Inhibited lubricants

Thermal, oxidative and hydrolytic stability. Organic esters and PAO inhibited lubricant base stocks resist oxidative and thermal degradation better than petroleum-based oil petroleum (121 °C), PAO (121-177°C), diesters (149-177°C), and polyol esters (177-218°C). 

Organic compositions claimed to be useful as insecticidal, rust-inhibiting, lubricant und fuel-oil additives were obtained on heating monoolefinic polymers, white phosphorus and S2CI2 or SCI2 to 195-200 for 4 h The reaction may also be initiated by Co -7-radiation at 15-90 °C... 

This contribution presents the degradation reaction mechanisms and processes of lubricants and the factors influencing them. In addition, mechanisms by which antioxidants inhibit lubricant oxidation with respect to specific industrial and engine oil applications are suggested. 

Some additives used as anti-wear agents can also have anti-corrosion properties such as TCP, sebacic acid and azelaic acid. However, corrosion inhibition is a fine balance of competition with the anti-wear/load-carrying capability of the lubricant. Like the anti-wear additive, the corrosion inhibitor is designed to react with the metal surface. Some corrosion inhibitors specifically aimed at preventing static water corrosion of ferrous metals compete with the anti-wear additive for the metal surface to the extent that the resulting lubricant has poorer anti-wear properties than non-corrosion-inhibited lubricants. 

Aquaiox . [Alox] Surfactant corrosion inhibits, lubricant antiwear additive for metalworking fonnulations. 

Inhibited greases were until recently the major and in fact unique material for preserving hardware. Today they tend to be replaced by liquid inhibited lubricants, thin coats and films. Sealing lubricants are used to tighten or to alleviate screwing/unscrewing of threaded joints in engineering, machine-tool construction and the oil and gas industry. 

The development of inhibited polymer materials for antifrictional purposes has been a new approach to the problem of raising performance and durability of friction joints operating in hostile environments. As experience has shown, protective inhibited lubricants are not always efficient for movable joints where the lubricant is squeezed with time from the friction zone. During long-term operation of a friction joint it is necessary that Cl be continuously supplied to the friction zone and the inhibited antifrictional plastics have proved to be most suitable for this purpose [37]. 

One of the ways of improving wear resistance and reliability of sealing elements is filling of porous semis by components able to form a secondary porous system [146]. For example, a blank of a polyurethane foam is impregnated with a mixture of dispersed PE with an inhibited lubricant. The formation of a gel under certain temperature regimes is accompanied by phase distribution within the material. The contact surface of the blank is cleaned by acetone to remove the lubricant. As the acetone evaporates, the prepared zones are zinc-plated and pores freed from the lubricant become filled with zinc. This makes the coating adhere strongly to the surface and allows zinc to penetrate to a depth acceptable for wear limits. 

Since the slider coating film may be in contact with disk lubricant, it is possible that the lubricant may dissolve in and soften the film. This could potentially lead to some flow of the slider coating at the elevated temperatures inside the disk drive. To assess the possibility of film shear flow from the slider, or development of tackiness, the rheological properties of the fluorosurfactant and various concentrations of lubricant were measured. The fluorosurfactant coating is also compared with several other types of alternative coatings in an accelerated tribological test for the ability of the coating to inhibit lubricant transfer and abrasion of the disk by the slider. 

Although the applications of dilute polymer solutions in which viscoelasticity is important are few, two examples may be cited. In the phenomenon of drag reduction, frictional resistance associated with turbulent flow of a liquid is substantially reduced by exceedingly small concentrations of dissolved polymer.29 Although the mechanism is not clearly established, it is evidently related to viscoelastic properties. Another phenomenon associated with polymers in dilute solution is vortex inhibition. Lubrication in bearings and gears is associated with periodic loading patterns, and because of the wide use of oils with polymeric ad-... 

Lithium hydroxide can be used for preparation of numerous lithium salts. The dominant use is the preparation of lithium stearate [4485-12-5], which is added to lubricating greases in amounts up to about 10% by weight. This salt has very low water solubiHty and extends the acceptable viscosity for the grease to both low and high temperatures (see Lubrication and lubricants). Lithium hydroxide is also used in production of dyes (62) and has been proposed as a source of lithium ion for inhibition of alkaH-aggregate expansive reactivity in concrete (63). 

