The present invention provides a process for preparing a polymer, employing the steps of: (1) contacting a free radical initiator; a chain transfer agent containing a thiocarbonyl thio group and a free radical leaving group; and a radically polymerizable monomer, to form a polymer chain; and (2) contacting the polymer chain of step (1) with at least one of a polyvalent coupling agent, a polymerization inhibitor, a grafting acylating agent, an amine and an oil of lubricating viscosity. The invention further provides compositions and uses for the polymer.

A method of using energy-efficient lubricant compositions to reduce wear between two surfaces exposed to a high shear condition is provided. The lubricant compositions comprise polysiloxane base oils having alkyl, aryl, or a combination of alkyl and aryl functionality. The polysiloxane base oils may be defined according to the formula: ##STR00001##
wherein R, and R′ are independently selected, such that R is an alkyl group having between 1-3 carbon atoms; R′ is an alkyl or aryl group having between 6 to 20 carbon atoms; and m and n are integers, such that 25<(m+n)<500 and the ratio of m/(m+n) is greater than 0.05 and less than 1.00.

[Problem]

From the points of view of improving the fuel efficiency of automobiles and industrial machines and saving energies thereof, the present invention provides lubricants having outstanding shear stability and low-temperature viscosity characteristics.

[Solution]

A lubricant composition includes a lubricant base oil (A) having a kinematic viscosity at 100° C. of 1 to 10 mm.sup.2/s, and an ethylene/α-olefin copolymer (B) in which (B1) the peak top molecular weight is 3,000 to 10,000, (B2) the copolymer shows no melting peak, (B3) the value B is not less than 1.1 and (B4) the kinematic viscosity at 100° C. is 140 to 500 mm.sup.2/s. The lubricant composition has a kinematic viscosity at 100° C. of not more than 20 mm.sup.2/s, a peak top of molecular weight in the range of 3,000 to 10,000, and a weight fraction of components having a molecular weight not less than 20,000 of 1 to 10% relative to all components having a molecular weight not less than the molecular weight that gives the peak top.

A high-molecular-weight compound having a plurality of polymer chains linked through a divalent or higher-valent linking group, in which the divalent or higher-valent linking group has a thiol group and at least one of a thioether structure and a thiourethane structure, and a ratio of an absolute weight-average molecular weight to a relative weight-average molecular weight (absolute Mw/relative Mw) of the high-molecular-weight compound is 1.25 or more; and a method for producing the same are provided.

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.

The invention relates to polymeric-inorganic nanoparticle compositions and preparation processes thereof. The invention also relates to an additive and lubricant compositions comprising these polymeric-inorganic nanoparticle compositions, as well as to the use of these polymeric-inorganic nanoparticle compositions in an oil lubricant formulation to improve tribological performance, in particular to improve extreme pressure performance and friction reduction on metal parts.

A lubricating oil composition including: a lubricating base oil; (A) a first defoaming agent, the first defoaming agent being (A1) a first polymer, or (A2) a second polymer, or any combination thereof; and (B) a second defoaming agent, the second defoaming agent being a silicone defoaming agent, the (A1) first polymer including: a first polymer chain including a polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 2000 and being represented by the following general formula (1); and a second polymer chain bonded with the first polymer chain, the second polymer chain including a repeating unit represented by the following general formula (2), the (A2) second polymer being a copolymer of a first monomer component and a second monomer component, the first monomer component represented by the general formula (7) or (8), the second monomer component represented by the general formula (9).

##STR00001##

The invention relates to lubricating greases based on alkali metal soaps and/or earth-alkali metal soaps and metal complex soaps based on (R)-10-hydroxyoctadecanoic acid and to the use thereof.

A continuous process for producing a polyurea concentrate or powder. The process includes combing at least one amine and an isocyanate in the presence of a liquid diluent or a base oil in a rotor stator mixer. The concentrate comprises a polyurea in a base oil wherein the concentration of from about 20 weight percent to about 50, or 40 or 35 or 30 weight percent of polyurea based on total weight of grease thickener. The powder has particle size of 2 to 400 microns. This concentrate or powder can then be formulated by grease manufacturers to the desired final properties without the need for handling of the isocyanate and amine raw materials.

A lubricating oil composition for hydraulic oils including 10 to 99% by mass of a lubricant base oil (A) with a kinematic viscosity at 100° C. of 1 to 14 mm.sup.2/s, a viscosity index of 100 or more, and a pour point of 0° C. or lower, and 90 to 1% by mass of a liquid random copolymer (B) of ethylene and α-olefin prepared using a specific catalyst, wherein the total amount of (A) and (B) is 100% by mass, and having a kinematic viscosity at 100° C. of 10 to 300 mm.sup.2/s.