| abstract |
PURPOSE:To increase, without degrading oxidation stability, the low temperature fluidity and viscosity index of a lubricating oil, which are normally low in the case of a lubricating oil made of an ester of a tertiary fatty acid by employing an ester of neopentyl alcohol with a mixture of a tertiary fatty acid and a dibasic acid. CONSTITUTION:A neopentyl-type complex ester (molecular weight: 270-5,000, acid number: 1mgKOH/g or less, hydroxyl number: 40mgKOH/g or less) which is prepared from a mixture consisting of 60-97mol% (preferably 70-95mol%) tertiary fatty acid of the formula (wherein R represents 1-6C alkyl; and R<1> and R<2> each represent 1-2C alkyl, provided that the total carbon number of R, R<1> and R<2> is 6 or less); 3-40mol% (preferably 5-30mol%) 4-8C dibasic acid (e.g. succinic acid) and neopentyl polyol is employed as a base oil for a lubricating oil which can be advantageously employed as a base oil for a high-- performance engine oil. |