Note: Descriptions are shown in the official language in which they were submitted.
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LUBRICANTS WITH IMPROVED SEAL COMPATIBILITY
Field of the Invention
[0001] The present invention relates to lubricating compositions and
particularly
gear oil compositions that include a minimum level of a specific antioxidant
component, where the antioxidant component includes (i) a phenolic
antioxidant, (ii)
an aminic antioxidant, or (iii) a combination thereof, where the antioxidant
component is present in the lubricating composition at 1.0 percent by weight
or
higher. Such compositions provide surprisingly good seal compatibility
compared
to compositions with other triazoles and/or alternative additives.
Background of the Invention
[0002] In many industrial applications lubricating compositions come
into
contact with seals within the equipment in which they are used. Seals are made
out
of various materials, including nitrile-butadiene rubber (NBR) due to its
relatively
low cost and high availability, as well as fluorinated elastomers, silicones,
and
polycarbonates. It is essential that the lubricating composition used has good
compatibility with the seals otherwise seals are degraded over time to the
point that
they fail, leading to fluid leakage increasing maintenance costs, longer down
time
for the equipment, and even the risk of equipment damage.
[0003] Seals, particularly those made using NBR, break down over time
under
even normal operating conditions. High temperatures in particular can be very
detrimental to some seals. In other cases seals can sometimes be susceptible
to
attack by chemical additive components of some lubricating compositions,
including
those used frequently in industrial applications, including some extreme-
pressure
agents like sulfurized olefins, rust inhibitors like aminic compounds,
antiwear agents
like phosphates, phosphites, phosphate esters, and phosphate amine salts. In
some
cases even the base oil itself can attack seal materials including NBR.
[0004] There is an on-going need for industrial lubricating
compositions that can
provide the required performance and protection for the equipment, but which
also
protect the seals attack or degradation thus reducing the risk of lubricant
leakage,
down time and ultimately equipment damage or failure.
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[0005] Wind turbines in particular represent an industrial application
that
requires lubricating compositions with good seal compatibility. Wind turbines
as an
alternative renewable energy source are attracting more interest, since they
produce
electricity by converting clean wind energy to electrical energy. A gear box,
which
is typically situated between the rotor of the wind turbine and the generator,
requires
a lubricant. The high torque puts a large amount of stress on the gears and
bearings
in the gear box of these wind turbines, placing high performance requirements
on
the lubricating composition. In addition, the gear boxes are located in
nacelles of
the wind turbine high off the ground and the unit themselves are often in
remote
areas. Thus the gear boxes are often inaccessible or only accessible with
great cost
and difficulty such that a long service life with limited maintenance is
desired.
Lubricating compositions with improved seal compatibility but which still
provide
good lubricating performance are expected to reduce maintenance and down time
caused by failed seals. Thus there is a need for lubricating compositions with
improved seal compatibility, that still provide good lubricating performance
in wind
turbines and similar applications.
Summary of the Invention
[0006] The invention provides an industrial lubricating composition
comprising
an oil of lubricating viscosity and an antioxidant component comprising: (i) a
phenolic antioxidant, (ii) an aminic antioxidant, or (iii) a combination
thereof where
the antioxidant component is present in the lubricating composition at 0.4
percent by
weight or higher, and in other embodiments at 1.0 percent by weight or higher,
[0007] The phenolic antioxidant may be present in the lubricating
composition
from at least 0.2, 0.4, 0.5 or at least 1.0 percent by weight and the aminic
antioxidant
may be present in the lubricating composition from at least 0.2, 0.4, 0.5 or
at least
1.0 percent by weight.
[0008] The invention provides for the described compositions where the
oil of
lubricating viscosity includes a mineral base oil, where the oil of
lubricating
viscosity includes a synthetic base oil, and even where the oil of lubricating
viscosity includes a combination of a mineral base oil and a synthetic base
oil. In
some embodiments the oil of lubricating viscosity is substantially free of, or
even
free of, a synthetic ester base oil.
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[0009] The invention provides a method of lubricating a gear assembly
comprising supplying to said assembly a lubricating composition comprising an
oil
of lubricating viscosity and an antioxidant component comprising: (i) a
phenolic
antioxidant, (ii) an aminic antioxidant, or (iii) a combination thereof where
the
antioxidant component is present in the lubricating composition at 0.4, 0.5 or
1.0
percent by weight or higher. Any of the antioxidant components described
herein
may be used in such methods.
[0010] The invention provides for the use of the described antioxidant
components in lubricating compositions, at the minimum required level, as a
seal
protectant, including lubricating compositions for industrial applications.
The
invention provides even more specifically for wind turbines and other
applications
that require fatigue or micro-pitting resistant formulations and even
applications that
have stringent seal compatibility requirements.
[0011] The invention further provides for all of the compositions,
methods, and
uses described herein, where the specified lubricant includes a demulsifier,
where
the specified lubricant includes a combination of a demulsifier and a
sulfurized
olefin, where the specified lubricant includes a combination of a substituted
triazole
and a substituted thiadiazole, where the specified lubricant is essentially
free of or
even completely free of dithiophosphates including zinc dialkyl
dithiophosphates,
where the specified lubricant is essentially free of or even completely free
of
overbased metal-containing detergents, where the specified lubricant is
essentially
free of or even completely free of zinc, or any combination thereof
Detailed Description of the Invention
[0012] Various features and embodiments of the invention will be
described
below by way of non-limiting illustration.
