Senju Metal Industry Co., Ltd.

Kengo Ohta

Sakie Okada

Ryuji Ukai

Kazuya Kitazawa

Hiroaki Kawamata

Yutaka Hashimoto

Shuta Akatsuka

Hayato Kaise

Syuta Akatsuka

A solder paste includes a solder powder and a flux. The flux includes a rosin, an activator, a solvent, and a thixotropic agent containing a polyethylene glycol. A content of the polyethylene glycol is 10 mass % to 20 mass % with respect to a total mass of the flux, a content of the thixotropic agent excluding the polyethylene glycol is 5 mass % or less with respect to the total mass of the flux, and a content of the rosin is more than 15 mass % and 50 mass % or less with respect to the total mass of the flux.

Solder paste

A flux containing: a rosin; a solvent (S); a thixotropic agent; and an activator is disclosed. The rosin contains a rosin amine. The solvent (S) contains a first solvent (S1) having a boiling point of 250° C. or less, and the amount of the first solvent (S1) relative to the total amount of the solvent (S) is 50% by mass or more and 100% by mass or less.

Flux and solder paste

Provided is flux containing rosin-based resin, a solvent, a thixotropic agent and an activator. The thixotropic agent includes any or both of hardened castor oil and bisamide-based thixotropic agent. The contents of the hardened castor oil and the bisamide-based thixotropic agent are respectively within the range of 4 wt. % or more and 10 wt. % or less and the range of 1 wt. % or more and 5 wt. % or less based on the total weight of the flux. The contents of the thixotropic agent are within the range of 5 wt. % or more and 15 wt. % or less based on the total weight of the flux. The activator includes hydrohalide, a halogenated aliphatic compound and an imidazole compound. The contents of the halogen in the flux are within the range of 9000 ppm or more and 50000 ppm or less.

Flux and solder paste using the same

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Kanagawa, Japan

Kengo Ohta