Lubricant composition

摘要

An antioxidant composition suitable for ester fluid lubricants is the reaction product of diphenylamine and N-aryl naphthylamine in the presence of an organic peroxide. The mole ratio of diphenylamine:N-aryl naphthylamine is about 1:1 to about 10:1. This results in more oligomeric reaction products and significantly less unreacted monomeric residual reactants. The resultant product composition comprises DPA homo-oligomers and DPA-NPA cross oligomers. The diphenylamine and N-aryl naphthylamine are desirably substituted with alkyl groups having from 1 to 20 carbon atoms or styryl groups. The reaction temperature is preferably about 130° to about 150° C. Controlled reaction conditions allow the use of solvents with extractable hydrogen atoms without producing significant amounts of dehydrocondensation between the solvent and the diamines. The reaction products have superior oxidative resistance in the Oxidation Corrosion Stability Test (OCS) and Vapor Phase Coker Test over dehydrocondensation products produced under other conditions and are useful in lubricant composition, especially in synthetic ester fluid lubricants such as turbine engine oils.