Synthetic lubricating oil containing an ester and working fluid composition for refrigerating machine containing same

摘要

A synthetic lubricating oil comprises an ester derived from (a) a monohydric alcohol having 4 to 18 carbon atoms which has a branched alcohol content of not less than 50 mol % and/or a neopentylpolyol having not more than 30 carbon atoms, (b) a hydroxycarboxylic acid condensate having an average degree of polymerization of not less than 1.2, and (c) a monocarboxylic acid having 4 to 18 carbon atoms which has a branched carboxylic acid content of not less than 50 mol %.