The present disclosure provides a lubricating oil composition which has a viscosity much lower than that of a conventional lubricating oil composition, and which is excellent in metal fatigue life, wear resistance and electrical insulating properties. The lubricating oil composition according to the present disclosure comprises: (A) a lubricating base oil; and (B) from 0.6 to 4.0% by weight, based on the total weight of the lubricating oil composition, of a polydiene having a number average molecular weight of from 500 to 3,000 and containing a functional group on at least one end thereof. The above described lubricating oil composition does not comprise a viscosity index improver, and has a kinematic viscosity at 100 C. of not less than 1 and less than 5 mm.sup.2/s.

The present invention relates to a lubricant base oil containing an aromatic ester lubricant represented by Chemical Formula 1 and to a method for preparing the aromatic ester lubricant. By containing an aromatic ester lubricant, the lubricant base oil exhibits an excellent dispersibility and fluidity and is ecofriendly due to a high biodegradability. In addition, the method for preparing the aromatic ester lubricant does not generate such toxic substances as S, N, aromatic compounds and heavy metals and enables an easy control of the physical properties of a desired lubricant base oil by selecting a suitable alcohol compound to be introduced for an esterification reaction. ##STR00001##

A transformer oil basestock is disclosed that includes at least 99 wt % of naphthenes and paraffins, based on the total weight of the transformer oil basestock, wherein the weight ratio of naphthenes to paraffins is at least 1, as measured by GC-MS, and wherein the paraffins consist essentially of isoparaffins, as determined by GC-FID. In addition, a transformer oil composition is disclosed that includes the transformer oil basestock, an anti-gassing agent and an antioxidant.

Disclosed is a cutting oil composition, which is vastly superior in view of layer separation, dispersibility, viscosity, ingot-cleaning time after sawing, and wafer warpage after sawing, compared to conventional cutting oil compositions, and which includes mineral oil that is highly hydrogenated, as represented by Chemical Formulas 1 to 3, bentonite clay as a thickener, and glycerol trioleate as a dispersant. A cutting method using the cutting oil composition is also provided.

Provided is a refrigerating machine oil composition for a mixed refrigerant comprising difluoromethane, the composition comprising a polymer (A) below and an ester (B) of polyhydric alcohol(s) with aliphatic monocarboxylic acid(s). The polymer (A): a polymer which is obtained by polymerizing monomer(s) consisting of at least one monomer of monosubstituted ethylenes and disubstituted ethylenes, and in which a ratio of a monomer represented by the following general formula (I): ##STR00001##
wherein R.sup.1 represents an alkyl group having 1 to 14 carbon atoms, R.sup.2 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and the sum of carbon numbers in R.sup.1 and R.sup.2 is 2 to 14, is 75 to 100% by mass based on a total mass of monomers constituting the polymer.

A lubricant composition is described. The novel lubricant composition has superior thermal stability, and can reduce the need to replenish the lubricant. The lubricant composition includes at least a soap component, a thickener component, an oil component, and a spherical polyolefin component (optionally Microthene). The spherical polyolefin component includes polyolefin microparticles.

A lubricant contains alcohol initiated propylene oxide homopolymer, an oil soluble polyalkylene glycol other than the alcohol initiated propylene oxide homopolymer, and a calcium salt of dinonylnaphthalene sulphonate where the lubricant is further characterized by containing less than ten weight-percent of polyol esters based on total lubricant weight is useful as a lubricant for compressors.

This invention provides A methacrylic copolymer (C) comprising 25 to 35 mass % of a methyl methacrylate unit (A), and 75 to 65 mass % of an alkyl methacrylate ester unit (B) containing an alkyl group having 10 to 36 carbon atoms, the methacrylic copolymer having (a) a weight average molecular weight of 10,000 to 500,000, (b) a molecular weight distribution (Mw/Mn) of 1.01 to 1.60, (c) a triad syndiotacticity (rr) of 65% or more, and (d) a solubility of 5.0 mass % or more at 0 C. in at least one lubricant base oil (D) selected from the group consisting of API groups III, III+, and IV.

The present invention provides a refrigerating machine oil comprising a base oil; a sulfide compound; and an orthophosphoric acid ester, wherein a content of the sulfide compound is 0.01 to 2.0% by mass and a content of the orthophosphoric acid ester is 0.1 to 5.0% by mass, based on a total amount of the refrigerating machine oil, and the refrigerating machine oil having a kinematic viscosity at 40 C. of 3 to 500 mm.sup.2/s.

The purpose of the present invention is to provide organometallic salt compositions that are useful as lubricant additives and/or in lubricant additive compositions to reduce friction and wear, and also have improved solubility in all four types of hydrocarbon base oils (Groups I-IV) at a variety of concentrations and under a variety of conditions. The organometallic salt composition is derived from at least one long chain monocarboxylic acid and a single metal in combination with at least one short or medium branched-chain monocarboxylic acid. The compositions are particularly useful in combination with activated complexes comprising a first metal component, a second metal component and particles comprising the first metal component.