Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
HYDROXY-CONTAINING TERTIARY AMINES AS FRICTION MODIFIERS
FOR AUTOMATIC TRANSMISSION FLUIDS
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the field of additives for
fluids such
as automatic transmission fluids, traction fluids, fluids for continuously
variable
transmission fluids (CVTs), dual clutch automatic transmission fluids, farm
tractor fluids, and engine lubricants.
[0002] In the automatic transmission marketplace, where there is rapid
engineering change driven by the desire to reduce weight and increase transmis-
sion capacity, there is a desire for automatic transmission fluids that
exhibit a
high static coefficient of friction for improved clutch holding capacity. At
the
same time, there is a desire to improve the retention of positive slope
character-
istics in the i.t/v (coefficient of friction vs. sliding speed) curve. There
are
newer tests in the marketplace which are used to define these characteristics.
The static torque can be measured in tests such as the Toyota SAE#2 friction
test procedure and the retention of positive slope can be measured by
procedures
like the JASO LVFA (Japan Automotive Standards Organization, Low Velocity
Friction Apparatus) in which the slope of the i.t/v curve is periodically
measured
during oxidative and mechanical aging.
[0003] There are patents, for example, US 5,750,476, where a type of
fric-
tion modifier technology used to achieve this performance is described. The
combined requirements of high static coefficient of friction and durable
positive
slope are often incompatible with traditional ATF friction modifier technology
which is extremely well described in the patent literature. Many of the com-
monly used friction modifiers result in a low static coefficient of friction
and are
not durable enough on positive slope to be of sufficient use. Additional
patent
literature describing technology for retaining positive mu/v or anti-shudder
characteristics include US 5,858,929. These may employ metal detergents and
combinations of friction modifiers.
[0004] PCT Publication W004/007652, Adams et al, January 22, 2004,
discloses a fluid composition of (a) a friction modifier derived from the
reaction
of a carboxylic acid with an amino alcohol, the friction modifier containing
at
least two hydrocarbyl groups, and (b) a dispersant, which provides good
friction
properties in an automatic transmission.
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[0005] U.S. Patent 4,886,612 discloses a lubricating oil comprising at
least
one of various products, which can be various imidazolines or an oxazoline of
the structure
RI¨C----N¨C¨(R2)(R3)
¨ CH2
where R2 and R3 each represent CH2OCORI, CH2OH or H, prepared by the
condensation of a carboxylic acid (or a reactive equivalent thereof) with an
amino alcohol; for example, the condensation of two moles of isostearic acid
with one mole of tris-hydroxymethylaminomethane (THAM).
[0006] The present invention solves the problem of developing new and
relatively simple and inexpensive friction modifiers to obtain high static
coeffi-
cients of friction and maintain a durable positive slope during oxidative and
mechanical stressing of the friction system, particularly for use in an
automatic
transmission. This is accomplished by the use of a friction modifier which
comprises a tertiary amine having at least two alkyl groups of at least 6
carbon
atoms, as further described below.
SUMMARY OF THE INVENTION
[0007] The present invention provides a composition suitable for
lubricating
a transmission, comprising:
(a) a major amount of an oil of lubricating viscosity;
(b) a tertiary amine being represented by the formula
RI R2NR3
wherein RI and R2 are each independently an alkyl group of at least 6 carbon
atoms and R3 is a polyhydroxyl-containing alkyl group or a polyhydroxyl-
containing alkoxyalkyl group; and
(c) a dispersant.
[0008] The present invention further provides a method for lubricating
a
transmission, comprising supplying thereto the above composition.
[0009] The present invention further provides a concentrate suitable for
dilution with oil of lubricating viscosity to prepare a lubricant for a
transmis-
sion, comprising (a) a concentrate-forming amount of an oil of lubricating
viscosity; (b) a tertiary amine as described above; and (c) a dispersant.
10009A1 In another embodiment, the invention provides a method for lubricat-
ing a transmission, comprising supplying thereto a lubricant comprising:
(a) an oil of lubricating viscosity in an amount greater than 50% by
weight; and
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(b) a tertiary amine being represented by the formula
R1R2NR3
wherein R1 and R2 are each independently an alkyl group of at least 6 carbon
atoms and R3 is a polyhydroxyl-containing alkyl group or a polyhydroxyl-
containing alkoxyalkyl group.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Various preferred features and embodiments will be
described below
by way of non-limiting illustration.
,
2a
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[0011] One component of the present 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. 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
lubri-
cating viscosity is present in an amount of 75 to 95 percent by weight, and
often
greater than 80 percent by weight of the composition. For concentrates, the
oil
of lubricating viscosity may be present at lower concentration or in a minor
amount, for example, from 10 to 50% by weight, and in one embodiment 10 to
30% by weight.
[0012] Natural oils useful in making the inventive lubricants and
functional
fluids include animal oils and vegetable oils as well as mineral lubricating
oils
such as liquid petroleum oils and solvent-treated or acid-treated mineral
lubri-
cating oils of the paraffinic, naphthenic or mixed paraffinic/-naphthenic
types
which may be further refined by hydrocracking and hydrofinishing processes.
