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 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.

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.

A refrigeration cycle apparatus includes refrigerant circuits in which a high pressure shell compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are connected; a mixed refrigerant containing 1,1,2-trifluoroethylene and a refrigerant other than 1,1,2-trifluorothylene and circulating through the refrigerant circuits; and a refrigerating machine oil enclosed in the refrigerant circuits and adjusted such that 1,1,2-trifluoroethylene will be more soluble therein than the other refrigerant is.

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 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.

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.

A working fluid composition for a refrigerating machine comprises a refrigerant comprising monofluoroethane and a refrigerating machine oil comprising, as a base oil, at least one selected from a mineral oil having % C.sub.N in an n-d-M ring analysis of 10 to 60 and a pour point of −15° C. or lower and a synthetic hydrocarbon oil having a pour point of −15° C. or lower, and the refrigerating machine oil having a kinematic viscosity at 40° C. of 3 to 500 mm.sup.2/s.

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):

##STR00001##

wherein R.sup.1, R.sup.2 and R.sup.3, which may be the same as or different from each other, represent a hydrogen atom or a hydrocarbon group; and R.sup.4 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.