| 摘要 |
PURPOSE:To enable solder joining at a low reflow temp. and to relieve thermal load on electronic parts, etc., by adding an exothermic material into a flux constituting the solder paste. CONSTITUTION:The material which induces an exothermic reaction at about 150 to 180 deg.C is previously mixed into the flux for soldering and the solder is locally heated to a high temp. to assist melting of the solder at the time of soldering. For example, a nitrocellulose which is dissolved and plasticized by a butyl phthalate is used as the exothermic material. The nitroceellulose starts reaction gradually at 135 deg.C and exhibits the vigorous exothermic reaction at about 180 deg.C. The solder powder may be any of various alloys by combinations of Sn, Pb, Ag, etc. This flux is not limited to any of rosins, synthetic resins or water-soluble high polymers, etc. |
