Abstract: Provided are a flux, resin flux cored solder and a flux coated pellet which are washable with water. Resin flux cored solder is composed of solder having a linear shape and a flux filled in a substantially central part (core) of the cross section of the solder. The flux contains an amine for salt formation and an organic acid for salt formation, in which the amount of the organic acid is within a range between 10 parts by mass or more and 645 parts by mass or less based on 100 parts by mass of the amine. The organic acid for salt formation is composed of at least one organic acid selected from the group consisting of malonic acid, succinic acid, glutaric acid, tartaric acid, malic acid, diglycolic acid, and citric acid.

Abstract: Provided are a flux, resin flux cored solder and a flux coated pellet which are washable with water. Resin flux cored solder is composed of solder having a linear shape and a flux filled in a substantially central part (core) of the cross section of the solder. The flux contains an amine for salt formation and an organic acid for salt formation, in which the amount of the organic acid is within a range between 10 parts by mass or more and 645 parts by mass or less based on 100 parts by mass of the amine. The organic acid for salt formation is composed of at least one organic acid selected from the group consisting of malonic acid, succinic acid, glutaric acid, tartaric acid, malic acid, diglycolic acid, and citric acid.

Abstract: A flux for a resin flux cored solder or a flux coated solder, in which scattering of flux and solder in using the solder is suppressed, and a resin flux cored solder or a flux coated solder including such a flux are provided. The flux for a resin flux cored solder can include a rosin resin, an activator, and at least one selected from an acrylic polymer and a vinyl ether polymer, which has a weight average molecular weight of 8000 to 100000, in an amount of 0.1 to 3 mass-% based on the total mass of the flux.

Abstract: An object of the present invention is to provide a resin flux cored solder, or a flux coated solder, for which scattering of flux and solder in using the solder is suppressed, and a flux to be contained therein. A flux for a resin flux cored solder comprising a rosin resin, an activator, and at least one selected from an acrylic polymer and a vinyl ether polymer, which has a weight average molecular weight of 8000 to 100000, in an amount of 0.1 to 3 mass-% based on the total mass of the flux.

Abstract: A flux for a resin flux cored solder contains 30% or more by mass but 80% or less by mass rosin ester and 5% or more by mass but 15% or less by mass activator. The total content ratio of base materials including the rosin ester is preferably equal to or more than 85% by mass but equal to or less than 95% by mass.

Abstract: A flux for a resin flux cored solder contains 30% or more by mass but 80% or less by mass rosin ester and 5% or more by mass but 15% or less by mass activator. The total content ratio of base materials including the rosin ester is preferably equal to or more than 85% by mass but equal to or less than 95% by mass.