| abstract |
A high quality lubricant for heavy duty service air conditioner and refrigerator compressors, especially those using chlorine free hydrofluorocarbon refrigerant working fluids, is provided by mixed esters of hindered polyols, most desirably di-pentaerythritol, usually mixed with some pentaerythritol, with a mixture of carboxylic acids including at least some of each of iso-pentanoic acid and iso-nonanoic acid. |