Note: Descriptions are shown in the official language in which they were submitted.
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METHOD OF LUBRICATING-AN ALUMINIUM SILICATE COMPOSITE SURFACE WITH A LUBRICANT
COMPRISING ASHLESS, SULPHUR, PHOSPHORUS FREE ANTIWEAR AGENT
FIELD OF INVENTION
The invention provides a method of lubricating an aluminium-alloy or
aluminium composite surface by supplying to the surface a lubricating
composition comprising an oil of lubricating viscosity and an ashless antiwear
agent. The invention further provides a lubricating composition suitable for
lubricating the aluminium-alloy or aluminium composite surface.
BACKGROUND OF THE INVENTION
[0001] It is well known for lubricating oils to contain a number of
additives
used to protect the mechanical devices such as internal combustion engines
from
wear, soot deposits and acidity build up. A common antiwear additive for
engine
lubricating oils is zinc dialkyldithiophosphate (ZDDP). It is believed that
ZDDP
antiwear additives protect the engine by forming a protective film on metal
surfaces.
[0002] In recent years engine lubricants containing phosphorus compounds
and sulphur have been shown to contribute in part to particulate emissions,
and
emissions of other pollutants. In addition, sulphur and phosphorus tend to
poison the catalysts used in catalytic converters, resulting in a reduction in
performance of said catalysts.
[0003] Other developments in engine technology, such as new engine
design,
employ non-ferric components or whole engines. Typically non-ferric engines or
components thereof, are based on aluminium-alloy, silicates, oxides, or other
ceramic materials. However, well known antiwear agents ZDDP, are believed
to result in poorer engine wear performance in aluminium-alloy based engine
compared with ferric based engines.
[0004] In addition, with increasing control of emissions (often
associated
with contributing to NO formation, SO x formation, formation of sulphated ash
and reducing the efficiency of after-treatment catalytic converters) there a
desire
towards reduced amounts of sulphur, phosphorus and sulphated ash in engine
oils. However, reducing the levels of antiwear additives such as ZDDP, is
likely
to increase wear and result in other detrimental performance of an engine.
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[0005] US Patent Application 2006/0025315 discloses a method of lubricating
an
aluminium alloy surface with a lubricating composition containing an effective
friction reducing amount of an oil soluble tri-nuclear organo-molybdenum
compound.
[0006] Canadian Patent CA 1 183 125 discloses lubricants for gasoline
engines containing alkyl-ester tartrates, where the sum of carbon atoms on the
alkyl groups is at least 8.
[0007] Consequently, it would be desirable to provide an alternative
antiwear
agent capable of at least one of (i) reducing or preventing phosphorus
emissions,
(ii) reducing or preventing sulphur emissions, and (iii) wholly or partially
replacing ZDDP in lubricating oils. The present invention provides an antiwear
agent capable of achieving at least one of (i), (ii) or (iii). In addition it
may also
be desirable for the antiwear agent to not have a detrimental affect on other
components of a mechanical device e.g., a seal or to provide lead and/or
copper
corrosion inhibition.
SUMMARY OF THE INVENTION
[0008] In one embodiment the invention provides a method of lubricating an
aluminium-alloy or aluminium composite surface comprising supplying to the
aluminium-alloy or aluminium composite surface a lubricating composition
comprising an oil of lubricating viscosity and an ashless, phosphorus-free,
sulphur-free antiwear agent.
[0009] In one embodiment the aluminium-alloy or aluminium composite
surface is an aluminium-silicate surface.
[0010] In one embodiment the invention provides a method of lubricating an
internal combustion engine comprising an aluminium-alloy or aluminium
composite surface, the method comprising supplying to the surface a
lubricating
composition comprising an oil of lubricating viscosity and an ashless,
phosphorus-free, sulphur-free antiwear agent.
[0011] In one embodiment invention provides for the use of a lubricating
composition comprising an ashless antiwear agent to lubricate an aluminium-
alloy or aluminium composite surface. In one embodiment the invention
provides for the use of a lubricating composition comprising an ashless
antiwear
agent to lubricate an internal combustion engine comprising an aluminium-alloy
or aluminium composite surface.
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[0012] In one
embodiment the invention provides a lubricating composition
comprising an ashless, phosphorus-free, sulphur-free antiwear agent, and
wherein the
lubricating composition is characterised as having at least one of (i) a
sulphur
content of 0.8 wt % or less, (ii) a phosphorus content of 0.2 wt % or less, or
(iii)
a sulphated ash content of 2 wt % or less.
[0013] In one
embodiment the invention provides a lubricating composition
comprising an ashless, phosphorus-free, sulphur-free antiwear agent, and
wherein the
lubricating composition is characterised as having (i) a sulphur content of
0.5 wt
% or less, (ii) a phosphorus content of 0.1 wt % or less, and (iii) a
sulphated ash
content of 1.5 wt % or less.
[0014] In one
embodiment the lubricating compositions disclosed herein
further comprises a molybdenum compound. Examples
of a suitable
molybdenum compound include molybdenum dialkyldithiophosphates,
molybdenum dithiocarbamates, amine salts of molybdenum compounds, or
mixtures thereof.
