SOLDER COMPOSITION AND METHOD FOR MANUFACTURING FLEXIBLE CIRCUIT BOARD

To provide a solder composition which hardly acts on an insulating coat and is excellent in solder spreadability.SOLUTION: A solder composition contains: a flux composition containing an (A) rosin resin, an (B) activator, a (C) thixotropic agent, and a (D) solvent; and (E) solder powder, in which the (B) component contains a (B1) dicarboxylic acid having 3 to 8 carbon atoms, the (C) component contains at least one selected from the group consisting of a (C1) amide thixotropic agent having a hydroxy group in one molecule and a (C2) glycerol thixotropic agent having a hydroxy group in one molecule, and the solder composition satisfies a condition represented by Numerical Formula (F1) below provided that a total of contents of the (C1) component and the (C2) component is defined as X and a content of the (B1) component is defined as Y. X/2≤Y≤5X...(F1).SELECTED DRAWING: None 【課題】絶縁被膜に作用しにくく、はんだの広がり性に優れるはんだ組成物を提供すること。【解決手段】（Ａ）ロジン系樹脂、（Ｂ）活性剤、（Ｃ）チクソ剤、および（Ｄ）溶剤を含有するフラックス組成物と、（Ｅ）はんだ粉末とを含有し、前記（Ｂ）成分が、（Ｂ１）炭素数が３以上８以下であるジカルボン酸を含有し、前記（Ｃ）成分が、（Ｃ１）１分子中にヒドロキシ基を有するアマイド系チクソ剤、および（Ｃ２）１分子中にヒドロキシ基を有するグリセロール系チクソ剤からなる群から選択される少なくとも１つを含有し、前記（Ｃ１）成分および前記（Ｃ２）成分の合計配合量をＸとし、前記（Ｂ１）成分の配合量をＹとしたとき、下記数式（Ｆ１）で示される条件を満たす、はんだ組成物。Ｘ／２≦Ｙ≦５Ｘ・・・（Ｆ１）【選択図】なし