[0013] Synthetic lubricating oils include hydrocarbon oils and halo-
substituted hydrocarbon oils such as polymerized and interpolymerized olefins,
also known as polyalphaolefins; polyphenyls; alkylated diphenyl ethers; alkyl-
or dialkylbenzenes; and alkylated diphenyl sulfides; and the derivatives,
analogs
and homologues thereof. Also included are alkylene oxide polymers and inter-
polymers and derivatives thereof, in which the terminal hydroxyl groups may
have been modified by esterification or etherification. Also included are
esters
of dicarboxylic acids with a variety of alcohols, or esters made from C5 to
C12
monocarboxylic acids and polyols or polyol ethers. Other synthetic oils
include
silicon-based oils, liquid esters of phosphorus-containing acids, and
polymeric
tetrahydrofurans. The synthetic oils may be produced by Fischer-Tropsch
reactions and typically may comprise hydroisomerized Fischer-Tropsch hydro-
carbons and/or waxes, or hydroisomerized slack waxes.
[0014] Unrefined, refined and rerefined oils, either natural or synthetic,
can
be used in the lubricants of the present invention. Unrefined oils are those
obtained directly from a natural or synthetic source without further
purification
treatment. Refined oils have been further treated in one or more purification
steps to improve one or more properties. They can, for example, be hydrogen-
ated, resulting in oils of improved stability against oxidation.
[0015] In one embodiment, the oil of lubricating viscosity is an API
Group
II, Group III, Group IV, or Group V oil, including a synthetic oil, or
mixtures
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thereof. These are classifications established by the API Base Oil Interchange-
ability Guidelines. Both Group II and Group III oils contain < 0.03 percent
sulfur and > 99 percent saturates. Group II oils have a viscosity index of 80
to
120, and Group III oils have a viscosity index > 120. Polyalphaolefins are
categorized as Group IV. Group V is encompasses "all others" (except for
Group I, which contains > 0.03% S and/or < 90% saturates and has a viscosity
index of 80 to 120).
[0016] In one embodiment, at least 50% by weight of the oil of
lubricating
viscosity is a polyalphaolefin (PAO). Typically, the polyalphaolefins are
derived from monomers having from 4 to 30, or from 4 to 20, or from 6 to 16
carbon atoms. Examples of useful PAOs include those derived from 1-decene.
These PAOs may have a viscosity of 1.5 to 150 mm2/s (cSt) at 100 C. PAOs
are typically hydrogenated materials.
[0017] The oils of the present invention can encompass oils of a single
viscosity range or a mixture of high viscosity and low viscosity range oils.
In
one embodiment, the oil exhibits a 100 C kinematic viscosity of 1 or 2 to 8 or
10 mm2/sec (cSt). The overall lubricant composition may be formulated using
oil and other components such that the viscosity at 100 C is 1 or 1.5 to 10 or
15
or 20 mm2/sec and the Brookfield viscosity (ASTM-D-2983) at ¨40 C is less
than 20 or 15 Pa-s (20,000 cP or 15,000 cP), such as less than 10 Pa-s, even 5
or
less.
[0018] Component (b) is a tertiary amine, which can serve as a friction
modifier. The amine will contain three substituent hydrocarbyl groups, two of
which are alkyl groups. The amine is represented by the formula
R1R2NR3
wherein Rl and R2 are each independently an alkyl group of at least 6 carbon
atoms (e.g., 8 to 20 carbon atoms or 10 to 18 or 12 to 16) and R3 is a polyhy-
droxyl-containing alkyl group or a polyhydroxyl-containing alkoxyalkyl group
[0019] In one embodiment the amine comprises a product of di-cocoalkyl
amine or homologous amines. Di-cocoalkyl amine (or di-cocoamine) is a
secondary amine in which two of the R groups in the above formula are pre-
dominantly c12 groups, derived from coconut oil and the remaining R group is
H.
[0020] In one embodiment, R3 is a polyol-containing alkyl group (that
is, a
group containing 2 or more hydroxy groups) or a group containing one or more
hydroxy groups and one or more amine groups. For instance, R3 may be ¨CH2¨
CHOH¨CH2OH or a homologue thereof, containing, for example, 3 to 8 carbon
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atoms or 3 to 6 carbon atoms or 3 to 4 carbon atoms, and 2, 3, 4 or more hy-
droxy groups (normally no more than one hydroxy group per carbon atom). A
typical resulting product may thus be represented by
R1R2N¨CH2¨CHOH¨CH2OH
or homologues thereof, where Rl and R2 are, as described above, independently
alkyl groups of 8 to 20 carbon atoms. Such products may be obtained by the
reaction of a dialkyl amine with an epoxide or chlorohydroxy compound. In
particular, reaction of a secondary amine with glycidol (2,3-epoxy-1-propanol)
or "chloroglycerine" (that is, 3-chloropropane-1,2-diol) may be effective
under
conditions as described above. Such materials based on the reaction of dico-
coamine with one or more moles of glycidol or chloroglycerine are particularly
useful in providing friction-modifying performance. If reaction is with
multiple
moles of glycidol or chloroglycerine, or other epoxyalkanols or chlorodiols, a
dimeric or oligomeric ether-containing group, that is, a hydroxyl-substituted
alkoxyalkyl group, may result.
