A refrigerator oil composition with a base oil (A), and a first phosphorus compound (B). The first phosphorus compound (B) is a first phosphite ester (B1) represented by formula (1) and a second phosphite ester (B2) represented by formula (2):

(R.sup.11—O—).sub.n—PO—R.sup.12).sub.3-n   (1)

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A method of producing a refrigerator oil composition by mixing a base oil (A) with a first phosphorus compound (B). A refrigerator mixture composition includes the refrigerator oil composition and a refrigerant.

The present disclosure describes lubricant compositions effective to minimize average engine sludge through selection of lubricant additives that control the total nitrogen as well as the origin of the nitrogen in the lubricant composition. In aspects, the lubricant compositions herein include at least a base oil of lubricating viscosity, a dispersant system, and at least one antioxidant.

A mixed composition including a refrigerant including at least one unsaturated fluorinated hydrocarbon compound selected from the compound having a formula C.sub.xF.sub.yH.sub.z, x is an integer of 2 to 6, y is an integer of 1 to 11, z is an integer of 1 to 11, and the compound has at least one unsaturated carbon-carbon bond, and a refrigerator oil including a base oil (A); a phosphorus-based extreme pressure agent (B); a decomposition inhibitor (C) that inhibits the decomposition of the unsaturated fluorinated hydrocarbon in the presence of an iron; and an antioxidant (D), wherein (C) controls the amount of fluorine in the refrigerator oil composition at 30 ppm by mass or less after mixing the refrigerator oil with R1234yf at a mass ratio of 1:1, and subjecting the mixture to an autoclave test at 175° C. for 336 hours with a metal catalyst including iron, copper, and aluminum.

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.

A lubricating oil composition may be capable of satisfactorily exhibiting sludge prevention properties and wear resistance evaluated by scoring resistance and seizure resistance over a long period of time. Such a lubricating oil composition may contain: a base oil (A); a hindered phenol-based antioxidant (B); one or more imide compounds (C) selected from the group consisting of a monoimide compound (C1) and a bisimide compound (C2); and an extreme pressure agent (D), in which the hindered phenol-based antioxidant (B) is 2,6-di-tert-butylphenol, the monoimide compound (C1) is one or more selected from the group consisting of an alkenyl succinic monoimide compound and an alkyl succinic monoimide compound, and the bisimide compound (C2) is one or more selected from the group consisting of an alkenyl succinic bisimide compound and an alkyl succinic bisimide compound.

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 mm.sup.2/s and a second hydrocarbon base oil having a kinematic viscosity at 40° C. of 6 mm.sup.2/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.

The invention relates to a grease composition having a base oil and a thickener that includes hydrophilic metal oxide particles and one or more amines that contain one or more unsaturated C—C bonds and/or at least one OH group. The hydrophilic metal oxide particles have a BET specific surface area of at least 10 m.sup.2/g and at least 80% of the hydrophilic metal oxide particles have a particle size in the range of from 5 nm to 900 μm. The amount of the thickener is in the range of from 0.1-40% by weight, based on the total weight of the grease composition. The invention further relates to methods for manufacturing the grease composition, and the use of the grease composition for lubricating bearings, gears and couplings.

The invention relates to a grease composition including a base oil and a thickener that provides hydrophilic metal oxide particles and one or more amides which contain one or more unsaturated C—C bonds and/or at least one OH group. The hydrophilic metal oxide particles have a BET specific surface area of at least 10 m2/g and at least 80% of the hydrophilic metal oxide particles have a particle size in the range of from 5 nm to 900 μm. The amount of the thickener is in the range of from 0.1-40% by weight, based on the total weight of the grease composition. The invention further relates to methods for manufacturing the grease composition, and the use of the grease composition for lubricating bearings, gears and couplings.

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):

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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.