| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject base oil excellent in compatibility with mixed cooling media, also exhibiting excellent electrical insulation (volume resistivity) and lubricity, by including a polyalkylene oxide derivative of specific structure. SOLUTION: This lubricating base oil comprises a polyalkylene oxide derivative bearing one intramolecular cyclohexane skeleton [pref. a derivative of the formula (R<1> is a cyclohexane skeleton-bearing hydrocarbon; R<2> is a 2-4C alkylene; R<3> is H or a 1-4C alkyl; (m) is an integer of 2-35: (n) is an integer of 1-3)]. This derivative is pref. 200-2,000 in weight-average molecular weight and 5-200 cSt in kinematic viscosity at 40 deg.C, and is obtained by adding an alkylene oxide to a cyclohexane skeleton-bearing alcohol in the presence of an alkaline catalyst such as KOH or an acidic catalyst such as BF3 . This lubricating base oil is applicable to a mixed cooling medium (R-410A) composed of difluoromethane and pentafluoroethane. |
