No-clean, low-residue, volatile organic compound free soldering flux and method of use

Abstract

A no-clean, low-residue, rosin-free foam flux solution is described which comprises a cosolvent system free of volatile organic compound solvents which is comprised of (i) at least about 90% by weight demineralized water based on total weight of the flux solution and (ii) from about 1% by weight to about 5% by weight based on total weight of the flux solution of a non-volatile organic solvent forming a cosolvent with said demineralized water, said nonvolatile organic solvent having a boiling point above about 190.degree. C. and a vapor pressure below 0.1 millimeters Hg at 25.degree. C.; a fluxing agent present in an amount from about 1% to about 4% by weight based on total weight of the soldering flux, said fluxing agent comprising at least two carboxylic acids selected from the group consisting of C.sub.2 -C.sub.10 dicarboxylic acids, monocarboxylic acids and hydroxy acids, said fluxing agent being present as solute in said cosolvents; and nonionic surfactant present in an amount of less than about 1% by weight based on total weight of soldering flux.

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