Soldering flux for circuit board and circuit board

摘要

There is provided a soldering flux for circuit board, which is designed to be employed on an occasion of soldering electronic parts on a circuit board, the soldering flux being free from any organic solvent which may become a cause for contaminating air atmosphere and being capable of providing an excellent insulating property. This soldering flux comprises; a rosin-based modified resin having an acid value of not less than 100, a nondissociative activator formed of a nondissociative halogenide, and an aqueous solvent containing a volatile basic agent. There is also provided a circuit board having a flux film formed from such a soldering flux.