Note: Descriptions are shown in the official language in which they were submitted.
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Case No. 3372
TITLE
Lubricating Compositions
This application claims priority from US 60/592,356, 20 Jul 2004 and US
60/660,650, 11 Mar 2005.
FIELD OF INVENTION
The present invention relates to a method of lubricating an internal
combustion engine by monitoring engine performance and adding an additive
package accordingly. The invention further relates to a composition suitable
for
the method.
BACKGROUND OF THE INVENTION
[0001] It is known to add various additives to an oil of lubricating viscosity
for diesel or gasoline engines, for instance, a 2-stroke engine, to reduce
wear
and improve cleanliness. In diesel engines an oil of lubricating viscosity is
used
particularly to reduce wear of cylinder liners and piston rings. Often engine
operating temperatures and pressures are sufficient to break down the film of
the
oil of lubricating viscosity on the internal walls of the cylinder, and
increased
wear and decreased engine cleanliness due to deposits occurs.
[0002] In many 2-stroke engines, especially marine diesel engines or
stationary power diesel engines, there are two lubricating compositions. One
composition is a system oil of viscosity generally less than 12 mm2/s which is
used to lubricate the crankcase of the 2-stroke engines and has a low Total
Base
Number (TBN). The system oil is normally unsuitable for lubricating cylinder
liners and piston rings because of its low TBN and low viscosity. The second
lubricating composition used in a 2-stroke engine has a higher viscosity and
TBN and is suitable for lubricating cylinder liners and piston rings. This is
sometimes referred to as a cylinder oil. (All viscosities reported herein are
kinematic viscosity measured at 100 C, unless otherwise specified).
[0003] Further, in 2-stroke engines associated with marine vessels or
stationary
power stations, typical fully formulated lubricating compositions suitable for
lubricating cylinder liners and piston rings have a total base number of 70 to
80.
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However, due to variations in sulphur content of fuel, the amount of TBN
required
varies as amount of base required to neutralise sulphuric acid produced during
combustion changes. The presence of excessive amounts of unreacted compounds
in an additive package providing TBN, e.g., detergents, can contribute to the
formation of deposits. To overcome differences in the sulphur content of fuel,
two
or more lubricating compositions with differing TBN are independently
available
for use. One lubricating composition has TBN of 40 to 50 suitable for low
sulphur
containing fuel, whereas the second lubricating composition has a TBN of 70 or
more and is used for higher sulphur containing fuel.
[0004] Increased amounts of deposits and contaminants from cylinder wear
are known to contaminate system oil and/or other unused oil suitable for
lubricating the cylinder liners and piston rings. When contaminated, the
system
oil and/or oil suitable for lubricating the cylinder liners and piston rings
needs to
be replenished to prevent contaminants having a detrimental effect on
performance.
[0005] When the system oil is contaminated to levels exceeding those defined
in CIMAC guidelines titled "Guidelines for the Lubrication of Two-Stroke
Crosshead Diesel Engines," (page 42, section 8, 1997), it is removed from the
crankcase and replenished with fresh system oil. The removed system oil is
typically stored in a sludge tank until it undergoes waste management
treatment.
[0006] US Patent Application 2003/0196632 Al discloses a method to
employ instrumentation to effectuate variation in lubricant flow rate in
response
to actual engine conditions. The method regularly monitors one or more engine
parameters with instruments such as XRF or IR for base number measurement.
The measured engine parameters are used to calculate the feed rate of
lubricant
to the engine.
[0007] US Patent Application 2003/0159672 Al discloses a method of
regularly monitoring one or more engine parameters of an all-loss lubricating
system and calculating from the engine parameters an amount of a secondary
fluid that is required to be added to base fluid to create a modified base
lubricant that is applied to the engine during operations.
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[0008] US Patent Application 2003/0183188 Al discloses a device and a
process for real time optimizing engine lubricating oil properties in response
to
actual operating conditions. The process includes on-line modification of
lubricant properties by repeatedly measuring a system that recirculates a base
lubricant and one or more system condition parameters at a location of
interest.
The process then calculates an amount of secondary fluid to add to the
lubricant
followed by mixing the base fluid with the secondary fluid creating a modified
base lubricant and applying to a location of interest.
[0009] International Application WO 99/64543 Al discloses diesel cylinder
oil having a viscosity of 15 to 27 mm2/s (or cSt), a viscosity index of at
least 95
and a TBN of at least 40 mg KOH/g. The oil is a neutral base stock of no more
than 725 SUS viscosity at 100 C and 2 to 15 wt % of the oil a liquid
polyisobutylene with a viscosity of 1500 to 8000 mm2/s (cSt) at 100 C.
[0010] Therefore it would be advantageous to provide a lubricating
composition and method of imparting the lubricating composition with the
correct properties to control deposit formation, wear and reduced waste
treatment costs. The present invention provides a lubricating composition and
a
method of imparting a lubricating composition with such properties using a
selected additive package to control deposit formation or wear.
SUMMARY OF THE INVENTION
[0011] In one embodiment the present invention provides a method of
lubricating an internal combustion engine with a power output of at least 1600
kilowatts, with a lubricating composition, the method comprising:
(1) monitoring one or more performance characteristics of the
engine;
(2) selecting an additive package to provide a desired TBN level
to a lubricating composition to modify the performance characteristics of
the engine;
(3) combining the additive package of step (2) with (a) a
component having a viscosity of 2 mm2/s to 12 mm2/s, comprising a light
neutral base oil, and optionally (b) a component having a viscosity of
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above 12 mm2/s to 35 mm2/s or 40 mm2/s, comprising heavy neutral base
oil or a brightstock, to form a lubricating composition; and
(4) supplying the lubricating composition of step (3)
to the engine,
wherein the lubricating composition has a total base number of at least
mg KOH/g; and the component comprising the light neutral base oil is
supplied from an oil reservoir available to said internal combustion engine.
