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.

The lubricating oil composition for a refrigerator of the present invention is a lubricating oil composition for a refrigerator that is used in combination with a refrigerant containing at least one fluorine-containing organic compound selected from compounds represented by the following molecular formula (A):

C.sub.pF.sub.rR.sub.s  (A)

wherein R represents Cl, Br, I, or H; p represents an integer of from 2 to 6; r represents an integer of from 1 to 12; and s represents an integer of from 0 to 11, provided that the molecule contains at least one carbon-carbon unsaturated bond, and the lubricating oil composition for a refrigerator contains a base oil and a cyclic organic compound having a cyclic hydrocarbon structure and having one or more non-conjugated double bond in a cyclic structure or a side chain thereof.

The present invention provides a refrigerating machine oil comprising: a base oil; a compound represented by the following formula (1):

##STR00001##

wherein R.sup.1 and R.sup.2 each independently represent a monovalent hydrocarbon group, R.sup.3 represents a divalent hydrocarbon group and R.sup.4 represents a hydrogen atom or a monovalent hydrocarbon group; and an epoxy compound.

A composition comprising a heat transfer portion and a lubricating portion, wherein the lubricating portion comprises one or more compounds according to formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br and I; Y is independently selected from the group consisting of F, Cl, Br and I; Z is independently selected from the group consisting of H, OH, (CW.sub.2).sub.PCW.sub.3, CY.sub.3, OCW.sub.3, O(CW.sub.2).sub.pCW.sub.3, OCW((CY.sub.2).sub.mCY.sub.3)CWCW.sub.2, polyalkylene glycol and polyolester; n is an integer from 2 to 250; m is an integer from 0 to 3; and p is an integer from 0 to 9.

The refrigeration oil composition for HFC-based refrigerants or HC-based refrigerants of the invention includes a product of the esterification of an alcohol ingredient including pentaerythritol and dipentaerythritol and a fatty acid ingredient including at least one of a linear or branched fatty acid having 5 carbon atoms and a linear or branched fatty acid having 6 carbon atoms and at least one of a linear or branched fatty acid having 8 carbon atoms and a linear or branched fatty acid having 9 carbon atoms, wherein at least one of the fatty acid having 5 carbon atoms and the fatty acid having 6 carbon atoms in the fatty acid ingredient accounts for 20 to 100% by mol of the total amount of the fatty acid ingredient, and either the alcohol ingredient or the fatty acid ingredient is a mixture.

The present invention relates to compounds according to formula (Ia) or formula (Ib);

##STR00001##

wherein each W is independently selected from the group consisting of H, F, Cl, Br, I and (CY.sub.2).sub.mCY.sub.3; each Y is independently selected from the group consisting of F, Cl, Br and I; each Z is independently selected from the group consisting of H, OH, (CW.sub.2).sub.pCW.sub.3, CY.sub.3, OCW.sub.3, O(CW.sub.2).sub.pCW.sub.3, OCW((CY.sub.2).sub.mCY.sub.3)CWCW.sub.2, (CW.sub.2).sub.pOH, polyalkylene glycol and polyolester; n is an integer from 2 to 49; m is an integer from 0 to 3; p is an integer from 0 to 9; the molecular weight average (M.sub.W) is ≤5500; and the polydispersity index is ≤1.45; compositions comprising these compounds and methods for their production.

The present invention is able to provide a lubricating oil composition for compression refrigerating machine having excellent thermal/chemical stability even when used for a compression refrigerating machine using a saturated fluorinated hydrocarbon refrigerant having a low carbon number and a low global warming potential, by using a refrigerant containing a saturated fluorinated hydrocarbon having from 1 to 3 carbon atoms, which uses, as a base oil, an oxygen-containing organic compound composed of at least one member selected from a polyoxyalkylene glycol, a polyvinyl ether, a copolymer of a poly(oxy)alkylene glycol and a polyvinyl ether, a copolymer of a poly(oxy)alkylene glycol monoether and a polyvinyl ether, and a polyol ester, each having a hydroxyl value of not more than 15 mgKOH/g.

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.

The invention provides a lubricating composition containing an aromatic compound and an oil of lubricating viscosity. The invention further relates to the use of the lubricating composition in an internal combustion engine. The invention further relates to the use of the aromatic compound as an antiwear agent.

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.