| 摘要 |
PROBLEM TO BE SOLVED: To provide a lubricating oil base oil which has a low viscosity and, simultaneously, a high viscosity index with an extremely reduced evaporation loss. SOLUTION: The mineral oil based lubricating oil base oil has not more than 10% fraction having a boiling point of not higher than 371 deg.C by gas chromatographic distillation and, simultaneously, not less than 70% fraction having a boiling point of not lower than 371 deg.C to lower than 491 deg.C, and a 20% distilling temperature of not lower than 397 deg.C, a kinematic viscosity at 100 deg.C of not greater than 5.5 mm<2> /s, and a viscosity index of not smaller than 120. |
