A comb copolymer viscosity modifier may be made by polymerization comprising at least, or consisting essentially of, the following monomers: (a) (optionally from 7.0 wt % to 18 wt %, by repeat units, of) a hydrogenated polybutadiene-based (alk)acrylate ester macromonomer; (b) (optionally from 33 wt % to 64 wt % or from 38 wt % to 58 wt %, by repeat units, of) a C.sub.3-C.sub.8 alkyl (alk)acrylate ester monomer; (c) (optionally up to 35.0 wt %, by repeat units, of) a C.sub.12-C.sub.24 alkyl (alk)acrylate ester monomer; and (d) (optionally from 3.0 wt % to 27 wt %, by repeat units, of) a C.sub.6-C.sub.20 aryl, aralkyl, or alkaryl (alk)acrylate ester monomer, such that a sum of repeat units due to (c) plus (d) constitute at least 21.0 wt % of repeat units of the comb copolymer viscosity modifier. Lubricant compositions comprising the comb copolymer viscosity modifier, as well as uses thereof and methods for modifying viscosity and dispersancy, are also contemplated.

The present disclosure relates to a lubricant composition including an anti-wear additive and metal nanoparticles. The lubricant composition according to the disclosure has, simultaneously, good stability as well as good, long-lasting friction properties.

The present invention is directed to the use of poly(polyisobutylenemethacrylate) as viscosity index improving component in lubricating oil compositions. The invention is further related to lubricating oil compositions comprising poly(polyisobutylenemethacrylate) with enhanced shear stability.

A lubricant composition of an oil of lubricating viscosity, a grafted copolymer viscosity modifier that is an ashless condensation reaction product of an olefm polymer, having a number average molecular weight of about 1000 to about 10,000, comprising carboxylic acid or equivalent functionality grafted onto the polymer backbone, with a monoamine or a polyamine often having a single primary amino group, which exhibits good dispersancy and viscometric performance in a driveline device.

Ethylene-C.sub.3-C.sub.10 alpha olefin copolymers, dispersants and lubricating oils/fuel compositions incorporating dispersants, and related methods are generally described herein. The copolymer may comprise ethylene-derived units and C.sub.3-C.sub.10 alpha-olefin-derived units. The C.sub.3-C.sub.10 alpha-olefin-derived units may have a carbon number from three to ten. For example, the C.sub.3-C.sub.10 alpha-olefin-derived units may be propylene-derived units. The dispersants may be made from copolymers having low metal and/or fluorine contents.

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 multi-functional olefin copolymer viscosity index improver and a lubricating oil composition including such lubricant additive that provides improved viscometric properties and helps reduce low speed pre-ignition events at the same time. In one approach, the multi-functional olefin copolymer viscosity index improver is silicone functionalized and includes an acylated olefin copolymer with aminosilane or aminosiloxone pendant or side groups.

A lubricant composition comprising an oil of lubricating viscosity and 0.01 to 5 percent by weight of a substantially sulfur-free alkyl phosphate amine salt, where at least 30 mole percent of the phosphorus atoms are in an alkyl pyrophosphate salt structure, exhibits good antiwear performance. In the phosphate amine salt, at least 25 mole percent of the alkyl groups are primary alkyl groups of 3 to 12 carbon atoms.

The present invention relates to a hyperbranched polyether of formula (I) R.sub.mQ.sub.n-0-R.sup.1 (I), wherein Q is a branching unit of formula, n is 2.sup.k1, m is 2.sup.k, k is 2, 3, 4, 5 or 6, each R is independently a hydrocarbon radical having at least 10 carbon atoms, R.sup.1 is a polymer having a number average molecular weight M.sub.n of at least 250 g/mol, wherein each branching unit Q is connected via ether linkage to adjacent branching units Q and each terminal oxygen of Q, not connected to adjacent branching units Q, is connected to R via ether linkage, as well as mixtures thereof. The present invention further relates to formulations comprising said hyperbranched polyether or mixture of ethers as well as their use.

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Provided are; a lubricating oil composition excellent in fuel saving performance, seizure resistance, wear resistance, fatigue lifetime and shear stability, which contains a base oil (A), an olefin polymer (B) having a number average molecular weight of 1,000 or more and 12,000 or less, and a specific sulfur compound (C) and wherein the content of all sulfur atoms based on the total amount of the composition is 1.2% by mass or more and 2.5% by mass or less; and a lubrication method using the lubricating oil composition.