Abstract: The present invention provides a refrigerating machine oil comprising: a base oil; 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.

Abstract: The refrigerating machine oil according to the present invention comprises a polyalkylene glycol represented by the following formula (1): R1—(OR3)n—OR2??(1) [R1 and R2 may be the same or different from each other and each represent a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, or an acyl group having from 2 to 5 carbon atoms, R3 represents an alkylene group having from 2 to 4 carbon atoms, n represents an integer such that a number average molecular weight of the polyalkylene glycol represented by the formula (1) is from 1000 to 2500] the polyalkylene glycol having a ratio of the weight average molecular weight Mw to the number average molecular weight Mn, Mw/Mn, of from 1.00 to 1.15, the refrigerating machine oil being used with a mildly flammable hydrofluorocarbon refrigerant.

Abstract: The present invention provides a refrigerating machine oil comprising at least one oxygen-containing oil having a carbon/oxygen molar ratio of 2.5 or more and 5.8 or less as a base oil, and the refrigerating machine oil being used with a trifluoroethylene refrigerant.

Abstract: The invention provides a refrigerating machine oil comprising as a base oil at least one oxygen-containing oil having a carbon/oxygen molar ratio of 2.5 or more and 5.8 or less, and being used in combination with a (Z)-1,1,1,4,4,4-hexafluoro-2-butene refrigerant.

Abstract: The working fluid composition for a refrigerating machine of the present invention comprises a refrigerant comprising a first refrigerant component and a second refrigerant component, and having a global warming potential (GWP) of 500 or less, wherein the first refrigerant component is at least one selected from difluoromethane and tetrafluoropropene, and the second refrigerant component is at least one selected from carbon dioxide and a hydrocarbon having 3 to 4 carbon atoms; and a refrigerating machine oil comprising at least one selected from a polyol ester, a polyvinyl ether and a polyalkylene glycol compound as a base oil, wherein a carbon/oxygen molar ratio of the base oil is 2.5 or more and 5.8 or less.

Abstract: The present invention provides a refrigerating machine oil comprising, as a base oil, a polymer having a structural unit represented by the following formula (1): wherein R1, R2 and R3, which may be the same as or different from each other, represent a hydrogen atom or a hydrocarbon group; and R4 represents a hydrocarbon group or an organic group containing an oxygen atom, and having a number average molecular weight Mn of 300 or more and 3000 or less and a ratio of a weight-average molecular weight Mw to a number average molecular weight Mn (Mw/Mn) of 1.10 or more and 2.00 or less, and the refrigerating machine oil being used with a refrigerant selected from the group consisting of difluoromethane, a mixture of difluoromethane and pentafluoroethane, a mixture of difluoromethane, pentafluoroethane and 1,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane, 1,1,1,2-tetrafluoroethane and 1,1,1-trifluoroethane, unsaturated hydrofluorocarbons, hydrocarbons and carbon dioxide.

Abstract: The present invention provides a refrigerating machine oil comprising: a base oil containing an ester of dipentaerythritol with 2-methylbutanoic acid and n-pentanoic acid; and at least one epoxy compound selected from the group consisting of a glycidyl ester compound and a glycidyl ether compound, the refrigerating machine oil being used with a difluoromethane refrigerant.

Abstract: The present invention provides a refrigerating machine oil containing an ester base oil obtained from pentaerythritol and mixed fatty acids of a fatty acid having 8 carbon atoms and a fatty acid having 9 carbon atoms, wherein a ratio of a weight average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, of the ester base oil is 1.06 to 1.20, and used with a mildly flammable hydrofluorocarbon refrigerant.

Abstract: The invention provides a refrigerating machine oil comprising a hydrocarbon-based base oil, the refrigerating machine oil having a viscosity index of 120 or less, and being used with a 1-chloro-3,3,3-trifluoropropene refrigerant.

Abstract: The working fluid composition for a refrigerating machine of the present invention comprises a refrigerant comprising a first refrigerant component and a second refrigerant component, and having a global warming potential (GWP) of 500 or less, wherein the first refrigerant component is at least one selected from difluoromethane and tetrafluoropropene, and the second refrigerant component is at least one selected from carbon dioxide and a hydrocarbon having 3 to 4 carbon atoms; and a refrigerating machine oil comprising at least one selected from a polyol ester, a polyvinyl ether arid a polyalkylene glycol compound as a base oil, wherein a carbon/oxygen molar ratio of the base oil is 2.5 or more and 5.8 or less.

Abstract: The working fluid composition for a refrigerating machine of the present invention comprises a refrigerant comprising a first refrigerant component and a second refrigerant component, and having a global warming potential (GWP) of 500 or less, wherein the first refrigerant component is at least one selected from difluoromethane and tetrafluoropropene, and the second refrigerant component is at least one selected from carbon dioxide and a hydrocarbon having 3 to 4 carbon atoms; and a refrigerating machine oil comprising at least one selected from a polyol ester, a polyvinyl ether and a polyalkylene glycol compound as a base oil, wherein a carbon/oxygen molar ratio of the base oil is 2.5 or more and 5.8 or less.

