Refrigerating machine oil and working fluid composition for refrigerating machines

摘要

H:/txb/Interwoven/NRPortbl/DCC/TXB/7966327_1.docx - 25/6/15 This refrigerating machine oil comprises esters of a polyhydric alcohol with fatty acids. In the fatty acids, the molar ratio of C4_6 fatty acids to branched C7 _9 fatty acids is 15:85 to 90:10, and the C 4 _6 fatty acids contain 2-methylpropanoic acid, with the sum total of the C4_6 fatty acids and the branched C7 _9 fatty acids accounting for at least 20mol% of the whole of the fatty acids constituting the esters. This working fluid composition for refrigerating machines comprises the refrigerating machine oil and a difluoromethane refrigerant and/or an unsaturated fluorinated hydrocarbon refrigerant.