the group consisting of an epoxy resin, a polyimide resin, a polycarbonate resin, a polyamide resin, a polyester resin, a polyurea resin, a polyolefin resin and a polysulfone resin. The solder composition requires no washing for removing a flux residue and also a cream solder from the composition is less prone to the change of its viscosity, printing characteristics, solderability or the like with the elapse of time after the preparation thereof. |