Senju Metal Industry Co., Ltd.

Hiroshi Sugii

Hiroyoshi Kawasaki

Yasuhiro Kajikawa

Yoshinori Hiraoka

Masato Shiratori

Atsumi Takahashi

Daisuke Maruko

Yo Yamada

Ayaka Shirakawa

A flux containing 1 to 10 wt % of an organic sulfonic acid activator, 10 to 40 wt % of a high-molecular-weight nonionic surfactant that is a nonionic surfactant having a mass-average molecular weight Mw of more than 1200 and 5 to 75 wt % of a low-molecular-weight nonionic surfactant that is a nonionic surfactant having a mass-average molecular weight Mw of 1200 or less, in which the content of the low-molecular-weight nonionic surfactant is equal to or larger than the content of the organic sulfonic acid activator. This flux contains no cationic surfactant or contains more than 0 wt % and 5 wt % or less of the cationic surfactant. A solder paste containing this flux and a Sn-based solder metal.

Flux and solder paste

A flux comprising an organic acid; a solvent; and polyoxyethylene behenyl alcohol having an average number of moles of ethylene oxide added of 7 to 40 mol.

Provided are a flux composition that is applicable without any film formation step, and solder paste, a solder joint and a solder joining method using the flux composition. The flux composition contains 20 wt % or more and 50 wt % or less of an epoxy resin, 15 wt % or more and 45 wt % or less of diallyl bisphenol A, and 1 wt % or more and 30 wt % or less of organic acid.

Flux composition, solder paste, solder joint and solder joining method

Provided is a flux that includes a heat-resistant activator having low reactivity with thermosetting resins, and a solder paste in which the flux is used. The flux includes 5 wt % or more and 20 wt % or less of any one of a dimer acid, a trimer acid, a hydrogenated dimer acid obtained by hydrogenating the dimer acid, and a hydrogenated trimer acid obtained by hydrogenating the trimer acid, on in total, of two or more of a dimer acid, a trimer acid, a hydrogenated dimer acid obtained by hydrogenating the dimer acid, and a hydrogenated trimer acid obtained by hydrogenating the trimer acid; 30 wt % or more and 70 wt % or less of a thermosetting resin; and 3 wt % or more and 15 wt % or less of an amine. The solder paste includes solder powder and the flux.

Growing community of inventors

Tochigi, Japan

Hiroshi Sugii