An object is to provide a grease composition for a ball joint capable of reducing the starting torque, reducing the operating torque, and improving the low temperature property as compared with the related art. The grease composition for a ball joint according to the present invention contains a silicone oil as a base oil and an additive, and contains an amino-modified silicone and a modified polyolefin as the additive. The silicone oil preferably includes at least one of dimethyl silicone oil and phenyl-modified silicone oil.

Provided is a rust-preventive composition showing excellent rust-preventive performance for plate joining parts such as doors of automotive bodies, the composition having sufficient corrosion resistance and being capable of preventing dripping from automotive bodies. A rust-preventive composition including: a rust-preventive additive; a wax having a melting point within the range of 60° C. to 130° C. selected from microcrystalline waxes and polyethylene-based or polypropylene-based synthetic waxes; bentonite; a hydrogenated oil; and two or more kinds of diluents having different viscosities; the rust-preventive additive being contained in an amount within the range of 12% by mass to 39% by mass with respect to the total composition, the bentonite being contained in an amount within the range of 2% by mass to 6% by mass with respect to the total composition, the wax being contained in an amount within the range of 3% by mass to 13% by mass with respect to the total composition.

A lubricating oil composition for a continuously variable transmission contains at a specific content: (A) a mineral oil or PAO having a sulfur content of 0.03 mass % or less and a kinematic viscosity at 100 degrees C. from 1.5 mm.sup.2/s to 3 mm.sup.2/s; (B) a mineral oil or PAO having a sulfur content of 0.03 mass % or less and a kinematic viscosity at 100 degrees C. from 5.5 mm.sup.2/s to 8 mm.sup.2/s; (C) PAO having a kinematic viscosity at 100 degrees C. from 30 mm.sup.2/s to 400 mm.sup.2/s; and (D) a polymethacrylate having a mass average molecular weight of 10000 to 40000, in which the total content of the components (C) and (D) is 19 mass % or more and the lubricating oil composition has a kinematic viscosity at 100 degrees C. from 5.5 mm.sup.2/s to 6.5 mm.sup.2/s and a kinematic viscosity at −20 degrees C. of 680 mm.sup.2/s or less.

A dispersant for a lubricating oil, containing at least one compound selected from a specific nitrogen-containing compound which is obtained by using, as raw materials, (A) at least one polyolefin selected from polybutene and polyisobutene, (B) at least one maleic acid compound selected from maleic acid and maleic anhydride, and (C) polyamine; a boride of the specific nitrogen-containing compound; and an acylated product of the specific nitrogen-containing compound. The polyolefin (A) satisfies at least one of the following conditions (α) and (β). (α) a ratio (Sb/Sa) of an integrated value (Sb) of a peak present at 4.40 to 5.00 ppm in a .sup.1H-NMR spectrum to an integrated value (Sa) of a peak present at 5.01 to 5.60 ppm in the 1H-NMR spectrum is 2 or more. (β) a ratio (Sd/Sc) of an integrated value (Sd) of a peak present at 1.76 to 2.10 ppm in the .sup.1H-NMR spectrum to an integrated value (Sc) of a peak present at 1.65 to 1.75 ppm in the .sup.1H-NMR spectrum is 1 or more.

The disclosed technology provides a lubricating composition comprising an oil of lubricating viscosity and a detergent comprising a polyolefin-substituted hydroxy-aromatic carboxylic acid or salt thereof, wherein the polyolefin is derived from a branched alkene having at least 4 carbon atoms and wherein the polyolefin has a number average molecular weight of 150 to 800. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.

A polyisobutylene-substituted hydroxyaromatic compound and derivatives thereof which are suitable for use as additives in lubricating compositions. The polyisobutylene-substituted hydroxyaromatic compound may include the reaction product of a hydroxyaromatic compound with a polyisobutylene having a number average molecular weight of 150 to 800.

The invention provides a lubricant composition for an eccentrically oscillating speed reducer of planetary gear type, which is capable of extending the life of the speed reducer under high temperatures and keeping low input torque at low temperatures, and includes (a) a base oil containing a synthetic oil, (b) a hydrocarbon wax, and (c) at least one calcium salt selected from the group consisting of a calcium salt of petroleum sulfonic acid, a calcium salt of alkyl aromatic sulfonic acid, a calcium salt of oxidized wax, an overbasic calcium salt of petroleum sulfonic acid, an overbasic calcium salt of alkyl aromatic sulfonic acid, and an overbasic calcium salt of oxidized wax.

A process for the preparation of polyisobutene derivatives involves bringing an oxygen-containing gas in contact with polyisobutene, in the presence of a photosensitizer, and irradiating the reaction mixture. The polyisobutene derivatives are useful, for example, in hydrocarbon mixtures or hydrocarbon-containing oils.

The invention provides a lubricant composition for an eccentric oscillating planetary gear type speed reducer comprising the following components (a) to (d): (a) a base oil containing a synthetic oil; (b) at least one calcium salt selected from the group consisting of calcium salts of petroleum sulfonic acids, calcium salts of alkyl aromatic sulfonic acids, calcium salts of salicylates, calcium salts of phenates, calcium salts of oxidized waxes, overbased calcium salts of petroleum sulfonic acids, overbased calcium salts of alkyl aromatic sulfonic acids, overbased calcium salts of salicylates, overbased calcium salts of phenates, and overbased calcium salts of oxidized waxes; (c) an antioxidant; and (d) a glycerin fatty acid ester.

The invention provides a lubricant composition for an eccentric oscillating planetary gear type speed reducer comprising the following components (a) to (d): (a) a base oil containing a synthetic oil; (b) at least one calcium salt selected from the group consisting of calcium salts of petroleum sulfonic acids, calcium salts of alkyl aromatic sulfonic acids, calcium salts of salicylates, calcium salts of phenates, calcium salts of oxidized waxes, overbased calcium salts of petroleum sulfonic acids, overbased calcium salts of alkyl aromatic sulfonic acids, overbased calcium salts of salicylates, overbased calcium salts of phenates, and overbased calcium salts of oxidized waxes; (c) an antioxidant; and (d) a glycerin fatty acid ester.