[0012] In one embodiment the invention further provides a method of
lubricating an internal combustion engine with a power output of at least 1600
10 kilowatts, with a lubricating composition, the method comprising contacting
(that is, lubricating or supplying) the internal combustion engine with a
lubricating composition comprising:
(a) a 2 mm2/s to 12 mm2/s light neutral base oil;
(b) 0 to 20 weight percent of a heavy neutral base oil or a brightstock
with a viscosity above 12 mm2/s to 40 mm2/s; and
(c) at least one performance additive comprising: a polymeric
thickener, a dispersant, an antiwear agent, a detergent or mixtures thereof;
wherein the polymeric thickener, when present, has a weight average molecular
weight (Mw) of more than 8000 and is present in an amount to provide a total
viscosity of the composition of 12 mm2/s to 29 mm2/s; the dispersant or
detergent when present imparts basicity to said lubricating composition; and
the
composition has a total base number of at least about 10 mg KOH/g.
[0013] In one embodiment the invention further provides a lubricating
composition comprising:
(a) a 2 mm2/s to 12 mm2/s light neutral base oil;
(b) a heavy neutral base oil or a brightstock with a viscosity of above 12
mm2/s to 35 mm2/s or 40 mm2/s; and
(c) at least one performance additive comprising: a polymeric thickener, a
dispersant, an antiwear agent, a detergent or mixtures thereof;
wherein the polymeric thickener when present has a weight average molecular
weight (Mw) of more than 8000 and is present in an amount to provide a total
viscosity of the composition of 12 mm2/s or 15 mm2/s to 26.1 mm2/s or 29
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mm2/s; the dispersant or detergent when present imparts basicity to said
lubricating composition; and the composition has a total base number of at
least
mg KOH/g.
DETAILED DESCRIPTION OF THE INVENTION
5 [0014] The present invention provides a method for lubricating an internal
combustion engine as described above.
[0015] As used herein all viscosity measurements of the light neutral base oil
of heavy neutral base all are at 100 C and quoted in units of mm2/s (or cSt).
[0016] In one embodiment the heavy neutral base oil or brightstock has a
10 viscosity of above 12 mm2/s to 35 mm2/s and in another embodiment a
viscosity
of above 12 mm2/s to 40 mm2/s.
[0017] In one embodiment total viscosity of the lubricating composition is
12 mm2/s or 15 mm2/s to 26.1 mm2/s and in another embodiment 12 mm2/s or 15
mm2/s to 21.9 mm2/s. Typically the lubricating composition with a total
viscosity of 12 mm2/s or 15 mm2/s to 26.1 mm2/s is an SAE 60 grade, and an
SAE 50 grade lubricating composition has a viscosity of 12 mm2/s or 15 mma/s
to 21.9 mm2/s.
[0018] The performance characteristics of an engine which may be
monitored include wear, engine load, variation in TBN, deposits, or corrosion,
and these may be monitored directly or indirectly. It is to be understood that
the
term "monitoring performance characteristics of the engine" not only includes
mechanical or power output measurements, but it further includes chemical or
physical properties of the lubricating oil in the engine. Wear may be measured
by a number of techniques including determining the metal or metal oxide
particles present in scrape down lubricant from a cylinder liner. Other
examples
of monitoring engine performance include measuring the sulphur content of the
fuel, the load of an engine and TBN of the lubricant. A more detailed
description of possible techniques for monitoring performance characteristics
of
an engine is disclosed in US Patent Application 2003/0159672.
[0019] The selection of an additive package to provide a desired TBN level
to a lubricating composition may be determined by analyzing fuel properties
such as sulphur content or other performance characteristics described above.
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In one embodiment when the sulphur content of the fuel is low (often less than
4
wt % of the fuel) the amount of TBN required to neutralise acids produced
during combustion, e.g., sulphuric acid, is reduced and the additive package
may contain less detergent. The TBN provided by the additive package is
typically provided in large part by the presence in the package of an
overbased
detergent, described in greater detail below. In one embodiment the sulphur
content of the fuel is high (often over 4 wt % of the fuel) and as a
consequence
the amount of TBN required from detergent may be higher.
[0020] The total base number (TBN) of the lubricating composition in one
embodiment is 30 or higher, in another embodiment 40 or higher, in another
embodiment 50 or higher, in another embodiment 60 or higher, in another
embodiment 65 or higher and in another embodiment 70 or higher. Examples of
the TBN of the lubricating composition include 40, 50, 60, 65, 70, 80 or 100.
[0021] The selected additive package of step (2) is combined with a base oil
defined above by known methods such as in a blender. In one embodiment the
blender is typically located in situ available relative to an internal
combustion
engine, which will typically have a power output of at least 1600 kilowatts.
In
one embodiment the internal combustion engine has a power output of at least
2000 kilowatts, in another embodiment at least 3000 kilowatts and in another
embodiment at least 4700 kilowatts.
[0022] The lubricating composition of step (3) in one embodiment is
supplied to the combustion engine directly from a "day tank" (or cylinder oil
service tank) and in another embodiment from a storage tank.
[0023] In one embodiment the invention provides a lubricating composition
comprising:
(a) a 2 mm2/s to 12 mm2/s light neutral base oil;
(b) a heavy neutral base oil or a brightstock with a viscosity of above 12
mm2/s to 40 mm2/s; and
(c) at least one performance additive comprising: a polymeric
thickener, a dispersant, an antiwear agent, a detergent or mixtures thereof;
wherein the polymeric thickener when present has a weight average molecular
weight (Mw) of more than 8000 and is present in an amount to provide a total
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viscosity of the composition of 15 mm2/s to 29 mm2/s; the dispersant or
detergent, when present, imparts basicity to said lubricating composition; and
the composition has a total base number of at least 10 mg KOH/g.
