| 摘要 |
PROBLEM TO BE SOLVED: To obtain a biodegradable lubricating oil high in viscosity index, excellent in lubricating properties, having low-temperature fluidity and heat stability, hardly deteriorating a rubber material, especially a nitrile-based rubber material. SOLUTION: This lubricating oil is a synthetic ester obtained from a dimethylol 5-7C alkane and a saturated and unsaturated 10-20C straight-chain fatty acids in a blending molar ratio of 10/90-50/50 and having 20-40cSt kinematic viscosity at 40%oC, >=120 viscosity index and <=-30 deg.C pour point. |
