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.

The present invention provides a working fluid composition for a refrigerating machine, comprising: a refrigerating machine oil comprising, as a base oil, a mixed ester of (A) a complex ester obtainable by synthesis of at least one polyhydric alcohol selected from neopentyl glycol, trimethylolpropane and pentaerythritol, a C6-C12 polybasic acid, and a C4-C18 monohydric alcohol or a C4-C18 monocarboxylic fatty acid, and (B) a polyol ester obtainable by synthesis of at least one polyhydric alcohol selected from neopentyl glycol, trimethylolpropane, pentaerythritol and dipentaerythritol, and a C4-C18 monocarboxylic fatty acid, in a mass ratio of (A) the complex ester/(B) the polyol ester of 5/95 to 95/5; and a hydrocarbon refrigerant having 3 or 4 carbon atoms, wherein a refrigerant dissolved viscosity, at a temperature of 80° C. and an absolute pressure of 1.5 MPa, is 1.0 mm.sup.2/s or more.

A lubricant film-forming composition includes as a composition: 40 to 80 mass % of a base oil consisting of one or more selected from pentaerythritol fatty acid ester and trimethylolpropane fatty acid ester; 5 to 20 mass % of a solidifying agent consisting of paraffin wax; and 10 to 40 mass % of a solid lubricant consisting of one or more selected from alkali metal salt of hydroxystearic acid and alkali earth metal salt of hydroxystearic acid. A total content of the base oil, the solidifying agent, and the solid lubricant is 85 mass % or more and 100 mass % or less, and the lubricant film-forming composition does not contain heavy metals.

The present invention relates to conveyor lubricant compositions including an emulsion of a lipophilic compound and also including an emulsifier and/or an anionic surfactant. The present invention also relates to methods employing such lubricant compositions. In an embodiment, the method includes applying the present lubricant composition to a conveyor with a non-energized nozzle.

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.

The present invention relates to esters of at least one polyol and of a mixture of fatty acids comprising at least one C.sub.5-C.sub.12 saturated fatty acid and at least one C.sub.10-C.sub.12 unsaturated fatty acid.

Compositions, systems and methods for introducing lubricants, and additives, that are designed to work with environmentally friendly refrigerants into vehicle heat management systems including passenger compartment air conditioning (A/C) systems are disclosed. Methods for charging lubricants and specific additives using environmentally desirable (low GWP) refrigerant or refrigerant blend compositions into an environmentally friendly system, such as a system that uses HFO-1234yf, are also disclosed.

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.

A lubricating oil composition for refrigerating machines contains a base oil and an additive in a form of a hydrocarbon compound having a biphenyl structure or a stilbene structure. When the present lubricating oil composition for refrigerating machines is used in refrigerating equipment such as an open-type automobile air-conditioner, an electric automobile air-conditioner, a gas heat pump, other air-conditioning equipment, a refrigerating machine, a vending machine, a showcase, a water-heating system and a refrigerating/heating system, it is possible to detect the leakage of a refrigerant with a long-lasting stability. Therefore, when an unsaturated chlorofluorocarbon refrigerant with a poor stability is used in the above-listed equipment, the present lubricating oil composition for refrigerating machines is significantly advantageous.

The present invention provides a working fluid composition for a refrigerating machine, comprising: a refrigerating machine oil comprising, as a base oil, a mixed ester of (A) a complex ester obtainable by synthesis of at least one polyhydric alcohol selected from neopentyl glycol, trimethylolpropane and pentaerythritol, a C6-C12 polybasic acid, and a C4-C18 monohydric alcohol or a C4-C18 monocarboxylic fatty acid, and (B) a polyol ester obtainable by synthesis of from at least one polyhydric alcohol selected from neopentyl glycol, trimethylolpropane, pentaerythritol and dipentaerythritol, and a C4-C18 monocarboxylic fatty acid, in a mass ratio of (A) the complex ester/(B) the polyol ester of 5/95 to 95/5; and tetrafluoropropene as a refrigerant, wherein a refrigerant dissolved viscosity, at a temperature of 80° C. and an absolute pressure of 1.6 MPa, is 1.5 mm.sup.2/s or more.