[0021] The amine, component (b), may alternatively be described, in
certain
embodiments, as a compound comprising a core portion comprising 3 to 8
carbon atoms, (e.g, 3 to 6, or 3 carbon atoms), said core portion being substi-
tuted by: (i) at least two hydroxy groups, or at least one hydroxy group and
at
least one alkoxy group of 1 to 4 carbon atoms wherein said alkoxy group is
further substituted by at least one hydroxy group or another such alkoxy
group;
and (ii) at least one amino group, the nitrogen atom thereof bearing two hydro-
carbyl groups, each such hydrocarbyl group independently having 6 to 30
carbon atoms.
[0022] The amount of component (b) in the compositions of the present
invention is generally an amount suitable to reduce or inhibit shudder in an
automatic transmission, that is, a performance defect observed during wet
clutch
operation when the friction characteristics of the transmission fluid are
inade-
quately balanced. The effective amount can be 0.01 to 10.0 percent by weight
of the finished fluid formulation. Alternative amounts include 0.02 percent to
5
percent, or 0.1 percent to 3 percent, or 0.1 to 2 percent, or 0.5 to 1.5
percent. In
a concentrate, the amounts will be proportionately higher.
[0023] Component (c) is a dispersant. It may be described as "other
than a
species of (b)," in the event that some of the friction modifiers of (b) may
exhibit some dispersant characteristics. Examples of "carboxylic dispersants"
are described in many U.S. Patents including the following: 3,219,666,
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3,316,177, 3,340,281, 3,351,552, 3,381,022, 3,433,744, 3,444,170, 3,467,668,
3,501,405, 3,542,680, 3,576,743, 3,632,511, 4,234,435, Re 26,433, and
6,165,235.
[0024] Succinimide dispersants, a species of carboxylic dispersants,
are
prepared by the reaction of a hydrocarbyl-substituted succinic anhydride (or
reactive equivalent thereof, such as an acid, acid halide, or ester) with an
amine,
as described above. The hydrocarbyl substituent group generally contains an
average of at least 8, or 20, or 30, or 35 up to 350, or to 200, or to 100
carbon
atoms. In one embodiment, the hydrocarbyl group is derived from a polyalkene.
_
Such a polyalkene can be characterized by an IVI. (number average molecular
_
weight) of at least 500. Generally, the polyalkene is characterized by an n of
500, or 700, or 800, or 900 up to 5000, or to 2500, or to 2000, or to 1500. In
_
another embodiment n varies from 500, or 700, or 800, to 1200 or 1300. In
one embodiment the polydispersity (M i
w /MO s at least 1.5.
[0025] The polyalkenes include homopolymers and inter-polymers of poly-
merizable olefin monomers of 2 to 16 or to 6, or to 4 carbon atoms. The
olefins
may be monoolefins such as ethylene, propylene, 1-butene, isobutene, and 1-
octene; or a polyolefinic monomer, such as diolefinic monomer, such 1,3-
butadiene and isoprene. In one embodiment, the inter-polymer is a homo-
polymer. An example of a polymer is a polybutene. In one instance about 50%
of the polybutene is derived from isobutylene. The polyalkenes can be prepared
by conventional procedures.
[0026] In one embodiment, the succinic acylating agents are prepared by
reacting a polyalkene with an excess of maleic anhydride to provide
substituted
succinic acylating agents wherein the number of succinic groups for each
equivalent weight of substituent group is at least 1.3, e.g., 1.5, or 1.7, or
1.8.
The maximum number of succinic groups per substituent group generally will
not exceed 4.5, or 2.5, or 2.1, or 2Ø The preparation and use of substituted
succinic acylating agents wherein the substituent is derived from such polyole-
fins are described in U.S. Patent 4,234,435.
[0027] The substituted succinic acylating agent can be reacted with an
amine, including those amines described above and heavy amine products
known as amine still bottoms. The amount of amine reacted with the acylating
agent is typically an amount to provide a mole ratio of CO:N of 1:2 to 1:0.75,
.
If the amine is a primary amine, complete condensation to the imide can occur.
Varying amounts of amide product, such as the amidic acid, may also be pre-
sent. If the reaction is, rather, with an alcohol, the resulting dispersant
will be
an ester dispersant. If both amine and alcohol functionality are present,
whether
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in separate molecules or in the same molecule (as in the above-described con-
densed amines), mixtures of amide, ester, and possibly imide functionality can
be present. These are the so-called ester-amide dispersants.
[0028] "Amine dispersants" are reaction products of relatively high
molecu-
lar weight aliphatic or alicyclic halides and amines, such as polyalkylene
poly-
amines. Examples thereof are described in the following U.S. Patents:
3,275,554, 3,438,757, 3,454,555, and 3,565,804.
[0029] "Mannich dispersants" are the reaction products of alkyl phenols
in
which the alkyl group contains at least 30 carbon atoms with aldehydes (espe-
cially formaldehyde) and amines (especially polyalkylene polyamines). The
materials described in the following U.S. Patents are illustrative: 3,036,003,
3,236,770, 3,414,347, 3,448,047, 3,461,172, 3,539,633, 3,586,629, 3,591,598,
3,634,515, 3,725,480, 3,726,882, and 3,980,569.
[0001] Post-treated dispersants are also part of the present invention.