[0024] In one embodiment the invention further provides a lubricating
composition comprising:
(a) a 2 mm2/s to 12 mm2/s light neutral base oil;
(b) a heavy neutral base oil or a brightstock with a viscosity above 12
mm2/s to 40 mm2/s;
(c) a polymeric thickener; and
(d) at least one performance additive comprising: a dispersant, an
antiwear agent, a detergent or mixtures thereof;
wherein the polymeric thickener has a weight average molecular weight (Mw)
of more than 8000 and is present in an amount to provide a total viscosity of
the
composition of 15 mm2/s to 29 mm2/s; the dispersant or detergent when present
imparts basicity to said lubricating composition; and the composition has a
total
base number of at least 10 mg KOH/g.
[0025] In one embodiment the invention provides a lubricating composition
comprising:
(a) a 2 mm2/s to 12 mm2/s light neutral base oil;
(b) 0 to 20 weight percent of a heavy neutral base oil or a brightstock
with a viscosity above 12 mm2/s to 40 mm2/s;
(c) a polymeric thickener; and
(d) at least one performance additive comprising: a dispersant, an
antiwear agent, a detergent or mixtures thereof;
wherein the polymeric thickener has a weight average molecular weight (Mw)
of more than 8000 and is present in an amount to provide a total viscosity of
the
lubricating composition of 15 mm2/s to 29 mm2/s (or viscosity grade ranging
from SAE 30 to SAE 60 (typically SAE 50)); the dispersant or detergent when
present imparts basicity to said lubricating composition; and the composition
has a total base number of at least 10 mg KOH/g.
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[0026] In one embodiment the invention employs oil of lubricating viscosity
with a 2 mm2/s to 12 mm2/s (typically with an SAE 30 grade) light neutral base
oil and optionally a heavy neutral base oil or a brightstock with a viscosity
above 12 mm2/s to 40 mm2/s. Such oils include natural and synthetic oils, oil
derived from hydrocracking, hydrogenation, and hydrofinishing, unrefined,
refined and re-refined oils and mixtures thereof. Hydrotreated naphthenic oils
are also known and can be used, as well as oils prepared by a Fischer-Tropsch
gas-to-liquid synthetic procedure as well as other gas-to-liquid oils. In one
embodiment the dispersant mixture of the present invention is useful when
employed in a gas-to-liquid oil.
[0027] The source of the light neutral base oil in one embodiment is a new or
used crankcase system oil from a 2-stroke engine or fresh from a system oil
tank
without further processing. In one embodiment the used system oil is additised
with an additive package to make it useful as a cylinder lubricant. In one
embodiment the used system oil is additised with an additive package to
prolong
oil life or improve performance of the system oil based on the monitoring data
of step (1).
[0028] When present, the heavy neutral base oil or brightstock, in one
embodiment, is used oil from a sump used to lubricate the internal combustion
engine.
[0029] In one embodiment the lubricating composition is an SAE 50 grade
lubricant.
[0030] The light neutral base oil is present in one embodiment from 40 to
99.9, in another embodiment 50 to 99.9, in another embodiment 60 to 99.9 and
in another embodiment 70 to 99.9 weight percent of the lubricating
composition.
[0031] The heavy neutral base oil or brightstock is present in one
embodiment from 0 to 35, in another embodiment 0 to 30, in another
embodiment 0.01 to 25 and in another embodiment 0.05 to 20 weight percent of
the lubricating composition. In one embodiment the heavy neutral base oil is
present from 1 to 25 or 5 to 20 weight percent of the lubricating composition.
[0032] In several other embodiments the amount of heavy neutral base oil or
brightstock is present from 0 to 20 weight percent, or 0 to 10 weight percent
of
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0 to 5 weight percent of the lubricating composition. In one embodiment the
amount of heavy neutral base oil or brightstock is zero weight percent.
Performance Additives
[0033] Optionally the lubricating composition includes at least one
performance additive selected from the group consisting of metal deactivators,
polymeric thickeners, dispersants, antioxidants, antiwear agents, corrosion
inhibitors, antiscuffing agents, extreme pressure agents, foam inhibitors,
demulsifiers, friction modifiers, pour point depressants and mixtures thereof.
Typically, fully-formulated lubricating oil will contain one or more of these
performance additives.
[0034] The total combined amount of the optional performance additives
present in one embodiment from 0 or 0.01 to 25, in another embodiment 0 or
0.01 to 20, in another embodiment 0 or 0.01 to 15 and in another embodiment
0.05 or 0.1 or 0.5 to 10 weight percent of the lubricating composition.
The Polymeric Thickener
[0035] The polymeric thickener includes styrene-butadiene rubbers, ethylene-
propylene copolymers, hydrogenated styrene-isoprene polymers, hydrogenated
radical isoprene polymers, poly(meth)acrylate acid esters, polyalkyl styrenes,
polyolefins (such as polyisobutylene), polyalkylmethacrylates and esters of
maleic anhydride-styrene copolymers. In one embodiment the polymeric
thickener is free of polyisobutylene; and in another embodiment the polymeric
thickener is a polyisobutylene. In one embodiment the polymeric thickener is
poly(meth)acrylate.
[0036] The polymeric thickener in several embodiments has a weight average
molecular weight (Mw) of more than 8000, or 8400 or more, at least 10,000, or
at
least 15,000, or at least 25,000 or at least 35,000. The polymeric thickener
generally has no upper limit on Mw, however in one embodiment the Mw is less
than 2,000,000 in another embodiment less than 500,000 and in another
embodiment less than 150,000. Examples of suitable ranges of Mw include in
one embodiment 12,000 to 1,000,000, in another embodiment 20,000 to 300,000
and in another embodiment 30,000 to 75,000.
