FLUX FOR AQUEOUS SOLDERING

摘要

PURPOSE: To provide a soldering flux which can be washed out by water and/or detergent and besides does not adversely impact the surface insulation resistance(SIR) of a circuit board. CONSTITUTION: A water-soluble soldering flux which does not adversely impact the surface insulation resistance of a circuit board is comprised of a water-soluble vehicle, an activator and a hydrophobic surfactant preferentially adsorbed at the circuit board surface. At soldering temperatures, the activator reacts to clean metallized areas on a circuit board and promote solder wetting. The hydrophobic surfactant, which is preferentially adsorbed at the circuit board surface, acts to block the diffusion of hydrophilic vehicle molecules into the circuit board to prevent the degradation of circuit board's surface insulation resistance.