They
are generally obtained by reacting at carboxylic, amine or Mannich dispersants
with reagents such as urea, thiourea, carbon disulfide, aldehydes, ketones,
carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitriles, epox-
ides, boron compounds such as boric acid (to give "borated dispersants"),
phosphorus compounds such as phosphorus acids or anhydrides, or 2,5-
dimercaptothiadiazole (DMTD). Exemplary materials of this kind are described
in the following U.S. Patents: 3,200,107, 3,282,955, 3,367,943, 3,513,093,
3,639,242, 3,649,659, 3,442,808, 3,455,832, 3,579,450, 3,600,372, 3,702,757,
and 3,708,422. Other related dispersants include composition comprising the
product prepared by heating together: (a) a dispersant as described above and
(b) 2,5 -dimercapto-1,3 ,4-thiadiazole or a hydro carbyl-sub stituted 2,5 -di-
mercapto-1,3,4-thiadiazole which is substantially insoluble in a hydrocarbon
oil
of lubricating viscosity at 25 C, and further either (c) a borating agent or
(d) an
inorganic phosphorus compound, or both (c) and (d), said heating being suffi-
cient to provide a reaction product of (a), (b), and (c) or (d) which is
soluble in
said hydrocarbon oil at 25 C. These materials are described in US Application
2005-0041395.
[0030] Mixtures of dispersants can also be used.
[0031] The amount of component (c) in the compositions of the present
invention is generally 0.3 to 10 percent by weight. In other embodiments, the
amount of component (c) is 0.5 to 7 percent or 1 to 5 percent of the final
blended fluid formulation. In a concentrate, the amounts will be
proportionately
higher.
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[0032] Other components which are conventionally employed in a transmis-
sion fluid, in particular, and automatic transmission fluid (ATF) are
typically
also present.
[0033] The functional fluid may contain one or more viscosity modifiers
and/or dispersant viscosity modifiers. Viscosity modifiers (VM) and dispersant
viscosity modifiers (DVM) are well known. Examples of VMs and DVMs
include polymethacrylates, polyacrylates, polyolefins, styrene-maleic ester
copolymers, and similar polymeric substances including homopolymers, co-
polymers and graft copolymers. The DVM may comprise a nitrogen-containing
methacrylate polymer, for example, a nitrogen-containing methacrylate polymer
derived from methyl methacrylate and dimethylaminopropyl amine.
[0034] Examples of commercially available VMs, DVMs and their chemical
types include the following: polyisobutylenes (such as IndopolTM from BP
Amoco or ParapolTM from ExxonMobil); olefin copolymers (such as LubrizolTM
7060, 7065, and 7067 from Lubrizol and LucantTM HC-2000L and HC-600 from
Mitsui); hydrogenated styrene-diene copolymers (such as ShellvisTM 40 and 50,
from Shell and LZ 7308, and 7318 from Lubrizol); styrene/maleate copoly-
mers, which are dispersant copolymers (such as LZ 3702 and 3715 from
Lubrizol); polymethacrylates, some of which have dispersant properties (such
as
those in the ViscoplexTM series from RohMax, the HitecTM series from Afton,
and LZ 7702TM, LZ 7727TM, LZ 7725TM and LZ 7720CTM from Lubrizol); olefin-
graft-polymethacrylate polymers (such as ViscoplexTM 2-500 and 2-600 from
RohMax); and hydrogenated polyisoprene star polymers (such as ShellvisTM 200
and 260, from Shell). Viscosity modifiers that may be used are described, for
instance, in U.S. patents 5,157,088, 5,256,752 and 5,395,539. The VMs and/or
DVMs may be used in the functional fluid at a concentration of up to 20% by
weight. Concentrations of 1 to 12%, or 3 to 10% by weight may be used.
[0035] Another component that may be used in the composition used in
the
present invention is a supplemental friction modifier. Friction modifiers are
well
known to those skilled in the art. A useful list of friction modifiers is
included
in U.S. Pat. No. 4,792,410. U.S. Patent 5,110,488 discloses metal salts of
fatty
acids and especially zinc salts, useful as friction modifiers. A list of
friction
modifiers includes:
(i) fatty phosphites
(ii) fatty acid amides
(iii) fatty epoxides
(iv) borated fatty epoxides
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(v) fatty amines other than component (b) above
(vi) glycerol esters, e.g., partial esters
(vii) borated glycerol esters
(viii) alkoxylated fatty amines
(ix) borated alkoxylated fatty amines
(x) metal salts of fatty acids
(xi) sulfurized olefins
(xii) fatty imidazolines
(xiii) condensation products of carboxylic acids and polyalkylene-
polyamines
(xiv) metal salts of alkyl salicylates
(xv) amine salts of alkylphosphoric acids
(xvi) ethoxylated alcohols
and mixtures thereof.
[0036] Representatives of each of these types of friction modifiers are
known
and are commercially available. For instance, (i) fatty phosphites are
generally
of the formula (R0)2PHO. The dialkyl phosphite, as shown in the preceding
formula, is typically present with a minor amount of monoalkyl phosphite of
the
formula (R0)(HO)PHO. In these structures, the term "R" is conventionally
referred to as an alkyl group. It is, of course, possible that the alkyl is
actually
alkenyl and thus the terms "alkyl" and "alkylated," as used herein, will
embrace
other than saturated alkyl groups within the phosphite. The phosphite should
have sufficient hydrocarbyl groups to render the phosphite substantially oleo-
philic. In one embodiment, the hydrocarbyl groups are substantially un-
branched. Many suitable phosphites are available commercially and may be
synthesized as described in U.S. Patent 4,752,416. The phosphite may contain 8
to 24 carbon atoms in each of R groups. In certain embodiments, the fatty
phosphite contains 12 to 22 carbon atoms in each of the fatty radicals,
alterna-
tively 16 to 20 carbon atoms. In one embodiment the fatty phosphite can be
formed from oleyl groups, thus having 18 carbon atoms in each fatty radical.
