A lubricant composition of an oil of lubricating viscosity; an esterified copolymer with a backbone comprising units derived from (i) an α-olefin monomer of at least about 6 carbon atoms and (ii) an ethylenically unsaturated carboxylic acid in a mole ratio of 1:3 to 3:1; and a polymer comprising olefin monomer units of 3 to 5 carbon atoms, wherein at least 50 percent by weight of such units contain fewer than 6 carbon atoms and wherein less than 5 percent by weight of such units are ethylene monomer units; exhibits good power transfer efficiency and elastohydrodynamic film thickness.

Provided are: a lubricating oil composition for transmissions having a long fatigue life and a low viscosity, which contains a base oil and an olefin copolymer and in which the mass-average molecular weight of the olefin copolymer is 5,000 or more and 30,000 or less, the hydrodynamic radius of the olefin copolymer is 1.00 nm or more and 5.00 nm or less, and the content of the olefin copolymer based on the total amount of the composition is 1.0% by mass or more and 8.0% by mass or less; and a production method for the composition, a lubricating method using a lubricating oil composition for transmissions, and a transmission.

The invention provides a lubricating composition comprising an oil of lubricating viscosity and synergistic mixture of a functionalized ethylene-α-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.

A lubricant composition said composition comprising at least one base oil and from 1 to 70 wt % of at least one friction modifying additive, wherein the composition is such that the viscosity reversibly reduces at a pressure from 50 MPa to 3 GPa. A mechanical system comprising the lubricant composition; use of the lubricant composition and methods of reducing friction using the lubricant composition are also disclosed.

The presently disclosed technology relates to a nano-additives to improve the performance of lubricants, oils, and greases. More specifically, the presently disclosed technology relates to applying capped metal oxide nanoparticles, such as capped zirconia nanoparticles, in the lubricants to produce a tribofilms on the lubricating surfaces to provide wear protection to the said surfaces. Also, the interaction of the capped zirconia nanoparticles with other commonly used additives in lubricants may further optimize the performance of the resulting tribofilms.

This disclosure provides a method for improving wear control, while maintaining or improving energy efficiency, in a mechanical component having sliding or rolling between contacting surfaces. The method involves using a lubricant composition in the mechanical component having sliding or rolling between contacting surfaces. The lubricant composition has a base stock blend as a major component, and at least one lubricant additive, as a minor component. The base stock blend has at least one first base stock having a viscosity from 1 to 50 cSt at 40 C. and at least one second base stock having viscosity from 100 to 2000 cSt at 40 C. The first base stock is present in an amount greater than 50 to 95 wt % of the base stock blend, and the second base stock is present in an amount from 5 to less than 50 wt % of the base stock blend. The second base stock is miscible with the first base stock.

The presently disclosed technology relates to a nano-additives to improve the performance of lubricants, oils, and greases. More specifically, the presently disclosed technology relates to applying capped metal oxide nanoparticles, such as capped zirconia nanoparticles, in the lubricants to produce a tribofilms on the lubricating surfaces to provide wear protection to the said surfaces. Also, the interaction of the capped zirconia nanoparticles with other commonly used additives in lubricants may further optimize the performance of the resulting tribofilms.

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.

A lubricant composition comprising a high-viscosity PAO lubricant base stock having a KV100 of at least 200 cSt and comprising multiple PAO molecules comprising at least 200 carbon atoms per molecule, wherein (i) each of the PAO molecules comprises multiple pendant groups; (i) the average pendant group length of all the pendant groups excluding one methyl on each of the PAO molecules among at least 90 mol % of all of the PAO molecules, if one or more methyl is present, is at least 6.0, and (iii) the concentration of the high-viscosity PAO base stock is no more than 75 wt % of the total weight of the lubricant composition. The lubricant composition exhibits provides a high degree of protection of gear surfaces as measured by ASTM D5182.

A lubricating oil composition including: a lubricating base oil; (A) a dispersant poly(meth)acrylate compound having a weight average molecular weight of 30,000 to 200,000 in an amount of 1 to 10 mass % on the basis of the total mass of the composition; and (B) a non-dispersant poly(meth)acrylate compound having a weight average molecular weight of 15,000 to 100,000 in an amount of no more than 15 mass % on the basis of the total mass of the composition, wherein the ratio MA/MB of the amount MA of the component (A) to the amount MB of the component (B) is 0.05 to 1; and the ratio MwB/MwA of the weight average molecular weight MwB of the component (B) to the weight average molecular weight MwA of the component (A) is 0.05 to 2.