[0015] In
different embodiments the lubricating compositions disclosed
herein contain 0 ppm to 500 ppm, or 5 ppm to 300 ppm, or 20 ppm to 250 ppm
of molybdenum. In certain embodiments a molybdenum compound is present in
an amount to provide 0.5 ppm to 2000 ppm, 1 ppm to 700 ppm, or 20 ppm to 250
ppm molybdenum.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The
present invention provides a lubricating composition and a
method for lubricating an engine as disclosed above.
Ashless Antiwear Agent
[0017] In one embodiment the ashless, phosphorus-free, sulphur-free
antiwear agent includes imides, di-esters, di-amides, di-imides, ester-amides,
ester-imides, imide-amides. In one embodiment the antiwear agent includes
imides, di-esters, di-amides, or ester-amides.
[0018] In one
embodiment the ashless antiwear agent includes a compound
derived from a hydroxycarboxylic acid.
[0019] In one
embodiment the ashless antiwear agent is derived from at least
one of a hydroxy-carboxylic acid di-ester, a hydroxy-carboxylic acid di-amide,
a
hydroxy-carboxylic acid di-imide, a hydroxy-carboxylic acid ester-amide, a
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hydroxy-carboxylic acid ester-imide, and a hydroxy-carboxylic acid imide-
amide. In one
embodiment the ashless antiwear agent is derived from at least one of the
group consisting
of a hydroxy-carboxylic acid di-ester, a hydroxy-carboxylic acid di-amide, and
a hydroxy-
carboxylic acid ester-amide.
[0020] Examples of a suitable hydroxy-carboxylic acid include citric acid,
tartaric
acid, malic acid (or hydroxy-succinic acid), lactic acid, oxalic acid,
glycolic acid, hydroxy-
propionic acid, hydroxyglutaric acid, or mixtures thereof. In one embodiment
ashless
antiwear agent is derived from tartaric acid, citric acid, hydroxy-succinic
acid, dihydroxy
mono-acids, mono-hydroxy diacids, or mixtures thereof. In one embodiment the
ashless
antiwear agent includes a compound derived from tartaric acid. In another
embodiment it is
derived from citric acid.
[0021] US Patent Application 2005/198894 discloses suitable hydroxy-
carboxylic acid
compounds, and methods of preparing the same.
[0022] Canadian Patent 1183125; US Patent Publication numbers US
2006/0183647,
US 2006/0079413, and US 2010/0286007; and British Patent 2 105 743 A, all
disclose
examples of suitable tartaric acid derivatives.
[0023] In one embodiment the di-esters, di-amides, di-imides, ester-amide,
ester-imide,
imide-amide compounds are derived from a compound of Formula (Ia) and/or (Ib).
In one
embodiment the di-esters, di-amides, ester-amide, compounds are derived from a
compound of Formula (Ia) and/or (Ib).
[0024] A detailed description of methods for preparing suitable tartrimides
(by reacting
tartaric acid with a primary amine) is disclosed in US Patent 4,237,022.
[0025] In one embodiment the ashless antiwear agent includes imide, di-
esters, di-
amides, ester-amide derivatives of tartaric acid.
[0026] The ashless antiwear agent of the invention, typically a tartrate,
may also
function as rust and corrosion inhibitors, friction modifiers, antiwear agents
and
demulsifiers.
[0027] In one embodiment the ashless antiwear agent is represented by a
compound of
Formula (Ia) and/or (Ib):
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7 \
0
ity 11 (X)n
\ /P
Formula (la)
0 0
Ity 11 (X)n 11 Y R2
Formula (lb)
wherein
n is 0 to 10, 0 to 6, 0 to 4, 1 to 4, or 1 to 2 for Formula (lb), and 1 to 10,
1
to 4, or 1 to 2 for Formula (la);
pis 1 to 5, or 1 to 2, or 1;
Y and Y' are independently -0-, >NH, >NR3, or an imide group formed
by taking together both Y and Y' groups in (lb) or two Y groups in (la) and
forming a Ri-N< group between two >C=0 groups;
X is independently -CH2-, >CHR4 or >CR4R5, >CHOR6, or >C(CO2R6)2,
>C(0R6)CO2R6, >C(CH2OR6)CO2R6, -CH3, -CH2R4 or -CHR4R5, -CH2OR6, or
-CH(CO2R6)2, C-R6, or mixtures thereof to fulfill the valence of Formula (la)
and/or (lb), with the proviso that C-R6 only applies to Formula (la), the C
referring to three single bonds to the carbon atom;
Rl and R2 are independently hydrocarbyl groups, typically containing 1 to
150,4 to 30, or 6 to 20, or 10 to 20, or 11 to 18 carbon atoms;
R3 is a hydrocarbyl group;
R4 and R5 are independently keto-containing groups (such as acyl
groups), ester groups or hydrocarbyl groups; and
R6 is independently hydrogen or a hydrocarbyl group, typically containing
1 to 150, or 4 to 30 carbon atoms.
