Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic sulfur compound – wherein the sulfur is single bonded...
Patent
1998-11-09
2000-11-28
Howard, Jacqueline V.
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic sulfur compound, wherein the sulfur is single bonded...
508435, 508460, 508574, C10M15920, C10M15922, C10M15924
Patent
active
061535656
DESCRIPTION:
BRIEF SUMMARY
This invention relates to compositions suitable, inter alia, as lubricant additives, and especially to calcium overbased detergents, and more especially to such materials suitable for use as additives to lubricants for use in marine engines.
To meet intense pressures on capital, maintenance, and running costs, marine engine manufacturers are producing new engines designed to minimize fuel and lubricant consumption, and are placing heavy demands on suppliers to provide lubricants that reduce wear and extend the period between overhauls. There is a continuing need for lubricant additives that provide detergency, antioxidant properties, and rust protection, and that neutralize corrosive acids from sulphur-containing fuels. Overbased detergents are uniquely able to fulfil all of these necessary roles.
Lubricant formulators are, as a result of the requirements placed on them by engine manufacturers and users, in turn seeking higher total base number (TBN) overbased detergents, in order to reduce the treat rate while maintaining effectiveness. (In this specification, the TBN of an overbased detergent is the TBN, in mg KOH/g, as measured by ASTM D2896.) There is also a need for products which, while being highly effective as additives, can be more cost-effective than existing products, and which are relatively easy to prepare and to handle.
Overbased metal-containing detergents suitable for use as lubricant additives are typically prepared as concentrates in oil. In such concentrates, a basic metal-containing material is maintained in dispersion or solution in the oil by a surfactant system comprising, for example, phenate, salicylate, sulphonate or naphthenate anions.
Overbased detergents initially contained a single type of anion, for example a member or members of the phenate group, or of the sulphonate group, but for many years compositions have been available that contain anions of two or more such groups, obtained either by adding two or more overbased detergents having different types of anion or by the manufacture of a hybrid material in which two or more anions of different groups are incorporated during the overbasing process. As basic materials, compounds of members of the alkali and alkaline earth groups are used, compounds of calcium being most frequently employed.
For a number of applications, for example, for lubricants for use in marine engines, it is in some cases desirable, for maximum effectiveness, that overbased detergents contain a relatively high proportion of phenate and/or salicylate anions. Such overbased detergents may also be useful in other applications.
The present invention provides a calcium overbased detergent comprising a surfactant system derivable, and preferably derived, from at least two surfactants other than (a) an acid of the formula R.sup.a --CH(R.sup.b)--COOH, wherein R.sup.a represents an alkyl or alkenyl group containing 10 to 24 carbon atoms and R.sup.b represents hydrogen, an alkyl group with 1 to 4 carbon atoms, or a CH.sub.2 COOH group, or an acid anhydride, acid chloride or ester thereof, and (b) a di- or polycarboxylic acid containing from 36 to 100 carbon atoms or an acid anhydride, acid chloride or ester thereof, at least one of the surfactants being a sulphurized or non-sulphurized phenol or a derivative thereof and the other, or at least one other, of the surfactants being a surfactant other than a phenol surfactant, the proportion, measured as described herein, of the said phenol in the surfactant system being at least 35 mass %, and the overbased detergent having a TBN: % surfactant ratio (as hereinafter defined) of at least 15.
Independently of the TBN: % surfactant ratio, the said proportion of phenol in the surfactant system is advantageously at least 45 mass %, preferably at least 55 mass %, especially at least 70 mass %. Independently of the proportion of phenol, the TBN: % surfactant ratio is advantageously at least 16, preferably at least 18, more preferably at least 20, particularly at least 21. Preferably, the phenol proportion and the TBN: % surfa
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Lenack Alain Louis Pierre
Skinner Philip
Exxon Chemical Patents Inc
Howard Jacqueline V.
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