Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic compound containing boron
Reexamination Certificate
2001-09-24
2004-04-13
McAvoy, Ellen M (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic compound containing boron
C508S287000, C508S371000, C508S373000, C508S375000, C508S390000, C508S502000, C508S539000, C508S586000
Reexamination Certificate
active
06720293
ABSTRACT:
The present invention relates to a low viscosity crankcase lubricant, i.e., SAE J300 classification of 0W or 5W, which exhibits superior performance properties in combustion engines, preferably diesel (compression ignited) engines, especially in heavy duty (HD) diesel engines. Such lubricants may also be referred to as lubricating oils, lubricating oil compositions, and lubricating oil formulations.
The heavy duty trucking market has come to adopt the diesel engine as its preferred power source due to both its excellent longevity and its economy of operation. Specialized lubricants have been developed to meet the more stringent performance requirements of HD diesel engines compared with passenger car engines.
Several engine tests are required to demonstrate satisfactory HD performance, including the Cummins M11 test to evaluate soot-related valve train wear, filter plugging and sludge.
There is a need in the art for low viscosity lubricating oils that are capable of meeting the HD diesel requirements. Surprisingly, a low viscosity lubricating oil which affords improved performance in the Cummins M11 test has now been discovered.
The present invention is based on the discovery that low viscosity lubricating oil compositions, such as heavy duty (HD) diesel lubricating oil compositions, can be successfully formulated provided that the base blend viscosity of the components that exhibit Newtonian behaviour is at least 8.2, such as from 8.2 to 30, preferably 8.2 to 10, mm
2
s
−1
at 100° C.
Thus, in a first aspect, the present invention provides a low viscosity lubricating oil composition, preferably a diesel engine lubricating oil composition, more preferably a heavy duty diesel engine lubricating oil composition, having a CCS viscosity less than 3500 mPa.s at −25° C. and a sulfated ash value of up to 2.0 mass %, based on the mass of the oil composition, which composition comprises an admixture of:
(a) 1 to 10 mass % of a dispersant, based on the mass of the oil composition;
(b) 0.05 to 0.60 mass % of elemental calcium or 0.05 to 0.30 mass % of elemental magnesium or both the calcium and magnesium in the corresponding amounts, based on the mass of the oil composition, wherein the calcium or magnesium or both calcium and magnesium are derived from one or more detergents;
(c) 0 to 0.16 mass %, based on the mass of the oil composition, of phosphorus, preferably derived from a zinc dihydrocarbyl dithiophosphate;
(d) 0 to 5 mass % of an antioxidant, based on the mass of the oil composition;
(e) 0 to 2 mass % of a pour depressant, based on the mass of the oil composition;
(f) 0 to 2 mass % of a viscosity modifier, expressed as solid polymer, based on the mass of the oil composition; and
(g) the balance a lubricating oil basestock selected from the group consisting of Group I, II, III, IV IV, V basestocks and any mixture thereof,
with the proviso that when all the components, which exhibit Newtonian behaviour, are admixed together, the base blend viscosity of the resulting admixture or composition is at least 8.2 mm
2
s
−1
at 100° C.
For the avoidance of doubt, components (c), (d), (e) and (f) can be optional.
In a second aspect, the present invention provides a method for preparing the lubricating oil composition of the first aspect which comprises the steps of selecting components (a) to (g) so as to provide a composition having a base blend viscosity, as defined in the first aspect, of at least 8.2 mm
2
s
−1
at 100° C., and thereafter admixing the components so as to provide a lubricating oil composition having a CCS viscosity of less than 3500 mPa.s at −25° C.
In a third aspect, the present invention provides a method of lubricating an engine, preferably a diesel engine, especially a heavy duty engine, which comprises supplying to the engine a lubricating oil composition of the first aspect.
In a fourth aspect, the present invention provides the use of a lubricating oil composition of the first aspect for meeting the requirements in the M11 cross-head wear engine test.
In a fifth aspect, the present invention provides a method of meeting the requirements of the M11 cross-head wear engine test, which comprises using a lubricating oil composition of the first aspect in the test.
As used herein, all mass % numbers are on an active ingredient (a.i.) basis unless otherwise noted, and a.i. refers to the additive material which is not diluent or carrier oil.
As used herein, the term “base blend viscosity” refers to the viscosity, measured according to ASTM D445, of a composition comprising, or an admixture of, components that exhibit Newtonian behaviour, which in the present invention are all the components (including the carrier oil such as the basestock) but excluding the solid polymer or ‘active ingredient’ of the viscosity modifier, which is considered not to exhibit Newtonian behaviour. Thus, the base blend viscosity can refer to the viscosity of a composition comprising the basestock oil, the dispersant, the detergent, the ZDDP, the antioxidant, all carrier oils and diluent oils of the components, the pour depressant and any other components which exhibit Newtonian behaviour, such as anti-foamants.
According to the present invention, it is found that if the base blend viscosity parameter is satisfied, and if the CCS viscosity of the lubricating oil composition, which may comprise a viscosity modifier, is less than 3500 mPa.s at −25° C., then the composition will pass the Cummins M11 200 hour cross-head wear test, which satisfies ACEA E5 and API CH-4 specification limits.
Computer modeling systems may also be employed to predict the base blend viscosity of a lubricating oil composition based on the viscosity of the components present therein.
It will be understood that the additives of the composition may react under the conditions of formulation, storage, or use and that the present invention also extends to the product obtainable or obtained as a result of any such reaction.
In a preferred aspect of the present invention, the oil composition of the present invention has less than 1.5% of ash, preferably less than 1.25%, especially less than 1% of ash, such as in the range from 0 to 0.5% ash, according to method ASTM D874.
Preferably the amount of phosphorus in the lubricating oil composition is 0 to 0.14 or 0.12, especially less than 0.09, less than 0.08, less than 0.07 or less than 0.06, mass %; more preferably at most 0.05, at most 0.04 or at most 0.03, mass %; such as in the range from 0.001 to 0.03 mass %; for example at most 0.02, or at most 0.01, mass %. In a preferred embodiment, the phosphorus content is zero in the lubricating oil composition.
Preferably, the lubricating oil composition contains, independent of the amount of phosphorus, 0 to 2, preferably at most 1.5, such as at most 1, mass %, based on the mass of the oil composition, of sulfur. In a preferred aspect, the amount of sulfur is at most 0.4, at most 0.3 or at most 0.25, mass %; especially at most 0.2, or at most 0.15, mass %; such as in the range from 0.001 to 0.1 mass %. In a more preferred aspect, the sulfur content is zero in the lubricating oil composition.
The amount of elemental phosphorus and sulfur in the lubricating oil composition is measured according to ASTM D5185.
The components of the invention will now be discussed in further detail as follows.
Dispersant (a)
The dispersant comprises an oil-soluble polymeric hydrocarbon backbone having functional groups that are capable of associating with particles to be dispersed.
Dispersants are preferably present in amounts of from 1 to 7, more preferably 1.5 to 6.5, such as 3 to 6 or 5, mass %. Typically, the dispersants comprise amine, alcohol, amide, or ester polar moieties attached to the polymer backbone often via a bridging group. The dispersant may be, for example, selected from oil-soluble salts, esters, amino-esters, amides, imides, and oxazolines of long chain hydrocarbon substituted mono- and dicarboxylic acids or their anhydrides; thiocarboxylate derivatives of long chain hydrocarbons; long chain aliphatic hy
Bovington Charles H.
Kelly Terence
Locke Christopher J.
Infineum International Ltd.
McAvoy Ellen M
LandOfFree
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