Patent ID: 8491810

Claim:
A lubricating oil for a compression type refrigerator, comprising: a polyvinyl ether-based compound containing alkylene glycol or polyoxyalkylene glycol units and vinyl ether units in a molecule and having a molecular weight in a range of 300 to 3,000; and an organic carboxylic acid ester of sorbitol in which the ester contains two or more free hydroxyl groups, and derived from at least one organic carboxylic acid selected from the group consisting of an aliphatic saturated monocarboxylic acid, an aliphatic unsaturated carboxylic acid, an aliphatic dicarboxylic acid, and an aromatic carboxylic acid, wherein the polyvinyl ether-based compound has a carbon/oxygen molar ratio of 4.0 or less, and wherein the lubricating oil has a viscosity index of 90 or more.