Abstract: A method of producing a powder of fatty acid metal salt for forming ultrafine metal particles includes washing the fatty acid metal salt so that the amount of unreacted substance or by-product is 4.0 mol % or less when the fatty acid metal salt is formed; preparing a pressed cake by pressing the fatty acid metal salt; and drying the pressed cake so that the water content is 200 ppm or less. The powder has a property for deodorizing mercaptan smelling components and/or a property for inactivating microproteins.

Abstract: A master batch for use in forming ultrafine metal particles serving as an adsorptive material, a method of producing the same, and a method of molding an article containing ultrafine metal particles by using the master batch. The master batch comprises a thermoplastic resin and a metal organoate contained therein, the metal of the metal organoate being selected from the group consisting of Cu, Ag, Au, In, Pd, Pt, Fe, Ni, Co, Zn, Nb, Sn, Ru and Rh. Adsorption performance is not expressed by the master batch but is expressed by an article molded by blending the resin with the master batch.

Abstract: An adsorptive composition comprising a composition that contains at least one kind of fatty acid metal salt of any one of Ni, Cu or Co and ultrafine metal particles having a plasmon absorption over 300 to 700 nm. The adsorptive composition has an excellent effect of adsorbing both amine-type smelling components and sulfur-containing smelling components.

Abstract: An adsorptive composition comprising a composition that contains at least one kind of fatty acid metal salt of any one of Ni, Cu or Co and ultrafine metal particles having a plasmon absorption over 300 to 700 nm. The adsorptive composition has an excellent effect of adsorbing both amine-type smelling components and sulfur-containing smelling components.

Abstract: A master batch for use in forming ultrafine metal particles serving as an adsorptive material, a method of producing the same, and a method of molding an article containing ultrafine metal particles by using the master batch. The master batch comprises a thermoplastic resin and a metal organoate contained therein, the metal of the metal organoate being selected from the group consisting of Cu, Ag, Au, In, Pd, Pt, Fe, Ni, Co, Zn, Nb, Sn, Ru and Rh. Adsorption performance is not expressed by the master batch but is expressed by an article molded by blending the resin with the master batch.

Abstract: A fatty acid metal salt used for forming ultrafine metal particles satisfying at least one of that: (i) the water content is 200 ppm or less; (ii) the volume-cumulative particle diameter D90 is 80 ?m or smaller as measured by the particle size distribution measuring method of the laser diffraction/scattering type; or (iii) a metal of an atomic weight of 50 to 200 is contained, and the amount of the unreacted substance or the by-product is 4.0 mol % or less when the fatty acid metal salt is formed. The fatty acid metal salt can be favorably used for forming ultrafine metal particles in a resin, or for forming a resin composition, a coating, a dispersion solution or a molded article containing the ultrafine metal particles.