[0013] The invention provides an industrial lubricating composition
comprising
an oil of lubricating viscosity and an antioxidant component comprising: (i) a
phenolic antioxidant, (ii) an aminic antioxidant, or (iii) a combination
thereof where
the antioxidant component is present in the lubricating composition at 1.0
percent by
weight or higher.
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The Oil of Lubricating Viscosity
[0014] One component of the compositions of the invention is an oil of
lubricating viscosity, which can be present in a major amount, for a lubricant
composition, or in a concentrate forming amount, for a concentrate.
[0015] Suitable oils include natural and synthetic lubricating oils and
mixtures
thereof In a fully formulated lubricant, the oil of lubricating viscosity is
generally
present in a major amount (i.e. an amount greater than 50 percent by weight).
Typically, the oil of lubricating viscosity is present in an amount of 75 to
95 percent
by weight, and often greater than 80 percent by weight of the overall
composition.
The base oil component generally makes up 100 parts by weight (pbw) of the
overall
composition with the pbw ranges for the other components being provided with
this
100 pbw of base oil in mind. In other embodiments the pbw ranges of the
various
components, including the base oils, are provided such that the total of the
pbw of
all components is 100, and thus the pbw values are equivalent to percent by
weight
values. The pbw ranges provided for the various components described below may
be taken either way, however in most embodiments they are to be read so as to
be
equivalent to percent by weight values.
[0016] The oil of lubricating viscosity may include natural and
synthetic oils, oil
derived from hydrocracking, hydrogenation, and hydrofinishing, unrefined,
refined
and refined oils or mixtures thereof. Unrefined oils are those obtained
directly from
a natural or synthetic source generally without (or with little) further
purification
treatment. 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.
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.
[0017] Natural oils useful as the oil of lubricating viscosity include
animal oils,
vegetable oils (e.g., castor oil, lard oil), mineral lubricating oils such as
liquid
petroleum oils and solvent-treated or acid-treated mineral lubricating oils of
the
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paraffinic, naphthenic or mixed paraffinic naphthenic types and oils derived
from
coal or shale or mixtures thereof.
[0018] Synthetic oils of lubricating viscosity include hydrocarbon
oils such as
polymerized and interpolymerised olefins (e.g., polybutylenes, polypropylenes,
propyleneisobutylene copolymers); poly( 1 -hex enes), poly( 1 -o ctenes),
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 biphenyl
ethers and
alkylated biphenyl sulfides and the derivatives, analogs and homologs thereof
or
mixtures thereof.
[0019] Another synthetic oil of lubricating viscosity includes polyol
esters other
than the hydrocarbyl-capped polyoxyalkylene polyol as disclosed herein,
dicarboxylic esters, liquid esters of phosphorus-containing acids (e.g.,
tricresyl
phosphate, trioctyl phosphate, and the diethyl ester of decane phosphonic
acid), or
polymeric tetrahydrofurans. Synthetic conventional oil of lubricating
viscosity also
include those produced by Fischer-Tropsch reactions and typically may be
hydroisomerised Fischer-Tropsch hydrocarbons or waxes. In one embodiment, the
oil of lubricating viscosity may be prepared by a Fischer-Tropsch gas-to-
liquid
synthetic procedure as well as other gas-to-liquid oils.
[0020] Oils of lubricating viscosity may further be defined as specified in
the
American Petroleum Institute (API) Base Oil Interchangeability Guidelines. The
five base oil groups are as follows: Group I (sulfur content >0.03 wt %,
and/or <90
wt % saturates, viscosity index 80-120); Group II (sulfur content <0.03 wt %
and
>90 wt % saturates, viscosity index 80-120); Group III (sulfur content <0.03
wt %
and >90 wt % saturates, viscosity index >120); Group IV (all polyalphaolefins
PAOs such as PA0-2, PA0-4, PA0-5, PA0-6, PA0-7 or PA0-8); and Group V.
The oil of lubricating viscosity includes API Group I, Group II, Group III,
Group
IV, Group V oil or mixtures thereof In one embodiment, 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.
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[0021] The various described oils of lubricating viscosity may be used
alone or
in combinations. The oil of lubricating viscosity is used in the range of
about 70 wt
% to about 99 wt %, and in another embodiment, in the range of about 75 wt %
to
about 98 wt %, in another embodiment in the range of about 88 wt % to about 97
wt
% of the lubricant.
[0022] In some embodiments the lubricating oil component of the
present
invention includes a Group II or Group III base oil, or a combination thereof.
These
are classifications established by the API (American Petroleum Institute).
Group III
oils contain < 0.03 percent sulfur and > 90 percent saturates and have a
viscosity
index of > 120. Group II oils have a viscosity index of 80 to 120 and contain
<0.03
percent sulfur and > 90 percent saturates. The oil can also be derived from
the
hydroisomerization of wax, such as slack wax or a Fischer-Tropsch synthesized
wax. Such "Gas-to-Liquid" oils are typically characterized as Group III.
[0023] The compositions of the present invention may include some
amount of
Group I base oils, and even Group IV and Group V base oils. Polyalphaolefins
are
categorized as Group IV. Group V encompasses "all others". However, in some
embodiments the lubricating oil component of the invention contains no more
than
20, 10, 5, or even 1 percent by weight Group I base oil. These limits may also
apply
to Group IV or Group V base oils. In other embodiments the lubricating oil
present
in the compositions of the invention is at least 60, 70, 80, 90, or even 95
percent by
weight Group II and/or Group III base oil. In some embodiments the lubricating
oil
present in the compositions of the invention is essentially only Group II
and/or
Group III base oil, where small amounts of other types of base oils may be
present
but not in amounts that significantly impact the properties or performance of
the
overall composition.
