The present invention relates to a lubricating composition for an engine, in particular for a motor vehicle engine, comprising at least one base oil and at least one compound able to release formaldehyde under the temperature and pressure conditions of the combustion chamber of the engine. It also relates to the use, in a lubricating composition intended for an engine, of a compound able to release formaldehyde under the temperature and pressure conditions of the combustion chamber of the engine, as an additive for preventing and/or reducing pre-ignition, in particular low-speed pre-ignition (LSPI).

A lubricating grease composition containing a base oil having a kinematic viscosity of 10 mm.sup.2/s or more and 60 mm.sup.2/s or less at 40° C.; a thickener containing at least one soap selected from a metal soap and a metal complex soap; and a solid lubricant containing porous polyamide particles. An amount of the porous polyamide particles blended is 1% by mass or more and 20% by mass or less based on a total mass of the lubricating grease composition.

Trisubstituted triazine antioxidants.

Trisubstituted triazine antioxidants.

Provided is a grease composition which is excellent in fire extinguishing performance without water and can suppress fuming, malodor, and liquefaction on burning and a method for producing the grease composition. A grease composition contains a base oil (A), a thickener (B), and a fire retardant (C), wherein the base oil (A) contains a base oil (A1) having a 40° C. kinematic viscosity of 300 mm.sup.2/s or more, a sulfur content of 20 ppm by mass or less, and an initial boiling point of 400° C. or higher, the fire retardant (C) is at least one of aluminum hydroxide (C1) and 1,3,5-triazine-1,3,5 (2H, 4H, 6H)-tris(ethanol) (C2), and a content of the fire retardant (C) is 1.0 to 12.0 mass % based on a total amount of the grease composition.

A metal working fluid having increased resistance to bacterial growth. The metal working fluid includes a cross-linked polymeric ester emulsifier; and an amine represented by the formula (H.sub.2N).sub.a-Q-(NH.sub.2).sub.b, where a and b are each integers, and Q is at least one carbon atom. Q may also be represented by XYZ, where a+b2; X is a cyclic ring system including 3 to 24 carbon atoms; and Y and Z are groups that include at least one carbon atom directly attached to the cyclic ring system. The metal working fluid may also include a biocide, and may also include an amide that is formed by reacting the amine with a carboxylic acid.

A lubricating grease composition includes a base oil, a thickener, and a solid lubricant, wherein the base oil is a synthetic hydrocarbon oil with a kinematic viscosity of 600 to 2000 mm.sup.2/s at 40 C., the thickener is a barium complex soap, and the solid lubricant is an inorganic fine particle with Mohs hardness of 3 to 6 and an average particle size of 10 to 40 m.

A metal working fluid having increased resistance to bacterial growth. The metal working fluid includes a cross-linked polymeric ester emulsifier; and an amine represented by the formula (H.sub.2N).sub.a-Q-(NH.sub.2).sub.b, where a and b are each integers, and Q is at least one carbon atom. Q may also be represented by XYZ, where a+b2; X is a cyclic ring system including 3 to 24 carbon atoms; and Y and Z are groups that include at least one carbon atom directly attached to the cyclic ring system. The metal working fluid may also include a biocide, and may also include an amide that is formed by reacting the amine with a carboxylic acid.

A lubricating grease composition containing a base oil having a kinematic viscosity of 10 mm.sup.2/s or more and 60 mm.sup.2/s or less at 40 C.; a thickener containing at least one soap selected from a metal soap and a metal complex soap; and a solid lubricant containing porous polyamide particles. An amount of the porous polyamide particles blended is 1% by mass or more and 20% by mass or less based on a total mass of the lubricating grease composition.

Provided is a grease composition for a ball joint that can reduce the wear of a ball seat at a slide region and also has excellent compatibility with a dust cover. The grease composition for a ball joint comprises a base oil, a thickener, and an additive. The base oil contains an ethylene--olefin copolymer and the kinetic viscosity of the base oil at 40 C. is 2,000 to 6,000 mm.sup.2 /s. The additive contains a polar wax (e.g., monoamide wax or ester wax).