A grease composition may contain a base oil (A) and a urea-based thickener (B). Particles containing the urea-based thickener (B) in the grease composition may satisfy requirement (I). The base oil (A) may be a mixed base oil containing a high-viscosity base oil (A1) having a kinematic viscosity at 40° C. of 250 mm.sup.2/s to 550 mm.sup.2/s, a low-viscosity base oil (A2) having a kinematic viscosity at 40° C. of 5.0 mm.sup.2/s to 110 mm.sup.2/s, and an ultra-high viscosity hydrocarbon-based synthetic oil (A3) having a number average molecular weight (Mn) of 2,500 to 4,500 and a kinematic viscosity at 40° C. of 25,000 mm.sup.2/s to 50,000 mm.sup.2/s. The base oil (A) may have a kinematic viscosity at 40° C. of 25 mm.sup.2/s to 105 mm.sup.2/s and a viscosity index of 120 or more. Both low-temperature characteristics and a lubricating life can be achieved.

A grease composition may contain a base oil (A) and a urea-based thickener (B). Particles containing the urea-based thickener (B) in the grease composition may satisfy requirement (I). The base oil (A) may be a mixed base oil containing a high-viscosity base oil (A1) having a kinematic viscosity at 40° C. of 250 mm.sup.2/s to 550 mm.sup.2/s, a low-viscosity base oil (A2) having a kinematic viscosity at 40° C. of 5.0 mm.sup.2/s to 110 mm.sup.2/s, and an ultra-high viscosity hydrocarbon-based synthetic oil (A3) having a number average molecular weight (Mn) of 2,500 to 4,500 and a kinematic viscosity at 40° C. of 25,000 mm.sup.2/s to 50,000 mm.sup.2/s. The base oil (A) may have a kinematic viscosity at 40° C. of 25 mm.sup.2/s to 105 mm.sup.2/s and a viscosity index of 120 or more. Both low-temperature characteristics and a lubricating life can be achieved.

The present invention relates to a lubricating oil composition containing: (A) a poly-α-olefin base oil obtained by using a metallocene catalyst; (B) a mineral oil-based base oil exhibiting a distillation curve with a temperature gradient Δ|Dt| of distillation temperature between two points 2.0 vol % and 5.0 vol % of distillation amount being 6.8° C./vol % or less; and (C) an ester-based base oil in an amount of 6% by mass or more based on a total amount of the composition.

The present invention relates to a lubricating oil composition containing: (A) a poly-α-olefin base oil obtained by using a metallocene catalyst; (B) a mineral oil-based base oil exhibiting a distillation curve with a temperature gradient Δ|Dt| of distillation temperature between two points 2.0 vol % and 5.0 vol % of distillation amount being 6.8° C./vol % or less; and (C) an ester-based base oil in an amount of 6% by mass or more based on a total amount of the composition.

An improved process for making a base oil and for improving base oil yields by combining an atmospheric resid feedstock with a base oil feedstock and forming a base oil product via hydroprocessing. The process generally involves subjecting a base oil feedstream comprising the atmospheric resid to hydrocracking and dewaxing steps, and optionally to hydrofinishing, to produce a light and heavy grade base oil product. A process is also disclosed for making a base oil having a viscosity index of 120 or greater from a base oil feedstock having a viscosity index of about 100 or greater that includes a narrow cut-point range vacuum gas oil. The invention is useful to make Group II and/or Group III/III+ base oils, and, in particular, to increase the yield of a heavy base oil product relative to a light base oil product produced in the process.

An improved process for making a base oil and for improving base oil yields by combining an atmospheric resid feedstock with a base oil feedstock and forming a base oil product via hydroprocessing. The process generally involves subjecting a base oil feedstream comprising the atmospheric resid to hydrocracking and dewaxing steps, and optionally to hydrofinishing, to produce a light and heavy grade base oil product. A process is also disclosed for making a base oil having a viscosity index of 120 or greater from a base oil feedstock having a viscosity index of about 100 or greater that includes a narrow cut-point range vacuum gas oil. The invention is useful to make Group II and/or Group III/III+ base oils, and, in particular, to increase the yield of a heavy base oil product relative to a light base oil product produced in the process.

A hydrocarbon fluid is disclosed that has a pour point of at most −30° C., as measured by ASTM D5950, and that comprises at least 99 wt % of naphthenes and paraffins, based on the total weight of the hydrocarbon fluid, wherein the weight ratio of naphthenes to paraffins is at least 1, as measured by GC-MS, and wherein the paraffins consist essentially of isoparaffins, as determined by GC-FID. In addition, preferred uses of said hydrocarbon fluid are disclosed.

A hydrocarbon fluid is disclosed that has a pour point of at most −30° C., as measured by ASTM D5950, and that comprises at least 99 wt % of naphthenes and paraffins, based on the total weight of the hydrocarbon fluid, wherein the weight ratio of naphthenes to paraffins is at least 1, as measured by GC-MS, and wherein the paraffins consist essentially of isoparaffins, as determined by GC-FID. In addition, preferred uses of said hydrocarbon fluid are disclosed.

A lubricating oil composition for agricultural machines, containing: at least one base oil selected from the group consisting of mineral oil-based base oils and synthetic oil-based base oils; and a polyalkyl methacrylate-based viscosity index improver having a weight average molecular weight of from 20,000 to 80,000, in which a kinematic viscosity at 100° C. is from 8.00 mm.sup.2/s to 10.00 mm.sup.2/s, a kinematic viscosity reduction rate at 100° C. in an ultrasonic shear stability test is 10.0% or less, and a Brookfield viscosity at −40° C. is 20,000 mPa.Math.s or less.

A lubricating oil composition for agricultural machines, containing: at least one base oil selected from the group consisting of mineral oil-based base oils and synthetic oil-based base oils; and a polyalkyl methacrylate-based viscosity index improver having a weight average molecular weight of from 20,000 to 80,000, in which a kinematic viscosity at 100° C. is from 8.00 mm.sup.2/s to 10.00 mm.sup.2/s, a kinematic viscosity reduction rate at 100° C. in an ultrasonic shear stability test is 10.0% or less, and a Brookfield viscosity at −40° C. is 20,000 mPa.Math.s or less.