[0024] In some embodiments the compositions of the invention include
some
amount of Group I and/or Group II base oils. In other embodiments the
compositions of the invention are lubricating compositions where the oil of
lubricating viscosity is primarily Group I and/or Group II base oils, or even
essentially Group I and/or Group II base oils, or even exclusively Group I
and/or
Group II base oils.
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[0025] In some embodiments the compositions of the invention include
some
amount of Group I base oils. In other embodiments the compositions of the
invention are lubricating compositions where the oil of lubricating viscosity
is
primarily Group I base oils, or even essentially Group I base oils, or even
exclusively Group I base oils.
[0026] In some embodiments the compositions of the invention include
some
amount of Group II base oils. In other embodiments the compositions of the
invention are lubricating compositions where the oil of lubricating viscosity
is
primarily Group II base oils, or even essentially Group II base oils, or even
exclusively Group II base oils.
[0027] In some embodiment's the oil of lubricating viscosity may be
present in
the range from 60 to 99.9, from 88.5 to 99.6, from 96.9 to 99.5, or from 98.2
to 99.4
weight percent of the lubricating oil composition. Each oil of lubricating
viscosity
described above may be used alone or as mixtures of one or more thereof.
The Antioxidant Component
[0028] The present invention requires the described lubricant
compositions to
include a minimum level of a specific antioxidant component. The antioxidant
component includes: (i) a phenolic antioxidant, (ii) an aminic antioxidant, or
(iii) a
combination thereof. The antioxidant component must be present in the
described
lubricating compositions at a minimum of 0.4, 0.5 or a minimum 1.0 percent by
weight or higher.
[0029] Suitable phenolic antioxidants that may be used in the
invention include
substituted phenol that contains at least one alkyl substituent group. In some
embodiments the phenolic antioxidant includes compounds free of nitrogen which
are also ashless. In some embodiments the phenolic antioxidant includes a
substituted phenol containing at least two branched alkyl substituent groups.
In
some embodiments the phenolic antioxidant comprises a substituted phenol
containing at least two branched alkyl substituent groups and further
containing a
ester containing substituent group.
[0030] The phenolic antioxidant can include a sterically hindered phenols
that
contain an alkyl group ortho to the hydroxyl group, two alkyl groups ortho to
the
hydroxyl group that occupy the 2-position and 6-position of the phenolic ring,
or a
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mixture thereof The alkyl groups can contain 1 to 24 carbon atoms and in other
instances 3 to 18 and 3 to 12 carbon atoms. The alkyl groups can be linear,
branched to include tertiary alkyl groups, or a mixture thereof The sterically
hindered phenol can also contain one or more additional alkyl groups and/or
one or
more hydrocarbyl groups such as a propionate ester group. Useful sterically
hindered phenols can include ortho-alkylated phenolic compounds such as for
example 2,6-ditertbutylphenol, 4-methyl-2,6-di-tertbutylphenol,
2,4,6-
tritertbutylphenol, 2-tert-butylphenol, 2,6-diisopropylphenol, 2-methy1-6-tert-
butylphenol, 2,4-dimethy1-6-tert-butylphenol, 4-(N,N-dimethylaminomethyl)-2,6-
di-
tertbutyl phenol, 4-ethyl-2,6-di-tertbutylphenol, and their analogs and
homologs.
Mixtures of two or more such mononuclear phenol compounds are also suitable.
[0031] In an embodiment of the invention the sterically hindered phenol
can
be represented by the following formula:
014
(1)
wherein R4 is an alkyl group containing 1 up to 24 carbon atoms and a is an
integer of 1 to 5. In some embodiments R4 contains 4 to 18 carbon atoms or
even from 4 to 12 carbon atoms. R4 may be either straight chained or branched
chained, and in some embodiments is branched. The value for a can be 1 to 4,
1 to 3, or 2, or 3. In some embodiments the phenol is a butyl substituted
phenol
containing 2 or 3 t-butyl groups. In some embodiments one R4 group is located
in the 4 position on the ring and is hydrogen, a hydrocarbyl such as methyl,
ethyl, or dodecyl. In any of these embodiments, when a is 2 and t-butyl groups
occupy the 2- and 6-positions of phenol, the phenol is extremely sterically
hindered and has the following structure:
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014
0
(II)
[0032] In one embodiment of the invention the sterically hindered
phenol
can be represented by the following formula:
t-alkyl
HO
CD V
CH2CH2COR3
t-alkyl (III)
wherein the t-alkyl groups can have 4 to 8 carbon atoms, and R3 is a straight
chain or branched chain alkyl group containing 2 to 22, 2 to 8, 2 to 6 carbon
atoms or even just 4 carbon atoms. R3 is desirably a 2-ethylhexyl group or an
n-
butyl group. Hindered, ester-substituted phenols such as those of formula
(III)
can be prepared by heating a 2,6-dialkylphenol with an acrylate ester under
base catalysis conditions such as aqueous KOH as described in International
Publication No. W001/74978. In another embodiment of this invention the
sterically hindered phenol is an alkylation reaction product of an alkylphenol
such as a dodecylphenol and isobutylene to form a product containing a di-t-
butylated alkylphenol. An embodiment of the invention is a sterically hindered
phenol having two or more alkyl substituents that contain 1 to 24 carbon atoms
and that occupy the 2-position and 6-position of the phenolic ring.
