Abstract: A working fluid filled in a refrigerant circulation system comprising a compressor, a condenser, an expansion mechanism, an evaporator, and an accumulator, the working fluid comprising: a refrigerant; and a refrigerating machine oil, wherein the refrigerant comprises a hydrocarbon refrigerant having 2 to 4 carbon atoms, the refrigerating machine oil has a mixed aniline point of 20° C. or higher and 50° C. or lower and a viscosity index of 110 or more, an amount of the refrigerant dissolved in the working fluid is 40% by mass or less under conditions of a temperature of 80° C. and an absolute pressure of 2.8 MPa, and the refrigerating machine oil has a kinematic viscosity at ?10° C. of 200 mm2/s or more and 3000 mm2/s or less.

Abstract: A refrigerating machine oil having a flash point of 130° C. or lower and a carbon residue of 10% residual oil of 0.02% by mass or more.

Abstract: A refrigerating machine oil containing a hydrocarbon base oil having a 90% distillation temperature of 270° C. or lower.

Abstract: One aspect of the present invention is a refrigerating machine oil containing: a base oil; and a partial ester of a carboxylic acid and a polyhydric alcohol, wherein the carboxylic acid contains an unsaturated carboxylic acid.

Abstract: A lubrication method including lubricating a sliding member which contains at least one selected from the group consisting of a liquid crystal polymer and polyetheretherketone by using a lubricating oil composition which contains an ester as a lubricating base oil.

Abstract: The present invention provides a method for producing a refrigerating machine oil, comprising blending a hydrocarbyl hydrogen phosphite having an acid value of 100 mgKOH/g or less with a lubricating base oil or an oil composition containing a lubricating base oil, and a refrigerating machine oil obtained by the method.

Abstract: An aspect of the present invention provides a refrigerating machine oil containing: a lubricating base oil; and a polymer containing an unsaturated carboxylic acid ester as a monomer unit, wherein the unsaturated carboxylic acid ester contains an ester of an unsaturated carboxylic acid and an alcohol having a hydrocarbon group represented by the following formula (1): wherein x represents an integer of 5 to 18, and y represents an integer of 3 to 18.

Abstract: An aspect of the present invention provides a refrigerating machine oil containing: a lubricating base oil; a phosphorus-containing additive; and a polymer comprising an unsaturated carboxylic acid ester as a monomer unit.

Abstract: An aspect of the present invention provides a refrigerating machine oil containing an ester-based base oil, at least one epoxy compound selected from an alkyl glycidyl ether and an aryl glycidyl ether, and a phenol-based antioxidant, wherein a content of the epoxy compound is 0.7% by mass or more based on a total amount of the refrigerating machine oil, and the refrigerating machine oil is used with a refrigerant containing trifluoroiodomethane.

Abstract: An aspect of the present invention provides a refrigerating machine oil containing a mixed base oil of a first hydrocarbon base oil having a kinematic viscosity at 40° C. of less than 6 mm2/s and a second hydrocarbon base oil having a kinematic viscosity at 40° C. of 6 mm2/s or more, wherein a (A)/(B) ratio is more than 1 and 1.5 or less, wherein (A) is a kinematic viscosity at 40° C. of the mixed base oil, and (B) is the kinematic viscosity at 40° C. of the first hydrocarbon base oil.

Abstract: A refrigerating machine oil containing: a lubricating base oil; and 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 hydrogen atom or a monovalent hydrocarbon group, and the refrigerating machine oil having a kinematic viscosity at 100° C. of 0.5 mm2/s or more and 2.5 mm2/s or less.

Abstract: The present invention provides a refrigerating machine oil comprising a hydrocarbon-based base oil having a viscosity index of 120 or less, and the refrigerating machine oil being used with a 1-chloro-2,3,3,3-tetrafluoropropene refrigerant.

Abstract: A refrigerating oil comprising a lubricating base oil, a first extreme pressure agent containing sulfur and phosphorus as constituent elements and a second extreme pressure agent containing phosphorus but not containing sulfur as constituent elements, and having a kinematic viscosity at 100° C. of 0.5 mm2/s or more and 2.5 mm2/s or less.

Abstract: The present invention provides a refrigerating machine oil comprising a lubricating base oil and at least one selected from the group consisting of an amine salt of phosphonic acid and an amine salt of phosphonic acid monoester, and a method for producing the same.

Abstract: A working fluid composition for a refrigerating machine, containing: a refrigerant containing trifluoroiodometbane; and a refrigerating machine oil containing a polyol ester and a hindered phenol compound, wherein a content of the hindered phenol compound is 0.6 to 10% by mass based on a total amount of the refrigerating machine oil.

Abstract: A working fluid composition for a refrigerating machine, containing: a refrigerant containing trifluoroiodomethane; and a refrigerating machine oil containing a complex ester synthesized from a polyhydric alcohol, a polybasic acid, and at least one selected from a monohydric alcohol and a monocarboxylic fatty acid.

Abstract: The present invention provides a refrigerating machine oil containing a lubricating base oil, a dialkyl hydrogen phosphite having two alkyl groups having 1 to 12 carbon atoms in the molecule, and an epoxy compound.

Abstract: A method for operating a refrigerant circulation system comprising a compressor, a condenser, an expansion mechanism, and an evaporator connected in this order with piping, wherein a refrigerant comprising trifluoroiodomethane is used as a refrigerant; a refrigerating machine oil comprising, as a base oil, a polyolester synthesized from a polyhydric alcohol and fatty acids, with a proportion of a fatty acid having 9 carbon atoms in the fatty acids being 65 mol % or less is used as a refrigerating machine oil; and a temperature of an entire area of the refrigerant circulation system is kept at 160° C. or lower.

Abstract: One aspect of the present invention is a refrigerating machine oil containing: a base oil containing an ester of an alcohol and a fatty acid; 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 hydrogen atom or a monovalent hydrocarbon group, and the refrigerating machine oil having a kinematic viscosity at 40° C. of 10 mm2/s or less.

Abstract: One aspect of the present invention is a refrigerating machine including a refrigerant circulation system including a compressor, a condenser, an expansion mechanism, and an evaporator, and the refrigerant circulation system being filled with a refrigerant and a refrigerating machine oil, wherein the refrigerating machine oil contains: a first base oil having a compatible region with the refrigerant in a range of a temperature of 30° C. or lower and an oil ratio of 1 to 80% by mass; and a second base oil having a kinematic viscosity at 40° C. lower than the first base oil and having a narrower compatible region with the refrigerant than the first base oil.