The present invention provides an application of nano copper in a cutting fluid. The nano copper is self-dispersible nano copper with an organic long-carbon chain, wherein the surface of copper metal is coated with a long carbon chain organic matter, and the long chain organic matter is dialkyl dithiophosphoric acid (HDDP) and a derivative thereof. In the present invention, the nano copper substitutes functional additives which comprises one or more of a preservative, an anti-rust agent, a sterilizing agent, a compression-resisting agent and a lubricant to solve the technical problems of the existing fluid in the prior art being unable to simultaneously have efficient anti-corrosion, anti-rust, compression-resistant, lubricating and sterilizing properties as well as the variety, the relatively high amount, the high cost and the limited selection of added additives.

A method for reducing the tendency of a hydrocarbon fluid to oxidise comprises combining an additive having a chemical structure comprising a 6-membered aromatic ring sharing two adjacent aromatic carbon atoms with a 6- or 7-membered saturated heterocyclic ring, the 6- or 7-membered saturated heterocyclic ring comprising a nitrogen atom directly bonded to one of the shared carbon atoms to form a secondary amine and an atom selected from oxygen or nitrogen directly bonded to the other shared carbon atom, the remaining atoms in the 6- or 7-membered heterocyclic ring being carbon with the hydrocarbon fluid. The additive may also be used for protecting a system in which a hydrocarbon fluid is used from the effects of oxidation.

The present invention provides a compound represented by formula (1) (in formula (1), R.sup.1 and R.sup.2 each independently represent a group represented by formula (2) or NHR.sup.0 (where R.sup.1 and R.sup.2 are not simultaneously NHR.sup.0), R.sup.0 represents any one of hydrogen, an alkyl group having 1-20 carbon atoms, an alkenyl group having 2-30 carbon atoms, an aryl group having 6-30 carbon atoms, an alkylaryl group having 7-30 carbon atoms, and an arylalkyl group having 7-30 carbon atoms, each R.sup.3 independently represents hydrogen or a hydrocarbon group having 1-30 carbon atoms, l represents an integer of 0-4, m represents an integer of 1-4 (where m is an integer of 2-4 in the case where R.sup.1 and R.sup.2 are a group represented by formula (2)), and each n independently represents an integer of 0-4, and, in formula (2), R.sup.4 represents a hydrocarbon group having 6-24 carbon atoms, and X.sup.1 and X.sup.2 each independently represent an oxygen atom or a sulfur atom). ##STR00001##

Disclosed is a lubricating oil composition capable of having a good balance of electrical insulation, seizure resistance and wear resistance. In particular, the lubricating oil composition comprises: (A) a lubricant base oil; (B) an alkaline earth metal detergent; (C) a triazole-based compound represented by the following general formula (1) or (2):

##STR00001##

wherein R.sup.1-R.sup.6 are as defined herein; (D) at least one sulfur-containing compound selected from the group consisting of a sulfur-containing heterocyclic ether compound and a sulfide compound; and (E) an ashless dispersant.

The present invention provides an application of nano copper in a cutting fluid. The nano copper is self-dispersible nano copper with an organic long-carbon chain, wherein the surface of copper metal is coated with a long carbon chain organic matter, and the long chain organic matter is dialkyl dithiophosphoric acid (HDDP) and a derivative thereof. In the present invention, the nano copper substitutes functional additives which comprises one or more of a preservative, an anti-rust agent, a sterilizing agent, a compression-resisting agent and a lubricant to solve the technical problems of the existing fluid in the prior art being unable to simultaneously have efficient anti-corrosion, anti-rust, compression-resistant, lubricating and sterilizing properties as well as the variety, the relatively high amount, the high cost and the limited selection of added additives.

Disclosed is a method for reducing corrosion in a hybrid engine. The method includes the steps of lubricating a hybrid engine with a lubricating oil composition having a major amount of an oil of lubricating viscosity; a minor amount of a salicylate detergent derived from an isomerized normal alpha olefin; and a minor amount of a dispersant.

A lubricating oil composition for a transmission, the composition including: (A) a lubricant base oil comprising a mineral base oil and/or a synthetic base oil; and (B) a poly(meth)acrylate having a weight average molecular weight of no more than 25,000, wherein the composition has a kinematic viscosity at 100° C. of 2.5 to 4.9 mm.sup.2/s.

A composite material comprising a plurality of polymer chains fixed to a base and swelled with a mixture which contains a salt and a hydrogen bond-donating compound and has a melting point maintained at 100° C. or less.

A lubricating composition includes at least one base oil, at least one borated dispersant, at least two antioxidants selected from amine antioxidants, phenolic antioxidants substituted with one or more linear or branched alkyl groups having from 1 to 30 carbon atoms, and mixtures thereof, and at least one phosphite polymer having the formula (I) wherein: - each of the R.sup.1, R.sup.2, R.sup.3 and R.sup.4 can be independently selected from the C1-C20 alkyl, C3-C22 alkenyl, C6-C40 cycloalkyl, C7-C40 cycloalkenyl, C1-20 methoxy alkyl glycol ethers and Y-OH groups; - Y is selected from C2-C40 alkylene, C2-C40 alkyl lactone, —R.sup.7— N(R.sup.8)—R.sup.9— groups, in which R.sup.7, R.sup.8 and R.sup.9 are independently selected from hydrogen, C1-C20 alkyl, C3-C22 alkenyl, C6-C40 cycloalkyl, C7-C40 cycloalkenyl, C1-20 methoxy alkyl glycol ethers; - m is an integer from 2 to 100; - n is an integer from 1 to 1000.

A metalworking fluid includes a pH buffer system having one or more organic acids and one or more organic amines. The organic acids, which include aromatic carboxylic acids and C.sub.10 or higher aliphatic carboxylic acids, may replace boric acid, such that boric acid may be excluded from the metalworking fluid. The organic acids may include at least one of phthalic acid, isophthalic acid, and terephthalic acid. The one or more organic amines include aliphatic and aromatic amines having an amine value of at least 50 mg KOH/g. A method of using the metalworking fluid includes shaping a metal by contacting the metal surface with a tool while cooling and lubricating at least one of the metal surface or tool with the metalworking fluid.