[0033] The phenolic antioxidant can also include an alkylene or
alkylidene
coupled sterically hindered phenol oligomer. The coupled sterically hindered
phenol oligomer can contain two or more phenolic rings where each ring is
occupied at the 2-, 4- and 6-positions by an alkyl group such as a methyl or t-
butyl group or an arylalkyl group such as a 3,5-di-t-butyl-4-hydroxybenzyl
group. The alkylene and alkylidene coupling groups can be respectively
methylene and ethylidene groups. The alkyl groups can have 1 to 24 carbon
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atoms and in other instances can have 3 to 18 and 3 to 12 carbon atoms. The
alkyl groups can be linear, branched to include tertiary alkyl groups, or a
mixture thereof. The coupled sterically hindered phenol oligomer can include a
mixture of two or more oligomers where each oligomer contains a different
number of phenolic rings. The coupling of the phenolic rings in an oligomer
can be at ortho ring positions, at para ring positions, or at a mixture of
ortho
and para ring positions.
[0034] In an embodiment of the invention the phenolic antioxidant is a
coupled
alkylphenol which can be represented by the formula:
OH OH OH
R5
R6 0 R6 0 R5
n
10 X Y Z (IV)
wherein each R5 is independently a tertiary alkyl group containing from 4 to
about 8
carbon atoms, each of X, Y and Z is independently hydrogen or a hydrocarbon
radical, each R6 is independently an alkylene or alkylidene group, and n is a
number
ranging from zero to about 4. Each R5 group must be a tertiary alkyl group.
Tertiary
alkyl groups have the general structure:
J
1
K¨C
1
L (V)
wherein each of J, K and L is an alkyl group of 1-4 carbon atoms.
Representative
tertiary alkyl groups are tertiary butyl, tertiary amyl, tertiary hexyl and
tertiary octyl.
The R5 groups may be the same or different. In some embodiments all R5 are the
same, and in still further embodiments are all tertiary butyl groups. Each R6
is
independently a divalent group such as an alkylene or an alkylidene group.
These
groups may be substituted for example by various hydrocarbyl groups such as
alkyl
and aryl groups. Representative examples of suitable R6 groups are methylene,
ethylene, propylene, phenyl substituted methylene, methyl substituted
methylene,
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methyl substituted ethylene and the like. Typically, each R6 contains from one
to
about 10 carbon atoms, or from one to about three carbon atoms. In one
embodiment, R6 is phenyl substituted methylene. In another embodiment, each is
methylene, that is a group of the formula ¨CH2-. Each X, Y and Z is
independently
hydrogen or a hydrocarbon-based group. These groups may be the same or
different. In one embodiment, each of X, Y and Z is independently an aliphatic
hydrocarbon group. Thus each of these groups will contain at least one carbon
atom, but may contain more. In still further embodiments they contain from 1
to
about 500 carbon atoms, from 4 to about 100 carbon atoms, or even from about 4
to
about 30 carbon atoms.
[0035] In an embodiment of the invention the phenolic antioxidant is a
methylene coupled oligomer of a sterically hindered phenol such as for example
4,4'-methylene-bis(6-tert-buty1-2-methylphenol), 4,4' -methylene-bis(2-tert-
amy1-6-
methylphenol), 2,2' -methylene-bis(4-methyl-6-tert-butylphenol), 4,4
'methylene-
bis(2,6-di-tert-butylphenol), and similar compounds. In an embodiment of this
invention a methylene coupled oligomer of a sterically hindered phenol is 2,2'-
methylene-bis(6-tert-buty1-4-dodecylphenol) as described in U.S. Patent No.
6,002,051 regarding its preparation and use.
[0036] Suitable aminic antioxidants that may be used in the invention
include
alkaryl amines and in some embodiments the aminic antioxidant is an
alkylphenyl
amine. Suitable examples include a bis(4-alkylphenyl)amine.
[0037] The aminic antioxidant can include a secondary aromatic amine,
typically a monoamine, that contains one aryl group, two aryl groups, or a
mixture
thereof An embodiment of the invention is a secondary aromatic amine
containing
one aryl group such as for example N-methylaniline. The secondary aromatic
amine
containing one aryl group can also have Ci-C16 alkyl or arylalkyl substituents
on the
aryl group. In another embodiment of the invention the secondary aromatic
amine
can be a diarylamine such as for example diphenylamine, N-pheny1-1-
naphthylamine or combinations thereof The diarylamine can contain one, two or
more alkyl and/or arylalkyl substituents. The alkyl and arylalkyl substituents
can
have 1 to 16 carbon atoms and in other instances can have 3 to 14 and 4 to 12
carbon
atoms. The alkyl and arylalkyl substituents can be linear, branched, or a
mixture
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thereof In an embodiment of the present invention the diarylamine is an
alkylated
diphenylamine which can be represented by formula:
R7-C6H4-NH-C6H4-R8 (VI)
wherein R7 and R8 are independently a hydrogen or an alkyl group containing 1
to 24 carbon atoms. The diphenylamine of formula (VI) can be a mixture of
diphenylamine and monoalkylated and dialkylated diphenylamine. R7 and/or R8
can be alkyl groups containing from 4 to 20 carbon atoms. In another
embodiment of the invention the diphenylamine of formula (VI) is prepared by
alkylating diphenylamine with nonenes using well known alkylation methods.
Alkylated diarylamines are also commercially available.