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[0037] If a polyisobutylene polymeric thickener is present, the weight average
molecular weight (Mw) may be more than 8000, or 8400 or more, at least 10,000
to 15,000 or 25,000. Examples of a suitable range include more than 8000 to
25,000 or 8400 to 15,000.
[0038] The polymeric thickener in one embodiment is present from 0 or 0.01
to 15 and in another embodiment 0.05 to 10 weight percent of the lubricating
composition.
Antiwear Agent
[0039] In one embodiment of the invention the lubricating composition
further comprises an antiwear agent such as a metal hydrocarbyl
dithiophosphate. Examples of a metal hydrocarbyl dithiophosphate include zinc
dihydrocarbyl dithiophosphates (often referred to as ZDDP, ZDP or ZDTP).
Examples of suitable zinc hydrocarbyl dithiophosphates compounds include the
reaction product(s) of butyl/pentyl, heptyl, octyl, and/or nonyl
dithiophosphoric
acid zinc salts or mixtures thereof.
[0040] In an alternative embodiment the antiwear agent is ashless, i.e., the
antiwear agent is metal-free (prior to mixture with other components). In one
embodiment the metal-free antiwear agent is an amine salt. The ashless
antiwear agent often contains an atom including sulphur, phosphorus, boron or
mixtures thereof.
Detergent
[0041] The invention optionally includes a detergent such as an overbased
sulphonate detergent. The sulphonate detergent of the composition includes
compounds represented by the formula:
(R)k-A-S03M (I)
wherein each Rl is a hydrocarbyl group in one embodiment containing 6 to 40
carbon atoms, in another embodiment 8 to 35 carbon atoms and in another
embodiment 12 to 30 carbon atoms; A may be independently a cyclic or acyclic
divalent or multivalent hydrocarbon group; M is hydrogen, a valence of a metal
ion, an ammonium ion or mixtures thereof; and k is an integer of 0 to 5, for
example 0, 1, 2, 3, 4, 5. In one embodiment k is 1, 2 or 3, in another
embodiment 1 or 2 and in another embodiment 1. In one embodiment M is
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hydrogen and is present on less than 30%, in another embodiment less than
20%, in another embodiment less than 10% and in another embodiment less than
5% of the available M entities, the balance of the M entities being a metal or
ammonium ion.
[0042] In one embodiment k is 1 and Rl is a branched alkyl group with 6 to
40 carbon atoms. In one embodiment k is 1 and Rl is a linear alkyl group with
6 to 40 carbon atoms.
[0043] Examples of suitable sulphonic acids capable of forming the
overbased sulphonate detergent include polypropene benzene sulphonic acid,
undecyl benzene sulphonic acid, dodecyl benzene sulphonic acid, tridecyl
benzene sulphonic acid, tetradecyl benzene sulphonic acid, pentadecyl benzene
sulphonic acid, hexadecyl benzene sulphonic acid and mixtures thereof. In one
embodiment the sulphonic acid includes tridecyl benzene sulphonic acid,
tetradecyl benzene sulphonic acid, octadecyl benzene sulphonic acid,
tetraeicosyl benzene sulphonic acid or mixtures thereof. In one embodiment of
the invention the sulphonic acid is a polypropene benzene sulphonic acid,
where
the polypropene contains 18 to 30 carbon atoms.
[0044] In one embodiment of the invention the sulphonate components are
calcium polypropene benzenesulphonate and calcium monoalkyl and dialkyl
benzenesulphonates wherein the alkyl groups contain at least 10 or 12 carbons,
for example 11, 12, 13, 14, 15, 18, 24 or 30 carbon atoms.
[0045] When M is a valence of a metal ion, the metal may be monovalent,
divalent, trivalent or mixtures of such metals. When monovalent, the metal M
includes an alkali metal such as lithium, sodium, or potassium, and when
divalent, the metal M includes an alkaline earth metal such as magnesium,
calcium or barium. In one embodiment the metal is an alkaline earth metal. In
one embodiment the metal is calcium.
[0046] When A is cyclic hydrocarbon group, suitable groups include
phenylene or fused bicyclic groups such as naphthylene, indenylene,
indanylene,
bicyclopentadienylene or mixtures thereof. In one embodiment A comprises a
benzene ring.
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[0047] When A is an acyclic divalent hydrocarbon group, the carbon chain
may be linear or branched. In one embodiment A is an acyclic linear
hydrocarbon group.
[0048] The overbased sulphonate detergent in one embodiment has a TBN
(total base number) of at least 350, in another embodiment at least 400, in
another embodiment at least 425, in another embodiment at least 450 and in
another embodiment at least 475. In one embodiment the overbased sulphonate
detergent has a TBN of 400 or 500.
[0049] The sulphonate detergent is present in one embodiment at 0.1 to 35,
in another embodiment 2 to 30, in another embodiment 5 to 25 and in another
embodiment 10 to 25 weight percent of the lubricating composition.
Overbasing the Sulphonate Detergent
[0050] In one embodiment the sulphonate detergent is overbased. Overbased
materials, otherwise referred to as overbased or superbased salts, are
generally
single phase, homogeneous Newtonian systems characterised by a metal content
in excess of that which would be present for neutralisation according to the
stoichiometry of the metal and the particular acidic organic compound reacted
with the metal. The overbased materials are prepared by reacting an acidic
material (typically an inorganic acid or lower carboxylic acid, often carbon
dioxide) with a mixture comprising an acidic organic compound, a reaction
medium comprising at least one organic solvent and promoter such as phenol or
a mixture of alcohols. A mixture of alcohols typically contains methanol and
at
least one alcohol with 2 to 7 carbon atoms, and may contain 50-60 mole percent
methanol. The acidic organic material (substrate) will normally have a
sufficient number of carbon atoms to provide a degree of solubility in oil.
