A lubricating oil composition comprising at least 50 percent by mass, based on the mass of the composition of an oil of lubricating viscosity and 0.01 to 25 percent by mass, based on the mass of the composition of a polymer comprising units (a) and one or both units (b) and (c):

N(COR.sup.1)(CH.sub.2).sub.x(a)

NH(CH.sub.2).sub.y(b)

N(CH.sub.2CH.sub.2-k(CH.sub.3).sub.kCOOR.sup.2)(CH.sub.2).sub.z (c) where the total number (n) of units (a), (b) and (c) is an integer between 4 and 500; wherein x, y and z are independently 2 or 3; wherein k is zero or 1. The polymer shows good solubility in the lubricating oil and provides friction modification. A method of synthesising a polymer is also disclosed.

A lubricating oil composition comprises a major amount of an oil of lubricating viscosity and a minor amount of an unsymmetrical bis-succinimide, or a mixture of unsymmetrical bis-succinimides, of the structure (I): ##STR00001##
wherein one of R.sub.1 and R.sub.2 is a polyisobutylene group having a weight average molecular weight of 400 to 5,000, as determined by GPC with reference to linear polystyrene standards, and the other of R.sub.1 and R.sub.2 is a hydrocarbon group made by the metallocene-catalysed polymerisation of an -olefin feedstock; and x is from 1 to 10 and is the same for all molecules of structure (I), or an average of all molecules of structure (I) in a mixture of molecules of structure (I).

One or more fatty amines are soluble in a lubricating composition for preventing and/or reducing the metal losses of the parts of an engine, such as a marine engine. The parts are brought into contact with the lubricating composition in order to prevent or reduce the metal losses.

An oleaginous nanoparticle dispersion of nanoparticles having a core of an organic base material immobilized within a surfactant layer, the use thereof as a low ash, or ash-free source of TBN in lubricating oil compositions, and lubricating oil compositions formulated with such oleaginous nanoparticle dispersions.

A lubricating oil composition comprises a major amount of an oil of lubricating viscosity and a minor amount of an unsymmetrical bis-succinimide, or a mixture of unsymmetrical bis-succinimides, of the structure (I):

##STR00001##

wherein one of R.sub.1 and R.sub.2 is a polyisobutylene group having a weight average molecular weight of 400 to 5,000, as determined by GPC with reference to linear polystyrene standards, and the other of R.sub.1 and R.sub.2 is a hydrocarbon group made by the metallocene-catalysed polymerisation of an -olefin feedstock; and x is from 1 to 10 and is the same for all molecules of structure (I), or an average of all molecules of structure (I) in a mixture of molecules of structure (I).

A method for controlling formation and dissipation of at least one oligomeric or polymeric aminic antioxidant in a lubricating oil, during operation of an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and at least one oligomeric or polymeric aminic antioxidant, as a minor component. The at least one oligomeric or polymeric aminic antioxidant is formed over time in situ from at least one monomeric aminic antioxidant during operation of the engine or other mechanical component. The at least one oligomeric or polymeric aminic antioxidant is dissipated over time in the lubricating oil during operation of the engine or other mechanical component. The at least one monomeric aminic antioxidant is present in an amount from greater than 2 to 10 wt. % of the lubricating oil.

Relating to the field of lubricant, more particularly relates to lubricant for marine engine, notably for a two-stroke marine engine. More particularly, relates to a lubricant for a marine engine including at least one lubricant base oil and at least one fatty amine.

Compositions comprising an acrylamide polymer emulsion and a nonionic surfactant suitable for use as friction reducers for hydraulic fracturing are disclosed. The nonionic surfactants include aralkylated phenol ethoxylates, amine ethoxylates, amidoamine ethoxylates, linear or branched alcohol EO/PO alkoxylates, ethoxylated alcohols, alkylphenol ethoxylates, and EO-capped poly(oxypropylene) block copolymers. Improved hydraulic fracturing processes in which an acrylamide polymer emulsion is used as a friction reducer are also described. In these processes, the surfactant is included in the composition with the acrylamide polymer friction reducer, or it is introduced separately into the process. The performance of low-cost polyacrylamide friction reducers can be boosted with a small proportion of certain readily available nonionic surfactants. The inventive compositions are effective in high-salinity environments, and their performance can sometimes exceed that of more-expensive salt-tolerant friction reducers, thereby reducing fresh water demand and enabling greater utilization of produced water.

The present disclosure relates to new and optimized processes for the preparation of micro- and nano-scale capsules containing lubricant chemical additives. The present disclosure also relates to micro- and nano-scale capsules prepared by such processes, which are useful in a variety of applications, including automotive lubricants, diesel lubricants, industrial lubricants, metal-working lubricants, coolants, and process fluids. Micro-and nano-scale capsules prepared as described herein have the required properties that such capsules need to exhibit in order to function effectively and meet the requirements imposed by engine lubrication conditions. The microcapsules may be dispersed in a lubricating oil such that the lubricant exhibits improved stability and anti-wear performance, thereby improving engine fuel efficiency and performance.

A method for preventing or reducing engine knock or pre-ignition in a high compression spark ignition engine lubricated with a lubricating oil by introducing to a combustion chamber of the engine from 0.1 to 5% by volume of the gasoline used a lubricating oil as a formulated oil, said formulated oil having a composition comprising (i) a major amount of a lubricating oil base stock comprising at least 80% by weight of one branched ester having at least 15% of the total carbons in the form of methyl groups, and (ii) a minor amount of at least one ashless amine phosphate antiwear additive. Also provided is a lubricating engine oil for high compression spark ignition engines including (i) a major amount of a lubricating oil base stock comprising at least 80% by weight formula I below: ##STR00001##
esterified (per OH basis) with 25 to 100% isobutyric acid and 0 to 75% 3,5,5-trimethylhexanoic acid, wherein R is a H, methyl, ethyl, isopropyl, or isobutyl, and (ii) a minor amount of at least one amine phosphate ashless antiwear additive.