[0038] The antioxidant component must be present in the composition at
least
1.0 percent by weight. This treat rate is with respect to the final lubricant
composition to be used in a mechanical device, but could also be applied to
additive
packages and concentrates which are then diluted, typically with oil, to
produce the
final lubricant. The weight percent discussed here are with respect to the
overall
lubricant composition. Any diluent that may be present in the antioxidant
component is generally not considered when determining the percent by weight
at
which the antioxidant component is present in the composition. In addition,
any
materials in the antioxidant component other than the phenolic and aminic
antioxidants described herein may be excluded when determining the percent by
weight at which the antioxidant component is present in the composition, such
that
the weight percent values discussed only apply to the phenolic and aminic
antioxidants.
[0039] Also it is noted that in some embodiments the antioxidant
component
includes one or more phenolic antioxidants and no aminic antioxidants. In
other
embodiments the antioxidant component includes one or more aminic antioxidants
and no phenolic antioxidants. In still other embodiments the antioxidant
component
includes a combination of one or more aminic antioxidants and one or more
phenolic antioxidants.
[0040] In some embodiments the phenolic antioxidant is present in the
lubricating composition from at least 0.5 percent by weight and the aminic
antioxidant is present in the lubricating composition from at least 0.5
percent by
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weight. In some embodiments the phenolic antioxidant is present in the
lubricating
composition from at least 1.0 percent by weight and the aminic antioxidant is
present in the lubricating composition from at least 1.0 percent by weight or
from
0.5 percent by weight.
Additional Additives
[0041] Optionally the lubricating compositions of the invention
include one or
more additional additives, which may be selected from the group including: a
foam
inhibitor, a demulsifier, a pour point depressant, an antioxidant other than
those
described above, a dispersant, a metal deactivator (such as a copper
deactivator), an
antiwear agent, extreme pressure agent, viscosity modifiers, or mixtures
thereof.
The optional additives may each be present in the range from 0.0005 to 1.3,
from
0.00075 to 0.5, from 0.001 to 0.4, or from 0.0015 to 0.3 percent by weight of
the
lubricating oil composition. However it is noted that some optional additives,
including viscosity modifying polymers, which may alternatively be considered
as part of the base fluid, may be present in higher amounts including up to
30,
40, or even 50% by weight when considered separate from the base fluid. The
optional additives may be used alone or mixtures thereof.
[0042] Antifoams, also known as foam inhibitors, are known in the art
and
include but are not limited to organic silicones and non-silicon foam
inhibitors.
Examples of organic silicones include dimethyl silicone and polysiloxanes.
Examples of non-silicon foam inhibitors include but are not limited to
polyethers,
polyacrylates and mixtures thereof as well as copolymers of ethyl acrylate, 2-
ethylhexylacrylate, and optionally vinyl acetate. In some embodiments the
antifoam
is a polyacrylate. Antifoams may be present in the composition from 0.001 to
0.012
or 0.004 pbw or even 0.001 to 0.003.
[0043] Demulsifiers are known in the art and include but are not
limited to
derivatives of propylene oxide, ethylene oxide, polyoxyalkylene alcohols,
alkyl
amines, amino alcohols, diamines or polyamines reacted sequentially with
ethylene
oxide or substituted ethylene oxides or mixtures thereof. Examples of
demulsiflers
include polyethylene glycols, polyethylene oxides, polypropylene oxides,
(ethylene
oxide-propylene oxide) polymers, including block copolymers of ethylene oxide
and
propylene oxide, and mixtures thereof. In some embodiments the demulsiflers is
a
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polyether. Demulsifiers may be present in the composition from 0.002 to 0.012
pbw.
[0044] Pour point depressants are known in the art and include but are
not
limited to esters of maleic anhydride-styrene copolymers, polymethacrylates;
polyacrylates; polyacrylamides; condensation products of haloparaffin waxes
and
aromatic compounds; vinyl carboxylate polymers; and terpolymers of dialkyl
fumarates, vinyl esters of fatty acids, ethylene-vinyl acetate copolymers,
alkyl
phenol formaldehyde condensation resins, alkyl vinyl ethers and mixtures
thereof.
[0045] The compositions of the invention may also include a rust
inhibitor.
Suitable rust inhibitors include hydrocarbyl amine salts of alkylphosphoric
acid,
hydrocarbyl amine salts of dialkyldithiophosphoric acid, hydrocarbyl amine
salts of
hydrocarbyl arenesulphonic acid, fatty carboxylic acids or esters thereof, an
ester of
a nitrogen-containing carboxylic acid, an ammonium sulfonate, an imidazoline,
mono-thio phosphate salts or esters, or any combination thereof; or mixtures
thereof.
[0046] Suitable hydrocarbyl amine salts of alkylphosphoric acid of the
invention are represented by the following formulas:
RA
R21,0 CY 1425
R220 P\ /=/I
0 R23
(VII)
wherein R21 and R22 are independently hydrogen, alkyl chains or hydrocarbyl,
and
in some embodiments at least one of R21 and R22 are hydrocarbyl. R21 and R22
contain about 4 to about 30, about 8 to about 25, or even about 8 or 10 to
about 20,
or even from 13 to about 19 carbon atoms. R23, R24 and R25 are independently
hydrogen, alkyl branched or linear alkyl chains with about 1 to about 30, in
other
embodiments about 4 to about 24, or even from about 6 to about 20, and in some
embodiments about 8 or 10 to about 16 carbon atoms. R23, R24 and R25 are
independently hydrogen, alkyl branched or linear alkyl chains, and in some
embodiments at least one, or even two of R23, R24 and R25 are hydrogen, and
further
where at least one of R23, R24 and R25 is a hydrocarbyl group containing at
least 8
carbon atoms.