The
amount of excess metal is commonly expressed in terms of metal to substrate
ratio. The term "metal to substrate ratio" or "metal ratio" is the ratio of
the total
equivalents of the metal to the equivalents of the substrate. An overbased
sulphonate detergent in one embodiment has a metal ratio of 12.5:1 to 40:1, in
another embodiment 13.5:1 to 40:1, in another embodiment 14.5:1 to 40:1, in
another embodiment 15.5:1 to 40:1 and in another embodiment 16.5:1 to 40:1.
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Furthermore the overbased detergent often has a low in-process viscosity and a
low final viscosity.
[0051] A sulphonate detergent with 500 TBN and its preparation are
disclosed in U.S. Patent 5,792,732. In Example 2 thereof, a 500 TBN all-linear
alkylbenzene sulphonate is prepared by reacting an alkyl benzene sulphonate
from Witco Corp. (now known as Crompton) with Ca(OH)2 and CaO in n-
heptane and methanol and bubbling with CO2. It is also reported in the
aforementioned patent (col. 5) that a 500 TBN overbased sulphonate containing
highly branched alkylbenzene sulphonate is available from Witco Corp. (now
known as Crompton) as Petronate& C-500. Another method for preparing an
overbased sulphonate detergent of high metal ratio is disclosed in U.S. Patent
6,444,625 (see, for instance, column 3, bottom). The latter process includes
providing a sulphonic acid to a reactor, adding a lime reactant for
neutralization
and overbasing, adding a lower aliphatic C1 to C4 alcohol and a hydrocarbon
solvent, and carbonating the process mixture with carbon dioxide during which
process the exotherm of the reaction is maintained between 27 C and 57 C.
Alternatively, a high metal-ratio detergent may be prepared by using a mixture
of short chain alcohols, with or without a hydrocarbon solvent, conducting the
addition of lime reactants and carbon dioxide in multiple iterations, and, if
desired the process of adding lime and carbon dioxide and of removal of
volatile
materials may be repeated. The overbased sulphonate detergent in the present
invention may be used alone or with other overbased sulphonates. In one
embodiment the sulphonate detergent is in a mixture with other sulphonate
detergents. Alternatively a 500 TBN sulphonate detergent may be prepared by
the process shown in Preparative Example S-1.
Preparative Example S-1
[0052] A sample of a 500 TBN sulphonate detergent is prepared using a
vessel with flange and clip, overhead stirrer with paddle and
polytetrafluoroethylene (PTFE) stirrer gland, Dean Stark trap and double
surface condenser, a mantle/thermocouple temperature controller system, the
equipment from just above the mantle to just below the condenser being covered
with glass wool. The vessel is charged with 35.1 parts by weight of C16-C24
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alkylbenzene sulphonic acid and 31.8 parts by weight of mineral oil (SN 150)
and heated to 30 C. The reactor is charged through a port with 11.6 parts by
weight of alcohols containing methanol and a mixture of iso-butanol/amyl
alcohol. The weight ratio of methanol to the mixture of iso-butanol/amyl
alcohol is 1.31. The reactor is charged with 14.9 parts by weight of calcium
hydroxide and the mixture is heated to 54 C at which temperature carbon
dioxide is added to form a carbonated product. The carbonated product is
further treated three more times with similar (or equal) portions of calcium
hydroxide and carbon dioxide. Water is removed by stripping before repeating
the addition of alcohol, calcium hydroxide and carbon dioxide two times. The
product is stripped and filtered.
[0053] Optionally the lubricating composition further includes a phenate
detergent. The phenate detergent is known and includes neutral and overbased
metal salts of a sulphur-containing phenate, a non-sulphurised phenate or
mixtures thereof. Suitable metal salts are the same as those described for the
sulphonate detergent.
[0054] The phenate detergent in one embodiment has a TBN from 30 to 450,
in another embodiment 30 to 350 or 290, in another embodiment 40 to 265, in
another embodiment 50 to 190 and in another embodiment 70 to 175. In one
embodiment the sulphur containing phenate detergent has a TBN of 150, in
another embodiment a TBN of 225 and in another embodiment 250.
[0055] Other suitable detergent compounds include a salicylate, carboxylate,
phosphate, salixarate or mixtures thereof.
Dispersant
[0056] The invention optionally further includes a dispersant. The
dispersant is known and includes an ash-containing dispersant or an ashless-
type
dispersant, "ashless" dispersant being so named because, prior to mixing with
other components of the lubricant, they do not contain metals which form
sulfated ash. After admixture, of course, they may acquire metal ions from
other components; but they are still commonly referred to as "ashless
dispersants." The dispersant may be used alone or in combination with other
dispersants. In one embodiment the ashless dispersant does not contain ash-
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forming metals. Ashless type dispersants are characterised by a polar group
attached to a relatively high molecular weight hydrocarbon chain. Typical
ashless dispersants include a N-substituted long chain hydrocarbon succinimide
such as alkenyl succinimide. Examples of N-substituted long chain alkenyl
succinimides include polyisobutylene succinimide with number average
molecular weight of the polyisobutylene substituent in one embodiment from
350 to 5000, and in another embodiment 500 to 3000. Succinimide dispersants
and their preparation are disclosed, for instance in US Patent 4,234,435.
Succinimide dispersants are typically the imide formed from a polyamine,
typically a poly(ethyleneamine).
[0057] In one embodiment the invention the dispersant is derived from
polyisobutylene, an amine and zinc oxide to form a polyisobutylene succinimide
complex with zinc.