[0028] In one embodiment the compound of Formula (lb) contains an imide
group. The imide group is typically formed by taking together the Y and Y'
groups and forming a Ri-N< group between two >C=0 groups.
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[0029] In one embodiment the compound of Formula (la) and/or (lb) has n,
X, and Rl, R2 and R6 defined as follows: n is 1 to 2, X is >CHOR6; and Rl, R2
and R6 are independently hydrocarbyl groups containing 4 to 30 carbon atoms.
[0030] In one embodiment Y and Y' are both -0-.
[0031] In one embodiment the compound of Formula (la) and/or (lb) has n,
X, Y, Y' and Rl, R2 and R6 defined as follows: n is 1 to 2, X is >CHOR6; Y and
Y' are both -0-, and Rl, R2 and R6 are independently hydrocarbyl groups
containing 4 to 30 carbon atoms.
[0032] The di-esters, di-amides, di-imides, ester-amide, ester-imide, imide-
amide compounds of Formula (la) and/or (lb) may be prepared by reacting a
dicarboxylic acid (such as tartaric acid), with an amine or alcohol,
optionally in
the presence of a known esterification catalyst. The amine or alcohol
typically
has sufficient carbon atoms to fulfill the requirements of Rl and/or R2 as
defined
in Formula (la) and/or (lb). Derivatives of the hydroxycarboxylic acid include
imides, di-esters, di-amides, di-imides (applicable for tetra-acids and
higher),
ester-amides, ester-imides (applicable for tri-acids and higher, such as
citric
acid), imide-amides (applicable for tri-acids and higher, such as citric
acid). In
one embodiment the antiwear agent includes imides, di-esters, di-amides, or
ester-amides.
[0033] In one embodiment Rl and R2 are independently linear or branch
hydrocarbyl groups. In one embodiment the hydrocarbyl groups are branched.
In one embodiment the hydrocarbyl groups are linear. The Rl and R2 may be
incorporated into Formula (la) and/or (lb) by either an amine or an alcohol.
The
alcohol includes both monohydric alcohol and polyhydric alcohol.
[0034] In one embodiment the ashless antiwear agent is derived from a
compound of Formula (lb).
[0035] Examples of a suitable branched alcohol include 2-ethylhexanol,
isotridecanol, Guerbet alcohols, or mixtures thereof
[0036] Examples of a monohydric alcohol include methanol, ethanol,
propanol,
butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol,
dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol,
octadecanol, nonadecanol, eicosanol, or mixtures thereof In one embodiment the
monohydric alcohol contains 5 to 20 carbon atoms.
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[0037] The
alcohol includes either a monohydric alcohol or a polyhydric alcohol.
Examples of a suitable polyhydric alcohol include ethylene glycol, propylene
glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,5-pentane diol, 1,6-hexane
diol, glycerol, sorbitol, pentaerythritol, trimethylolpropane, starch,
glucose,
sucrose, methylglucoside, or mixtures thereof. In one
embodiment the
polyhydric alcohol is used in a mixture along with a monohydric alcohol.
Typically, in such a combination the monohydric alcohol constitutes at least
60
mole percent, or at least 90 mole percent of the mixture.
[0038] In one
embodiment ashless antiwear agent is derived from tartaric
acid. The tartaric acid used for preparing the tartrates of the invention can
be
commercially available (for instance obtained from Sargent Welch), and it is
likely to exist in one or more isomeric forms such as d-tartaric acid, /-
tartaric
acid or mesotartaric acid, often depending on the source (natural) or method
of
synthesis (e.g. from maleic acid). These derivatives can also be prepared from
functional equivalents to the diacid readily apparent to those skilled in the
art,
such as esters, acid chlorides, or anhydrides.
[0039] When the
compound of Formula (la) and/or (lb) is derived from
tartaric acid, resultant tartrates may be solid, semi-solid, or oil depending
on the
particular alcohol used in preparing the tartrate. For use
as additives in
oleaginous compositions including lubricating and fuel compositions the
tartrates
are advantageously soluble and/or stably dispersible in such oleaginous
compositions. For example, compositions intended for use in oils are typically
oil-soluble and/or stably dispersible in an oil in which they are to be used.
The
term "oil-soluble" as used in this specification and appended claims does not
necessarily mean that all the compositions in question are miscible or soluble
in
all proportions in all oils. Rather, it is intended to mean that the
composition is
soluble in an oil (mineral, synthetic, etc.) in which it is intended to
function to an
extent which permits the solution to exhibit one or more of the desired
properties. Similarly, it is not necessary that such "solutions" be true
solutions
in the strict physical or chemical sense. They may instead be micro-emulsions
or
colloidal dispersions which, for the purpose of this invention, exhibit
properties
sufficiently close to those of true solutions to be, for practical purposes,
interchangeable with them within the context of this invention.
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[0040] The ashless antiwear agent of the may be present at 0.01 wt % to 20
wt %, or 0.05 to 10 wt %, or 0.1 to 5 wt % of the lubricating composition.
Oils of Lubricating Viscosity
[0041] The lubricating composition comprises an oil of lubricating
viscosity.
