This invention encompasses lubricating oil compositions comprising a base oil, a biodiesel fuel and a dispersant. A method for inhibiting viscosity increase in a diesel engine fueled at least in part with a biodiesel fuel is also described.

Polymeric compositions obtainable by free-radical polymerization of at least two different alkyl (meth)acrylates in the presence of at least one ethylene-vinyl ester copolymer, the alkyl (meth)acrylates used being a mixture comprising alkyl (meth)acrylates having linear C.sub.12- to C.sub.60-alkyl radicals and different alkyl (meth)acrylates having linear C.sub.1- to C.sub.11-alkyl radicals and/or branched C.sub.4- to C.sub.60-alkyl radicals and/or cyclic C.sub.5- to C.sub.20-alkyl radicals. The use of such polymeric compositions as pour point depressants for crude oils, mineral oils or mineral oil products.

The present invention relates to novel uses of corrosion inhibitors in fuels and lubricants.

A base oil for a refrigerating machine oil, having cyclic saturates of 40% by mass or less and non-cyclic saturates of 60% by mass or more in saturates, a density at 15? C. of 0.805 g/cm.sup.3 or lower, and a normal paraffin content of 50% by mass or less.

An anticorrosive agent including: a high-consistency material having a lubricant base oil and an amide compound, a composition of a phosphorus compound comprising one or more compounds represented by the general formulae (1) and (2) and a metal, and at least one kind of resin selected from a rosin-based resin, a terpene resin, a terpene phenol resin, a phenol resin, a coumarone-indene resin, and a petroleum resin, wherein a mass ratio of the high-consistency material and the composition is within a range of 50:50 to 98:2, and a content of resin is 2 to 20 parts by mass with respect to 100 parts by mass of the total of the high-consistency material and the composition.

The present invention relates to novel uses of corrosion inhibitors in fuels and lubricants.

A polymer comprises a polymeric backbone, at least one piperidine ester moiety extending from the polymeric backbone, and generally at least one C.sub.8 to C.sub.22 ester moiety extending from the polymeric backbone. The polymer is useful for adjusting the total base number and viscosity index of a lubricant composition. The lubricant composition generally comprises a base oil in addition to the polymer. A method of forming the polymer comprises the steps of providing a first component and providing a second component. The first component comprises at least one of A1) a piperidine methacrylate, or A2) a methacrylate. The second component comprises at least one of B) a C.sub.8 to C.sub.22 methacrylate. Optionally, the method further comprises the step of providing a third component, which comprises at least one of C) a piperidine-ol. The method further comprises at least one reaction step involving the aforementioned components to form the polymer.

Polymeric compositions obtainable by free-radical polymerization of at least two different alkyl (meth)acrylates in the presence of at least one ethylene-vinyl ester copolymer, the alkyl (meth)acrylates used being a mixture comprising alkyl (meth)acrylates having linear C.sub.12- to C.sub.60-alkyl radicals and different alkyl (meth)acrylates having linear C.sub.1- to C.sub.11-alkyl radicals and/or branched C.sub.4- to C.sub.60-alkyl radicals and/or cyclic C.sub.6- to C.sub.20-alkyl radicals. The use of such polymeric compositions as pour point depressants for crude oils, mineral oils or mineral oil products.

A lubricating oil composition including: a lubricant base oil; (A) a first defoaming agent obtainable by a process, the process including the step of: polymerizing (b) at least one defoaming agent monomer in (a) a polymerization solvent under coexistence of (c) a polymer soluble in the polymerization solvent; and (B) a second defoaming agent being a silicone defoaming agent.

A defoaming agent comprising: a polymer comprising a repeating unit represented by the following general formula (1):

##STR00001##

where in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Y.sup.1 is a side chain comprising a linear or branched polysiloxane structure, the polysiloxane structure comprising a repeating unit represented by the following general formula (2) and having a polymerization degree of 5 to 300; and Z.sup.1 is a linking group linking the repeating unit X.sup.2 and the side chain Y.sup.1;

##STR00002##

wherein in the general formula (2), R.sup.1 and R.sup.2 are each independently an organic group having a carbon number of 1 to 18.