Abstract: A solder precipitating composition comprises a powder of a metal having the highest ionization level among metals constituting a solder alloy to be prepared, and a salt between a carboxylic acid and a remaining metal of the solder alloy. The composition is applied to a surface on which the solder is to be precipitated, and the solder is precipitated, thereby performing soldering.

Abstract: A conductive high molecular composition which comprises a non-conductive polymer component incorporated with a metal salt, characterized in that the metal salt is a salt of a metal with an acid substance selected from an organic carboxylic acid, rosin and a rosin derivative. This composition has an insulating property in normal state but functions as an electroconductive material only in the event it is interposed between slightly spaced metals and heated. Thus, the composition can be used not only as an insulating binder but also for imparting conductivity only in the desired spots of electronic parts, keeping the other areas of the parts electrically insulated. The composition thus possessing a specific dual function is particularly useful in the field of electronic industry.

Abstract: A method for forming a metal film on the surface of a substrate metal, which comprises soaking a substrate metal or a non-metal support carrying the substrate metal thereon in a solution of a metal salt in a high boiling point solvent under heating conditions, characterized in that the metal salt is a salt of the metal to be formed on the surface of the substrate metal with an acidic substance selected from an organic carboxylic acid, a rosin and a rosin derivative. The metal is precipitated from the solution exclusively on the surface of the substrate metal without forming any solid metal particle in the solution or on the substrate metal. Thus, the method is applicable to the formation of a soldering alloy as a film on the surface of a substrate metal without leaving thereon any free metal particle which may cause short circuits in electronic circuits.

Abstract: A conductive high molecular composition which comprises a non-conductive polymer component incorporated with a metal salt, characterized in that the melt salt is a salt of a metal with an acid substance selected from an organic carboxylic acid, rosin and a rosin derivative. This composition has an insulating property in the normal state but functions as an electroconductive material only in the event it is interposed between slightly spaced metals and heated. Thus, the composition can be used not only as an insulating binder but also for imparting conductivity only in the desired spots of electronic parts, keeping the other areas of the parts electrically insulated. The composition thus possessing a specific dual function is particularly useful in the electronic industry field.

Abstract: A rubber composition in which a metal salt between a resin acid and cobalt is blended in a content of from 0.05 to 0.7 part by weight in terms of the content of a metal element with respect to 100 parts by weight of rubber containing not less than 70% by weight of at least one rubber of natural rubber and a synthetic polyisoprene rubber; as the metal salt is used a cobalt resinate which has a melting point in a range of 140.degree. to 180.degree. C., an oxidation degree of not more than 60% in a gas chromatography (GLC), and not more than 2,000 ppm of a sulfur concentration in the metal salt; when the metal salt is divided into a dissolved portion and an undissolved portion by using toluene and water, the undissolved portion in both toluene and water has a characteristic absorption of around 3,600 cm.sup.-1 in an infrared absorption spectrum (IR); and when elevated in temperature at a rate of 5.degree. C./min.