Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
2002-01-31
2003-11-04
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
Reexamination Certificate
active
06642190
ABSTRACT:
This invention relates to oil-soluble overbased salicylate-phenate detergent additives, or concentrates, for lubricating oil compositions, such as compression-ignited (diesel) marine engine lubricating oil compositions.
The term “marine” does not restrict the engines to those used in water-borne vessels; as is understood in the art, it also includes those for auxiliary power generation applications and for main propulsion stationary land-based engines for power-generation.
One type of marine diesel engine is a medium-speed four-stroke engine, frequently referred to as a trunk piston engine. Lubricants (or lubricating oil compositions) for such engines are known and may be referred to as trunk piston engine oils or TPEO's.
Manufacturers commonly design marine diesel engines to use a variety of diesel fuels, ranging from good quality light distillate fuel with low sulfur and asphaltene content to poor quality intermediate or heavy fuel such as “Bunker C” or residual fuel oil with generally higher sulfur and asphaltene content. Lubricants used in such engines are often contaminated with asphaltene components from the fuel. This leads to severe engine cleanliness problems in service (sometimes referred to as “black paint”), a problem which is particularly widespread in four-stroke trunk piston engines where dirty cam boxes, deposits in piston scraper rings and sludge coatings on crankcase walls are found. Further, the lubricant handling system, for example, the heaters, filters and centrifuges, may function less well. The problem may not be confined to four-stroke engines; two-stoke cross-head engines may also be affected.
EP-A-0 662 508 describes a way of overcoming the problem using a composition that includes, as a detergent, a hydrocarbyl-substituted phenate concentrate having a TBN greater than 300 and a hydrocarbyl-substituted salicylate. The data in Example 2 thereof demonstrate that, for a combination of the two detergents, performance is inferior using more salicylate than phenate compared with more phenate than salicylate.
The present invention surprisingly establishes that, when the salicylate and phenate are present in the form of a complex, superior results are achieved when more salicylate than phenate is used. A complex offers the advantages of superior convenience and handleability.
Complex detergents are known: see, for example International Publication Numbers WO's 97/46643, 97/46644, 97/46645, 97/46646 and 97/46647; and EP-A-0 750 659. But, none of the above specifically describes high salicylate content salicylate-phenate detergents according to this invention.
In a first aspect, the present invention is an oil-soluble overbased salicylate-phenate detergent additive comprising a complex wherein basic material of the detergent is stabilised by both salicylate and phenate surfactants, wherein the mass % of the salicylate, as a percentage of the total surfactant mass, is at least 50, preferably greater than 50, provided that, when said mass % is less than 60, the TBN: mass % surfactant ratio of the detergent is 10 or less.
In a second aspect, the present invention is a lubricating oil composition comprising an admixture of an oil of lubricating viscosity, in a major amount, and a detergent additive of the first aspect of the invention, in a minor amount.
In a third aspect, the present invention is a method of lubricating a trunk piston marine diesel engine comprising supplying to the engine a lubricating oil composition of the second aspect of the invention.
In a fourth aspect, the invention is a combination comprising:
(a) mechanical parts to be lubricated of a trunk piston marine diesel engine; and
(b) a lubricating oil composition of the second aspect of the invention.
In a fifth aspect, the invention is the use of a detergent additive of the first aspect of the invention in a lubricating oil composition to suspend asphaltene components in the composition when used in a trunk piston marine diesel engine.
In this specification:
“Major amount” means in excess of 50 mass % of the composition;
“Minor amount” means less than 50 mass % of the compositions, both in respect of the stated additive and in respect of the total mass % of all of the additives present in the composition, reckoned as active ingredient of the additive or additives;
“Comprises or comprising” or cognate words are taken to specify the presence of stated features, steps, integers, or components, but does not preclude the presence or addition of one or more other features, steps, integers, components or groups thereof;
“TBN” is Total Base Number as measured by ASTM D2896; and
“Oil-soluble” or “oil-dispersable” do not necessarily indicate that the additive(s) are soluble, dissolvable, miscible or capable or being suspended in oil, in all proportions. They do mean, however, that they are, for example, soluble or stably dispersably in oil to an extent sufficient to exert their intended effect in the environment in which the oil is employed. Moreover, the additional incorporation of other additives may also permit incorporation of higher levels of a particular additive, if desired.
All percentages reported are mass % on an active ingredient basis, i.e., without regard to carrier or diluent oil, unless otherwise stated.
The percentage of surfactant in the overbased detergent, and the percentages of the individual surfactants, for example, phenol, in the surfactant system, are the percentages measured by the method set out below, which also indicates how the “standardized TBN” of an overbased detergent is determined.
1. Dialysis of the Overbased Detergent and Determination of Standardized TBN
A known amount (A g, approximately 20 g) of the liquid overbased detergent (substantially free from other lubricating oil additives) is dialysed through a membrane in a Soxhlet extractor (150 mm height×75 mm internal diameter) using n-hexane siphoning at a rate of 3 to 4 times per hour for 20 hours. The membrane should be one that retains substantially all the metal-containing material, and passes substantially all the remainder of the sample. An example of a suitable membrane is a gum rubber membrane supplied by Carters Products, Division of Carter Wallace Inc., New York, N.Y. 10105 under the trade name Trojans. The dialysate and residue obtained on completion of the dialysis step are evaporated to dryness, any remaining volatile material then being removed in a vacuum oven (100° C. at less than 1 torr or less than about 130 Pa). The mass of the dried residue, in grams, is designated B. The percentage (C) of overbased detergent material in the liquid sample is given by the equation:
C
=
B
A
×
100
%
The “standardized TBN” of the overbased detergent (that is, the TBN expressed in a manner which is independent of the amount of diluent) is the TBN measured according to ASTM D2896 on the dried residue.
Background information for the dialysis technique is given by Amos, R. and Albaugh, E. W. in “Chromatography in Petroleum Analysis”, Altgelt, K. H. and Gouw, T. H., Eds, pages 417 to 422, Marcel Dekker, Inc., New York and Basel, 1979.
2. Determination of TBN: % Total Surfactant Ratio
A known amount (D g, approximately 10 g) of the dried residue is hydrolyzed as specified in sections 8.1 to 8.1.2 of ASTM D3712, except that at least 200 ml of 25% by volume hydrochloric acid (sp. gr. 1.18) is used in section 8.1.1. The amount of hydrochloric acid used should be sufficient to effect acidification/hydrolysis of the overbased detergent residue into organic materials (surfactants) and inorganic materials (calcium-containing materials, for example, calcium chloride). The combined ether extracts are dried by passing them through anhydrous sodium sulphate. The sodium sulphate is rinsed with clean ether, and the combined ether solutions are evaporated to dryness (at approximately 110° C.) to yield a hydrolyzed residue. The mass of the dried hydrolyzed residue, in grams, is designated E.
The percentage, Y, of total surfactants in the original liquid overbased detergent is given by the equation
Y
=
E
D
&t
Hammond Steve
Price Mark A.
Skinner Philip
Infineum International Ltd.
McAvoy Ellen M.
LandOfFree
Overbased detergent additives does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Overbased detergent additives, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Overbased detergent additives will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3141241