Method for preventing elution of nickel from water-contact instrument of copper alloy by formation of a protective film

Abstract

There are provide a nickel elution prevention method for preventing a water-contact instrument made of copper alloy from eluting nickel even when being water-contact with a fluid, such as city water, a protective film formation agent for preventing the elution of nickel and a detergent for preventing the elution of nickel. The water-contact instrument includes valves for city water, feedwater or hot water, pipe joints, strainers, water faucet clasps, pump supplies materials, water meters, water purifiers, water feeders, hot water feeders or other such water-contact instruments each made of copper alloy, such as bronze, brass, etc., plated with a material containing nickel, for example. The nickel elution prevention method for the water-contact instrument of copper alloy includes applying the protective film formation agent containing at least one species of benzotriazole, benzotriazole derivatives and organic acids including a straight-chain fatty acid to at least a water-contact surface of the water-contact instrument of copper alloy to form a protective film, thereby suppressing elution of nickel via the protective film.

1 . A protective film formation agent for preventing elution of nickel from a water-contact instrument made of copper alloy, comprising a nickel coat that wraps around and adheres to at least a water-contact surface of a water-contact instrument made of copper alloy and plated with a material containing nickel to form a protective film, wherein the protective film consists essentially of at least one compound selected from the group consisting of benzotriazole or benzotriazole derivatives and a straight chain fatty acid 
     
     
         2 . The protective film according to  claim 1 , wherein the protective film consists essentially of benzotriazole and a straight chain fatty acid.