| abstract |
A flux composition for solder, a solder paste, and a solder paste using these, which exhibit high wettability and are excellent in reliability after bonding, and have excellent storage stability. The flux composition is a compound obtained by reacting a carboxylic acid compound with a vinyl ether compound. (X), a compound (Y) obtained by reacting an anhydrous carboxylic acid compound with a hydroxy vinyl ether compound, and a compound (Z) obtained by addition polymerization of a reaction product of an acid anhydride with a polyhydric alcohol with a divinyl ether compound. At least one compound having a blocked carboxyl group, and also non-curable. |