Rosin base resin for lead-free solder flux, lead-free solder flux, and lead-free solder paste

摘要

[Problem] It is a main object to provide a novel lead-free rosin-based base resin for solder flux, which is easy to dissolve in a solvent, exhibits improved wettability and storage stability even when a solder flux is used, and has high transparency of the flux residue after mounting. [Solution] A rosin-based base resin for lead-free solder flux containing dehydroabietic acid, dihydroabietic acid and tetrahydroabietic acid, wherein the content of tetrahydroabietic acid in the base resin is 45 to 80 wt. % Rosin-based base resin for lead-free solder fluxes.