The grease composition including: a base oil having a kinematic viscosity of 5 to 30 mm.sup.2/s at 100° C., a thickener, a polymer having a weight average molecular weight of 1,000 to 500,000, and an aliphatic amide compound. The grease composition is used for sliding between a metal member and a resin member, and capable of reducing friction between them.

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.

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 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.

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 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.

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 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.

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.

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.