Oil field uses are primarily imidazolines for surfactant and corrosion inhibition (see Petroleum). Besides the lubrication market for metal salts, the miscellaneous market is comprised of free acids used ia concrete additives, motor oil lubricants, and asphalt-paving applications (47) (see Asphalt Lubrication AND lubricants). Naphthenic acid has also been studied ia ore flotation for recovery of rare-earth metals (48) (see Flotation Lanthanides). 

Sulfonic acid salts have found widespread use in the area of corrosion inhibition. Lubrizol Corporation produces a wide variety of sulfonic acids, particularly in the form of magnesium salts, for use in lubricant formulations, anticorrosion coatings, greases, and resins (146,147). Petroleum sulfonates are used in epoxy resin elastomers to improve anticorrosion properties of coatings and sealants (qv) (148,149). 

Sulfuiized and sulfurchlorinated unsaturated compounds and meicaptans are used as lubricant additives (antiwear, friction modification, load-carrying, extreme pressure and temperature, corrosion inhibition, and antioxidants), refinery catalyst regeneration compounds, steel processing (annealing) aids, and vulcanization catalysts (see Lubrication and lubricants). 

Petroleum sulfonates are widely used as solubilizers, dispersants (qv), emulsifiers, and corrosion inhibitors (see Corrosion and corrosion inhibitors). More recentiy, they have emerged as the principal surfactant associated with expanding operations in enhanced oil recovery (66). Alkaline-earth salts of petroleum sulfonates are used in large volumes as additives in lubricating fluids for sludge dispersion, detergency, corrosion inhibition, and micellar solubilization of water. The chemistry and properties of petroleum sulfonates have been described (67,68). Principal U.S. manufacturers include Exxon and Shell, which produce natural petroleum sulfonates, and Pilot, which produces synthetics. 

Other dimer acid markets include intermediates for nitriles, amines and diisocyanates. Dimers are also used in polyurethanes, in corrosion inhibition uses other than for downweU equipment, as a "mildness" additive for metal-working lubricants, and in fiber glass manufacture. 

Ethers, esters, amides and imidazolidines containing an epithio group are said to be effective in enhancing the antiwear and extreme pressure peiformance of lubricants. Other uses of thiiranes are as follows fuel gas odorant (2-methylthiirane), improvement of antistatic and wetting properties of fibers and films [poly(ethyleneglycol) ethers of 2-hydroxymethyl thiirane], inhibition of alkene metathesis (2-methylthiirane), stabilizers for poly(thiirane) (halogen adducts of thiiranes), enhancement of respiration of tobacco leaves (thiirane), tobacco additives to reduce nicotine and to reduce phenol levels in smoke [2-(methoxymethyl)thiirane], stabilizers for trichloroethylene and 1,1,1-trichloroethane (2-methylthiirane, 2-hydroxymethylthiirane) and stabilizers for organic compounds (0,0-dialkyldithiophosphate esters of 2-mercaptomethylthiirane). The product of the reaction of aniline with thiirane is reported to be useful in the flotation of zinc sulfide. 

The products of oil oxidation will attack metals, and this can be prevented by keeping the system free from pro-oxidative impurities and by the use of anti-oxidants. These additives will not, however, prevent rusting of ferrous surfaces when air and water are present in the mineral oil. The presence of absorbed air and moisture is inevitable in lubricating systems and therefore the oil must be inhibited against rusting. These additives, which are homogeneously mixed with the oil, have an affinity for metal, and a strongly absorbed oil film is formed on the metal surface, which prevents the access of air and moisture. 

Rust and oxidation inhibited oils EP lubricants Viscosity (40° o ... 

Brook, J.H.T., Corrosion Control by Lubricating Oils, Proc. Symp. Practical Aspects of Corrosion Inhibition, Soc. Chem. Ind., London (1980)... 

Environments are either gases or liquids, and inhibition of the former is discussed in Section 17.1. In some situations it would appear that corrosion is due to the presence of a solid phase, e.g. when a metal is in contact with concrete, coal slurries, etc. but in fact the corrosive agent is the liquid phase that is always present. Inhibition of liquid systems is largely concerned with water and aqueous solutions, but this is not always so since inhibitors may be added to other liquids to prevent or reduce their corrosive effects — although even in these situations corrosion is often due to the presence of small quantities of an aggressive aqueous phase, e.g. in lubricating oils and hydraulic fluids (see Section 2.11). 

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