A hydraulic lubricating oil composition is provided which contains a synergistic mixture of three phosphorous antiwear components in order to provide good thermal stability and good demulsibility to the lubricating oil composition.

Provided are a pressure medium oil, containing a Group-14 element-containing organic compound selected from an organic germanium compound, an organic tin compound, and an organic lead compound, and a method for using a pressure medium oil, which includes applying a pressure to a substance via the pressure medium oil. The pressure medium oil does not solidify even under an ultrahigh pressure of more than 3.7 GPa at room temperature (25° C.) and has a low pour point, and hardly dissolves a conductive paste.

A lubricating oil including a lubricating oil base stock as a major component, and one or more lubricating oil additives having at least one protected active group, as a minor component. The one or more lubricating oil additives having at least one protected active group are converted into one or more lubricating oil additives having at least one unprotected active group in the lubricating oil in-service in an engine or other mechanical component. Compositions including one or more lubricating oil additives having at least one protected active group. A method for improving solubility of one or more lubricating oil additives in a lubricating oil. A method for improving oxidative stability of a lubricating oil and extending performance life of one or more lubricating oil additives. A method for improving friction control in an engine or other mechanical component lubricated with a lubricating oil.

A shock absorber oil composition of the invention includes a base oil: (A) at least one of phosphate, amine phosphate salt, phosphite and amine phosphite salt; (B) an amide compound; and (C) an N-substituted derivative of sarcosine.

The lubricating oil composition for a shock absorber of the present invention contains (A) a base oil composed of a mineral oil and/or a synthetic oil, (B) a tertiary amine represented by the following general formula (I), and (C) a zinc dithiophosphate represented by the following general formula (II): ##STR00001## wherein R.sup.1 and R.sup.2 each independently represent an aliphatic hydrocarbon group having from 1 to 5 carbon atoms, and R.sup.3 represents an aliphatic hydrocarbon group having from 12 to 24 carbon atoms in the general formula (I), ##STR00002## wherein R.sup.4 to R.sup.7 each independently represent one selected from an alkyl group and an alkenyl group each having 1 to 24 carbon atoms in the general formula (II).

A novel hydraulic (e.g., a biohydraulic) fluid which has high performance attributes is disclosed herein. Such a novel hydraulic fluid includes a contribution of a range of 10% up to about 85% by weight of at least one of: natural esters, synthetic esters, polyols, a vegetable oil, 1% up to about 40% by weight of polyalphaolefin (PAO), 1% up to about 40% by weight of polyalkylene glycol (PAG), and mixtures thereof, and wherein up to about 10% by weight quantity of one or more additives are introduced to provide desired properties that include at least one of: a high viscosity index, a low pour point, a hydrolytic stability, and an oxidative stability, as part of the hydraulic fluid contribution.

The present invention relates to a multifunctional lubricant composition which serves as a base oil for lubrication or as an additive for lubrication, including, with respect to 100 parts by mass of phosphorus compound (A) having a specific structure specified in the Description, 26 parts by mass to 43 parts by mass of phosphorus compound (B) having a specific structure specified in the Description, 0 parts by mass to 1.3 parts by mass of phosphorus compound (C) having a specific structure specified in the Description, and a total of 0 parts by mass to 1.3 parts by mass of triphenyl phosphate and tricresyl phosphate.

A lubricating composition includes an oil of lubricating viscosity and a low-ash additive system including a low molecular weight amine with a Total Base Number of at least 150, and an N-substituted hydrocarbyl-substituted succinimide dispersant. The low-ash additive system provides the lubricating composition with a significant boost in TBN without substantially lowering the flashpoint. The composition is particularly suited to use as a marine diesel engine lubricant.

Disclosed is a method for preparing a low-viscosity oil including more than 50 wt % of 9-methyl-11-octyl-heneicosane. The method uses a specific metallocene catalyst and makes it possible to prepare a polyalphaolefin oil (PAO) in which the kinematic viscosity at 100° C., measured according to standard ASTM D445, ranges from 3 to 4 mm.sup.2/s.sup.−1. The oil can be used as a high-performance lubricant for lubrication in the fields of engines, gears, brakes, hydraulic fluids, coolants and greases

An ionic liquid composition having the following generic structural formula:

##STR00001##

wherein Z is N or P, and R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are independently selected from hydrogen atom and hydrocarbon groups having one to four carbon atoms with optional interconnection to form a cyclic group that includes Z, and wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are all hydrocarbon groups when Z is P, and X.sup.− is a phosphorus-containing or carboxylate anion, particularly an organophosphate, organophosphonate, or organophosphinate anion, or a thio-substituted analog thereof containing hydrocarbon groups with at least three carbon atoms. Also described are lubricant compositions comprising the above ionic liquid and a base lubricant, wherein the ionic liquid is dissolved in the base lubricant. Further described are methods for applying the ionic liquid or lubricant composition onto a mechanical device for which lubrication is beneficial, with resulting improvement in friction reduction, wear rate, and/or corrosion inhibition.