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[0047] Examples of alkyl groups suitable for R23, R24 and R25 include
but are not
limited to butyl, sec butyl, isobutyl, tert-butyl, pentyl, n-hexyl, sec-hexyl,
n-octyl, 2-
ethyl, hexyl, ethyl-hexyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl,
pentadecyl,
hexadecyl, heptadecyl, octadecyl, octadecenyl, nonadecyl, eicosyl or mixtures
thereof.
[0048] In one embodiment the hydrocarbyl amine salt of an
alkylphosphoric
acid is the reaction product of a C14 to C18 alkylated phosphoric acid with
Primene
81R (produced and sold by Rohm & Haas) which is a mixture of C11 to C14
tertiary
alkyl primary amines.
[0049] Hydrocarbyl amine salts of dialkyldithiophosphoric acid of the
invention
used in the rust inhibitor package are represented by the formula:
R2-4
/\i*-151
P
µ / 1I
11
R26,--0
142-5 (VIII)
wherein R26 and R27 are independently branched or linear alkyl groups. R26 and
R27
contain about 3 to about 30, or from about 4 to about 25, or from about 5 to
about
20, or even from about 6 to about 19 carbon atoms. R23, R24 and R25 are as
described above.
[0050] Examples of hydrocarbyl amine salts of dialkyldithiophosphoric
acid of
the invention include but are not limited to the reaction product(s) of
diheptyl or
dioctyl or dinonyl dithiophosphoric acids with ethylenediamine, morpholine or
Primene 81R or mixtures thereof.
[0051] Suitable hydrocarbyl amine salts of hydrocarbyl arenesulphonic
acids
used in the rust inhibitor package of the invention are represented by the
formula:
142-4
\ R25
/
(14)-CY-003r
/=/ I
R23
(IX)
wherein Cy is a benzene or naphthalene ring. R28 is a hydrocarbyl group with
about
4 to about 30, or from about 6 to about 25, or from about 8 to about 20 carbon
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atoms. z is independently 1, 2, 3, or 4 and in some embodiments z is 1 or 2.
R23,
R24 and R25 are as described above.
[0052]
Examples of hydrocarbyl amine salts of hydrocarbyl arenesulphonic acid
of the invention include but are not limited to the ethylenediamine salt of
dinonylnaphthalene sulphonic acid.
[0053]
Examples of suitable fatty carboxylic acids or esters thereof include
glycerol monooleate and oleic acid. An example of a suitable ester of a
nitrogen-
containing carboxylic acid includes oleyl sarcosine.
[0054] The
rust inhibitors may be present in the range from 0.02-0.2, from 0.03
to 0.15, from 0.04 to 0.12, or from 0.05 to 0.1 pbw of the lubricating oil
composition. The rust inhibitors of the invention may be used alone or in
mixtures
thereof.
[0055] The
lubricating compositions of the invention may also include a metal
deactivator. Metal deactivators are used to neutralise the catalytic effect of
metal for
promoting oxidation in lubricating oil. Suitable metal deactivators include
but are
not limited to triazoles, tolyltriazoles, a thiadiazole, or combinations
thereof, as well
as derivatives thereof
Examples include derivatives of benzotriazoles,
benzimidazole, 2-alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles, 2-
(N,N'-
dialkyldithio-carbamoyl)benzothiazoles, 2,5
-bis(alkyl-dithio)-1,3 ,4 -thiadiazoles ,
2,5 -bis (N,N ' -di alkyldithio carb amoy1)-1,3 ,4-thiadiazo les, 2-
alkyldithio-5-mercapto
thiadiazoles or mixtures thereof. These additives may be used from 0.01 to
0.25
percent by weight in the overall composition.
[0056] In
some embodiments the metal deactivator is a hydrocarbyl substituted
benzotriazole compound. The
benzotriazole compounds with hydrocarbyl
substitutions include at least one of the following ring positions 1- or 2- or
4- or 5-
or 6- or 7- benzotriazoles. The hydrocarbyl groups contain about 1 to about
30,
preferably about 1 to about 15, more preferably about 1 to about 7 carbon
atoms,
and most preferably the metal deactivator is 5-methylbenzotriazole used alone
or
mixtures thereof.
[0057] The metal
deactivators may be present in the range from 0.001 to 0.1,
from 0.01 to 0.04 or from 0.015 to 0.03 pbw of the lubricating oil
composition.
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Metal deactivators may also be present in the composition from 0.002 or 0.004
to
0.02 pbw. The metal deactivator may be used alone or mixtures thereof.
[0058] Antioxidants other than those described above may also be
present
including a substituted hydrocarbyl mono-sulfide. In some embodiments the
substituted hydrocarbyl monosulfides include n-dodecy1-2-hydroxyethyl sulfide,
1-
(tert-dodecylthio)-2-propanol, or combinations thereof. In some embodiments
the
substituted hydrocarbyl monosulfide is 1-(tert-dodecylthio)-2-propanol.
[0059] Dispersants may also be present including: (i) a
polyetheramine; (ii) a
borated succinimide dispersant; (iii) a non-borated succinimide dispersant;
(iv) a
Mannich reaction product of a dialkylamine, an aldehyde and a hydrocarbyl
substituted phenol; or any combination thereof. In some embodiments the
dispersant component is present from 0.05 to 0.5 pbw of the overall
composition.