[0037] (iv) Borated fatty epoxides are known from Canadian Patent No.
1,188,704. These oil-soluble boron- containing compositions are prepared by
reacting, at a temperature from 80 C to 250 C, boric acid or boron trioxide
with
at least one fatty epoxide having the formula
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0
/ \
R1R2C¨CR3R4
wherein each of RI, R2, R3 and R4 is hydrogen or an aliphatic radical, or any
two
thereof together with the epoxy carbon atom or atoms to which they are at-
tached, form a cyclic radical. The fatty epoxide may, in one embodiment,
contain at least 8 carbon atoms.
[0038] The
borated fatty epoxides can be characterized by the method for
their preparation which involves the reaction of two materials. Reagent A can
be
boron trioxide or any of the various forms of boric acid including metaboric
acid (HB02), orthoboric acid (H3B03) and tetraboric acid (H2B407). Boric acid,
and especially orthoboric acid, may be used. Reagent B can be at least one
fatty
epoxide having the above formula. In the formula, each of the R groups is most
often hydrogen or an aliphatic radical with at least one being a hydrocarbyl
or
aliphatic radical containing at least 6 carbon atoms. The molar ratio of
reagent A
to reagent B is generally 1:0.25 to 1:4. Ratios of 1:1 to 1:3 may be used,
with
about 1:2 being exemplary. The borated fatty epoxides can be prepared by
merely blending the two reagents and heating them at temperature of 80 to
250 C, such as 1000 to 200 C, for a period of time sufficient for reaction to
take
place. If desired, the reaction may be effected in the presence of a
substantially
inert, normally liquid organic diluent. During the reaction, water is evolved
and
may be removed by distillation.
[0039] (iii)
Non-borated fatty epoxides, corresponding to "Reagent B"
above, are also useful as friction modifiers.
[0040] Borated amines are generally known from U.S. Patent 4,622,158.
Borated amine friction modifiers (including (ix) borated alkoxylated fatty
amines) are conveniently prepared by the reaction of a boron compounds, as
described above, with the corresponding amines. The amine can be a simple
fatty amine or hydroxy containing tertiary amines. The borated amines can be
prepared by adding the boron reactant, as described above, to an amine
reactant
and heating the resulting mixture at a 50 to 300 C, such as 100 C to 250 C or
150 C to 230 C, with stirring. The reaction is continued until by-product
water
ceases to evolve from the reaction mixture indicating completion of the
reaction.
[0041] Among
the amines useful in preparing the borated amines are com-
mercial alkoxylated fatty amines known by the trademark "ETHOMEEN" and
available from Akzo Nobel. Representative examples of these ETHOMEENTm
materials is ETHOMEENTm C/12 (bis
[2-hydroxyethyl] -coco-amine);
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ETHOMEENTm C/20 (polyoxyethylene[10]cocoamine); ETHOMEENTm S/12
(bis[2-hydroxyethyl]soyamine); ETHOMEENTm T/12 (bis[2-hydroxyethyl]-
tallow-amine); ETHOMEENTm T/15 (polyoxyethylene-[5]tallowamine);
ETHOMEENTm 0/12 (bis[2-hydroxyethyl]oleyl-amine); ETHOMEENTm 18/12
(bis[2¨hydroxyethyl]octadecylamine); and ETHOMEENTm 18/25 (poly-
oxyethyl-ene[15]octadecylamine). Fatty amines and ethoxylated fatty amines
are also described in U.S. Patent 4,741,848.
[0042] The (viii) alkoxylated fatty amines, and (v) fatty amines
themselves
(such as oleylamine) are generally useful as friction modifiers in this
invention.
Such amines are commercially available.
[0043] Both borated and unborated fatty acid esters of glycerol can be
used
as friction modifiers. The (vii) borated fatty acid esters of glycerol are
prepared
by borating a fatty acid ester of glycerol with boric acid with removal of the
water of reaction. In one embodiment, there is sufficient boron present such
that
each boron will react with from 1.5 to 2.5 hydroxyl groups present in the reac-
tion mixture. The reaction may be carried out at a temperature in the range of
60 C to 135 C, in the absence or presence of any suitable organic solvent such
as methanol, benzene, xylenes, toluene, or oil.
[0044] (vi) Fatty acid esters of glycerol themselves can be prepared by
a
variety of methods well known in the art. Many of these esters, such as
glycerol
monooleate and glycerol tallowate, are manufactured on a commercial scale.
The esters useful are oil-soluble and may be prepared from C8 to C22 fatty
acids or mixtures thereof such as are found in natural products and as are de-
scribed in greater detail below. Fatty acid monoesters of glycerol are
suitable,
although, mixtures of mono- and diesters may be used. For example, commer-
cial glycerol monooleate may contain a mixture of 45% to 55% by weight
monoester and 55% to 45% diester.
