Nanoparticle compositions contain a graphene-based material. A preparation process involves providing several components and milling a mixture. The nanoparticle compositions can be used as a lubricant additive to improve tribological performance, in particular to improve anti-friction and anti-wear performance on metal parts. A corresponding lubricant composition contains these nanoparticle compositions.

Nanoparticle compositions contain a graphene-based material. A preparation process involves providing several components and milling a mixture. The nanoparticle compositions can be used as a lubricant additive to improve tribological performance, in particular to improve anti-friction and anti-wear performance on metal parts. A corresponding lubricant composition contains these nanoparticle compositions.

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 (?) and a structural unit derived from a particular monomer (A1), the macromonomer (?) having a (meth)acryloyl group at one end, and having a structural unit derived from a monomer (?1) 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 (?) and a structural unit derived from a particular monomer (A1), the macromonomer (?) having a (meth)acryloyl group at one end, and having a structural unit derived from a monomer (?1) selected from butadiene and hydrogenated butadiene.

Provided is a non-Newtonian engine oil lubricant composition with improved fuel efficiency and engine wear protection. The lubricant composition includes a major amount of a base oil including a Group II base stock and an optional Group V base stock, from 0.1 to 9.0 wt. % of at least one viscosity modifier and from 0.1 to 1.2 wt. % of at least one friction modifier. The non-Newtonian engine oil lubricant composition has a kinematic viscosity at 100 deg. C. of less than or equal to 10 cSt and an HTHS (ASTM D4683) of less than or equal to 2.2 cP at 150 C. Also provided are methods of using the lubricant composition in internal combustion engines and methods of making the lubricant composition.

Provided is a non-Newtonian engine oil lubricant composition with improved fuel efficiency and engine wear protection. The lubricant composition includes a major amount of a base oil including a Group II base stock and an optional Group V base stock, from 0.1 to 9.0 wt. % of at least one viscosity modifier and from 0.1 to 1.2 wt. % of at least one friction modifier. The non-Newtonian engine oil lubricant composition has a kinematic viscosity at 100 deg. C. of less than or equal to 10 cSt and an HTHS (ASTM D4683) of less than or equal to 2.2 cP at 150 C. Also provided are methods of using the lubricant composition in internal combustion engines and methods of making the lubricant composition.

A method for improving fuel efficiency while maintaining or improving deposit control, in an engine lubricated with a lubricating oil. The lubricating engine oil has a composition including from 20 to 85 wt % of a first lubricating oil base stock selected from the group consisting of a Group I base stock, a Group II base stock, a Group III base stock, a Group IV base stock, and combinations thereof; from 5 to 55 wt % of a second lubricating oil base stock comprising at least one ester based Group V base stock; from 5 to 20 wt % of at least one viscosity modifier, and one or more other lubricating oil additives. The lubricating engine oils are useful in internal combustion engines including direct injection, gasoline and diesel engines.

A method for improving fuel efficiency while maintaining or improving deposit control, in an engine lubricated with a lubricating oil. The lubricating engine oil has a composition including from 20 to 85 wt % of a first lubricating oil base stock selected from the group consisting of a Group I base stock, a Group II base stock, a Group III base stock, a Group IV base stock, and combinations thereof; from 5 to 55 wt % of a second lubricating oil base stock comprising at least one ester based Group V base stock; from 5 to 20 wt % of at least one viscosity modifier, and one or more other lubricating oil additives. The lubricating engine oils are useful in internal combustion engines including direct injection, gasoline and diesel engines.

A polymer composition contains a comb-shaped polymer (X) containing the following structural units (a) to (c): (a): a structural unit derived from a short-chain alkyl (meth)acrylate (A) having a short-chain alkyl group having 1 to 5 carbon atoms; (b): a structural unit derived from a long-chain alkyl (meth)acrylate (B) having a long-chain alkyl group having 6 to 32 carbon atoms; and (c): a structural unit derived from a macromonomer (C), a content of the structural unit (a) being 70% by mass or more based on the total structural units of the comb-shaped polymer (X); and a hetero atom-containing base oil (Y). The hetero atom-containing base oil (Y) has a kinematic viscosity at 40? C. of 25 mm.sup.2/s or less.

A polymer composition contains a comb-shaped polymer (X) containing the following structural units (a) to (c): (a): a structural unit derived from a short-chain alkyl (meth)acrylate (A) having a short-chain alkyl group having 1 to 5 carbon atoms; (b): a structural unit derived from a long-chain alkyl (meth)acrylate (B) having a long-chain alkyl group having 6 to 32 carbon atoms; and (c): a structural unit derived from a macromonomer (C), a content of the structural unit (a) being 70% by mass or more based on the total structural units of the comb-shaped polymer (X); and a hetero atom-containing base oil (Y). The hetero atom-containing base oil (Y) has a kinematic viscosity at 40? C. of 25 mm.sup.2/s or less.