Such oils include natural and synthetic oils, oil derived from hydrocracking,
hydrogenation, and hydrofinishing, unrefined, refined and re-refined oils and
mixtures thereof.
[0042] Unrefined oils are those obtained directly from a natural or
synthetic
source generally without (or with little) further purification treatment.
[0043] Refined oils are similar to the unrefined oils except they have been
further treated in one or more purification steps to improve one or more
properties. Purification techniques are known in the art and include solvent
extraction, secondary distillation, acid or base extraction, filtration,
percolation
and the like.
[0044] Re-refined oils are also known as reclaimed or reprocessed oils, and
are obtained by processes similar to those used to obtain refined oils and
often
are additionally processed by techniques directed to removal of spent
additives
and oil breakdown products.
[0045] Natural oils useful in making the inventive lubricants include
animal
oils, vegetable oils (e.g., castor oil), mineral lubricating oils such as
liquid
petroleum oils and solvent-treated or acid-treated mineral lubricating oils of
the
paraffinic, naphthenic or mixed paraffinic-naphthenic types and oils derived
from coal or shale or mixtures thereof.
[0046] Synthetic lubricating oils are useful and include hydrocarbon oils
such
as polymerised and interpolymerised olefins (e.g., polybutylenes,
polypropylenes, propyleneisobutylene copolymers); poly(1-hexenes), poly(1-
octenes), poly(1-decenes), and mixtures thereof; alkyl-benzenes (e.g.
dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-
benzenes); polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls);
alkylated diphenyl ethers and alkylated diphenyl sulphides and the
derivatives,
analogs and homo logs thereof or mixtures thereof.
[0047] Other synthetic lubricating oils include polyol esters (such as
Prolube03970), diesters, liquid esters of phosphorus-containing acids (e.g.,
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tricresyl phosphate, trioctyl phosphate, and the diethyl ester of decane
phosphonic acid), or polymeric tetrahydrofurans. Synthetic
oils may be
produced by Fischer-Tropsch reactions and typically may be hydroisomerised
Fischer-Tropsch hydrocarbons or waxes. In one embodiment oils may be
prepared by a Fischer-Tropsch gas-to-liquid synthetic procedure as well as
other
gas-to-liquid oils.
[0048] Oils of
lubricating viscosity may also be defined as specified in the
American Petroleum Institute (API) Base Oil Interchangeability Guidelines. The
five base oil groups are as follows: Group I (sulphur content >0.03 wt %,
and/or
<90 wt % saturates, viscosity index 80-120); Group II (sulphur content <0.03
wt
%, and >90 wt % saturates, viscosity index 80-120); Group III (sulphur content
<0.03 wt %, and >90 wt % saturates, viscosity index >120); Group IV (all
polyalphaolefins (PA0s)); and Group V (all others not included in Groups I,
II,
III, or IV). The oil of lubricating viscosity comprises an API Group I, Group
II,
Group III, Group IV, Group V oil or mixtures thereof. Often the oil of
lubricating viscosity is an API Group I, Group II, Group III, Group IV oil or
mixtures thereof Alternatively the oil of lubricating viscosity is often an
API
Group II, Group III or Group IV oil or mixtures thereof.
[0049] The
amount of the oil of lubricating viscosity present is typically the
balance remaining after subtracting from 100 wt % the sum of the amount of the
ashless antiwear agent and the other performance additives.
[0050] The
lubricating composition may be in the form of a concentrate
and/or a fully formulated lubricant. If the ashless antiwear agent is in the
form
of a concentrate (which may be combined with additional oil to form, in whole
or in part, a finished lubricant), the ratio of the of components of the
invention to
the oil of lubricating viscosity and/or to diluent oil include the ranges of
1:99 to
99:1 by weight, or 80:20 to 10:90 by weight.
Other Performance Additives
[0051] The
composition optionally comprises other performance additives.
The other performance additives comprise at least one of metal deactivators,
viscosity modifiers, detergents, friction modifiers, antiwear agents (other
than
the ashless antiwear agent of the invention), corrosion inhibitors,
dispersants,
dispersant viscosity modifiers, extreme pressure agents, antioxidants, foam
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inhibitors, demulsifiers, pour point depressants, seal swelling agents and
mixtures thereof Typically, fully-formulated lubricating oil will contain one
or
more of these performance additives.
[0052] In one
embodiment the lubricating composition comprises the ashless
antiwear agent and further comprises at least one of a viscosity modifier, an
antioxidant, an overbased detergent, a succinimide dispersant, or mixtures
thereof.
[0053] In one
embodiment the lubricating composition comprising the ashless
antiwear agent further comprises a phosphorus-containing antiwear agent.
[0054] In one
embodiment the lubricating composition comprising the ashless
antiwear agent further comprises a molybdenum compound.
