| abstract |
A grease base oil containing a condensed ester of an alcohol (A) and a carboxylic acid (B), wherein the alcohol (A) contains a polyhydric alcohol represented by the general formula (1), and the carboxylic acid (B) is Fatty acid having 5 or more and 9 or less carbon atoms (B-1), branched fatty acid having 15 or more and 20 or less carbon atoms (B-2), cycloalkane monocarboxylic acid (B-3) having 4 or more and 8 or less carbon atoms, and aromatic carboxylic acid (B-4) is contained, and in the said carboxylic acid (B), the ratio of said (B-1) is 30 mol% or more and 50 mol% or less, and the ratio of said (B-2) is 30 mol% or more and 50 A grease base oil wherein (B-3) is 10 mol% or more and 30 mol% or less, and (B-4) is 1 mol% or more and 15 mol% or less. The grease base oil contains a condensed ester having heat resistance and low-temperature storage properties. |