[0060] The invention further provides for all of the compositions,
methods, and
uses described herein, where the specified lubricant includes a demulsifier,
where
the specified lubricant includes a combination of a demulsifier and a
sulfurized
olefin, where the specified lubricant includes a highly sulfurized olefin such
as a
sulfurized olefin containing at least 20% by weight sulfur, where the
specified
lubricant is essentially free or to even completely free of non-highly
sulfurized
olefins such as a sulfurized olefin containing less than 20% by weight sulfur,
where
the specified lubricant includes a combination of a substituted triazole and a
substituted thiadiazole, where the specified lubricant is essentially free of
or even
completely free of metal dialkyl dithiophosphates, where the specified
lubricant is
essentially free of or even completely free of overbased metal-containing
detergents, where the specified lubricant is essentially free of or even
completely
free of zinc, or any combination thereof
Industrial Application
[0061] The invention provides a process for the preparation of
lubricating oil
compositions. The lubricating oil compositions are prepared by the steps
comprising: a) mixing and/or dissolving in one another the components
described
above that includes the combination of an oil of lubricating viscosity, the
substituted
triazole and optionally one more addition additives. The materials are mixed
until
the additives are substantially or wholly dissolved, in some embodiments at
elevated
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temperatures in the range 40 C to 110 C, or 50 C to 95 C, or even 55 C to 85
C;
and for a period of time in the range 30 seconds to 24 hours, 2 minutes to 8
hours, or
minutes to 4 hours; and at pressures in the range 700 mm of Hg to 2000 mm of
Hg, 750 mm of Hg to 900 mm of Hg, or 755 mm of Hg to 800 mm of Hg.
5 [0062] The order of addition of the additives is not overly limited.
The optional
additives may be mixed in at the same time as the other components or at a
later
time using any of the mixing procedures described above.
[0063] In some embodiments a portion of oil or similar diluent is
present with
the components and the components are mixed into the oil. In other embodiments
a
minimal amount of oil or diluent is present, other than that amount inherently
present in the additive from their means of production and preparation and
additional base oil is added after the component have been mixed. In any event
the
described processes results in lubricating compositions.
[0064] In some embodiments the lubricating oil compositions may be
prepared
from a concentrate comprising the steps of: a) mixing all of the components
described above with minimal oil and/or diluent present, other than optionally
some
relatively small amount to allow for reasonable handling properties. The
resulting
concentrate may then be used in the preparation of a lubricating composition
by
mixing the concentrate with an effective amount of base oil or mixtures
thereof
resulting in a finished fluid. Optional additives may be added to the
concentrate or
to the resulting final fluid. These optional additives include any of those
described
above. In some embodiments these optional additives include a foam inhibitor,
a
demulsifier, a viscosity modifier, a pour point depressant, or mixtures
thereof, and
may be added such that they are present in the overall compositions in the
range
about 0, 0.01, 0.1 or even 0.25 or up to about 13, 10, 8 or even 6 pbw.
[0065] In some embodiments the compositions of the invention have an
ISO
viscosity grade from 100 to 1000, or from 100 to 460, or even from 100 or 150
to
320. In some embodiments the compositions of this invention are not grease
compositions or engine oil compositions. Rather these compositions can be
industrial gear oils, wind turbine lubricants, bearing lubricants, and the
like, and in
some embodiments even automotive gear oils.
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Specific Embodiment
[0066] The invention will be further illustrated by the following
examples,
which set forth particularly advantageous embodiments. While the examples are
provided to illustrate the invention, they are not intended to limit it.
[0067] The example sets below are designed to evaluate and compare the
following additives: Antioxidant A, an alkylated phenol; and Antioxidant B, an
alkaryl amine.
[0068] To evaluate the additives, the examples in the example sets
below are
tested to evaluate their seal compatibility. Using NBR 902 seals the samples
are
tested for approval under the Flender-Siemens specification (F-S) for wind
turbines,
which involves 1000 hours of testing at 130 C for each sample. Under this
specification, ideally the fluid must give results including a hardness change
of not
more than 5 points (-5 to +5), a percent volume change from a 2% decrease to a
5%
increase (-2% to +5%), a percent tensile decrease of no more than 60% (-60%
max)
and a percent elongation decrease of no more than 60% (-60% max). These
specifications, in particular the Flender-Siemens specification, are very hard
to meet,
and a relative improvement in performance over a conventional comparative
example, even if not a clean pass, would still be considered to be a
significant
improvement. In fact, a sample that meets the specification expect for having
a
hardness change up to +7, a volume change up to +6%, or a elongation change of
down to -65% is still considered to have met the a specification and passed
the test,
so long as only one of these areas is outside the normal pass range. This
secondary
allowance for one of the ratings allows for a passing result even if the
sample did not
show a "clean pass" with all ratings inside the ideal ranges.
[0069] However, as is evident from the results, it is important to consider
relative performance of the examples rather than just the pass fail result.
When
considering the Flender-Siemens specification (F-S) results of the example
sets and
comparing the relative performance it can be helpful to consider the degree to
which
a sample passed or failed. The following key can be used for this purpose with
the
best result at the top of the table and the worst result at the bottom:
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Result Key for Relative Performance Comparisons
Degree Rating Description of the Rating
A PASS Clean Pass, no ratings outside the ideal ranges.
B PASS Pass, one rating
outside the ideal range but within the secondary allowance,
discussed in the description of the test method above.
Fl 1st Degree Fail, the sample failed for having two ratings outside
the ideal ranges
but both within the secondary allowances.
F2 2nd
Degree Fail, the sample failed for having one rating outside both the ideal
range and the secondary allowances for that rating.
3rd Degree Fail, the sample failed for having one rating outside both the
ideal
F3 range and the secondary allowances for that rating and also having
another rating
outside the ideal ranges but within the secondary allowances.