[0045] Fatty acids can be used in preparing the above glycerol esters;
they
can also be used in preparing their (x) metal salts, (ii) amides, and (xii)
imida-
zolines, any of which can also be used as friction modifiers. Suitable fatty
acids
include those containing 6 to 24 carbon atoms, or 8 to 18. The acids can be
branched or straight-chain, saturated or unsaturated. Suitable acids include 2-
ethylhexanoic, decanoic, oleic, stearic, isostearic, palmitic, myristic,
palmitoleic, linoleic, lauric, and linolenic acids, and the acids from the
natural
products tallow, palm oil, olive oil, peanut oil, corn oil, and Neat's foot
oil. A
suitable acid is oleic acid.
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[0046] Suitable metal salts of acids include zinc and calcium salts.
Zinc salt
of carboxylic acids, for instance. These zinc salts may be acidic, neutral or
basic (overbased). These salts may be prepared from the reaction of a zinc
containing reagent with a carboxylic acid or salt thereof A useful method of
preparation of these salts is to react zinc oxide with a carboxylic acid.
Useful
carboxylic acids are those described hereinabove, and include those of the
formula RCOOH, where R is an aliphatic or alicyclic hydrocarbon radical. Also
suitable are those wherein R is a fatty group, e.g., stearyl, oleyl, linoleyl,
or
palmityl. Also suitable are zinc salts wherein zinc is present in a
stoichiometric
excess over the amount needed to prepare a neutral salt. Such salts include
those wherein the zinc is present from about 1.1 to about 1.8 times the
stoichiometric, especially from 1.3 to 1.6 times the stoichiometric amount of
zinc. These zinc carboxylates are known in the art and are described in U.S.
Pat. 3,367,869. Certain basic zinc salts can be represented by the general
formula Zn4Oleate601. Metal salts may also include calcium salts, such as
overbased calcium salts.
[0047] Suitable amides are those prepared by condensation of an acid
with
ammonia or with primary or secondary amines such as diethylamine and dietha-
nolamine. Fatty imidazolines are the cyclic condensation product of an acid
with a diamine or polyamine such as a polyethylenepolyamine. The imidazoli-
nes are generally represented by the structure
N¨.............
R ______________________________
<
N-----
1
R'
where R is an alkyl group and R' is hydrogen or a hydrocarbyl group or a
substituted hydrocarbyl group, including ¨(CH2CH2NH)n¨ groups. In one
embodiment the friction modifier is the condensation product of a C8 to C24
fatty acid with a polyalkylene polyamine, and in particular, the product of
isostearic acid with tetraethylenepentamine. The condensation products of
carboxylic acids and polyalkyleneamines (xiii) may generally be imidazolines
or
amides.
[0048] Sulfurized olefins (xi) are well known commercial materials used
as
friction modifiers. A suitable sulfurized olefin is one which is prepared in
accordance with the detailed teachings of U.S. Patents 4,957,651 and
4,959,168.
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Described therein is a cosulfurized mixture of 2 or more reactants selected
from
the group consisting of (1) at least one fatty acid ester of a polyhydric
alcohol,
(2) at least one fatty acid, (3) at least one olefin, and (4) at least one
fatty acid
ester of a monohydric alcohol.
[0049] Reactant (3), the olefin component, comprises at least one olefin.
This olefin may be an aliphatic olefin, which usually will contain 4 to 40
carbon
atoms, or 8 to 36 carbon atoms. Terminal olefins, or alpha-olefins, may be
used,
such as those having 12 to 20 carbon atoms. Mixtures of these olefins are
commercially available, and such mixtures are contemplated for use in this
invention.
[0050] The cosulfurized mixture of two or more of the reactants, is
prepared
by reacting the mixture of appropriate reactants with a source of sulfur. The
mixture to be sulfurized can contain 10 to 90 parts of Reactant (1), or 0.1 15
parts by weight of Reactant (2); or 10 to 90 parts, often 15 to 60 parts, more
often 25 to 35 parts by weight of Reactant (3), or 10 to 90 parts by weight of
reactant (4). The mixture, in the present invention, includes Reactant (3) and
at
least one other member of the group of reactants identified as reactants (1),
(2)
and (4). The sulfurization reaction generally is effected at an elevated
tempera-
ture with agitation and optionally in an inert atmosphere and in the presence
of
an inert solvent. The sulfurizing agents useful in the process of the present
invention include elemental sulfur, hydrogen sulfide, sulfur halide plus
sodium
sulfide, and a mixture of hydrogen sulfide and sulfur or sulfur dioxide. Typi-
cally often 0.5 to 3 moles of sulfur are employed per mole of olefinic bonds.
[0051] Metal salts of alkyl salicylates (xiv) include calcium and other
salts
of long chain (e.g. C12 to C16) alkyl-substituted salicylic acids.
[0052] Amine salts of alkylphosphoric acids (xv) include salts of oleyl
and
other long chain esters of phosphoric acid, with amines as described below.
Useful amines in this regard are tertiary-aliphatic primary amines, sold under
the tradename PrimeneTM. The supplemental friction modifier can be used in
addition to component (a). The amount of the supplemental friction modifier is
generally 0.1 to 1.5 percent by weight of the lubricating composition, such as
0.2 to 1.0 or 0.25 to 0.75 percent. In some embodiments, however, the amount
of the supplemental friction modifier is present at less than 0.2 percent or
less
than 0.1 percent by weight, for example, 0.01 to 0.1 percent. In one embodi-
ment the amount of bis-(2-hydroxyethyl)tallowamine (commercially sold as
Ethomeen-12TM) in particular is restricted to these low amounts or less.
