A comb polymer can be used for reducing a Noack evaporation loss of a lubricant composition, especially of an engine oil composition. Application of the comb polymer to the lubricant composition can bring about the desired reduction. The comb polymer can include specified amounts of macromonomer and alkyl acrylates. Resulting lubricant compositions can include the comb polymer.

This disclosure relates to grease compositions having at least one base oil, at least one soap or non-soap thickener, and at least one elastomeric triblock copolymer of the general configuration A-B-A, in which A is a relatively hydrophobic polymer block and B is a relatively hydrophilic polymer block, and in which A forms less than 50% by weight of the total molecular weight of the elastomeric triblock copolymer. When the grease compositions are used under high shear conditions, structural stability and resistance to breaking down in accordance with ASTM D7342 is improved. When the grease compositions are used in low temperature conditions, low temperature starting and running torque in accordance with ASTM D1478 is improved.

A lubricating oil composition comprising a GTL (Gas to-Liquid) base oil synthesized by the Fischer-Tropsch process and a viscosity index improver, wherein the content of the viscosity index improver is 0.1 to 20 mass %, and at least HTHSV 50 C./HTHSV 150 C. is 6.50 or less and KV 50 C./HTHSV 150 C. is 8.00 or less.

A lubricant composition contains a lubricant base oil, (A) a detergent containing magnesium, (B) a compound containing boron, and (C) a zinc dialkyl dithiophosphate. The amount of component (A) is in the range of 200 to 1200 mass ppm [Mg] based on the mass of the lubricant composition, and the amount of component (C) is in the range of 300 to 1000 mass ppm [P] based on the mass of the lubricant composition. Component (C) includes a zinc dialkyl dithiophosphate having a primary alkyl group or a secondary alkyl group; the lubricant composition includes zinc dialkyl dithiophosphate having a secondary alkyl group; the mass ratio of the zinc dialkyl dithiophosphate having a primary alkyl group and the zinc dialkyl dithiophosphate having a secondary alkyl group is from 70:30 to 0:100; and the concentration of [B] is from 100 to 300 mass ppm based on the mass of the lubricant composition.

The present invention is directed to a lubricating oil additive containing a vicinal diol and a particular detergent blend typically is low viscosity base oils whereby exhibiting improved fuel economy. In this respect, disclosed is a lubricating oil composition comprising: a major amount of base oil of lubricating viscosity; a friction modifier which is selected from the group consisting of C.sub.10-C.sub.30 alkane 1,2-diols and C.sub.10-C.sub.30 alkene 1,2-diols; an overbased alkyl alkaline earth metal hydroxybenzoate detergent having a metal ratio less than 3.0; and an overbased alkyl calcium sulfonate or an overbased alkyl calcium hydroxybenzoate having a metal ratio of 3.5 or greater.

Hydrogenated polymers with a radial structure having a core made up of calixarenes of the general formula (I), to the core of which is linked a number P of hydrogenated linear polymer segments selected from: hydrogenated homopolymers or co-polymers of conjugated dienes; or hydrogenated co-polymers of said conjugated dienes and monoalkenyl arenes, and mixtures thereof said formula (I) in which: R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently selected from hydrogen; a group containing carbon and hydrogen; a group also containing heteroatoms in addition to carbon and hydrogen; a group also containing silicon in addition to carbon, hydrogen and heteroatoms; one of the two substituents R.sub.5 and R.sub.6 is hydrogen, while the other may be hydrogen or alkyl, with a number of carbon atoms between 1 and 6, preferably methyl and ethyl; n is an integer in the range between 4 and 16.

##STR00001##

A defoaming agent including a polymer, the polymer including a repeating unit represented by the following general formula (1); and a repeating unit represented by the following general formula (3): ##STR00001##
wherein in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y.sup.1 is a side chain including a linear or branched polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 300; and Z.sup.1 is a linking group linking the repeating unit X.sup.1 and the side chain Y.sup.1; ##STR00002##
wherein in the general formula (3), X.sup.2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Y.sup.2 is a C.sub.1-30 hydrocarbyl side chain; and Z.sup.2 is a linking group linking the repeating unit X.sup.2 and the side chain Y.sup.2.

A defoaming agent comprising: a polymer comprising a repeating unit represented by the following general formula (1): ##STR00001##
where in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Y.sup.1 is a side chain comprising a linear or branched polysiloxane structure, the polysiloxane structure comprising a repeating unit represented by the following general formula (2) and having a polymerization degree of 5 to 300; and Z.sup.1 is a linking group linking the repeating unit X.sup.1 and the side chain Y.sup.1; ##STR00002##
wherein in the general formula (2), R.sup.1 and R.sup.2 are each independently an organic group having a carbon number of 1 to 18.

An object of the present invention is to provide a lubricating oil composition particularly excellent in viscosity characteristics at a low temperature. The present invention provides: a lubricating oil composition including a polymer (A) and a base oil (B), wherein the polymer (A) satisfies the following requirement (A-1), and the content ratio of the polymer (A) and the base oil (B) is such that the ratio of a resin (A) is within the range of from 0.1 to 50 parts by mass with respect to 100 parts by mass of the total amount of the polymer (A) and the base oil (B). (A-1) The polymer (A) is a polymer containing a structural unit derived from an -olefin having 20 or less carbon atoms.

A lubricant composition is described. The novel lubricant composition has superior thermal stability, and can reduce the need to replenish the lubricant. The lubricant composition includes at least a soap component, a thickener component, an oil component, and a spherical polyolefin component (optionally Microthene). The spherical polyolefin component includes polyolefin microparticles.