F4 4th Degree Fail, the sample failed for having two ratings outside
the both ideal
range and the secondary allowances for those ratings.
5th Degree Fail, the sample failed for having two ratings outside both the
ideal
F5 range and the secondary allowances for those ratings and also having
a third
rating outside the ideal ranges but within the secondary allowances.
6th Degree Fail, the sample failed for having three ratings outside the both
ideal
F6 range and the secondary allowances for those ratings and also having
a third
rating outside the ideal ranges but within the secondary allowances.
Example Set 1
[0070] A
set of examples is prepared in a Group I (GI) base oil. Each of the
examples contains the same conventional additives package in the same amount,
such that the sample is suitable for use as a lubricant in industrial gear
applications.
Each sample is top-treated with one of the antioxidant described above to see
the
impact the added materials have on the formulation's performance, specifically
in
regards to seal compatibility.
[0071] The
conventional additive package used in each of these examples, is
referred to as Additive Package A and contains a metal deactivator, a
demulsifier, a
rust inhibitor, a mixture of antiwear and extreme pressure agents, an antifoam
agent,
a detergent, and a corrosion inhibitor. None of the additives in Additive
Package A
meet the requirements for the antioxidant component of the invention.
[0072] The samples
are tested to evaluate their seal compatibility using the same
test method described above. The results from the testing of Example Set 1 are
summarized in the table below:
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Table 1 ¨ Summary of Results from Example Set 1
Ex Ex Ex Ex Ex Ex Ex Ex Ex Ex Ex Ex
1-11 1-2 1-3 1-4 1-51 1-6 1-71 1-8 1-91 1-10 1-11 1-12
Ex Type comp comp comp comp comp comp comp inv comp inv
inv inv
Base 0i12 GI GI GI GI GI GI GI GI GI GI
GI GI
AddPack A A A A A A A A A A A A
Antioxidant A 0.2 0.2 0.5 0.5 1.0 1.0
Antioxidant B 0.2 0.2 0.5 0.5 1.0
1.0
F-S Spec F4 F3 Fl Fl F4 F4 F3 B F4 A
A A
PASS
PASS PASS PASS
Hardness A 8 7 7 6 9 8 8 6 8 5 4 4
%Vol A 2 2 2 2 2 3 3 3 2 3 3 4
%Tensile A -3 0 -2 -4 11 -4 -1 -1 -3 -3 -2
-4
%Elong A -72 -71 -65 -68 -74 -71 -64 -59 -
72 -55 -55 -58
1 ¨ Examples 1-1, 1-5 and 1-9 are repeats of the baselines which was re-tested
for each set of
samples at different treat levels. These examples provide good baseline
comparisons while also
showing the repeatability of the test.
2 ¨ The base oil used in these examples is an API Group I base oil.
[0073] The
results show that the inventive examples provide improved seal
compatibility in Group I based formulations over the comparative examples.
Example Set 2
[0074] A set of
examples is prepared in a Group II (Gil) base oil. Each of the
examples contains the same conventional additives package described above in
Example Set 1. The samples are tested to evaluate their seal compatibility
using the
same test methods described above. The results from the testing of Example Set
2
are summarized in the table below:
Table 2 ¨ Summary of Results from Example Set 2
Ex Ex Ex Ex Ex Ex Ex Ex
2-11 2-2 2-3 2-4 2-51 2-6 2-71 2-8
Ex Type comp comp comp inv comp inv inv
inv
Base 0i12 Gil Gil Gil Gil Gil Gil
Gil Gil
AddPack A A A A A A A A
Antioxidant A 0.5 0.5 1.0 1.0
Antioxidant B 0.5 0.5 1.0 1.0
F-S Spec F4 F4 F3 F3 F4 F4 F3 F3
Hardness A 8 8 7 6 8 8 6 6
%Vol A 2 2 2 3 2 2 4 4
%Tensile A 11 6 8 2 6 5 3 2
%Elong A -74 -79 -71 -76 -76 -76 -67 -67
1 ¨ Examples 2-1 and 2-5 are repeats of the baselines which was re-
tested for each set of samples at different treat levels. These examples
provide good baseline comparisons while also showing the repeatability
of the test.
2 ¨ The base oil used in these examples is an API Group II base oil.
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[0075] The results show that the inventive examples provide improved
seal
compatibility in Group II based formulations. However, as is evident from the
results, here it is important to consider relative performance of the examples
rather
than just the pass fail result.
[0076] 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.
[0077] In this specification the terms "hydrocarbyl substituent" or
"hydrocarbyl
group," as used herein are used in their ordinary sense, which is well-known
to those
skilled in the art. Specifically, they refer to a group primarily composed of
carbon
and hydrogen atoms that is attached to the remainder of the molecule through a
carbon atom and does not exclude the presence of other atoms or groups in a
proportion insufficient to detract from the molecule having a predominantly
hydrocarbon character. 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. A more detailed definition of the terms "hydrocarbyl
substitu-
ent" or "hydrocarbyl group," is described in US Patent 6,583,092.
[0078] 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,
reaction
conditions, molecular weights, number of carbon atoms, and the like, are to be
understood as modified by the word "about." Unless otherwise indicated, all
percent
and formulation values listed herein are on a weight basis. 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, which may be customarily
present in
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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 can be used together with ranges or amounts for any of the other
elements.
As used herein, the expression "consisting essentially of' permits the
inclusion of
substances that do not materially affect the basic and novel characteristics
of the
composition under consideration.
23
