Patent ID: 7661577

Claim:
A soldering process comprising: contacting a copper or copper alloy-containing material with a water-based composition, the water-based composition comprising an imidazole compound, the imidazole compound is at least one member selected from the group consisting of 2-(2,3-dichlorophenyl)-4-phenyl-5-methylimidazole, 2-(2,6-dichlorophenyl)-4-phenyl-5-methylimidazole, 2-(3,4-dichlorophenyl)-4-phenyl-5-methylimidazole, 2-phenyl-4-(2,4-dichlorophenyl)-5-methylimidazole, 2-phenyl-4-(3,4-dichlorophenyl)-5-methylimidazole, 2-(2,3-dichlorophenyl)-4-phenylimidazole and 2-phenyl-4-(3,4-dichlorophenyl) imidazole, wherein the imidazole compound is present in an amount of 0.01 to 10% by weight based on the whole water-based composition and the water-based composition further comprising a copper compound, wherein the copper compound is at least one member selected from the group consisting of copper halides, copper salts of acids and copper hydroxide, and is present in an amount of 0.01 to 10% by weight based of the whole water-based composition, the water-based compound further comprising an acid, wherein the acid is present in an amount of 0.1 to 50% by weight based on the whole water-based composition, wherein the acid is at least one member selected from the group consisting of C 1 -C 12 saturated aliphatic mono-carboxylic acids, C 1 -C 12 unsaturated aliphatic mono-carboxylic acids, C 2 -C 6 saturated aliphatic di-carboxylic acids, C 2 -C 6 unsaturated aliphatic di-carboxylic acids, C 7 or C 8 aromatic carboxylic acids, C 6 -C 8 aromatic sulfonic acids, hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, and soldering the copper or copper alloy-containing material using a lead-free solder.