A lubricant composition contains a lubricant base oil, (A) a detergent containing magnesium, (B) a compound containing boron, and (C) a zinc dialkyl dithiophosphate. The amount of component (A) is in the range of 200 to 1200 mass ppm [Mg] based on the mass of the lubricant composition, and the amount of component (C) is in the range of 300 to 1000 mass ppm [P] based on the mass of the lubricant composition. Component (C) includes a zinc dialkyl dithiophosphate having a primary alkyl group or a secondary alkyl group; the lubricant composition includes zinc dialkyl dithiophosphate having a secondary alkyl group; the mass ratio of the zinc dialkyl dithiophosphate having a primary alkyl group and the zinc dialkyl dithiophosphate having a secondary alkyl group is from 70:30 to 0:100; and the concentration of [B] is from 100 to 300 mass ppm based on the mass of the lubricant composition.

A composition including at least one lubricant including polyol esters and a refrigerant fluid F including 1-chloro-3,3,3-trifluoropropene. Also, a composition including at least one lubricant based on polyol esters and a refrigerant fluid F including 1-chloro-3,3,3-trifluoropropene and at least one C3 to C6 alkene stabilizing compound including a single double bond. Also, different uses of the compositions.

The present invention relates to a polyalphaolefin having a uniform structure and a method of preparing the same, and more particularly to a method of preparing polyalphaolefin having a uniform comb-like structure by minimizing the formation of short chain branches, which deteriorate the properties of lubricant base oil, using a homogeneous single-active-site metallocene catalyst, an organometallic compound cocatalyst and an organoboron compound promoter.

A base oil includes an ester compound obtained by reacting a fatty acid component and a monohydric alcohol component. The fatty acid component includes a C.sub.4-C.sub.28 fatty acid. The monohydric alcohol component includes at least one C.sub.4-C.sub.22 straight chain monohydric alcohol and at least one C.sub.4-C.sub.22 branched chain monohydric alcohol. A lubricant oil composition including the base oil is also disclosed.

A base oil includes an ester compound obtained by reacting a fatty acid component and a monohydric alcohol component. The fatty acid component includes a C.sub.4-C.sub.28 fatty acid. The monohydric alcohol component includes at least one C.sub.4-C.sub.22 straight chain monohydric alcohol and at least one C.sub.4-C.sub.22 branched chain monohydric alcohol. A lubricant oil composition including the base oil is also disclosed.

Provided is a mineral base oil having a kinematic viscosity at 40 C. of 4.0 mm.sup.2/s or more and less than 6.0 mm.sup.2/s, a kinematic viscosity at 100 C. of 1.0 mm.sup.2/s or more and less than 2.0 mm.sup.2/s, and a flash point of 140 C. or higher. A lubricating oil composition containing the mineral base oil has a high flash point while having a low viscosity and thus having excellent fuel-saving performance when used as a driving system oil and the like.

The invention provides a lubricating composition comprising an oil of lubricating viscosity and synergistic mixture of a functionalized ethylene--olefin copolymer, a poly(meth)acrylate block polymer having a substantially oil soluble block and a substantially oil insoluble block. The invention also provides a method of lubricating a mechanical device using such a lubricating composition.

This lubricant base oil includes a condensation ester of an alcohol (A) and a carboxylic acid (B), wherein the alcohol (A) contains a polyhydric alcohol represented by general formula (1) (in formula (1), R.sup.1-R.sup.4 independently represent a hydrogen atom, a methyl group, or a hydroxyl group, and at least two of R.sup.1-R.sup.4 each represents a hydroxyl group), and the carboxylic acid (B) contains a C4-C8 cycloalkane monocarboxylic acid. The lubricant base oil has excellent heat resistance and lubricating property.

A viscosity index improver containing a copolymer (A) whose essential constituent monomer is a monomer (a) having a number average molecular weight of 800 to 4,000 represented by the following formula (1), the copolymer (A) having a solubility parameter in the range of 9.00 to 9.40:

##STR00001##

wherein R.sup.1 is a hydrogen atom or a methyl group; X.sup.1 is a group represented by O, O(AO).sub.m, or NH, AO is a C2-C4 alkyleneoxy group, m is an integer of 1 to 10, each AO may be the same or different when m is 2 or more, and the (AO).sub.m moieties may be randomly bonded or block-bonded; R.sup.2 is a residue after removal of one hydrogen atom from a hydrocarbon polymer whose essential constituent monomer is butadiene in which the butadiene is present in a proportion of 50% by weight or more based on the weight of R.sup.2, or after removal of one hydrogen atom from a polymer formed by partial hydrogenation of the hydrocarbon polymer; and p represents a number of 0 or 1.

A fluid contains a base oil consisting of an alcohol-initiated polyalkylene glycol where polyalkylene glycol component is selected from a homopolymer of 1,2-butylene oxide and copolymer of 1,2-butylene oxide and propylene oxide; a glycerol-initiated unsaturated ester that is free of tertiary carbon atoms and quaternary carbon atoms; and an antioxidant.