Abstract: The refrigerating machine oil according to the present invention comprises a polyalkylene glycol represented by the following formula (1): R1—(OR3)n—OR2??(1) [R1 and R2 may be the same or different from each other and each represent a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, or an acyl group having from 2 to 5 carbon atoms, R3 represents an alkylene group having from 2 to 4 carbon atoms, n represents an integer such that a number average molecular weight of the polyalkylene glycol represented by the formula (1) is from 1000 to 2500] the polyalkylene glycol having a ratio of the weight average molecular weight Mw to the number average molecular weight Mn, Mw/Mn, of from 1.00 to 1.15, the refrigerating machine oil being used with a mildly flammable hydrofluorocarbon refrigerant.

Abstract: The present invention provides a working fluid composition for a refrigerating machine, comprising a refrigerating machine oil that comprises an ester of a polyhydric alcohol and a fatty acid, an epoxy compound, and a phosphorus compound, and a fluoropropene refrigerant, wherein the polyhydric alcohol constituting the ester comprises pentaerythritol and dipentaerythritol, the fatty acid constituting the ester comprises at least one selected from fatty acids having 4 to 9 carbon atoms, and the epoxy compound and the phosphorus compound satisfy a condition represented by the following formula (1). [ Formula ? ? 1 ] ? 0.10 ? ( N E M E · W E ) ( N P M P · W P ) ? 1.

Abstract: The present invention provides a refrigerating machine oil comprising a polyvinylether having a structural unit represented by the following formula (1): wherein R1, R2, and R3 may be the same or different from each other and each represent a hydrogen atom or a hydrocarbon group, R4 represents a divalent hydrocarbon group or an ethereal oxygen-containing divalent hydrocarbon group, R5 represents a hydrocarbon group, m represents an integer of 0 or more, and in the case where m is 2 or more, a plurality of R4 may be the same or different from each other, a number average molecular weight Mn is 500 or more and 2000 or less, a ratio of a weight average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, is 1.10 or more and 1.25 or less, and the refrigerating machine oil is used with a mildly flammable hydrofluorocarbon refrigerant.

Abstract: The present invention provides a refrigerating machine oil comprising: a base oil comprising an ester of a polyhydric alcohol and a fatty acid comprising 20 to 100% by mol of a branched fatty acid having 4 to 9 carbon atoms; and 0.2 to 0.5% by mass of a phenol-based antioxidant based on a total amount of the refrigerating machine oil, and the refrigerating machine oil being used with trifluoroethylene refrigerant.

Abstract: The present invention provides a refrigerating machine oil comprising, as a base oil, at least one oxygen-containing oil having a carbon/oxygen molar ratio of 2.5 or more and 5.8 or less, wherein the refrigerating machine oil is used with a refrigerant comprising 15% by mass or more of difluoromethane, 15% by mass or more of pentafluoroethane, 15% by mass or more of 2,3,3,3-tetrafluoropropene and 15% by mass or more of 1,1,1,2-tetrafluoroethane based on the total amount of the refrigerant.

Abstract: The refrigerating machine oil according to the present invention comprises a polyalkylene glycol represented by the following formula (1): R1—(OR3)n—OR2??(1) [R1 and R2 may be the same or different from each other and each represent a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, or an acyl group having from 2 to 5 carbon atoms, R3 represents an alkylene group having from 2 to 4 carbon atoms, n represents an integer such that a number average molecular weight of the polyalkylene glycol represented by the formula (1) is from 1000 to 2500] the polyalkylene glycol having a ratio of the weight average molecular weight Mw to the number average molecular weight Mn, Mw/Mn, of from 1.00 to 1.15, the refrigerating machine oil being used with a mildly flammable hydrofluorocarbon refrigerant.

Abstract: The invention provides a refrigerating machine oil comprising as a base oil at least one oxygen-containing oil having a carbon/oxygen molar ratio of 2.5 or more and 5.8 or less, and being used in combination with a (Z)-1,1,1,4,4,4-hexafluoro-2-butene refrigerant.

Abstract: The present invention provides a refrigerating machine oil comprising: a base oil containing an ester of dipentaerythritol with 2-methylbutanoic acid and n-pentanoic acid; and at least one epoxy compound selected from the group consisting of a glycidyl ester compound and a glycidyl ether compound, the refrigerating machine oil being used with a difluoromethane refrigerant.

Abstract: The present invention provides a refrigerating machine oil composition comprising an ester-based base oil, an epoxy compound, and a carbodiimide compound, the refrigerating machine oil composition being used with a refrigerant containing a fluoropropene in a refrigerating machine comprising a member containing polyethylene terephthalate and/or a member containing hydrogenated acrylonitrile butadiene rubber.