Provided are a lubricating oil composition for shock absorber, containing a base oil and a comb polymer having a mass average molecular weight of 510.sup.4 or more and 110.sup.6 or less, which has a high viscosity index and provides a shock absorber capable of keeping a damping force thereof substantially constant at any temperature and exhibiting excellent damping force characteristics; a method of producing the lubricating oil composition for shock absorber; a damping method; and a shock absorber.

This application relates to branched diester compositions that can be used as a base stock for lubricant applications, or as a base stock blend component for use in a finished lubricant or for particular applications, and methods for making the same.

A method for the regeneration of used lubricating oils to produce lubricant base oils includes the steps of (a) removing resin and impurities by distillation, (b) catalytic oxidation treatment and (c) adsorption process. The method can efficiently reduce the color, metal ions, and sulfur content under mild reaction conditions at low cost and obtain high yield of regenerated oil above 85 wt. %.

Provided are; a lubricating oil composition excellent in fuel saving performance, seizure resistance, wear resistance, fatigue lifetime and shear stability, which contains a base oil (A), an olefin polymer (B) having a number average molecular weight of 1,000 or more and 12,000 or less, and a specific sulfur compound (C) and wherein the content of all sulfur atoms based on the total amount of the composition is 1.2% by mass or more and 2.5% by mass or less; and a lubrication method using the lubricating oil composition.

An aircraft hydraulic system utilizes a hydraulic fluid that includes a heat transfer fluid and a friction modifier additive.

A compound having formula (Ph.sub.3C).sub.mAr(OR).sub.n, wherein Ph represents a phenyl group, Ar is an aromatic ring system having from six to twenty carbon atoms, R is C.sub.1-C.sub.18 alkyl or C.sub.7-C.sub.12 aralkyl, m is one or two, and n is an integer from one to four.

The present invention provides a mineral base oil having a kinetic viscosity at 100 C. of 7 mm.sup.2/s or more and less than 10 mm.sup.2/s, a viscosity index of 100 or more, and a temperature gradient |*| complex viscosity between two temperature points of 5 C. and 15 C. of 240 mPa.Math.s/ C. or less as measured with a rotary rheometer at an angular velocity of 6.3 rad/s. The use of the mineral base oil enables easy preparation of a lubricating oil composition and a grease composition having excellent oxidation stability while ensuring the freedom of selection of additives.

The present invention relates to a polyether compound having a halogen atom content of 0.1000% by mass or less in terms of a polymer molecule thereof as measured by combustion ion chromatography and a weight average molecular weight (Mw) of 140,000 or more and 1,000,000 or less.

Disclosed is a method of treating a used hydrocarbon lubricant of ISO Viscosity Grade 46 or higher comprising oxidation products that adversely affect lubricant performance. The hydrocarbon lubricant has a Group II hydrocarbon oil or Group III hydrocarbon oil, optionally one or more lubricant additives, and an amount of varnish. The hydrocarbon lubricant is free of zinc-containing additives. The method comprises adding to the used hydrocarbon lubricant from about 2 percent by weight to about 20 percent by weight of a polyhydroxy polypropylene oxide homopolymer that has a hydroxyl number of from about 12 mg KOH/g to about 58 mg KOH/g as measured according to ASTM D4274.

Levulinic-capped estolides having improved physical properties that make them more desirable and suitable as bio-based industrial or commercial products are disclosed. The physical properties of the disclosed estolide compositions have surprisingly low pour points that are substantially lower than previously known estolide compounds and superior to petroleum-based compounds designed for similar applications.