Detergents
[0055] The
lubricant composition optionally further comprises other known
neutral or overbased detergents. Suitable detergent substrates include
phenates,
sulphur containing phenates, sulphonates, salixarates, salicylates, carboxylic
acid, phosphorus acid, mono- and/or di- thiophosphoric acid, alkyl phenol,
sulphur coupled alkyl phenol compounds, or saligenins. Various overbased
detergents and their methods of preparation are described in greater detail in
numerous patent publications, including W02004/096957 and references cited
therein. The detergent substrate is typically salted with a metal such as
calcium,
magnesium, potassium, sodium, or mixtures thereof. In one embodiment the
lubricating composition further includes an overbased detergent. Typically the
overbased detergent includes phenates, sulphur containing phenates,
sulphonates,
salixarates, salicylates, or mixtures thereof.
[0056] The
detergent may be present at 0 wt % to 10 wt %, or 0.1 wt % to 8
wt %, or 1 wt % to 4 wt %, or greater than 4 to 8 wt %.
Dispersants
[0057]
Dispersants are often known as ashless-type dispersants because, prior
to mixing in a lubricating oil composition, they do not contain ash-forming
metals and they do not normally contribute any ash forming metals when added
to a lubricant and polymeric dispersants. Ashless
type dispersants are
characterised by a polar group attached to a relatively high molecular weight
hydrocarbon chain. Typical ashless dispersants include N-substituted long
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alkenyl succinimides. Examples
of N-substituted long chain alkenyl
succinimides include polyisobutylene succinimide with number average
molecular weight of the polyisobutylene substituent in the range 350 to 5000,
or
500 to 3000. Succinimide dispersants and their preparation are disclosed, for
instance in US Patent 3,172,892 or US Patent 4,234,435.
Succinimide
dispersants are typically the imide formed from a polyamine, typically a
poly(ethyleneamine).
[0058] In one
embodiment the invention further comprises at least one
polyisobutylene succinimide dispersant derived from polyisobutylene with
number
average molecular weight in the range 350 to 5000, or 500 to 3000. The
polyisobutylene succinimide may be used alone or in combination with other
dispersants.
[0059] In one
embodiment the invention further comprises at least one
dispersant derived from polyisobutylene succinic anhydride, an amine and zinc
oxide to form a polyisobutylene succinimide complex with zinc. The
polyisobutylene succinimide complex with zinc may be used alone or in
combination.
[0060] 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.
[0061] The
dispersants may also be post-treated by conventional methods by
a reaction with any of a variety of agents. Among these are boron, urea,
thiourea, dimercaptothiadiazoles, carbon disulphide, aldehydes, ketones,
carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic
anhydride,
nitriles, epoxides, and phosphorus compounds.
[0062] The
dispersant may be present at 0 wt % to 20 wt %, or 0.1 wt % to
15 wt %, or 0.1 wt % to 10 wt %, or 1 wt % to 6 wt %, or 7 wt % to 12 wt % of
the lubricating composition.
Antioxidants
[0063] Antioxidant compounds are known and include for example,
sulphurised olefins, alkylated diphenylamines (typically di-nonyl
diphenylamine,
octyl diphenylamine, di-octyl diphenylamine), hindered phenols, molybdenum
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compounds (such as molybdenum dithiocarbamates), or mixtures thereof.
Antioxidant compounds may be used alone or in combination. The antioxidant
may be present in ranges 0 wt % to 20 wt %, or 0.1 wt % to 10 wt %, or 1 wt %
to 5 wt %, of the lubricating composition.
[0064] The hindered phenol antioxidant often contains a secondary butyl
and/or a tertiary butyl group as a sterically hindering group. The phenol
group is
often further substituted with a hydrocarbyl group and/or a bridging group
linking to a second aromatic group. Examples of suitable hindered phenol
antioxidants include 2,6-di-tert-butylphenol, 4-methy1-2,6-di-tert-
butylpheno1, 4-
ethy1-2,6-di-tert-butylpheno1, 4-propy1-2,6-di-tert-butylphenol or 4-buty1-2,6-
di-
tert-butylphenol, or 4-dodecy1-2,6-di-tert-butylphenol. In one embodiment the
hindered phenol antioxidant is an ester and may include, e.g., IrganoxTM L-135
from Ciba. A more detailed description of suitable ester-containing hindered
phenol antioxidant chemistry is found in US Patent 6,559,105.
[0065] Suitable examples of molybdenum dithiocarbamates which may be
used as an antioxidant include commercial materials sold under the trade names
such as Molyvan 822TM and MolyvanTM A from R. T. Vanderbilt Co., Ltd., and
Adeka Sakura-LubeTM S-100, S-165 and S-600 from Asahi Denka Kogyo K. K
and mixtures thereof.
Viscosity Modifiers
[0066] Viscosity modifiers include hydrogenated copolymers of styrene-
butadiene, ethylene-propylene copolymers, polyisobutenes, hydrogenated
styrene-isoprene polymers, hydrogenated isoprene polymers, polymethacrylates,
polyacrylates, polyalkyl styrenes, hydrogenated alkenyl aryl conjugated diene
copolymers, polyolefins, esters of maleic anhydride-styrene copolymers.
