A solder composition of the invention contains: a flux composition containing (A) a rosin resin, (B) an activator, (C) an imidazoline compound having a phenyl group, and (D) an antioxidant; and (E) solder powder, in which the (B) component contains (B1) an organic acid, the (B1) component contains at least one selected from the group consisting of (B11) 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, and 1,4-dihydroxy-2-naphthoic acid, and the (C) component is at least one selected from the group consisting of 2-phenylimidazoline and 2-benzylimidazoline.

Provided is a flux for solder paste including an organic component as a main component, which is composed of a fatty acid and an aliphatic primary amine.

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.

A solder alloy is provided which can withstand the severe characteristics of a temperature cycle between a low temperature of −40° C. and a high temperature of 125° C., withstand an external force applied due to, for example, riding on a curb or collision with a vehicle ahead for a long period of time, and can suppress change in viscosity of a solder paste over time. In addition, a solder paste, a solder ball, and a solder preform in which the solder alloy is used; a solder joint formed through the use thereof; and an on-board electronic circuit, an ECU electronic circuit, an on-board electronic circuit device, and an ECU electronic circuit device which include this solder joint are provided. The solder alloy contains, by mass %, 1% to 4% of Ag, 0.5% to 1.0% of Cu, 1.5% to 5.5% of Bi, 1.0% to 5.3% of Sb (or greater than 5.5% and less than or equal to 7.0% of Bi and 2.0% to 5.3% of Sb), 0.01% to 0.2% of Ni, 0.0040% to 0.0250% of As, and a balance of Sn.

A resin composition for soldiering is provided. The resin composition includes 1 wt % or more and 40 wt % or less of a dimer acid, a trimer acid, or a combination thereof, 30 wt % or more and 99 wt % or less of a rosin, and 0 wt % or more and 13 wt % or less of a solvent. The dimer acid is selected from a dimer acid that is a reaction product of oleic acid and linoleic acid, a hydrogenated dimer acid obtained by adding hydrogen to a dimer acid that is a reaction product of oleic acid and linoleic acid, and a combination thereof. The trimer acid is selected from a trimer acid that is a reaction product of oleic acid and linoleic acid, a hydrogenated trimer acid obtained by adding hydrogen to a trimer acid that is a reaction product of oleic acid and linoleic acid, and a combination thereof.

A solder composition of the invention contains: a flux composition containing (A) a rosin resin, (B) an activator, (C) an imidazoline compound having a phenyl group, and (D) an antioxidant; and (E) solder powder, in which the (B) component contains (B1) an organic acid, the (B1) component contains at least one selected from the group consisting of (B11) 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, and 1,4-dihydroxy-2-naphthoic acid, and the (C) component is at least one selected from the group consisting of 2-phenylimidazoline and 2-benzylimidazoline.

A flux which imparts thixotropy, and which exhibits excellent printability, printing sagging-inhibiting ability, and heating sagging-inhibiting ability; and a solder paste which uses said flux. This flux includes a thixotropic agent, a rosin, an organic acid, and a solvent. The thixotropic agent includes a cyclic amide compound obtained by polycondensing a dicarboxylic acid and/or a tricarboxylic acid, and a diamine and/or a triamine into a cyclic shape; and an acyclic amide compound which is obtained by polycondensing a monocarboxylic acid, a dicarboxylic acid and/or a tricarboxylic acid into an acyclic shape. The flux includes at least 0.1 wt % but not more than 8.0 wt % of the cyclic amide compound, and at least 0.5 wt % but not more than 8.0 wt % of the acyclic amide compound. The total amount of the cyclic amide compound and the acyclic amide compound is at least 1.5 wt % but not more than 10.0 wt %.

Provided is a flux capable of obtaining predetermined rheological characteristics both at room temperature and under a thermal history that is assumed for soldering and capable of suppressing the amount of a residue after soldering to realize a low residue. The flux contains a first alcohol compound that has two or more OH groups and has a melting point of lower than 25° C. and a second alcohol compound that has two or more OH groups and has a melting point of higher than 25° C., the first alcohol compound is glycerin, the second alcohol compound is 2,5-dimethylhexane-2,5-diol, the flux has a viscosity of 10 Pa.Math.s or more and 50 Pa.Math.s or less at 25° C. and has a viscosity of more than 0 Pa.Math.s and 1 Pa.Math.s or less at 100° C., and, in a case where 10 mg of the flux is heated up to 25° C. to 250° C. under a N.sub.2 atmosphere at a temperature rise rate of 10° C./min, the weight of the flux after heating is 15% or less of the weight of the flux before heating.

Provided is flux for resin flux cored solder using in a soldering method in which the resin flux cored solder is supplied into a through hole formed along a central axis of a soldering iron. The flux contains volatile rosin in an amount of 70 wt % or more and 98 wt % or less, non-volatile rosin in an amount of 0 wt % or more and 10% or less, and an activator in an amount of 2 wt % or more and 30 wt % or less, the activator including an organic acid in an amount of 0 wt % or more and 15 wt % or less, an organohalogen compound in an amount of 0.5 wt % and 15 wt % or less, an amine in an amount of 0 wt % or more and 5 wt % or less, and an amine hydrohalide salt in an amount of 0 wt % or more and 2.5 wt % or less.

Thermally conductive adhesive materials having a first metallic component with a high melting point metal; a second metallic component having a low melting point metal; a fatty acid, an optional amine, an optional triglyceride and optional additives. Also provided are methods of making the same and uses thereof for adhering electronic components to substrates.