Provided is a lubricating grease used for lubricating mechanical elements having a reciprocating sliding ball interposed therebetween and maintaining flaking resistance even under a high load in mechanical elements having a reciprocating sliding ball interposed therebetween. The present invention therefore provides a grease composition comprising a base oil (a), a diurea compound (b), an amide compound (c), and a thiophosphorous compound or a thiophosphoric acid ester compound (d), wherein the diurea compound (b) includes a compound represented by Formula (1) R.sub.1—NHCONH—R.sub.2—NHCONH—R.sub.3 (1) wherein R.sub.1 and R.sub.3 represent an acyclic aliphatic hydrocarbon group having from 8 to 20 carbon atoms, and R.sub.2 represents a diphenylmethane group.

The invention relates to lubricating greases based on alkali metal soaps and/or earth-alkali metal soaps and metal complex soaps based on (R)-10-hydroxyoctadecanoic acid and to the use thereof.

A refrigeration machine oil composition may have good lubricating properties and sufficiently reduce friction even when a base oil containing a low-viscosity mineral oil is used and/or prevent seizure between sliding members. Such refrigeration machine oil compositions may contain a base oil containing a mineral oil, (A) at least one type selected from a specific neutral phosphate ester and an amine salt thereof, and (B) at least one type selected from a specific acidic phosphate ester, an acidic phosphite ester, and an amine salt thereof, and having a kinematic viscosity at 40° C. in a range of from 1.0 to 6.0 mm.sup.2/s.

Disclosed is a lubricating oil composition capable of having a good balance of electrical insulation, seizure resistance and wear resistance. In particular, the lubricating oil composition comprises: (A) a lubricant base oil; (B) an alkaline earth metal detergent; (C) a triazole-based compound represented by the following general formula (1) or (2): ##STR00001##
wherein R.sup.1-R.sup.6 are as defined herein; (D) at least one sulfur-containing compound selected from the group consisting of a sulfur-containing heterocyclic ether compound and a sulfide compound; and (E) an ashless dispersant.

There is provided a grease composition for improving the chemical stability of the grease composition and increasing the fatigue life of a member in which the grease composition is used. The problems can be solved by a grease composition including a poly-α-olefin; a urea-based thickener; molybdenum dithiophosphate; and barium sulfonate, wherein a difference between an SP value of the urea-based thickener and an SP value of the poly-α-olefin is 3.5 or less.

A lubricating oil composition excellent in the wear resistance and a refrigerator oil composition excellent in the oxidation stability using the lubricating oil composition are provided by a lubricating oil composition containing a base oil (A) and a phosphine derivative (B) having one or more oxygen atom in a molecule.

A lubricant composition comprising: at least one base oil; and from 0.1% to 30% by weight of a phosphorus ester compound of formula (A):

##STR00001## in which s is 0 or 1; and the radicals X represent, independently of each other, —OR′ or R′ moieties, where R′ represents hydrogen or a linear or branched hydrocarbon moiety, preferably having from 1 to 36 carbon atoms, with the proviso that: when s is 0, the three X radicals represent —OR′ moieties, and when s is 1, at least two of the three X radicals are —OR′ moieties.

Disclosed is an additive for lubricating oil, which comprises a phosphite ester compound (A) having a specific structure and a phosphite ester compound (B) having a specific structure, wherein a mass ratio of the phosphite ester compound (A) to the phosphite ester compound (B) (phosphite ester compound (A):phosphite ester compound (B)) is 99:1 to 80:20. According to the present invention, it is possible to provide an additive for lubricating oil, capable of imparting wear resistance and demulsibility with respect to a base oil for lubricating oil, and to impart durability even in the presence of water.

Disclosed is an additive for lubricating oil, which comprises a phosphite ester compound (A) having a specific structure and a phosphite ester compound (B) having a specific structure, wherein a mass ratio of the phosphite ester compound (A) to the phosphite ester compound (B) (phosphite ester compound (A):phosphite ester compound (B)) is 99:1 to 80:20. According to the present invention, it is possible to provide an additive for lubricating oil, capable of imparting wear resistance and demulsibility with respect to a base oil for lubricating oil, and to impart durability even in the presence of water.

The present invention relates to a polyester product having a relatively high atypical density of greater than 1 g/cm.sup.3 at 25° C., the polyester product comprises the reaction product of one or more C2 to C12 polybasic acid and one or more polyol. The invention also relates to methods of making the polyester product, compositions containing or comprising the polyester product and the use of such compositions. More especially, the polyester containing compositions may advantageously be utilised in aqueous environment applications, or other applications, where environmental containment is an important consideration.