This invention relates to a functional fluid, comprising: (A) from 50 to 85 wt.-% of alkoxy glycol according to formula (I): CH.sub.3O(CH.sub.2CH.sub.2O).sub.nH, wherein n is a number from 2 to 5, with the proviso that in at least 30 wt.-% of all compounds according to formula (I), n is 3, and (B) from 1 to 20 wt.-% of alkoxy glycol according to formula (II): R.sub.1O(CH.sub.2CH.sub.2O).sub.mH, wherein R.sub.1 is a C2 to C8 alkyl residue, m is a number from 2 to 6, with the proviso that in at least 65 wt.-% of all compounds according to formula (II), m is 3, and (C) from 6 to 35 wt.-% of at least one compound according to formula (III): HO(CH.sub.2CH.sub.2O).sub.kH, wherein k is a number of 2 or higher, with the proviso that in at least 80 wt.-% of all compounds according to formula (III), k is 2 or 3, (D) at least one additive.

A lubricating oil composition for a gas engine containing: a base oil (A), at least one overbased calcium detergent (B) selected from the group consisting of calcium salicylate (B1) and calcium phenate (B2), alkenyl succinimide (C), and a hindered amine-based antioxidant (D), where the content (X) of calcium atoms derived from the component (B) is less than 0.090% by mass based on the total amount of the lubricating oil composition; the content (Y) of calcium carbonate contained in the component (B) is 0.060% by mass or more based on the total amount of the lubricating oil composition; the content of boron atoms derived from the component (C) is less than 0.020% by mass based on the total amount of the lubricating oil composition, and the content of the component (D) is more than 0.20% by mass based on the total amount of the lubricating oil composition.

A lubricating oil composition for a gas engine containing: a base oil (A), at least one overbased calcium detergent (B) selected from the group consisting of calcium salicylate (B1) and calcium phenate (B2), alkenyl succinimide (C), and a hindered amine-based antioxidant (D), where the content (X) of calcium atoms derived from the component (B) is less than 0.090% by mass based on the total amount of the lubricating oil composition; the content (Y) of calcium carbonate contained in the component (B) is 0.060% by mass or more based on the total amount of the lubricating oil composition; the content of boron atoms derived from the component (C) is less than 0.020% by mass based on the total amount of the lubricating oil composition, and the content of the component (D) is more than 0.20% by mass based on the total amount of the lubricating oil composition.

A lubricating composition includes an oil of lubricating viscosity and an oil-soluble dispersant viscosity modifier. The dispersant viscosity modifier includes an olefin-based polymer backbone and at least one pendent group derived from a functionalized aliphatic amine. Each pendent group is independently attached to the olefin-based polymer backbone. The pendent group is non-ionic, non-basic, and non-acidic and includes a functional group which includes at least one heteroatom other than nitrogen.

A lubricating composition includes an oil of lubricating viscosity and an oil-soluble dispersant viscosity modifier. The dispersant viscosity modifier includes an olefin-based polymer backbone and at least one pendent group derived from a functionalized aliphatic amine. Each pendent group is independently attached to the olefin-based polymer backbone. The pendent group is non-ionic, non-basic, and non-acidic and includes a functional group which includes at least one heteroatom other than nitrogen.

The invention addresses a problem of providing a lubricating oil composition for gas engines capable of suppressing viscosity increase while reducing a sulfated ash content and excellent in high-temperature detergency and base number retention. The lubricating oil composition is used for gas engines and contains a base oil (A), at least one ash-free additive (B) selected from an ash-free sulfur-based antioxidant (B1) and a hindered amine compound (B2), and a boronated imide-type dispersant (C), and satisfies the following requirements (X1) to (X3): Requirement (X1): the sulfated ash content is 0.2% by mass or less. Requirement (X2): the content of the ash-free additive (B) is 1.2% by mass or less based on the total amount of the lubricating oil composition, provided that in the case where the ash-free additive (B) contains the hindered amine compound (B2), the content of the hindered amine compound (B2) is less than 1.0% by mass based on the total amount of the lubricating oil composition. Requirement (X3): the content of the boron atom derived from the boronated imide-type dispersant (C) is 200 ppm by mass or more based on the total amount of the lubricating oil composition.

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).

A composition for lubricating and/or descaling in the hot processing of metals includes a solid mixture containing the following constituents: (a) 20 to 60% by weight of condensed alkali phosphate, (b) 10 to 40% by weight boron compound selected from borosilicate glass, boric acid, boric acid salt, or a mixture thereof, (c) 10 to 30% by weight alkali or alkaline earth sulphates, (d) 5 to 25% by weight fatty acid, fatty acid salt, or a mixture thereof. The sum of the constituents (a) and (b) constitutes at least 50% by weight of the mixture and the sum of the constituents (a) to (d) constitutes at least 85% by weight of the mixture.

A method for preparing a nano suspension lubricant comprises providing substantially spherical nano particles of size ranging from about less than 50 nanometers to about 100 nanometers. The method further comprises mixing the nano particles and a surfactant in about 1:1 ratio in a solvent to form a mixture. The solvent is evaporated from the mixture to obtain surface modified nano particles. The surface modified nano particles include the nano particles coated with the surfactant. The method comprises mixing the surface modified nano particles with a lubricating fluid to form the nano suspension lubricant, where the lubricating fluid comprises about 90% to 99% base oil and about 1% to 10% additives.