Dispersant Viscosity Modifiers
[0067] Dispersant viscosity modifiers (often referred to as DVM), include
functionalised polyolefins, for example, ethylene-propylene copolymers that
have been functionalized with the reaction product of maleic anhydride and an
amine; polymethacrylates functionalised with an amine, or esterified maleic
anhydride-styrene copolymers reacted with an amine.
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[0068] The total
amount of viscosity modifier and/or dispersant viscosity
modifier may be 0 wt % to 20 wt %, or 0.1 wt % to 15 wt %, or 0.1 wt % to 10
wt %, of the lubricating composition
Antiwear Agents
[0069] The
lubricant composition optionally further comprises at least one
other antiwear agent other than the ashless antiwear agent of the invention.
Examples of suitable antiwear agents include phosphate esters, sulphurised
olefins, sulphur-containing anti-wear additives including
metal
dihydrocarbyldithiophosphates (such as zinc dialkyldithiophosphates or
molybdenum dialkyldithiophosphates), thiocarbamate-containing compounds
including, thiocarbamate esters, alkylene-coupled thiocarbamates, and bis(S-
alkyldithiocarbamyl) disulphides.
[0070] The
dithiocarbamate-containing compounds may be prepared by
reacting a dithiocarbamate acid or salt with an unsaturated compound. The
dithiocarbamate containing compounds may also be prepared by simultaneously
reacting an amine, carbon disulphide and an unsaturated compound. Generally,
the reaction occurs at a temperature of 25 C to 125 C. US Patents 4,758,362
and 4,997,969 describe dithiocarbamate compounds and methods of making them.
[0071] Examples
of suitable olefins that may be sulphurised to form the
sulphurised olefin include propylene, butylene, isobutylene, pentene, hexane,
heptene, octane, nonene, decene, undecene, dodecene, undecene, tridecene,
tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene,
eicosene or mixtures thereof. In one embodiment, hexadecene, heptadecene,
octadecene, nonadecene, eicosene or mixtures thereof and their dimers, trimers
and tetramers are especially useful olefins. Alternatively, the olefin may be
a
Diels-Alder adduct of a diene such as 1,3-butadiene and an unsaturated ester,
such as butylacrylate.
[0072] Another
class of sulphurised olefin includes fatty acids and their
esters. The fatty acids are often obtained from vegetable oil or animal oil
and
typically contain 4 to 22 carbon atoms. Examples of suitable fatty acids and
their esters include triglycerides, oleic acid, linoleic acid, palmitoleic
acid or
mixtures thereof. Often, the fatty acids are obtained from lard oil, tall oil,
peanut
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oil, soybean oil, cottonseed oil, sunflower seed oil or mixtures thereof. In
one
embodiment fatty acids and/or ester are mixed with olefins such as a-olefins.
[0073] In an alternative embodiment, the ashless antiwear agent (which may
also be described as a friction modifier) may be a monoester of a polyol and
an
aliphatic carboxylic acid, often an acid containing 12 to 24 carbon atoms.
Often
the monoester of a polyol and an aliphatic carboxylic acid is in the form of a
mixture with a sunflower oil or the like, which may be present in the ashless
antiwear agent mixture include 5 to 95, or in other embodiments 10 to 90, or
20
to 85, or 20 to 80 weight percent of said mixture. The aliphatic carboxylic
acids
(especially a monocarboxylic acid) which form the esters are those acids
typically containing 12 to 24 or 14 to 20 carbon atoms. Examples of carboxylic
acids include dodecanoic acid, stearic acid, lauric acid, behenic acid, and
oleic
acid.
[0074] Polyols include diols, triols, and alcohols with higher numbers of
alcoholic OH groups. Polyhydric alcohols include ethylene glycols, including
di-, tri- and tetraethylene glycols; propylene glycols, including di-, tri-
and
tetrapropylene glycols; glycerol; butane diol; hexane diol; sorbitol;
arabitol;
mannitol; sucrose; fructose; glucose; cyclohexane diol; erythritol; and
pentaerythritols, including di- and tripentaerythritol. Often the polyol is
diethyl-
ene glycol, triethylene glycol, glycerol, sorbitol, pentaerythritol or
dipentaerythritol. The commercial material known as glycerol monoleate is
believed to include about 60 + 5 percent by weight of the chemical species
"glycerol monooleate," along with 35 + 5 percent glycerol dioleate, and less
than
about 5 percent trioleate and oleic acid. The amounts of the monoesters,
described below, are the amounts of the commercial grade material.
[0075] The antiwear agent may be present in ranges including 0 wt % to 15
wt %, or 0 wt % to 10 wt %, or 0.05 wt % to 5 wt %, or 0.1 wt % to 3 wt % of
the lubricating composition.
[0076] In one embodiment the lubricating composition is free of zinc
dihydrocarbyl dithiophosphate. In one embodiment the lubricating composition
further includes zinc dihydrocarbyl dithiophosphate.
