Polyalkyl(meth)acrylate based polymers which include straight chained C.sub.18-24 alkyl(meth)acrylates and have an average carbon number of 7.0 to 7.5 and a weight-average molecular weight of 300,000 g/mol or greater are a useful component for a lubricant composition. Furthermore, lubricant compositions containing such polymers show improved high temperature-high shear performance, especially in engine oil (EO) compositions.

The present disclosure provides a grease composition with improved water resistance and mechanical stability at high-temperatures, including: at least one base oil; a water insoluble thickener; and a low molecular weight thixotropic polyamide composition having molecular weight distribution characteristics meeting the requirement described by the relationship: $\frac{\left(A+D\right)}{\left(B+C\right)}0.05$
where A=the % mass of the polyamide composition with a molecular weight greater than 1700 AMU; B=the % mass of the polyamide composition with a molecular weight between 1100 AMU and 1300 AMU; C=the % mass of the polyamide composition with a molecular weight between 700 AMU and 1000 AMU; and D=the % mass of the polyamide composition with a molecular weight of 600 AMU or lower (determined by GPC). The grease composition of the present disclosure provides a less than 50 penetration point change as determined by ASTM-D7342, a less than 10 mg weight loss as determined by ASTM-D4170, or both.

Traction fluid additive combination that is usable with any traction fluids base stock is provided. To optimize the traction, low temperature viscosity and shear stability performance, a combination of a polyisobutene and a polymethacrylate may be added to a base oil to obtain a traction fluid with good low temperature viscosity without degrading the shear strength properties of the fluid. To minimize foaming of the traction fluid, a combination of one, two, or more anti-foaming agents may be added to the fluid in addition to a standard additive package.

The invention provides a lubricating oil composition for diesel engines which contains a GTL base oil with a kinematic viscosity at 100 C. of 4.5 to 5.5 mm2/s, a comblike PMA (polymethacrylate) based viscosity index improver and a boron-containing dispersant and/or boron-containing detergent, the total content of the boron-containing dispersant and/or boron-containing detergent in terms of conversion to boron content relative to the total amount of the composition being not less than 0.025 mass %, and which satisfies 0W-30 or 5W-30 in the SAE J300 standard.

The present invention provides a lubricating oil composition for automatic transmissions which comprises: 55 to 85 mass % of a Fischer-Tropsch synthetic oil with a kinematic viscosity at 100 C. of 2 to 4 mm2/s as a low-viscosity base oil; 1 to 10 mass % of an olefin copolymer 5 with a kinematic viscosity at 100 C. of 150 to 1,000 mm2/s as a high-viscosity base oil; and a polymethacrylate with a weight-average molecular weight of 10,000 to 50,000. This lubricating oil composition is such that the viscosity index of the composition is not 10 less than 190, the Brookfield viscosity is not more than 6,000 mPa.Math.s at low temperature (40 C.), the kinematic viscosity at 100 C. is 6 to 7 mm2/s, and the rate of reduction of the kinematic viscosity after a KRL shear stability test (60 C., 20 hr) is kept to within not more 15 than 3%.

A method for improving fuel efficiency and energy efficiency, while maintaining or improving deposit control and cleanliness performance, in an engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil includes a base oil mixture. The base oil mixture includes a lubricating oil base stock as a major component, and at least one cobase stock, as a minor component. The at least one cobase stock is present in an amount sufficient to reduce kinematic viscosity (Kv.sub.100) of the base oil mixture as determined by ASTM D445, while maintaining or controlling cold cranking simulator viscosity (CCSV) of the lubricating oil as determined by ASTM D5293-15, such that the lubricating oil meets both kinematic viscosity (Kv.sub.100) and cold cranking simulator viscosity (CCSV) requirements for a SAE engine oil grade as determined by SAE J300 viscosity grade classification system. A lubricating oil having a composition including a lubricating oil base stock as a major component, and at least one cobase stock, as a minor component.

Polyalkyl(meth)acrylate based comb polymers with weight-average molecular weights of 700,000 g/mol or greater and number-average molecular weights of 130,000 g/mol or greater can be used to improve the high temperature-high shear performance of lubricant compositions, especially of engine oil (EO) compositions. These polymers can be obtained in a reaction mixture comprising monomers, a dilution oil, and an initiator. The resulting lubricant compositions can have improved kinematic viscosity and high temperature high shear performance.

In the field of lubricating compositions for motor vehicles, there is disclosed a lubricating composition of a grade according to the SAEJ300 classification defined by the formula (X) W (Y) wherein X represents 0 or 5 and Y represents an integer ranging from 4 to 20. This lubricating composition includes at least one polyalphaolefinic oil (PAO), from 10 to 80% by weight of the composition of at least one oil of group V and at least one comb polymer. Also isclosed is the use of this lubricating composition for improving the Fuel Eco (FE) of a lubricant or for reducing the fuel consumption of an engine, in particular a motor vehicle engine, notably a motor of a hybrid vehicle.

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 lubricating oil composition for automotive transmissions is disclosed. It offers an automotive transmission (especially a fuel-saving type) which satisfies all requirements as regards the properties of resistance to churning, maintenance of the oil film and low-temperature viscosity. It comprises a GTL low viscosity base oil and a Group 1 high viscosity base oil.