A lubricating oil composition for agricultural machines, containing: at least one base oil selected from the group consisting of mineral oil-based base oils and synthetic oil-based base oils; and a polyalkyl methacrylate-based viscosity index improver having a weight average molecular weight of from 20,000 to 80,000, in which a kinematic viscosity at 100° C. is from 8.00 mm.sup.2/s to 10.00 mm.sup.2/s, a kinematic viscosity reduction rate at 100° C. in an ultrasonic shear stability test is 10.0% or less, and a Brookfield viscosity at −40° C. is 20,000 mPa.Math.s or less.

An aspect of the present invention provides a refrigerating machine oil containing: a lubricating base oil; a phosphorus-containing additive; and a polymer comprising an unsaturated carboxylic acid ester as a monomer unit.

An aspect of the present invention provides a refrigerating machine oil containing: a lubricating base oil; a phosphorus-containing additive; and a polymer comprising an unsaturated carboxylic acid ester as a monomer unit.

A defoaming agent obtainable by a process that includes: polymerizing (A) at least one polymerizable monomer in a composition, the composition comprising (C) a solvent and (B) at least one non-polymerizable polysiloxane dissolved in the (C) solvent, wherein the component (A) optionally comprises at least one Si-atom-containing monomer in an amount of less than 10 mass % on the basis of the total mass of the component (A).

A defoaming agent obtainable by a process that includes: polymerizing (A) at least one polymerizable monomer in a composition, the composition comprising (C) a solvent and (B) at least one non-polymerizable polysiloxane dissolved in the (C) solvent, wherein the component (A) optionally comprises at least one Si-atom-containing monomer in an amount of less than 10 mass % on the basis of the total mass of the component (A).

The present invention relates to the use of lubricant composition containing a base oil and at least one alkyl methacrylate polymer, to reduce engine particulate emissions.

A method for the preparation of a sulfur-free copolymer proceeds by solution polymerization in the presence of a radical initiator, wherein the copolymer contains at least one alkyl methacrylate and maleic anhydride having a number average molecular weight of 3000 to 9000 g/mol.

Disclosed is a lubricating composition including a base oil, a surfactant system and a phase-change material, especially water. The lubricating composition according to the invention is used to lubricate engines, especially for a vehicle. It has improved thermal performances compared to lubricating compositions of prior art. It also reduces clogging of the engine parts.

Disclosed is a lubricating composition including a base oil, a surfactant system and a phase-change material, especially water. The lubricating composition according to the invention is used to lubricate engines, especially for a vehicle. It has improved thermal performances compared to lubricating compositions of prior art. It also reduces clogging of the engine parts.

Provided is a lubricating oil composition to be used in an internal combustion engine having a sliding mechanism including a piston ring and a liner, the lubricating oil composition including: a base oil; (A) a poly(meth)acrylate; and (B) an organic molybdenum compound, in which: (A) the poly(meth)acrylate contains a polymer (A1) including a repeating unit derived from a (meth)acrylate represented by the following formula (1) and having a mass-average molecular weight of from 1,000 to 500,000; and a content of (B) the organic molybdenum compound in a total amount of the composition is from 0.01 mass % to 0.2 mass % in terms of a molybdenum atom: wherein R.sup.1 represents a hydrogen atom or a methyl group, and X represents a hydrogen atom, a hydrocarbon group having 1 to 60 carbon atoms, or a functional group-containing hydrocarbon group having 1 to 60 carbon atoms.