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Extreme Pressure Agents
[0077] Extreme Pressure (EP) agents that are soluble in the oil include
sulphur- and chlorosulphur-containing EP agents, chlorinated hydrocarbon EP
agents and phosphorus EP agents. Examples of such EP agents include
chlorinated wax; organic sulphides and polysulphides such as
dibenzyldisulphide, bis¨(chlorobenzyl) disulphide, dibutyl tetrasulphide,
sulphurised methyl ester of oleic acid, sulphurised alkylphenol, sulphurised
dipentene, sulphurised terpene, and sulphurised Diels-Alder adducts;
phosphosulphurised hydrocarbons such as the reaction product of phosphorus
sulphide with turpentine or methyl oleate; phosphorus esters such as the
dihydrocarbon and trihydrocarbon phosphites, e.g., dibutyl phosphite, diheptyl
phosphite, dicyclohexyl phosphite, pentylphenyl phosphite; dip entylphenyl
phosphite, tridecyl phosphite, distearyl phosphite and polypropylene
substituted
phenol phosphite; metal thiocarbamates such as zinc dioctyldithiocarbamate and
barium heptylphenol diacid; amine salts of alkyl and dialkylphosphoric acids,
including, for example, the amine salt of the reaction product of a
dialkyldithiophosphoric acid with propylene oxide; and mixtures thereof.
Friction Modifiers
[0078] In one embodiment the further comprises a friction modifier, or
mixtures thereof. Typically the friction modifier may be present in ranges
including 0 wt % to 10 wt %, or 0.05 wt % to 8 wt %, or 0.1 wt % to 4 wt %.
[0079] Examples of suitable friction modifiers include long chain fatty
acid
derivatives of long chain fatty acid derivatives of amines, esters, or
epoxides;
fatty imidazolines (that is to say, long chain fatty amides, long chain fatty
esters,
long chain fatty epoxide derivatives, long chain fatty imidazolines); and
amine
salts of alkylphosphoric acids.
[0080] Friction modifiers may also encompass materials such as sulphurised
fatty compounds and olefins, molybdenum dialkyldithiophosphates, molybdenum
dithiocarbamates, sunflower oil or monoester of a polyol and an aliphatic
carboxylic acid (all these friction modifiers have been described as
antioxidants
or antiwear agents).
[0081] In one embodiment the friction modifier friction modifier is
selected
from the group consisting of long chain fatty amides, long chain fatty esters,
CA 02688094 2016-01-11
long chain fatty epoxide derivatives, long chain fatty imidazolines, and amine
salts of
alkylphosphoric acids; fatty alkyl tartrates such as C12-14 tartrates; fatty
alkyl tartrimides (such
as tridecyl tartrimide, oleyl tartrimide, or 2-ethylhexyl tartrimide); and
fatty alkyl tartramides.
[0082] In one embodiment the friction modifier is a long chain fatty acid
ester (previously
described above as an ashless antiwear agent). In another embodiment the long
chain fatty acid
ester is a mono-ester and in another embodiment the long chain fatty acid
ester is a (tri)glyceride.
Other Additives
[0083] Other performance additives such as corrosion inhibitors include
those described in
paragraphs 5 to 8 of International Publication No. WO 2006/047486 Al,
octylamine octanoate,
condensation products of dodecenyl succinic acid or anhydride and a fatty acid
such as oleic acid
with a polyamine. In one embodiment the corrosion inhibitors include the
Synalox corrosion
inhibitor. The Synalox corrosion inhibitor is typically a homopolymer or
copolymer of
propylene oxide. The Synalox corrosion inhibitor is described in more detail
in a product
brochure with Form No. 118-01453-0702 AMS, published by The Dow Chemical
Company. The
product brochure is entitled "SYNALOX Lubricants, High-Performance Polyglycols
for
Demanding Applications."
[0084] Metal deactivators including derivatives of benzotriazoles
(typically tolyltriazole),
dimercaptothiadiazole derivatives, 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.
Industrial Application
[0085] The lubricating composition may be utilised in a range aluminium-
alloy or aluminium
composite surfaces typically found in mechanical devices. The mechanical
devices include an
internal combustion engine, a gearbox, an automatic transmission, a hydraulic
device or a
turbine. Typically the
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lubricating composition may be an engine oil, a gear oil, an automatic
transmission oil, a hydraulic fluid, a turbine oil, a metal working fluid or a
circulating oil. In one embodiment the mechanical device is an internal
combustion engine.
[0086] As used herein, the terms "aluminium-alloy" and "aluminium
composite" are used interchangeably to describe a surface comprising aluminium
and another component intermixed or reacted on a microscopic or nearly
microscopic level, regardless of the detailed structure thereof. This would
include any conventional alloys with metals other than aluminium as well as
composite or alloy-like structures with non-metallic elements or compounds
such
as with ceramic-like materials. The aluminium-alloy or aluminium composite
thus includes aluminium silicates, aluminium oxides, or other ceramic
materials.
In one embodiment the aluminium-alloy is an aluminium-silicate surface.
[0087] In one embodiment the internal combustion engine may be 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 may be a diesel fuelled engine and in another embodiment a gasoline
fuelled engine.
[0088] The internal combustion engine may be a 2-stroke or 4-stroke engine.
