SOLDER PASTE PREPARATION METHOD Russian patent published in 2022 - IPC B23K35/40 B23K35/24 

FIELD: technological processes.

SUBSTANCE: invention can be used in assembly and surface mounting of SMD components on printed circuit boards. Soldering paste contains tin-lead solder powder, for example POS 61, POSK 50–18 and flux binder containing rosin, polyethylene glycol with molecular weight 1,500–20,000, sodium hydroxide, triethanolamine and ethylene glycol. Solder powder is pretreated in triethanolamine at temperature of 70–80 °C with continuous stirring. After cooling, they are washed in isopropyl alcohol. To obtain a flux binder, sodium hydroxide is dissolved in ethylene glycol, colophony and polyethylene glycol are mixed with triethanolamine at temperature of 85–100 °C until complete dissolution, cooled to temperature of 20–25 °C and mixed with the obtained sodium hydroxide solution. Flux binder is bonded with treated solder powder.

EFFECT: ensuring accuracy of reproduction of an imprint during screen printing, high quality of solder fusion and complete washing of flux-binder residues with distilled water.

1 cl, 1 tbl