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[0053] Yet other suitable friction modifiers include friction modifiers
de-
rived from the reaction of a carboxylic acid or a reactive equivalent thereof
with
an aminoalcohol, wherein the friction modifier contains at least two
hydrocarbyl
groups, each containing at least 6 carbon atoms. Examples include the reaction
product of isostearic acid or an alkyl succinic anhydride with tris-
hydroxymethylaminomethane, which may be in a 2:1 mole ratio. These friction
modifiers are described in greater detail in US Application 2005-0250655. Also
suitable are amide or thioamide friction modifiers represented by the formula
R1R2N¨C(X)R3
wherein X is 0 or S. Rl and R2 may be hydrocarbyl groups of at least 6 carbon
atoms, and R3 is a hydroxyalkyl group of 1 to 6 carbon atoms or a group formed
by the condensation of said hydroxyalkyl group, through a hydroxyl group
thereof, with an acylating agent. An example of such a friction modifier is
the
condensation product of dicocoamine with glycolic acid. These friction modifi-
ers are described in greater detail in International application serial No.
PCT/US
2006/039768, filed October 11, 2006. In certain embodiments, no (or less than
0.1%) additional friction modifier is present, other than that of component
(b).
[0054] The compositions of the present invention can also include a
deter-
gent. Detergents as used herein are metal salts of organic acids. The organic
acid portion of the detergent is a sulfonate, carboxylate, phenate,
salicylate. The
metal portion of the detergent is an alkali or alkaline earth metal. Suitable
metals include are sodium, calcium, potassium and magnesium. Typically, the
detergents are overbased, meaning that there is a stoichiometric excess of
metal
over that needed to form the neutral metal salt.
[0055] Suitable overbased organic salts include the sulfonate salts having
a
substantially oleophilic character and which are formed from organic
materials.
Organic sulfonates are well known materials in the lubricant and detergent
arts.
The sulfonate compound should contain on average 10 to 40 carbon atoms, such
as 12 to 36 carbon atoms or 14 to 32 carbon atoms on average. Similarly, the
phenates, salicylates, and carboxylates have a substantially oleophilic
character.
[0056] While the present invention allows for the carbon atoms to be
either
aromatic or in paraffinic configuration, in certain embodiments alkylated aro-
matics are employed. While naphthalene based materials may be employed, the
aromatic of choice is the benzene moiety.
[0057] A suitable composition is thus an overbased monosulfonated alky-
lated benzene, and may be the monoalkylated benzene. Typically, alkyl ben-
zene fractions are obtained from still bottom sources and are mono- or di-
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WO 2007/121205 PCT/US2007/066371
alkylated. It is believed, in the present invention, that the mono-alkylated
aromatics may be superior to the dialkylated aromatics in overall properties.
[0058] It is desired that a mixture of mono-alkylated aromatics
(benzene) be
utilized to obtain the mono-alkylated salt (benzene sulfonate) in the present
invention. The mixtures wherein a substantial portion of the composition
contains polymers of propylene as the source of the alkyl groups assist in the
solubility of the salt. The use of mono-functional (e.g., mono-sulfonated)
materials avoids crosslinking of the molecules with less precipitation of the
salt
from the lubricant.
[0059] In certain embodiments, the salt may be "overbased." By overbasing,
it is meant that a stoichiometric excess of the metal be present over that
required
to neutralize the anion of the salt. The excess metal from overbasing has the
effect of neutralizing acids which may build up in the lubricant. A second
advantage is that the overbased salt increases the dynamic coefficient of fric-
tion. Typically, the excess metal will be present over that which is required
to
neutralize the anion at in the ratio of up to 30:1, such as 5:1 to 18:1 on an
equivalent basis.
[0060] The amount of the overbased salt utilized in the composition is
typically 0.025 to 3 weight percent on an oil free basis, or 0.1 to 1.0
percent.
The overbased salt is usually made up in about 50% oil with a TBN range of 10-
600 on an oil free basis. Borated and non-borated overbased detergents are
described in U.S. Patents 5,403,501 and 4,792,410.
[0061] The compositions of the present invention can also include at
least
one phosphorus acid, phosphorus acid salt, phosphorus acid ester or derivative
thereof including sulfur-containing analogs in the amount of 0.002-1.0 weight
percent. The phosphorus acids, salts, esters or derivatives thereof include
phosphoric acid, phosphorous acid, phosphorus acid esters or salts thereof,
phosphites, phosphorus-containing amides, phosphorus-containing carboxylic
acids or esters, phosphorus-containing ethers, and mixtures thereof.
[0062] In one embodiment, the phosphorus acid, ester or derivative can be
an
organic or inorganic phosphorus acid, phosphorus acid ester, phosphorus acid
salt, or derivative thereof. The phosphorus acids include the phosphoric, phos-
phonic, phosphinic, and thiophosphoric acids including dithiophosphoric acid
as
well as the monothiophosphoric, thiophosphinic and thiophosphonic acids. One
group of phosphorus compounds are alkylphosphoric acid mono alkyl primary
amine salts as represented by the formula
CA 02648664 2008-10-07
WO 2007/121205 PCT/US2007/066371
0
11
R'0¨ P ¨ 0- 'NH3R3
1
R20
where R1, R2, R3 are alkyl or hydrocarbyl groups or one of R' and R2 can be H.