[0058] In one embodiment the dispersant is derived from half ester, ester or
salts of a long chain hydrocarbon acylating agent such as long chain alkenyl
succinic acid/anhydride.
[0059] Another class of ashless dispersant is Mannich bases. Mannich
dispersants are the reaction products of alkyl phenols with aldehydes
(especially
formaldehyde) and amines (especially polyalkylene polyamines). The alkyl
group typically contains at least 30 carbon atoms.
[0060] The dispersant may also be post-treated by conventional methods by a
reaction with any of a variety of agents. Among these are urea, thiourea,
dimercaptothiadiazole or derivatives thereof, carbon disulphide, aldehydes,
ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic
anhydride, acrylonitrile, epoxides, boron compounds, and phosphorus
compounds.
[0061] In one embodiment of the invention the dispersant is borated using a
variety of agents selected from the group consisting of the various forms of
boric acid (including metaboric acid, HBO2, orthoboric acid, H3BO3, and
tetraboric acid, H2B407), boric oxide, boron trioxide, and alkyl borates.
[0062] The borated dispersant may be prepared by blending the boron
compound and the N-substituted long chain alkenyl succinimides and heating
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them at a suitable temperature in one embodiment from 80 C to 250 C, in
another embodiment 90 C to 230 C and in another embodiment 100 C to 210 C,
until the desired reaction has occurred. The molar ratio of the boron
compounds
to the N-substituted long chain alkenyl succinimides is typically 10:1 to 1:4,
in
another embodiment 4:1 to 1:3, and in another embodiment about 1:2. An inert
liquid may be used in performing the reaction. The liquid may include toluene,
xylene, chlorobenzene, dimethylformamide and mixtures thereof.
[0063] Other performance additives may be used, such as an antioxidant
including a diphenylamine, a hindered phenol, a molybdenum dithiocarbamate,
a sulphurised olefin and mixtures thereof (in one embodiment the lubricating
composition is free of an antioxidant); corrosion inhibitors including
octylamine
octanoate; condensation products of dodecenyl succinic acid or anhydride and a
fatty acid such as oleic acid with a polyamine; metal deactivators including
derivatives of benzotriazoles, 1,2,4-triazoles, benzimidazoles, 2-
alkyldithiobenzimidazoles or 2-alkyldithiobenzothiazoles; foam inhibitors
including copolymers of ethyl acrylate and 2-ethylhexylacrylate and optionally
vinyl acetate; demulsifiers including trialkyl phosphates, polyethylene
glycols,
polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene
oxide) polymers; pour point depressants including esters of maleic anhydride-
styrene, polymethacrylates, polyacrylates or polyacrylamides; and friction
modifiers including fatty acid derivatives such as amines, esters, epoxides,
fatty
imidazolines, condensation products of carboxylic acids and polyalkylene-
polyamines and amine salts of alkylphosphoric acids.
Process
[0064] The invention also includes a process to prepare a lubricating
composition, comprising mixing:
(a) a 2 mm2/s to 12 mm2/s light neutral base oil;
(b) a heavy neutral base oil or a brightstock with a viscosity above 12
mm2/s to 40 mm2/s; and
(c) at least one performance additive comprising: a polymeric
thickener, a dispersant, an antiwear agent, a detergent or mixtures thereof;
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wherein the polymeric thickener has a weight average molecular weight (Mw)
of more than 8000 and is present in an amount to provide a total viscosity of
the
composition of 12 mm2/s or 15 mm2/s to 29 mm2/s; the dispersant or detergent
when present imparts basicity to said lubricating composition; and the
composition has a total base number of at least 10 mg KOH/g.
[0065] The mixing conditions include a temperature in one embodiment from
C to 130 C, in another embodiment 20 C to 120 C and in another
embodiment 25 C to 110 C; and for a period of time in one embodiment from
30 seconds to 48 hours, in another embodiment 2 minutes to 24 hours, and in
10 other embodiments 5 minutes to 16 hours or 20 minutes to 4 hours; and at
pressures in one embodiment from 86 kPa to 270 kPa (650 mm Hg to 2000 mm
Hg), in another embodiment 92 kPa to 200 kPa (690 mm Hg to 1500 mm Hg),
and in another embodiment 95 kPa to 130 kPa (715 mm Hg to 1000 mm Hg).
[0066] The process optionally includes mixing other performance additives
15 as described above. The optional performance additives may be added
sequentially, separately or as a concentrate. In one embodiment the
composition
is a concentrate.
Industrial Application
[0067] The lubricating composition of the present invention is useful for an
internal combustion engine, for example stationary combustion engine, such as
a
power station combustion engine; a diesel fuelled engine, a gasoline fuelled
engine, a natural gas fuelled engine or a mixed gasoline/alcohol fuelled
engine.
In one embodiment the internal combustion engine is a 4-stroke and in another
embodiment a 2-stroke engine. In one embodiment the diesel fuelled engine is a
marine diesel engine.
[0068] In one embodiment of the invention provides a method for lubricating
an internal combustion engine, comprising supplying thereto a lubricant
comprising the composition as described herein. The use of the composition
may impart one or more of TBN control, cleanliness properties, antiwear
performance and deposit control.
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[0069] In one embodiment the invention provides a method for lubricating a
2-stroke marine diesel cylinder comprising: lubricating said 2-stroke marine
diesel cylinder with a lubricating composition comprising:
(a) a 2 mm2/s to 12 mm2/s light neutral base oil;
(b) 0 to 20 weight percent of a heavy neutral base oil or a brightstock
with a viscosity above 12 mm2/s to 40 mm2/s;
(c) a polymeric thickener; and
(d) at least one performance additive comprising: a dispersant, an
antiwear agent, a detergent or mixtures thereof;
wherein the polymeric thickener has a weight average molecular weight (Mw)
of more than 8000 and is present in an amount to provide a total viscosity of
the
lubricating composition of 12 mm2/s or 15 mm2/s to 29 mm2/s (or viscosity
grade ranging from SAE 40 to SAE 60); the dispersant or detergent when
present imparts basicity to said lubricating composition; and the composition
has a total base number of at least 10 mg KOH/g.
