A seal swell agent for a lubricating fluid is described. The invention relates to a seal swell agent for use in lubricating oils, such as engine oils, turbine oils, automatic and manual transmission, or gear, fluids, drivetrain and gear oils and hydraulic fluids. The seal swell agent comprises a diester of sorbitol or a derivative thereof and at least one carboxylic acid. The invention extends to the use of a diester of sorbitol or a derivative thereof and at least one carboxylic acid as a seal swell agent, and a method of maintaining seal integrity.

Compositions have a high content of saturated or unsaturated isoparaffinic hydrocarbons with 12-24 carbon atoms and a polyalkyl (meth)acrylate. A method prepares said compositions to promote the raise of the flash point of hydraulic fluids where a good low temperature flow is important, e.g. compressor oils, shock absorber fluids, power steering fluids, and central hydraulic fluids.

Provided are a shock absorber-lubricating oil composition, a lubricating oil additive, and a method for adjusting the friction characteristics of the shock absorber-lubricating oil composition, capable of making both operation stability and ride comfort compatible with each other. A shock absorber-lubricating oil composition contains a base oil and a friction modifier. The friction modifier contains a pentaerythritol ester. The base oil contains an ester oil as a main component.

The present invention aims to provide a viscosity index improver composition capable of providing a lubricant composition that has an excellent viscosity index improving effect, excellent antifoaming properties, and excellent persistence of the antifoaming properties. The present invention relates to a viscosity index improver composition, containing: a (co)polymer (A) containing a monomer (a) represented by the following formula (1) as an essential monomer; a C18-C40 chain aliphatic alcohol (B); and a base oil, [Chem. 1] ##STR00001##
wherein R.sup.1 is a hydrogen atom or a methyl group; X.sup.1 is a group represented by O or NH; R.sup.2 is a C2-C4 alkylene group; R.sup.3 and R.sup.4 are each independently a C8-C24 linear or branched alkyl group; and p is an integer of 0 to 20, with each R.sup.2 being optionally the same as or different from each other when p is 2 or greater.

This invention provides a water-glycol hydraulic fluid comprises from 0.2 to 0.6% by mass of a dimer acid as a fatty acid lubricant, and more than 0.10% by mass and 0.20% by mass or less of a phosphoric acid ester of Formula (1), wherein the sum of the dimer acid and the phosphoric acid ester is more than 0.35% by mass wherein R.sub.1 and R.sub.2 may be the same or different, each representing a hydrogen atom or a hydrocarbon group having from 1 to 30 carbon atoms, R.sub.3 represents a hydrocarbon group having from 1 to 20 carbon atoms, R.sub.4 represents a hydrogen atom or a hydrocarbon group having from 1 to 30 carbon atoms, and X.sub.1, X.sub.2, X.sub.3 and X.sub.4 may be the same or different, each representing an oxygen atom or a sulfur atom. ##STR00001##

An alkylene oxide derivative represented by formula (1), wherein a ratio Mz/Mw of a weight average molecular weight (Mw) and z average molecular weight (Mz) calculated from a chromatogram obtained by gel permeation chromatography measurement of the alkylene oxide derivative satisfies formula (2) below: $\begin{array}{cc}{Z-\left[O-{\left(PO\right)}_a-{\left(PO\right)}_b/\left(EO\right)c\right]-H]}_n& \left(1\right)\end{array}$$\begin{array}{cc}5M_z/M_{w}60& \left(2\right)\end{array}$
where Z, n, PO, EO, a, b and c are as defined herein; a+b+c10, and b/c=1/55/1; (PO).sub.b/(EO).sub.c indicates that PO and EO are randomly added; and a random ratio x of PO and EO satisfies 0.1x1.

The present invention provides a magnetic viscous fluid comprising a magnetic particle, at least one selected from ester base synthetic oil, ether base synthetic oil, and alkylnaphthalene having an alkyl group with 10 to 20 carbons, an inorganic cation exchanger with a siloxane bond, and silicone oil.

The present disclosure relates to polysiloxanes, processes for preparing polysiloxanes, and hydraulic fluids comprising polysiloxanes. This disclosure also relates to hydraulic fluids comprising one or more polysiloxane compounds and diphosphonate compounds, and to the use of diphosphonate compounds in hydraulic fluids or as additives or components in various compositions, for example to provide fire retardant properties to a fluid or composition. This disclosure also relates to use of the compositions as hydraulic fluids, which may be used in various machines, vehicles and craft, including aircraft.

A liquid composition for providing enhanced lubrication and wear protection, particularly under high-performance and/or extreme-pressure conditions. The composition comprises components that are either solubilized, liquified, or sub-micronized, and are formulated to result in a stable, color-tunable composition that can be stored or implemented over extended periods of time without separation of solid components from the liquid. A composition can either be a lubricant in which the solubilized, liquified, or sub-micronized components are comprised within a base oil, or an additive composition in which the components are formulated to be later added to a base oil. Suitable base oils are industrial, automotive, or open gear oils such as those used in the oil and gas industry, sugar mills, or in rock crushers; rock drill, pneumatic, and air tool oils; anti-seize compounds; cutting, gun, engine, air compressor, or bearing oils; slideway lubricants; and oven, kiln, foundry, metalworking, metalforming, or aerospace lubricants.

Lubricating oil compositions are provided which contain bimodal copolymer compositions, and in particular bimodal ethylene--olefin copolymer compositions. The copolymer compositions comprise first and second ethylene--olefin copolymer components. The bimodal compositions are particularly useful as viscosity or rheology modifiers, e.g., in lubricating oil compositions. Lubricating oil compositions comprising the copolymer compositions advantageously exhibit enhanced shear stability index (SSI) and thickening efficiency (TE) values, while maintaining excellent low-temperature properties such as pour point, mini-rotary viscometer viscosity, and cold crank simulation performance.