| 摘要 |
PURPOSE:To control reaction of an activator to be incorporated into a flux and to realize satisfactory soldering by coating the activator with a material which is decomposed at the soldering temp. higher than a preheating temp. CONSTITUTION:The activator 2 for accelerating the wettability of the flux is coated to a capsule state by low-molecular polyurethane 1 and is then incorporated into a solid component 3 of the flux. This flux is coated on an object to be soldered and is preheated. The reaction of the activator 2 is suppressed at about 120-150 deg.C preheating temp. The low-molecular polyurethane 1 is thermally decomposed and the reaction of the activator 2 is exhibited when the flux is heated to about 180-240 deg.C soldering temp. in a soldering stage. The satisfactory soldering is thereby realized while the reaction of the activator in the flux is controlled.
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