The disclosed technology relates to an additive composition and lubricating grease composition containing a synergistic combination of ingredients for inhibiting rust, particularly rust on mechanical devices subject to contact with salt water.

Disclosed are Group III base stocks comprising greater than or equal to about 90 wt. % saturated hydrocarbons (saturates); a viscosity index from 120 to 145; a unique ratio of molecules with multi-ring naphthenes to single ring naphthenes (2R+N/1RN); a unique ratio of branched carbons to straight chain carbons (BC/SC); a unique ratio of branched carbons to terminal carbons (BC/TC); and unique MRV behavior as a function of base stock naphthene ratio (2R+N/1RN). A method for preparing the base stocks is also disclosed. Also disclosed is a lubricating oil having the base stock as a major component, and an additive as a minor component.

Phase change material compositions and methods for using the compositions to prepare substrate coatings or bulk blended polymers that advantageously lower friction between interacting substrate surfaces and lower substrate surface wear.

Disclosed is a lubricant base stock blend comprising a PAO base stock and an alkylated aromatics (AA) base stock, wherein at least the longer portion of the pendant groups attached to the carbon backbones of the PAO molecules have comparable length to at least the longer portion of the side chain groups attached to the aromatic ring structure of the AA molecules. The comparable lengths of at least the longer portion of the pendant groups and the side chain groups lead to enhanced improvement in oxidation stability of the blend.

In some embodiments, a compound has the formula (I) where: R.sub.1 and R.sub.2 are alkyl or, together with the carbon atom to which they are attached, cycloalkyl; R.sub.3, R.sub.4 and R.sub.5 are H or alkyl (formula II); R.sub.6 is alkyl or where: R.sub.7 and R.sub.8 are H, alkyl or, together with the carbon atom to which they are attached, cycloalkyl; R.sub.9 is H or alkyl; X is alkylene or is absent; and p is 0, 1, 2 or 3; and m and n are 0, 1, 2 or 3 provided that m is 0 when R.sub.4 and R.sub.5 are H. The compound is suitable for use as a base stock which provides low volatility for a given viscosity profile. The compound may be used in a lubricant composition for an internal combustion engine.

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A grease composition containing a base oil and a calcium complex soap as a thickening agent, wherein a C18-22 straight chain, substituted or unsubstituted higher fatty acid; a substituted or unsubstituted aromatic monocarboxylic acid having a benzene ring; a C2-4 straight-chain saturated lower fatty acid; and a substituted or unsubstituted saturated dicarboxylic acid are used as carboxylic acids constituting the calcium complex soap.

A grease composition containing a base oil and a calcium complex soap as a thickening agent, wherein a C18-22 straight chain, substituted or unsubstituted higher fatty acid; a substituted or unsubstituted aromatic monocarboxylic acid having a benzene ring; a C2-4 straight-chain saturated lower fatty acid; and a substituted or unsubstituted saturated dicarboxylic acid are used as carboxylic acids constituting the calcium complex soap.

The present disclosure provides a lubricating oil composition which has a viscosity much lower than that of a conventional lubricating oil composition, and which is excellent in metal fatigue life, wear resistance and electrical insulating properties. The lubricating oil composition according to the present disclosure comprises: (A) a lubricating base oil; and (B) from 0.6 to 4.0% by weight, based on the total weight of the lubricating oil composition, of a polydiene having a number average molecular weight of from 500 to 3,000 and containing a functional group on at least one end thereof. The above described lubricating oil composition does not comprise a viscosity index improver, and has a kinematic viscosity at 100 C. of not less than 1 and less than 5 mm.sup.2/s.

A comb polymer can be used for reducing a Noack evaporation loss of a lubricant composition, especially of an engine oil composition. Application of the comb polymer to the lubricant composition can bring about the desired reduction. The comb polymer can include specified amounts of macromonomer and alkyl acrylates. Resulting lubricant compositions can include the comb polymer.

The invention provides a lubricating oil composition for internal combustion engines, containing a base oil composition containing a GTL base oil as a main component, and having % Cn of 14 to 25% and an aniline point of 120 to 126 C., and a comb-like polymethacrylate based viscosity index improver having a weight average molecular weight (Mw) of 400,000 or more, wherein a N sulfur content is 0.3 mass % or less based on a total weight of the lubricating oil composition.