PURPOSE: To perform satisfactory soldering by forming the activator for soldering flux containing polyester carboxylic acid synthesized by esterification reaction of polyol with carboxylic acid (an anhydride).
CONSTITUTION: Since polyester carboxylic acid has high molecular weight and has a carboxyl group which is an effective active group in plenty in molecules, the width of activation can be extended. In addition, when a softening point and the molecular weight are more than specified values, conditions (a temperature and a time) under which this activator itself can be operated as the activator can be extended. Accordingly, the flux containing the activator which has this polyester carboxylic acid and has the extended width of activity can be obtained. In addition, since the activator itself has film formation such as base resin to rosin, etc., and enables uniform coating of the flux, defective soldering such as a solder ball, a bridge, etc., is reduced and satisfactory soldering is made possible.
ONISHI TATSUJI
AIHARA MASAMI
HARIMA CHEMICALS INC