The present invention relates to the field of multipurpose lubricants which may be used in the various components of automotive vehicles, notably in the engine, the transmission or the hydraulic circuit.

The invention relates to the use of at least one polymer which improves the viscosity index, chosen from hydrogenated copolymers of diene and of aromatic vinyl, in a lubricant composition for decreasing the viscosity of said lubricant composition in the course of the use of said lubricant composition during the lubrication of the various components of an industrial vehicle, notably of a diesel engine industrial vehicle, such as the engine, the gearbox and the hydraulic circuit, said lubricant composition undergoing at least one thermal shear during its use.

A base oil includes an ester compound obtained by reacting a fatty acid component and a monohydric alcohol component. The fatty acid component includes a C.sub.4-C.sub.28 fatty acid. The monohydric alcohol component includes at least one C.sub.4-C.sub.22 straight chain monohydric alcohol and at least one C.sub.4-C.sub.22 branched chain monohydric alcohol. A lubricant oil composition including the base oil is also disclosed.

A base oil includes an ester compound obtained by reacting a fatty acid component and a monohydric alcohol component. The fatty acid component includes a C.sub.4-C.sub.28 fatty acid. The monohydric alcohol component includes at least one C.sub.4-C.sub.22 straight chain monohydric alcohol and at least one C.sub.4-C.sub.22 branched chain monohydric alcohol. A lubricant oil composition including the base oil is also disclosed.

A VM concentrate comprising: from about 60 to about 95 parts (and at least 50 wt %) of a diluent oil (e.g., having a KV100 of about 2 cSt to about 40 cSt); and from about 5 parts to about 40 parts (and at least 6.0 wt %) of a linear triblock copolymer characterized by the formula: D′-PA-D″; wherein D′ represents a block derived from diene, PA represents a block derived from monoalkenyl arene, D″ represents a block derived from diene, and the linear triblock copolymer is present in an amount effective to modify a lubricating kinematic viscosity at approximately 100° C. (KV100) of the concentrate, and wherein the KV100 of the concentrate is about 3000 cSt or less. The linear triblock copolymer may additionally or alternatively have a thickening efficiency span of at most 0.5.

The present invention relates to drilling fluid comprising one or more linear internal olefin having from 15 to 18 carbon atoms and containing less than 25% branching based on the total amount of the linear internal olefin and a hydrogenated Fischer-Tropsch derived product.

A viscosity index improver containing a copolymer (A) whose essential constituent monomer is a monomer (a) having a number average molecular weight of 800 to 4,000 represented by the following formula (1), the copolymer (A) having a solubility parameter in the range of 9.00 to 9.40: ##STR00001##
wherein R.sup.1 is a hydrogen atom or a methyl group; —X.sup.1— is a group represented by —O—, —O(AO).sub.m—, or —NH—, AO is a C2-C4 alkyleneoxy group, m is an integer of 1 to 10, each AO may be the same or different when m is 2 or more, and the (AO).sub.m moieties may be randomly bonded or block-bonded; R.sup.2 is a residue after removal of one hydrogen atom from a hydrocarbon polymer whose essential constituent monomer is butadiene in which the butadiene is present in a proportion of 50% by weight or more based on the weight of R.sup.2, or after removal of one hydrogen atom from a polymer formed by partial hydrogenation of the hydrocarbon polymer; and p represents a number of 0 or 1.

Lubricating composition comprising (i) base oil and (ii) a metal-free phosphonate compound having the general formula P(O)(R.sup.1)(OR.sup.2)(OR.sup.3) wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different and each independently selected from a straight chain or branched, saturated or unsaturated, C.sub.4-C.sub.22 alkyl group. The lubricating composition of the present invention provides improved engine durability, improved wear and friction reduction, improved fuel economy and excellent oxidative stability.

A lubricating agent including an ionic liquid formed from a Bronsted acid (HX) and a Bronsted base (B), wherein the Bronsted base has a linear hydrocarbon group having 10 or more carbon atoms and the difference between the pKa value of the Bronsted acid in water and the pKa value of the Bronsted base in water is 12 or more.

The present invention provides a mineral base oil having a kinetic viscosity at 100 C. of 7 mm.sup.2/s or more and less than 10 mm.sup.2/s, a viscosity index of 100 or more, and a temperature gradient |*| complex viscosity between two temperature points of 5 C. and 15 C. of 240 mPa.Math.s/ C. or less as measured with a rotary rheometer at an angular velocity of 6.3 rad/s. The use of the mineral base oil enables easy preparation of a lubricating oil composition and a grease composition having excellent oxidation stability while ensuring the freedom of selection of additives.

A lubricating composition comprises a major amount of an oil of lubricating viscosity and 0.01 to 25 percent by mass, based on the mass of the composition of an oil-soluble copolymer. The copolymer comprises units (a) and units (b):
N(COR.sup.1)CH.sub.2CH.sub.2(a)
N(COR.sup.2)CH.sub.2CH.sub.2CH.sub.2(b)
wherein the polymer carries an inorganic or organic nucleophilic polymerisation terminating group (t), and an initiator group (i) connected to the N atom of a repeat unit (a) or (b), the initiator group (i) being effective to initiate the polymerisation of linear, branched or cyclic hydrocarbyl moieties. R.sup.1 and R.sup.2 are the same or different and comprise a single or a mixture of linear, branched or cyclic hydrocarbyl groups having 1-50 carbon atoms, some or all having 12-50 carbon atoms, or of at least one macro-monomeric hydrocarbyl group with more than 50 carbon atoms.