Suitable internal combustion engines include marine diesel engines, aviation
piston engines, low-load diesel engines, and automobile and truck engines.
[0089] The lubricant composition for an internal combustion engine may be
suitable for any engine lubricant irrespective of the sulphur, phosphorus or
sulphated ash (ASTM D-874) content. The sulphur content of the engine oil
lubricant may be 1 wt % or less, or 0.8 wt % or less, or 0.5 wt % or less, or
0.3
wt % or less. In one embodiment the sulphur content may be in the range of
0.001 wt % to 0.5 wt %, or 0.01 wt % to 0.3 wt %. The phosphorus content may
be 0.2 wt % or less, or 0.1 wt % or less, or 0.085 wt % or less, or even 0.06
wt %
or less, 0.055 wt % or less, or 0.05 wt % or less. In one embodiment the
phosphorus content may be 100 ppm to 1000 ppm, or 325 ppm to 700 ppm. The
total sulphated ash content may be 2 wt % or less, or 1.5 wt % or less, or 1.1
wt
% or less, or 1 wt % or less, or 0.8 wt % or less, or 0.5 wt % or less. In one
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embodiment the sulphated ash content may be 0.05 wt % to 0.9 wt %, or 0.1 wt
% or 0.2 wt % to 0.45 wt %.
[0090] In one
embodiment the lubricating composition is an engine oil,
wherein the lubricating composition is characterised as having (i) a sulphur
content of 0.5 wt % or less, (ii) a phosphorus content of 0.1 wt % or less,
and
(iii) a sulphated ash content of 1.5 wt % or less. In another embodiment the
sulphur content is 0.4 wt % or less, the phosphorus content is 0.08 wt % or
less,
and the sulphated ash is 1 wt % or less. In yet another embodiment the sulphur
content is 0.3 wt% or less, the phosphorus content is 0.05 wt % or less, and
the
sulphated ash is 0.8 wt % or less.
[0091] In one
embodiment the lubricating composition is suitable for a 2-
stroke or a 4-stroke marine diesel internal combustion engine. In one
embodiment the marine diesel combustion engine is a 2-stroke engine. The
ashless antiwear agent of the invention may be added to a marine diesel
lubricating composition at 0.01 to 20 wt %, or 0.05 to 10 wt %, or 0.1 to 5 wt
%.
[0092] The
following examples provide illustrations of the invention. These
examples are non-exhaustive and are not intended to limit the scope of the
invention.
EXAMPLES
[0093] Example
1: A lubricating composition is prepared containing 1 wt %
of di-2-ethylhexyl tartrate, 0.6 wt % of other antiwear agents, 7.9 wt % of
dispersants, 1.5 wt % of detergents, 3.6 wt % of antioxidants, 6.1 wt % of
viscosity modifier, 0.1 wt % of corrosion inhibitor, and 0.1 wt % of friction
modifier. The lubricating composition has a sulphated ash content of 0.6 wt %,
a
phosphorus content of about 570 ppm, and a sulphur content of 0.17 wt %.
[0094]
Comparative Example 1 is similar to Example 1 except the
composition does not contain the di-2-ethylhexyl tartrate.
[0095] Example 1
and Comparative Example 1 are evaluated by employing
the lubricating compositions in an internal combustion engine fitted with an
aluminium silicate liner and a steel top ring. The engine is then run under
varying loads and speeds and wear analysis is conducted when the engine is
running at 5000 rpm. Data obtained from the wear analysis (wear rate of
nanometers per hour) of the aluminium silicate liner is as follows:
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Example Wear Rate (nm/h)
Example 1 0.5
Comparative Example 1 2.1
[0096] Overall the results indicate that lubricating an aluminium-alloy
surface with a lubricating composition as disclosed herein is capable of at
least
one of (i) reducing or preventing phosphorus emissions, (ii) reducing or
preventing sulphur emissions, and (iii) wholly or partially replacing ZDDP in
lubricating oils, and (iv) having no detrimental affect on other components of
the internal combustion engine.
[0097] 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 lubricant 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
lubricant
composition prepared by admixing the components described above.
[0098]
Except in the Examples, or where otherwise explicitly indicated, all
numerical quantities in this description specifying amounts of materials,
reaction
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 inclusive 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.
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[0099] 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., cyclo alkyl, cycloalkenyl) substituents, and aromatic-,
aliphatic-,
and alicyclic-substituted aromatic substituents, as well as cyclic
substituents
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
sulphoxy);
(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.
[0100] Heteroatoms include sulphur, oxygen, nitrogen, and encompass
substituents as pyridyl, furyl, thienyl and imidazolyl. In general, no more
than
two, preferably 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.
[0101] As will be evident, the antiwear agent described herein may be an
oil-
soluble derivative of a molecule containing a first carboxy group and at least
one
additional ¨OH, ¨NHR, or =0 moiety separated from the carbon of said first
carboxy group by a chain of 2 or 3 atoms, where R is hydrogen or alkyl, e.g,
Cl-
6 alkyl.
[0102] While the invention has been explained in relation to its preferred
embodiments, 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.
