| abstract |
(57) [Summary] [Object] To provide a non-cleaning type flux and a circuit board capable of obtaining a flux film which does not generate microcracks even in an atmosphere having a large difference in temperature. A flux containing a resin having an acid value, a high-boiling solvent having a boiling point not lower than 150 ° C, and a glass transition temperature of a flux film not higher than 70 ° C. A circuit board having the flux film. [Effect] The above object can be achieved. |