| 摘要 |
PROBLEM TO BE SOLVED: To provide a lubricant composition for a compression-type refrigeration cycle, or a heat pump cycle, using carbon dioxide refrigerant, excellent in lubricity even when used for dissolving the carbon dioxide refrigerant, excellent in fluidity when used in a gas cooler, an expansion valve, and an evaporator, exhibiting enough oil-return characteristics, and further exhibiting excellent stability when coexisting with the carbon dioxide. SOLUTION: This lubricant composition is used as a lubricant for a vapor compression-type refrigeration unit where carbon dioxide is used as a refrigerant, and contains a lubricant base oil having the following characteristics as a main component: a 10%-distillation point of >=400 deg.C and an 80%-distillation point of <=600 deg.C when measured through a gas-chromatographic distillation method; a dynamic viscosity of 2-30 cm2/s at 100 deg.C; and a viscosity index of >=100. |
