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.

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 vinyl-based comb copolymer includes a polyisobutylene-based macromonomer unit and a vinyl-based monomer unit. A polyisobutylene-based macromonomer has at least 0.8 (meth)acryloyl groups represented by a specific formula at one end of a main chain per molecule, and is copolymerized with a vinyl-based monomer. A method for producing the vinyl-based comb copolymer includes copolymerizing the polyisobutylene-based macromonomer with the vinyl-based monomer. A viscosity index improver includes the comb copolymer. A lubricating oil composition includes the comb copolymer.

Selected comb polymers contain specified amounts of macromonomer and nitrogen-containing (meth)acrylates. Lubricant compositions can contain such comb polymers. The selected comb polymers can be used as solubilizers in lubricant compositions, especially in engine oil (EO) compositions.

A composition comprising olefin oligomers of one or more olefin monomers, the olefin monomers comprising a branched C.sub.10 olefin monomer comprising i) 3-propyl-1-heptene, ii) 4-ethyl-1-octene, iii) 5-methyl-1-nonene, or iv) any combination thereof. A composition comprising substantially hydrogenated olefin oligomers, wherein the olefin oligomers are oligomers of one or more olefin monomers, the olefin monomers comprising a branched C.sub.10 olefin monomer comprising i) 3-propyl-1-heptene, ii) 4-ethyl-1-octene, iii) 5-methyl-1-nonene, or iv) any combination thereof. A process comprising a) contacting 1) a catalyst system and 2) a monomer feedstock comprising a branched C.sub.10 olefin monomer comprising i) 3-propyl-1-heptene, ii) 4-ethyl-1-octene, iii) 5-methyl-1-nonene, or iv) any combination thereof in a reaction zone; and b) forming olefin oligomers.

The invention relates to a poly alkyl(meth)acrylate polymer comprising a combination of polybutadiene-based monomers having different average molecular weight, lubricant compositions comprising the polymer, a method for manufacturing the polymer and the use of the polymer as a viscosity index improver in a lubricating oil composition.

The present invention relates to a lubricating oil composition containing a base oil (A) and a viscosity index improver (B) such that in X-ray small-angle scattering spectra obtained through measurement at 40 C. and 100 C., a ratio [|(40)|/|(100)|] between |(40)| and |(100)|, each of which is an absolute value of a slope of a straight line calculated in a range of the scattering vector q as the x axis of from 0.1 nm .sup.1 to 1 nm .sup.by the least-squares method, is 1.5 or more.

Provided herein are lubricant compositions comprising renewable base oils as embodied by hydrocarbon mixtures with controlled structure characteristics in combination with lubricant additives that address performance requirements and stricter environmental and fuel economy regulations. The lubricant composition provides performance in the cold crank simulated viscosity (CCS) vs Noack volatility relationship, which allows for the formulation of lower viscosity engine oils with improved fuel economy, improved fuel economy retention, and retained LSPI prevention additionally conferring improved characteristics to other devices or apparatus requiring lubrication.

Bottlebrush poly(alpha olefin)s of high carbon number, greater than 12 such as poly(octadecene), are used as a thickener for a synthetic base oil grease lubricant that is based on oligomerized alpha olefin with carbon number from 7 to 12, such as oligo(decene). Dispersion aids are not required in the present lubricants because poly(octadecene) can be dissolved in oligo(decene). The lubricant is a solid grease formed by percolation/network of the poly(octadecene) crystals, at a sufficient concentration, after the crystallization of poly(octadecene), and water resistant having oxidation/high temperature stability.

One aspect of the present invention is a refrigerating machine oil containing: a base oil containing an ester of an alcohol and a fatty acid; a compound represented by the following formula (1):

##STR00001##

wherein R.sup.1 and R.sup.2 each independently represent a monovalent hydrocarbon group, R.sup.3 represents a divalent hydrocarbon group, and R.sup.4 represents hydrogen atom or a monovalent hydrocarbon group, and the refrigerating machine oil having a kinematic viscosity at 40 C. of 10 mm.sup.2/s or less.