abstract |
An ester-based lubricating oil for use in a rotary screw compressor utilizing a chlorine-free hydrofluorocarbon (HFC) refrigerant such as R-134a contains a product obtained from a reaction of tripentaerythritol and a mixed C5-C10 monocarboxylic acid, or a product obtained from a reaction of dipentaerythritol and a mixed C5-C10 monocarboxylic acid, and optionally a product obtained from a reaction of dipentaerythritol and a C5 monocarboxylic acid. |