| abstract |
The present invention describes a refrigerating oil composition for a carbon dioxide refrigerant comprising a base oil composition which comprises (A) a polyoxyalkylene glycol having a kinematic viscosity of 3 to 50 mm<2>/s at 100° C. and at least one component selected from (B) a carbonate-based carbonyl derivative having a kinematic viscosity of 3 to 50 mm<2>/s at 100° C. and (C) a polyol ester having a kinematic viscosity of 3 to 50 mm<2>/s at 100° C., wherein an amount of (B) and/or (C) is 0.1 to 40% by weight of the total base oil composition. The composition exhibits sufficient antiwear, excellent lubricity and miscibility with carbon dioxide refrigerants and can be used for a long time with stability in the refrigerating cycle using a refrigerant comprising carbon dioxide in the supercritical condition of a high temperature and a high pressure as the main component. |