The invention discloses non-cleaning flux for low temperature paste, and a preparing method of the flux and belongs to the technical field of
welding flux. The flux comprises, by
mass percent, 79 to 82% of a compound
solvent, 7 to 14% of an
active agent, 2 to 5% of a thixotropic agent, 0.1 to 0.5% of a
corrosion inhibitor, 1 to 8% of a pH conditioning agent, 0.5% of an
antioxidant and 0.25% of a film-forming agent. The compound
solvent is composed of a high-boiling-point
organic solvent with the
boiling point exceeding 200 DEG C and a low-boiling-point
organic solvent with the
boiling point lower than 200 DEG C, the high-boiling-point
organic solvent is a mixture of
ethylene glycol and
ethylene glycol butyl
ether, the low-boiling-point organic
solvent is a mixture of one or two of ethyl
alcohol and
isopropyl alcohol, the
active agent is
lactic acid, the thixotropic agent is
castor oil, the
corrosion inhibitor is
benzotriazole, the pH conditioning agent is organic amine, the
antioxidant is toluic acid
butyrate, and the film-forming agent is
polyethylene glycol 2000. The method is simple in technology, operation is easy, the flux can be used in cooperation with flux
powder with the
melting point lower than 100 DEG C, activity is high, wettability is good, post-
welding residue is little,
corrosion resistance is high, and no
tin sweat phenomenon happens.