[0070] The following examples provide an illustration of the invention.
These examples are non exhaustive and are not intended to limit the scope of
the
invention.
EXAMPLES
[0071] All additive components used in Preparative Examples 1-7 are
commercially available from The Lubrizol Corporation. All performance
additives used in the examples quote the weight percent as supplied, including
the conventional amount of diluent oil.
Preparative Example 1: System Oil Composition (P1)
[0072] A system oil is prepared having a TBN of 1-15, containing 1 wt %
dispersant, 0.5 wt % ZDDP, 6 wt % of 250 TBN phenate detergent, 0.5 wt % of
neutral sulphonate detergent and base oil containing light solvent neutral oil
and
brightstock. The system oil composition has a viscosity of 11 mm2/s.
Preparative Example 2: System Oil Composition (P2)
[0073] A System Oil is prepared having a TBN of 2-7, containing 0.5 wt %
dispersant, 0.3 wt % ZDDP, 1.0 wt % of 250 TBN phenate detergent, 1.2 wt %
of neutral sulphonate detergent, 0.2 wt % of an anti-oxidant and base oil
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containing 4.8 wt % of Exxon 150 light neutral base oil and 92.2 wt % of Exxon
600 light neutral base stock. The system oil composition has a viscosity of 11
mm2/s.
Preparative Example 3: SAE 50 Lubricating Oil Composition (P3)
[0074] A core lubricating oil composition is prepared having a TBN of 3-30,
containing 1.5 wt % dispersant, 0.5 wt % of ZDDP, 12 wt % of 250 TBN
phenate, and base oil containing solvent neutral oil and brightstock. The core
lubricating oil composition has a viscosity of 19.5 mma/s.
Preparative Example 4: SAE 50 Lubricating Oil Composition (P4)
[0075] A core lubricating oil composition is prepared having a TBN of 4-10,
containing 1 wt % of borated dispersant, 6.5 wt % of 250 TBN phenate, and
base oil containing solvent neutral oil and brightstock. The core lubricating
oil
composition has a viscosity of 19.5 mm2/s.
Pre-parative Example 5: High TBN Composition (P5)
[0076] A high TBN composition is prepared from a 200 TBN concentrate of
50 wt % of 400 TBN overbased sulphonate detergent and 50 wt % of 500 SN
basestock.
Preparative Example 6: High TBN Composition (P6)
[0077] A high TBN composition is prepared from a 400 TBN concentrate of
80 wt % of 500 TBN overbased sulphonate detergent and 20 wt % of 500 SN
basestock.
Preparative Example 7: Polymeric Thickener Composition (P7)
[0078] Preparative Example 7 is a polymethacrylate viscosity index improver
with a weight average molecular weight, Mw of 105 to 106.
Examples 1-10
[0079] Examples 1-10 are prepared by blending portions of preparative
examples 1-7 as shown:
Weight Percentage of Preparative Examples 1-7
Example TBN Pl P2 P3 P4 P5 P6 P7
EX1 40 94 6
EX2 40 97.3 2.7
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EX3 40 84 16
EX4 40 92 8
EX5 40 90.3 6.7 3
EX6 70 76.5 23.5
EX7 70 89 11
EX8 70 68 32
EX9 70 84.5 15.5
EX10 70 82.5 14.5 3
Example 11 (EX11)
[0080] A lubricating composition is prepared from 79.4 wt % of fresh system
oil from Preparative Example 2, 2.6 wt % of 150 TBN phenate detergent, 15 wt
% of 400 TBN sulphonate detergent, 0.8 wt % of borated dispersant and 2.2 wt
% of the product of Preparative Example 7. The lubricating composition has
TBN of 67.2, and a viscosity of 18.1 mm2/s.
Example 12 (EX12)
[0081] A lubricating composition is prepared with 40.3 wt % of fresh system
oil from Preparative Example 2, 40.3 wt % of used system oil containing
contaminants from an engine stuffing box (a stuffing box is fitted to a
crankcase
to separate system oil from used cylinder oil) from Preparative Example 2. The
used system oil is originally derived from the system oil of Preparative
Example
2. The lubricating composition further contains 2.5 wt % of 150 TBN phenate
detergent, 14.2 wt % of 400 TBN sulphonate detergent, 0.7 wt % of borated
dispersant and 2 wt % of the product of Preparative Example 7. The lubricating
composition has TBN of 67.2, and a viscosity of 18.1 mm2/s.
Example 13 (EX13)
[0082] A lubricating composition is prepared with 81.7 wt % of used system
oil containing contaminants from an engine stuffing box. The used system oil
is
originally derived from the system oil of Preparative Example 2. The
lubricating composition further contains 2.3 wt % of 150 TBN phenate
detergent, 13.4 wt % of 400 TBN sulphonate detergent, 0.7 wt % of borated
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dispersant and 1.9 wt % of the product of Preparative Example 7. The
lubricating composition has TBN of 66.2, and a viscosity of 17.8 mm2/s.
Reference Example 1 (RF1)
[0083] Reference Example is the same as Example 11, except the compound
of preparative Example 7 is absent. Furthermore the system oil is replaced
with
55 wt % of Exxon 600N base oil and 23.7 wt % of Exxon 150 brightstock base
oil. The Reference Examples has TBN of 68.9, and a viscosity of 18.7 mm2/s.
