An additive for a lubricating composition includes an ionic tetrahedral borate compound which includes a cation and a tetrahedral borate anion having a boron atom, the boron atom has at least one aliphatic bidentate di-oxo ligand. The cation may be selected to provide detergent and/or dispersant and/or antioxidant properties to a lubricating composition.

The invention relates to polymeric-inorganic nanoparticles and preparation processes thereof. The invention also relates to a powder, concentrate and lubricating composition comprising these polymeric-inorganic nanoparticles, to a method of dispersing nanoparticles in lubricating oil, as well as the use of these polymeric-inorganic particles in an oil lubricant formulation to reduce pour point, friction and wear.

Provided is a lubricating oil composition comprising a major amount of an oil of lubricating viscosity and a detergent system, and a method of improving brake and clutch capacity while maintaining low torque variation at low speed of a tractor hydraulic system.

To provide a lubricating oil composition for a shock absorber, an additive for friction adjustment, a lubricating oil additive, a shock absorber, and a method for adjusting friction of a shock absorber lubricating oil, capable of achieving both operation stability and riding comfort. A lubricating oil composition for a shock absorber contains a base oil and a friction adjusting agent, in which the friction adjusting agent contains zinc dithiophosphate and pentaerythritol.

Acrylate-olefin copolymers and a method for the preparation of these copolymers are provided. Lubricant compositions can contain the aforementioned copolymers. The copolymers are useful as a lubricant additive or a synthetic base fluid in a lubricating oil composition, preferably in a gear oil composition, a transmission oil composition, a hydraulic oil composition, an engine oil composition, a marine oil composition, an industrial lubricating oil composition or in grease.

A lubricating oil additive composition containing a polymer-based compound may be excellent in solubility in a mineral oil and wear resistance, and favorable as a friction modifier. A lubricating oil composition may contain the additive composition. Such a lubricating oil additive composition may contain a copolymer (X) containing: (a) a structural unit derived from a monomer (A) having a (meth)acryloyl group and a linear or branched alkyl group having 6 to 24 carbon atoms; (b) a structural unit derived from a monomer (B) having a (meth)acryloyl group and a polar group; and (c) a structural unit derived from a monomer (C) having a polymerizable functional group and a cyclic structure group. The copolymer (X) may have a content of the structural unit (a) of 43% by mol or more based on the total structural units of the copolymer (X), and a mass average molecular weight (Mw) of 5,000 to 90,000.

An object of the present invention is to provide a lubricant base oil for power transmission (in particular, a lubricant base oil for traction drives) having a high traction coefficient and a high flash point. The present invention relates to a lubricant base oil for power transmission comprising an alicyclic dicarboxylic acid diester compound represented by general formula (1):

##STR00001##

wherein R.sup.1 to R.sup.5 are the same or different, and each represents hydrogen or linear or branched C.sub.1-4 alkyl, and two R.sup.1, two R.sup.2, two R.sup.3, two R.sup.4, and two R.sup.5 may respectively be the same or different; and ring A is

##STR00002##

wherein R represents C.sub.1-3 alkyl, and n represents 0, 1, or 2; when n represents 2, R may be the same or different.

A lubricating composition includes an oil of lubricating viscosity and a low-ash additive system including a low molecular weight amine with a Total Base Number of at least 150, and an N-substituted hydrocarbyl-substituted succinimide dispersant. The low-ash additive system provides the lubricating composition with a significant boost in TBN without substantially lowering the flashpoint. The composition is particularly suited to use as a marine diesel engine lubricant.

A lubricating oil including a lubricating oil base stock as a major component, and one or more lubricating oil additives having at least one protected active group, as a minor component. The one or more lubricating oil additives having at least one protected active group are converted into one or more lubricating oil additives having at least one unprotected active group in the lubricating oil in-service in an engine or other mechanical component. Compositions including one or more lubricating oil additives having at least one protected active group. A method for improving solubility of one or more lubricating oil additives in a lubricating oil. A method for improving oxidative stability of a lubricating oil and extending performance life of one or more lubricating oil additives. A method for improving friction control in an engine or other mechanical component lubricated with a lubricating oil.

A lubricant base oil which contains an ester. The ester constituting the lubricant base oil includes: a component (A) derived from pentaerythritol in a molar percentage A.sub.mol % of 20 to 30 mol %; a component (B) derived from a straight-chain fatty acid having a carbon number of 14 to 22 in a molar percentage B.sub.mol % of 55 to 79 mol %; and a component (C) derived from adipic acid in a molar percentage C.sub.mol % of 1 to 15 mol %. A molar ratio (C.sub.mol/C.sub.mol) of the component (C) derived from adipic acid and the component (B) derived from the straight-chain fatty acid having a carbon number of 14 to 22 is 0.02 to 0.25, and the ester has a hydroxyl value of 10 to 100 mgKOH/g.