A continuous process for producing a polyurea concentrate or powder. The process includes combing at least one amine and an isocayante 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 grease composition for constant velocity joints can have excellent wear resistance, and may include a base oil (A) and a urea-based thickening agent (B) of formula (B1): R.sup.1—NHCONH—R.sup.3—NHCONH—R.sup.2 (B1), wherein R.sup.1 and R.sup.2 are independently a monovalent C6 to C24 hydrocarbon group, R.sup.1 and R.sup.2 optionally differing; and R.sup.3 is a divalent C6 to C18 aromatic hydrocarbon group, the monovalent hydrocarbon group containing an alicyclic hydrocarbon group and a hydrocarbon chain, and optionally containing an aromatic hydrocarbon group, wherein, in R.sup.1 and R.sup.2 of formula (B1), if the content of the alicyclic hydrocarbon group is X molar equivalent, the content of the hydrocarbon chain is Y molar equivalent, and the content of the aromatic hydrocarbon group is Z molar equivalent, (a) and (b) are satisfied: (a): a value of {(X+Y)/(X+Y+Z)}×100 is 90 or more; (b): an X/Y ratio is 10/90 to 75/25.

The present invention provides a grease composition for electrical contacts, including: a thickener; a base oil; and an organic sulfur compound, wherein the organic sulfur compound is a compound having no heterocycle containing nitrogen in a molecule thereof.

A grease composition containing a urea compound as a thickener, a base oil, an alkaline earth metal salicylate and/or an alkaline earth metal phenate as a first additive constituent, a metal soap, being a stearic acid metal salt, as a second additive constituent, and a calcium sulphonate and/or a zinc naphthenate as a third additive constituent.

A hybrid grease is provided having low coefficients of friction and high wear protection which is employable over a wide temperature range. The hybrid grease includes a combination of a grease based on a silicone oil in conjunction with a grease based on synthetic hydrocarbon oils, mineral oils or polyglycols. The hybrid grease may especially be used to lubricate joints in vehicle parts based on plastic-steel pairings.

A grease composition containing a base oil (A), a urea-based thickener (B), an antioxidant (C), and a rust inhibitor (D), wherein in a particle size distribution curve obtained by measuring the particle size of particles containing the urea-based thickener (B) in the grease composition on a volume basis with light scattering, a peak indicating the maximum frequency satisfies the following Requirements (I) and (II): (I) a particle size indicating the maximum frequency of the peak is 1.0 μm or less; and (II) a half width of the peak is 1.0 μm or less.

A bearing grease includes a base oil and a thickener, and the base oil includes mineral oil and poly-α-olefin. The poly-α-olefin may be a blend of poly-α-olefin having a kinetic viscosity higher than that of the mineral oil and poly-α-olefin having a kinetic viscosity equal to or lower than that of the mineral oil, and the kinetic viscosity of the base oil at 40° C. is in a range of 40 through 90 mm.sup.2/s. The amount of the poly-α-olefin by mass in the base oil is greater than the amount of the mineral oil by mass in the base oil. The worked penetration of the grease is in a range of 200 through 250. The grease reduces flying grease and outgas and has superior low-temperature characteristics.

The invention provides a grease composition for lubricating resins which contains a base oil, a diurea compound represented by formula (I) as a thickener: R.sup.1NHCONHR.sup.2NHCONHR.sup.3 (I) (wherein R.sup.2 represents a bivalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and R.sup.1 and R.sup.3 each independently represent a straight-chain or branched alkyl group having 8 to 22 carbon atoms), and a chained hydrocarbon polymer having a weight-average molecular weight of 20,000 to 300,000.

A lubricating grease composition, and more specifically, to a lubricating grease composition which, when used with an article clamping device, such as a chuck, produces excellent lubricating properties whilst remaining strongly adhered to metal parts in the clamping mechanism of the device and showing enhanced chemical and physical resistance to fluids such as cutting fluids with which they come into contact.

Provided is a grease composition including a thickener and a base oil, in which the thickener is a urea compound represented by formula (1)
R1-NHCONHR2-NHCONHR3(1)
wherein R2 represents a divalent C.sub.6-15 aromatic hydrocarbon group, and R1 and R3 may be the same or different and each represent an C.sub.8-22 alkyl group, a cyclohexyl group, or an C.sub.6-12 aryl group, and as the base oil, one or more types of a compound represented by formula (2) are contained at 40% by mass or more relative to a total mass of the base oil, wherein R4 and R5 may be the same or different and each represent a linear or branched C.sub.10-26 alkyl group, where m and n are real numbers being 0 or more which satisfy m+n=2.