Reference Example 2 (RF2~
[0084] Reference Example is the same as Example 11, except the compound
of preparative Example 7 is absent and ZDDP is present at 0.5 wt %.
Furthermore the system oil is replaced with 55.9 wt % of Exxon 600N base oil
and 23.8 wt % of Exxon 150 brightstock base oil. The Reference Examples has
TBN of 68.9, and a viscosity of 18.7 mm2/s.
Test 1: Cameron Plint Wear Test
[0085] The Cameron Plint TE-77TM is a reciprocating wear tester. In this test
a steel ball upper specimen is reciprocated against a steel flat lower
specimen.
The lubricant sample is initially treated with 3.5 wt % sulphuric acid. The
Cameron Plint is then charged with 10 ml of the sample and heated to 50 C and
held for 20 minutes. The sample is then subject to a load of 240 N over two
minutes while at the same time reciprocation is started at 10 Hz over 15 mm
stroke length. The sample is then heated to 350 C at 2 C per minute and then
held at temperature for 3 hours. At the end of the test the onset of film
failure is
measured. The onset of film failure is determined by the temperature at which
the oil film as measured by the contact potential first falls to 80 % of its
starting
value. The results obtained by testing the lubricants of the indicated
Examples
are as shown:
Example Temperature of Onset of Film Failure ( C)
EX11 320
EX12 300
EX13 290
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RF1 250
RF2 240
[0086] The analysis of the experimental data obtained indicates that presence
of the additive package of the invention provides one or more of TBN control,
cleanliness properties, antiwear performance and deposit control to a system
oil.
Examples 14 to 26
[0087] Examples 14 to 26 contain 2 wt % of various polymethacrylate
polymeric thickeners, 1.5 wt %' of a succinimide dispersant, 7 wt % of a
brightstock base oil, between 67.4 and 72.3 wt % of a light neutral base oil
and
a detergent package. The detergent package in Examples 14 to 22 contains a
mixture of sulphonate detergents with a TBN ranging from 350 to 500 TBN.
Examples 23 to 26 contain a mixture of sulphonate and phenate detergents.
[0088] Reference Example 3 (RF3) is a commercially available marine diesel
cylinder lubricant.
Test 2: Panel Coker
[0089] Approximately 233g of sample is placed in a 250 ml Panel Coker
apparatus and heated to 325 C. The sample is splashed against a metal plate
for
15 seconds and then baked for 45 seconds. The splashing and baking cycle is
continued for approximately 3 hours. The sample is cooled to room temperature
and the amount of deposits left on the metal plate is weighed. The results
obtained by testing the lubricants of the indicated Examples are as shown: .
Example Deposits (mg) Example Deposiis (mg)
RF3 121.0 EX20 41.1
EX14 43.2 EX21 78.7
EX15 23.7 EX22 101.8
EX16 77.3 EX23 27.4
EX17 57.7 EX24 55.3
EX18 45.7 EX25 22.6
EX19 106.2 EX26 62.8
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[0090] In summary the results of the Panel Coker test demonstrate that the
composition of the invention has reduced deposit formation than a conventional
marine diesel cylinder lubricant.
[0091] While the invention has been explained, it is to be understood that
various modifications thereof will become apparent to those skilled in the art
upon reading the specification. Therefore, it is to be understood that the
invention disclosed herein is intended to cover such modifications as fall
within
the scope of the appended claims.
[0092] Each of the documents referred to above is incorporated herein by
reference. Except in the Examples, or where otherwise explicitly indicated,
all
numerical quantities in this description specifying amounts of materials, reac-
tion conditions, molecular weights, number of carbon atoms, and the like, are
to
be understood as modified by the word "about." Unless otherwise indicated,
each chemical or composition referred to herein should be interpreted as being
a
commercial grade material which may contain the isomers, by-products,
derivatives, and other such materials which are normally understood to be
present in the commercial grade. However, the amount of each chemical
component is presented exclusive of any solvent or diluent oil, which may be
customarily present in the commercial material, unless otherwise indicated. It
is
to be understood that the upper and lower amount, range, and ratio limits set
forth herein may be independently combined. Similarly, the ranges and amounts
for each element of the invention may be used together with ranges or amounts
for any of the other elements. As used herein any member of a genus (or list)
may be excluded from the claims.
[0093] As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl
group" is used in its ordinary sense, which is well-known to those skilled in
the
art. Specifically, it refers to a group having a carbon atom directly attached
to
the remainder of the molecule and having predominantly hydrocarbon character.
Examples of hydrocarbyl groups include:
(i) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl),
alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-,
aliphatic-,
and alicyclic-substituted aromatic substituents, as well as cyclic
substituents
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wherein the ring is completed through another portion of the molecule (e.g.,
two
substituents together form a ring);
(ii) substituted hydrocarbon substituents, that is, substituents containing
non-hydrocarbon groups which, in the context of this invention, do not alter
the
predominantly hydrocarbon nature of the substituent (e.g., halo (especially
chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso,
and sulfoxy);
(iii) hetero substituents, that is, substituents which, while having a
predominantly hydrocarbon character, in the context of this invention, contain
other than carbon in a ring or chain otherwise composed of carbon atoms.
Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents as
pyridyl, furyl, thienyl and imidazolyl. In general, no more than two, or no
more
than one, non-hydrocarbon substituent will be present for every ten carbon
atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon
substituents in the hydrocarbyl group.
[0094] It is known that some of the materials described above may interact in
the final formulation, so that the components of the final formulation may be
different from those that are initially added. The products formed thereby,
including the products formed upon employing the composition of the present
invention in its intended use, may not be susceptible of easy description.
Nevertheless, all such modifications and reaction products are included within
the scope of the present invention; the present invention encompasses the
composition prepared by admixing the components described above.
24
