The present invention generally relates to lubricating oil compositions comprising a biobased base oil, methods of lubricating an engine with said lubricating oil compositions. Also disclosed is the use of said lubricating oil compositions in an engine.

Provided is a mineral base oil that conforms to viscosity grades VG22 to VG100 as defined in ISO 3448 and exhibits a distillation curve with a temperature gradient Δ|DT| of distillation temperature between two points of 2.0 vol % and 5.0 vol % of distillation amount being 6.8° C./vol % or less. A vacuum pump oil containing the mineral base oil is excellent in vacuum characteristics and can conform to viscosity grades VG22 to VG100 as defined in ISO 3448.

A sliding member has a sliding surface sliding under a wet condition in which a lubricant oil exists. The sliding surface is coated with a laminate film comprising an upper layer and a lower layer. The lower layer comprises hydrogen-free amorphous carbon (hydrogen-free DLC) and carbon particles dispersed on or in the hydrogen-free DLC. The hydrogen-free DLC has a hydrogen content of 5 atom % or less when the lower layer as a whole is 100 atom %. The upper layer comprises boron-containing amorphous carbon (B-DLC) and has protrusions on a surface side of the upper layer along the carbon particles of the lower layer. The B-DLC has a boron content of 1-40 atom % when the upper layer as a whole is 100 atom %. The protrusions have a particle diameter of 0.5-5 m and exist with a density of 20 protrusions/100 m.sup.2 or more.

Provided is a mineral base oil that conforms to viscosity grades VG22 to VG100 as defined in ISO 3448 and exhibits a distillation curve with a temperature gradient |DT| of distillation temperature between two points of 2.0 vol % and 5.0 vol % of distillation amount being 6.8 C./vol % or less. A vacuum pump oil containing the mineral base oil is excellent in vacuum characteristics and can conform to viscosity grades VG22 to VG100 as defined in ISO 3448.

A sliding member has a sliding surface sliding under a wet condition in which a lubricant oil exists. The sliding surface is coated with a laminate film comprising an upper layer and a lower layer. The lower layer comprises hydrogen-free amorphous carbon (hydrogen-free DLC) and carbon particles dispersed on or in the hydrogen-free DLC. The hydrogen-free DLC has a hydrogen content of 5 atom % or less when the lower layer as a whole is 100 atom %. The upper layer comprises boron-containing amorphous carbon (B-DLC) and has protrusions on a surface side of the upper layer along the carbon particles of the lower layer. The B-DLC has a boron content of 1-40 atom % when the upper layer as a whole is 100 atom %. The protrusions have a particle diameter of 0.5-5 m and exist with a density of 20 protrusions/100 m.sup.2 or more.

Provided is a vacuum pump oil which contains a mineral oil (A) having a temperature gradient |*| of complex viscosity between two points of t ( C.) and t10( C.) (where 15t10), as measured using a rotary rheometer at an angular velocity of 6.3 rad/s, of 10 Pa.Math.s/ C. or less, and one or more compounds selected from a phenol-based compound (B) and an amine-based compound (C), and which has a viscosity index of less than 160. The vacuum pump oil has a good ultimate vacuum degree and is excellent in water separability, oxidation stability and shear stability, and is therefore applicable to various applications.

A single chemical composition comprising to clean and/or lubricate fluid encompassing systems and systems' components comprising of fluid conduit(s), and/or fluid reservoir(s), and/or valve(s), and/or device(s).

Fluid encompassing systems that dispense a fluid or fluids for in vitro and/or in vivo procedures and/or for consumption must be cleaned. A fluid encompassing system and this system's encompassing fluid are both susceptible to contamination

This invention's chemical composition performed routinely cleans the contamination of this system, which also helps maintain the chemical and physical properties for this system's encompassing fluid. This chemical composition also lubricates the surfaces of this system's components. Lubricating this system's components such as valves helps enhance the functioning of said system. This chemical composition also improves this system's fluid flow and helps eliminate odor and foul tasting contaminates from this system.

This chemical composition enhances fluid encompassing systems' operation and efficiency, which helps prolong the life span of these systems and said systems' components.

A pressure medium containing at least one Group-14 element-containing organic compound (A) selected from the group consisting of a compound (A1) represented by the general formula (a1) and a compound (A2) represented by the general formula (a2):

##STR00001##

where each of R.sup.a11, R.sup.a12, R.sup.a13, and R.sup.a14 independently represents an alkyl group having 3 to 6 carbon atoms, and Z.sup.a1 represents a carbon atom or a silicon atom:

##STR00002##

where each of R.sup.a21, R.sup.a22, R.sup.a23, and R.sup.a24 independently represents an alkyl group having 3 to 6 carbon atoms, and Z.sup.a2 represents a silicon atom, a germanium atom, a tin atom, or a lead atom.