An object of the present invention is to provide a grease composition which has little influence on the environment and has good rust prevention and water resistance against salt water such as sea water. The grease composition comprises a biodegradable base oil and a rust-preventive agent comprising a calcium sulfonate complex and a sorbitan fatty acid ester, wherein a total content of biodegradable organic substances in the grease composition is 75% by mass or more, and wherein a content of the rust-preventive agent is 2.5 to 30% by mass.

A refrigerating machine oil containing: a lubricating base oil; and a polymer additive, wherein a carbon residue of 10% residual oil is 0.05% by mass or more.

A refrigerating machine oil containing: a lubricating base oil; and a polymer additive, wherein a carbon residue of 10% residual oil is 0.05% by mass or more.

The invention relates to a lubricant composition comprising: at least one base oil for coming into contact with food, selected from the groups II, III or V according to the categories defined in the API classification or the equivalents thereof according to the ATIEL classification; at least one hydrogenated polyisobutylene; and at least one ester polymer.

The invention relates to a lubricant composition comprising: at least one base oil for coming into contact with food, selected from the groups II, III or V according to the categories defined in the API classification or the equivalents thereof according to the ATIEL classification; at least one hydrogenated polyisobutylene; and at least one ester polymer.

An object is to provide a viscosity index improver composition that is capable of properly regulating the HTHS viscosity in the effective temperature range of a lubricating oil composition to a lower range, and a lubricating oil composition containing the viscosity index improver composition, and the viscosity index improver composition contains a comb-shaped polymer (A) containing a structural unit derived from a macromonomer (α) and a structural unit derived from a particular monomer (A1), the macromonomer (α) having a (meth)acryloyl group at one end, and having a structural unit derived from a monomer (α1) selected from butadiene and hydrogenated butadiene.

An object is to provide a viscosity index improver composition that is capable of properly regulating the HTHS viscosity in the effective temperature range of a lubricating oil composition to a lower range, and a lubricating oil composition containing the viscosity index improver composition, and the viscosity index improver composition contains a comb-shaped polymer (A) containing a structural unit derived from a macromonomer (α) and a structural unit derived from a particular monomer (A1), the macromonomer (α) having a (meth)acryloyl group at one end, and having a structural unit derived from a monomer (α1) selected from butadiene and hydrogenated butadiene.

Provided is a carbon transfer film excellent in wear suppression and friction reduction effects. A carbon transfer film 12 contains sp.sup.2-bonded carbon, wherein a ratio of zirconium calculated by elemental analysis of a surface by SEM-EDX measurement is 0.6 mass % or lower, and a thickness is less than 100 nm. A sliding member 1 includes a substrate 11 and a carbon transfer film 12 provided on at least one surface of the substrate 11, wherein the carbon transfer film 12 contains sp.sup.2-bonded carbon and has a thickness of less than 100 nm; and a ratio of zirconium calculated from elemental analysis the carbon transfer film 12 surface by SEM-EDX measurement of is 0.6 mass % or lower. A lubricant composition contains an organic dispersion medium as a lubricant base and nanodiamond particles nanodispersed in the organic dispersion medium, wherein a content ratio of zirconia is lower than 100 mass ppm.

The instant disclosure relates to a lubricant composition having an oil of lubricating viscosity, a polymeric surfactant compound that is an acylated polymer having a number average molecular weight of about 500 to about 50,000 where the polymer comprises a branched olefin having from 8 to 30 carbon atoms. The acylated polymer can further be reacted with an amine or alcohol to form an amide, imide, ester or combinations thereof. The present disclosure further relates to lubricant compositions that exhibit good dispersancy and viscometric performance.

The instant disclosure relates to a lubricant composition having an oil of lubricating viscosity, a polymeric surfactant compound that is an acylated polymer having a number average molecular weight of about 500 to about 50,000 where the polymer comprises a branched olefin having from 8 to 30 carbon atoms. The acylated polymer can further be reacted with an amine or alcohol to form an amide, imide, ester or combinations thereof. The present disclosure further relates to lubricant compositions that exhibit good dispersancy and viscometric performance.