| 摘要 |
PROBLEM TO BE SOLVED: To obtain an engine oil composition undergoing less deterioration or evaporation at high temperatures and having excellent hydrolysis stability, low temperature properties and a good viscosity index by mixing a hydrocarbon oil with an aromatic dicarboxylic acid ester and additives. SOLUTION: This composition comprises component A, component B (B1 and/or B2) and component C in such amounts that the ratio B/(A+B)=5-80wt.%, and 0.05-15 pts.wt. component C is present per 100 pts.wt. total of components A and B. Component A is a hydrocarbon oil. Component B1 is an aromatic dicarboxylic acid diester obtained by esterifying an aromatic dicarboxylic acid represented by the formula (wherein A is a 1-4C alkyl; and n is 0 or 1-4) or its anhydride with a 6-18C linear and/or branched aliphatic monohydrid alcohol. Component B2 is an aromatic dicarboxylic acid compound ester comprising the three components including the acid component and the alcohol component used in component B1 and a 2-10C aliphatic dihydric alcohol. Component C comprises a viscosity index improver and/or a pour point depressant. |
