Refrigerator oil

A refrigerating machine oil comprising:

• a base oil comprising an ester;
• a compound represented by the following formula (1):
• wherein R1 and R2 each independently represent a monovalent hydrocarbon group, R3 represents a divalent hydrocarbon group and R4 represents a hydrogen atom or a monovalent hydrocarbon group;
• and
• an epoxy compound consisting of at least one selected from the group consisting of glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, and oxirane compounds,
• wherein the ester is an ester of a polyhydric alcohol and a fatty acid,
• wherein the polyhydric alcohol comprises at least one selected from the group consisting of neopentylglycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane), pentaerythritol and dipentaerythritol, and
• the fatty acid comprises at least one selected from the group consisting of butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic, eicosanoic acid, 2-methylpropanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-methylheptanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid, and 2-ethylhexadecanoic acid, and,
• wherein a content of the compound represented by the formula (1) is 0.001% by mass or more and 3% by mass or less, a content of the epoxy compound is 0.1% by mass or more and 5.0% by mass or less, and a content of the base oil is 80% by mass or more based on a total amount of the refrigerating machine oil.

A working fluid composition for a refrigerating machine comprising:

• a refrigerant;
• and
• a refrigerating machine oil comprising:
• a base oil comprising an ester;
• a compound represented by the following formula (1):
• wherein R1 and R2 each independently represents a monovalent hydrocarbon group, R3 represents a divalent hydrocarbon group, and R4 represents a hydrogen atom or a monovalent hydrocarbon group;
• and
• an epoxy compound consisting of at least one selected from the group consisting of glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, and oxirane compounds,
• wherein the ester is an ester of a polyhydric alcohol and a fatty acid,
• wherein the polyhydric alcohol comprises at least one selected from the group consisting of neopentylglycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane), pentaerythritol and dipentaerythritol, and
• the fatty acid comprises at least one selected from the group consisting of butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic, eicosanoic acid, 2-methylpropanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-methylheptanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid, and 2-ethylhexadecanoic acid, and,
• wherein a content of the compound represented by the formula (1) is 0.001% by mass or more and 3% by mass or less, a content of the epoxy compound is 0.1% by mass or more and 5.0% by mass or less, and a content of the base oil is 80% by mass or more based on a total amount of the refrigerating machine oil.