Senju Metal Industry Co., Ltd.

Kazuyori Takagi

Tomoko Nagai

Nanako Miyagi

Yutaka Hashimoto

Akiko Takaki

Kenta Inoue

Ryo Saito

Tetsu Takemasa

Tsuyoshi Masaki

Megumi Hayakawa

Mutsuki Kaneko

Masayuki A Suzuki

Hiroyoshi Kawasaki

Shunsaku Yoshikawa

Tsukasa Ohnishi

Masato Shiratori

Masato Shimamura

Kazuya Kitazawa

Yoshie Yamanaka

Seiko Ishibashi

Kazuhiro Minegishi

Toru Hayashida

Tomoko Nonaka

Rina Horikoshi

Teppei Otsuki

Ryuichi Tsuda

Mitsuhiro Kosai

A flux containing rosin, a solvent, a thixotropic agent, a thiol compound, and an activator, in which the thiol compound includes a compound (Tp) having a benzenethiol skeleton in which one or more hydrogen atoms on a benzene ring are substituted with a mercapto group (—SH), is provided in the present invention. As the compound (Tp), at least one thiol compound selected from the group consisting of 2-aminobenzenethiol, 4-aminobenzenethiol, 3-aminobenzenethiol, and benzenethiol is preferable. According to such flux, a change in viscosity of the solder paste with time can be further suppressed.

Flux and solder paste

A flux containing rosin, a solvent, a thixotropic agent, an amine hydroiodide, and an activator (provided that the amine hydroiodide is excluded), in which the amine hydroiodide includes a heteroalicyclic amine hydroiodide, is provided in the present invention. As the heteroalicyclic amine hydroiodide, at least one selected from the group consisting of piperidine hydroiodide and pipecholine hydroiodide is preferable. According to such flux, the generation of voids during soldering can be further suppressed.

The present invention uses a flux containing a rosin, a solvent, a thixo agent, and an activator. The thixo agent contains a polyamide and a compound represented by general formula (1). The polyamide is a condensate between an amine and at least one selected from aliphatic carboxylic acids and hydroxy group-containing aliphatic carboxylic acids, and has an endothermic peak at a temperature of 120-200° C. In the general formula, Rrepresents a hydrocarbon group having 11-30 carbon atoms. Rrepresents a hydrogen atom or a hydrocarbon group having 12-31 carbon atoms. Rrepresents an n-valent hydrocarbon group having 4-12 carbon atoms. Rrepresents an alkylene group having 2-6 carbon atoms. Rrepresents a single bond or an alkylene group having 2-6 carbon atoms. n represents 1 or 2. When n represents 1, m represents an integer of 1-3. When n represents 2, m represents 1.

The present invention employs a flux which contains rosin, a solvent, a thixotropic agent and an activator. The thixotropic agent contains a polyamide (PA2). The PA2 is a condensation product of an aliphatic carboxylic acid, a hydroxy group-containing aliphatic carboxylic acid and an aliphatic amine having from 3 to 10 carbon atoms; and the aliphatic carboxylic acid includes an aliphatic dicarboxylic acid having from 11 to 20 carbon atoms. With respect to the endothermic amount calculated from the peak area of the differential scanning calorimetry curve of PA2 as obtained by differential scanning calorimetry measurement, the ratio of the endothermic amount within the range of from 50° C. to 190° C. to the total endothermic amount within the range of from 50° C. to 200° C. is 90% or more.

Provided are flux in which solder wettability is improved, and a solder paste in which the flux is used. The flux contains 0.5-20.0 wt % of a (carboxyalkyl)isocyanurate adduct, and 5.0-45.0 wt % of a rosin, and furthermore contains a solvent. The (carboxyalkyl)isocyanurate adduct is a mono(carboxyalkyl)isocyanurate adduct, a bis(carboxyalkyl)isocyanurate adduct, a tris(carboxyalkyl)isocyanurate adduct, or a combination of two or more of these.

By using a solder alloy consisting essentially of 0.2-1.2 mass % of Ag, 0.6-0.9 mass % of Cu, 1.2-3.0 mass % of Bi, 0.02-1.0 mass % of Sb, 0.01-2.0 mass % of In, and a remainder of Sn, it is possible to obtain portable devices having excellent resistance to drop impact and excellent heat cycle properties without developing thermal fatigue even when used in a high-temperature environment such as inside a vehicle heated by the sun or in a low-temperature environment such as outdoors in snowy weather.

Lead-free solder alloy

Growing community of inventors

Tokyo, Japan

Kazuyori Takagi