The disclosed technology relates to the use of toxicologically acceptable hydrocarbyl- (e.g. alkyl-) phenol detergents and their salts in automotive lubricating oils, such as, for example, automatic or manual transmissions.

A shock absorber oil composition of the invention includes a base oil: (A) at least one of phosphate, amine phosphate salt, phosphite and amine phosphite salt; (B) an amide compound; and (C) a primary amine.

An object of the present invention is to obtain a lubricating oil for machine tools, which has good lubricating properties and abrasion resistance and also exhibits a high flash point and a low pour point. A lubricating oil composition comprises, as a base oil, a base oil which includes an oil containing 20 mass % to 49 mass % of n-paraffin components and 51 mass % to 80 mass % of i-paraffin components at a quantity of 90 mass % or more of the total quantity of the base oil and which has a kinematic viscosity at 40 C. of 1 to 5 mm.sup.2/s. By blending a small quantity of -dithiophosphorylated propionic acid and/or an acidic phosphoric acid ester in this base oil, a lubricating oil composition suitable for use for a main shaft of a machine tool is obtained. The lubricating oil composition for a main shaft of a machine tool has a flash point of 100 C. or more, a pour point of 10 C. or less, and a Shell four-ball wear mark diameter of 0.7 mm or less.

A lubricant composition of 40 to 95% of an oil having a kinematic viscosity at 100 C. of 3 to 7.5; 0.3 to 2% of an amine salt of a phosphorus compound obtained by reacting phosphorus pentasulfide with one or more alcohols having 4 to about 13, or 4 to 8, or 6, carbon atoms, with an alkylene oxide, and further with phosphorus pentoxide, and salting the resulting material with one or more amines having 2 to 20 or 12 to 24 carbon atoms; and an active-sulfur containing agent in an amount to provide 0.5 to 7% sulfur to the composition provides good wear protection to gears at a relatively low viscosity of the composition.

The present invention provides a lubricating oil composition comprising: a lubricating base oil; 1.0% by mass or more and 15.0% by mass or less of a dispersant poly(meth)acrylate compound having the weight average molecular weight of 20000 or more and 200000 or less; 0.05% by mass or more and 6.0% by mass or less of a thiadiazole compound; 1.5% by mass or more and 4.0% by mass or less of a polysulfide compound; and 0.2% by mass or more and 1.5% by mass or less of a friction modifier, based on the total amount of the lubricating oil composition, wherein the mass ratio of the polysulfide compound content to the thiadiazole compound content (polysulfide compound/thiadiazole compound) is 0.4 or more and 50 or less, and the kinematic viscosity at 100 C. of the lubricating oil composition is 7.0 mm.sup.2/s or more and 35.0 mm.sup.2/s or less.

An oil additive includes a hydrotalcite-like compound, and a radical trapping agent having a melting point of 130 C. or higher.

This disclosure is directed to an additive package for a lubricant composition that provides improved compatibility with fluoropolymer seals. The additive package comprises a seal compatibility additive. The disclosure is also directed to a lubricant composition comprising a base oil and a seal compatibility additive. The seal compatibility additive improves the compatibility with fluoropolymer seals of the resultant lubricant composition.

A lubricant composition of an oil of lubricating viscosity and a phosphite ester reaction product of a monomeric phosphorous acid or an ester thereof with a first alkylene diol having two hydroxy groups in a 1,4 or 1,5 or 1,6 relationship and a second, alkyl-substituted, diol being a substituted 1,3-propylene diol, exhibits good wear and frictional performance.

A lubricating oil composition containing a lubricating base oil and on the basis of the total mass of the composition, (A) a boron-containing ashless dispersant in an amount of 100 to 500 ppm by mass as boron, (B) a phosphorous additive in an amount of 300 to 800 ppm by mass as phosphorus, (C) an amide- and/or imide-based friction modifier in an amount of 1 to 4 percent by mass, and (D) an alkali metal- and/or alkaline earth metal-based detergent in an amount of 100 to 300 ppm by mass as metal, and having a 40 C. kinematic viscosity of 30 mm2/s or lower is provided. The lubricating oil composition, which has a low viscosity to improve fuel efficiency, also has superior anti-wear, anti-seizure, and anti-shattering properties, even when the composition is degraded by oxidation or by the elution of compounds from sealing materials after long term use.

An additive for lubricating oil may include a phosphite ester compound (A) having a specific structure and a phosphite ester compound (B) having a specific structure, wherein the (A):(B) mass ratio of the phosphite ester compound (A) to the phosphite ester compound (B) is in a range of from 99:1 to 80:20. Such an additive may be provided to a lubricating oil, capable of imparting wear resistance and demulsibility with respect to a base oil for lubricating oil, and to impart durability even in the presence of water.