| abstract |
A lubricating oil composition for a refrigerator using a hydrofluorocarbon coolant, characterized as comprising, as a main component, a mixture comprising (a) an ester compound and (b) a mineral oil component in a weight ratio (a)/(b) of from 9/1 to 2/8, wherein the ester compound (a) is a polyol ester or a complex ester compound prepared from a neopentyl polyol and a monocarboxylic acid and/or a dicarboxylic acid, and the mineral oil component (b) has a % Cp of 70 % or less as measured by the n-d-M ring analysis and a temperature corresponding to 50 % distillation of 400°C or lower as measured by the gas chromatograph distillation method and a pour point of -30°C or lower. The lubricating oil composition is excellent in the compatibility with the above coolant, lubricativity, and electrical insulating property, and is reduced in the absorptivity for moisture and hydrolyzability, and further is excellent with respect to the property of dissolving impurities and the property of returning to a compressor in a refrigerator. |