Abstract: A surface treating agent containing a novel phenylnaphthylimidazole compound represented by the following formula is brought into contact with the surface of copper or a copper alloy. In the formula, when A1 is a phenyl group, then A2 represents a 1-naphthyl group or a 2-naphthyl group, and when A1 is a 1-naphthyl group or a 2-naphthyl group, then A2 represents a phenyl group; and R represents a hydrogen atom or a methyl group.

Abstract: A surface treating agent containing a novel phenylnaphthylimidazole compound represented by the following formula is brought into contact with the surface of copper or a copper alloy. In the formula, when A1 is a phenyl group, then A2 represents a 1-naphthyl group or a 2-naphthyl group, and when A1 is a 1-naphthyl group or a 2-naphthyl group, then A2 represents a phenyl group; and R represents a hydrogen atom or a methyl group.

Abstract: A surface treating agent containing a novel phenylnaphthylimidazole compound represented by the following formula is brought into contact with the surface of copper or a copper alloy. In the formula, when A1 is a phenyl group, then A2 represents a 1-naphthyl group or a 2-naphthyl group, and when A1 is a 1-naphthyl group or a 2-naphthyl group, then A2 represents a phenyl group; and R represents a hydrogen atom or a methyl group.

Abstract: It is an object to provide a water-soluble preflux containing a low-volatile solubilizing agent excellent in performance to dissolve an imidazole compound in water and capable of bringing out an excellent film-forming property of the imidazole compound and also to provide a treating method for the surface of a metal conductive part which comprises bringing the surface into contact with the above water-soluble preflux.

Abstract: A water-based composition for treating copper or copper alloy surface for lead-free soldering, the composition comprising a compound represented by general formula (1): wherein R1 is hydrogen or methyl, and either R2 and R3 represent chlorine and R4 and R5 represent hydrogen, or R2 and R3 represent hydrogen and R4 and R5 represent chlorine.

Abstract: It is an object to provide a water-soluble preflux containing a low-volatile solubilizing agent excellent in performance to dissolve an imidazole compound in water and capable of bringing out an excellent film-forming property of the imidazole compound and also to provide a treating method for the surface of a metal conductive part which comprises bringing the surface into contact with the above water-soluble preflux. Another object is to provide a printed wiring board wherein the surface of a metal conductive part has been brought into contact with the above water-soluble preflux and a soldering method which comprises bringing the surface of a metal conductive part into contact with the above water-soluble preflux and subsequently soldering the surface.

Abstract: A surface treating agent containing a novel phenylnaphthylimidazole compound represented by the following formula is brought into contact with the surface of copper or a copper alloy. In the formula, when A1 is a phenyl group, then A2 represents a 1-naphthyl group or a 2-naphthyl group, and when A1 is a 1-naphthyl group or a 2-naphthyl group, then A2 represents a phenyl group; and R represents a hydrogen atom or a methyl group.

Abstract: A water-based composition for treating copper or copper alloy surface for lead-free soldering, the composition comprising a compound represented by general formula (1): wherein R1 is hydrogen or methyl, and either R2 and R3 represent chlorine and R4 and R5 represent hydrogen, or R2 and R3 represent hydrogen and R4 and R5 represent chlorine.

Abstract: A surface treating agent for copper and a copper alloy, comprising an aqueous solution containing an imidazole compound or a benzimidazole compound, a complexon, and iron ions. The agent forms a chemical film selectively on the surface of copper while forming no film on other metals.

Abstract: A water-based surface treatment agent is used to provide a chemical layer on a copper or copper alloy printing wiring board (PWB). The chemical layer shows excellent heat-resistance and moisture-resistance. The treated PWB maintains excellent solderability for extended lengths of time. The water-based surface treatment agent contains as an active ingredient 2,4-diphenylimidazole, 2,4-diphenyl-5-methylimidazole or 2-phenyl-4-benzyl-5-methylimidazole. The treating compositions with a lower carboxylic acid of up to 4 carbon atoms are soluble in water, and have improved solder wetting properties and improved solder paste spreading property. A copper compound may be included in the aqueous solution to increase the rate at which the chemical layer is formed.

Abstract: An water-based surface treatment agent used for the copper on a printed wiring board (PWB). Chemical layer formed on PWB shows excellent heat-resistance and moisture-resistance; therefore, the treated PWB preserves excellent soldability for a long time. The water-based surface treatment agent contains, as an active ingredient, a 2-arylimidazole compound represented by the following formula, ##STR1## wherein R is a hydrogen atom or a methyl group, R1 and R2 are hydrogen atoms, lower alkyl groups or halogen atoms, and R3 and R4 are hydrogen atoms, lower alkyl groups, halogen atoms, lower alkoxy groups, di-lower alkylamino groups, cyano groups or nitro groups, ##STR2## wherein R is a hydrogen atom or a methyl group, and R1 and R2 are hydrogen atoms, lower alkyl groups or halogen atoms, but excluding the case where R, R1 and R2 are all hydrogen atoms.