PURPOSE: To obtain a corrosion inhibitor for metal having a stable anticorrosive effect in a water-petroleum mixed system over a long term by reacting a hydroxyalkylamine with an alkylene oxide in a specified ratio and using the resulting trihydroxyalkylamine as an essential component.
CONSTITUTION: This corrosion inhibitor for metal is added to an antifreezing fluid of a water-petroleum mixed system used for various kinds of metal or working oil for metal. A mono- or dihydroxyalkylamine such as mono- or diethanolamine or a mixture of hydroxyalkylamines is reacted with an alkylene oxide such as propylene oxide or butylene oxide or a mixture of alkylene oxides in 0.1W10.0 molar ratio at 50W200°C for 0.5W15hr in the presence of an alkali metallic hydroxide such as NaOH or KOH as catalyst. The resulting trihydroxyalkylamine substituted by different hydroxyalkyl groups is used as the principal essential component of this corrosion inhibitor.
SUGAWARA HARUSHIGE
IKEDA YOSHIHIRO
