Provided are: a lubricant base oil capable of achieving both a high traction coefficient and an excellent low-temperature fluidity at a higher level and having a high flash point, which contains a ring-containing compound having at least (i) a crosslinked bicyclic ring where two rings are bonded while sharing 3 or more carbon atoms, and (ii) an acyloxy group or a hydrocarbyloxycarbonyl group each containing a branched hydrocarbon group with a main chain having 4 or more carbon atoms, a lubricating oil composition containing the lubricant base oil, and a continuously variable transmission using the lubricating oil composition.

A lubricating oil composition for a push-belt continuously variable transmission includes: (A) a lubricant base oil including at least one wax-isomerized base oil, and having a specific kinematic viscosity and a specific viscosity index; (B) a poly(meth)acrylate having a specific weight average molecular weight; (C) a boron-containing succinimide compound; (D) a borate ester compound; and (E) an overbased calcium detergent, wherein the composition has a kinematic viscosity at 40 C. of no more than 25 mm.sup.2/s; a viscosity index of no less than 180; and the ratio of a boron content to a calcium content of 0.5 to 1.5.

A sliding member has a sliding surface sliding under a wet condition in which a lubricant oil exists. The sliding surface is coated with a laminate film comprising an upper layer and a lower layer. The lower layer comprises hydrogen-free amorphous carbon (hydrogen-free DLC) and carbon particles dispersed on or in the hydrogen-free DLC. The hydrogen-free DLC has a hydrogen content of 5 atom % or less when the lower layer as a whole is 100 atom %. The upper layer comprises boron-containing amorphous carbon (B-DLC) and has protrusions on a surface side of the upper layer along the carbon particles of the lower layer. The B-DLC has a boron content of 1-40 atom % when the upper layer as a whole is 100 atom %. The protrusions have a particle diameter of 0.5-5 m and exist with a density of 20 protrusions/100 m.sup.2 or more.

Provided is a lubricating oil composition, which has low viscosity but also prolonged anti-shudder life without reduction of intermetallic friction coefficient. The lubricating oil composition is characterized in comprising (A) a lubricating base oil, and (C) (C-1) a borated succinimide compound with a mass average molecular weight of 4,000-7,000 and (C-2) a borated succinimide compound with a mass average molecular weight of greater than 7,000-10,000.

A composition obtained by reacting an O,O-dialkyldithiophosphoric acid with a hydroxyalkyl acrylate or a hydroxyalkyl methacrylate, and reacting the product thereof with a dialkylphosphite provides good antiwear protection.

A traction fluid comprising a blend of 2,3-dicyclohexyl-2,3-dimethylbutane (HAD) and 2,3-dicyclohexyl-2,3-dimethylbutane (iso-HAD) is found to have a lower viscosity at low temperatures when compared to a traction fluid having only HAD or only iso-HAD as a base fluid with no compromise to traction coefficient. The traction fluid may comprise additives. The traction fluid usually comprises HAD:isoHAD between about 8:1 to about 1:3. Further, the HAD:iso-HAD traction fluid blend is produced by a method of simultaneous co-production of hydrogenated HAD and hydrogenated iso-HAD from an alpha styrene dimer and an iso-HAD precursor with a yield of about 90% in a method that does not require a purification step.

A lubricant composition of an oil of lubricating viscosity and a phosphite ester reaction product of a monomeric phosphorous acid or an ester thereof with a first alkylene diol having two hydroxy groups in a 1,4 or 1,5 or 1,6 relationship and a second, alkyl-substituted, diol being a substituted 1,3-propylene diol, exhibits good wear and frictional performance.

The invention relates to low molecular weight hydrogenated polybutadienes and to a method for the preparation of these polymers. The invention is also directed to lubricant compositions comprising these polymers and uses thereof.

A traction fluid comprising a blend of 2,3-dicyclohexyl-2,3-dimethylbutane (HAD) and 2,3-dicyclohexyl-2,3-dimethylbutane (iso-HAD) is found to have a lower viscosity at low temperatures when compared to a traction fluid having only HAD or only iso-HAD as a base fluid with no compromise to traction coefficient. The traction fluid may comprise additives. The traction fluid usually comprises HAD:isoHAD between about 8:1 to about 1:3. Further, the HAD:iso-HAD traction fluid blend is produced by a method of simultaneous co-production of hydrogenated HAD and hydrogenated iso-HAD from an alpha styrene dimer and an iso-HAD precursor with a yield of about 90% in a method that does not require a purification step.

Traction fluid additive combination that is usable with any traction fluids base stock is provided. To optimize the traction, low temperature viscosity and shear stability performance, a combination of a polyisobutene and a polymethacrylate may be added to a base oil to obtain a traction fluid with good low temperature viscosity without degrading the shear strength properties of the fluid. To minimize foaming of the traction fluid, a combination of one, two, or more anti-foaming agents may be added to the fluid in addition to a standard additive package.