The materials can be a 1:1 mixture of dialkyl and monoalkyl phosphoric acid
esters. Compounds of this type are described in U.S. Patent 5,354,484.
[0063] Eighty-five percent phosphoric acid is a suitable material for
addition
to the fully-formulated compositions and can be included at a level of 0.01-
0.3
weight percent based on the weight of the composition, such as 0.03 to 0.2 or
to
0.1 percent.
[0064] Other materials can optionally be included in the compositions
of the
present invention, provided that they are not incompatible with the afore-
mentioned required components or specifications. Such materials include
antioxidants (that is, oxidation inhibitors), including hindered phenolic
antioxi-
dants, secondary aromatic amine antioxidants such as dinonyldiphenylamine as
well as such well-known variants as monononyldiphenylamine and diphenyl-
amines with other alkyl substituents such as mono- or di-ocyl, sulfurized
pheno-
lic antioxidants, oil-soluble copper compounds, phosphorus-containing antioxi-
dants, and organic sulfides, disulfides, and polysulfides such as 2-hydroxy-
alkyl,alkyl thioethers or 1-t-dodecylthio-2-propanol or sulfurized 4-
carbobutoxycyclohexene or other sulfurized olefins. Other optional components
include seal swell compositions, such as isodecyl sulfolane or phthalate
esters,
which are designed to keep seals pliable. Also permissible are pour point
depressants, such as alkylnaphthalenes, polymethacrylates, vinyl ace-
tate/fumarate or /maleate copolymers, and styrene/maleate copolymers. Another
material is an anti-wear agent such as zinc dialkyldithiophosphates. These
optional materials are known to those skilled in the art, are generally commer-
cially available, and are described in greater detail in published European
Patent
Application 761,805. Also included can be known materials such as corrosion
inhibitors (e.g., tolyltriazole, dimercaptothiadiazoles), dyes, fluidizing
agents,
odor masking agents, and antifoam agents. Organic borate esters and organic
borate salts can also be included.
[0065] The above components can be in the form of a fully-formulated
lubricant or in the form of a concentrate within a smaller amount of
lubricating
oil. If they are present in a concentrate, their concentrations will generally
be
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directly proportional to their concentrations in the more dilute form in the
final
blend.
Examples
[0066]
Lubricant formulations are prepared with the following components:
Component\ Ex: 1 2 3 4 5 6 7 8 9 10
DISPERSANTS
Succinimide 4.0 4.0 4.0 5.0 4.0 5.0 4.5
dispersant (in-
cluding 40% oil)
Succinimide 1.0 1.0 1.0 1.0 0.5
Dispersant treated
with DMTDb
(incl. 49% oil)
Succinimide 0.5 0.5 5.0 0.5
Dispersant treated
with Boron (incl.
50% oil)
Succinimide 5.0
Dispersant treated
with TPAa (in-
cluding oil)
Succinimide 5.0
Dispersant treated
with phosphorus
and boron com-
pounds (incl. oil)
AMINE
Reaction product 0.5 0.5 0.5 0.8 0.8 0.8
of Armeen 2CTM
with 2,3-epoxy-1-
propanol (1:1
mole)
Reaction product 1.25
of Armeen 2CTM
with 3-chloro-
propane-1,2-diol
(1:1 mole)
Reaction product 1.0 1.25 1.25
of ArmeenTM
HTL8c with 2,3-
epoxy-1-propanol
(1:1 mole)
17
CA 02648664 2013-10-03
INHIBITORS
2-hydroxy- 0.5 0.5 0.5 0.5
0.5 0.5
alkyl,alkyl
thioether
Dinonyldiphenyl- 0.6 0.6 0.6 0.6 0.6
0.8 0.6 0.6 0.6
amine
Hindered phenolic 0.5 0.5
0.5 0.5
antioxidant
FRICTION
MODIFIERS
Borate Ester 0.2 0.2 0.2 0.2 0.2
0.2
Diphenylphosphite 0.25 0.25
Dibutyl hydrogen 0.11 0.11 0.2 0.2 0.2 0.2 0.2
phosphite
Phosphoric acid 0.1 0.1 0.06 0.06
0.06 0.06 0.06
OTHERS
Sulfolane seal 0.4 0.4 0.4 0.35 0.35 0.4 0.4
0.4 0.4
swell agent
Tolyltriazole 0.02 0.02 0.02
0.02 0.02
Fatty carboxylic 0.1 0.1 0.1 0.1
acid product with
polyamine
Oil of lubricating - balance -
viscosityd
a. Dispersant treated with terephthalic acid (TPA), optionally also treated
with
dimercaptothiadiazole, inorganic phosphorus acid, and/or boron
b. DMTD = dimercaptothiadiazole
c. secondary amine(s) having 2-ethylhexyl and hydrogenated tallow alkyl
groups
d. May include small amounts of other materials commonly present such as a
viscosity index improver or an anti-foam agent.
[0067] The friction modifier (a), used in combination with the dispersant
(b)
present in the base formulation, will provide good friction properties.
[0068] Except in the Examples, or where otherwise explicitly indicated,
all
numerical quantities in this description specifying amounts of materials, reac-
tion conditions, molecular weights, number of carbon atoms, and the like, are
to
be understood as modified by the word "about." Unless otherwise indicated,
each chemical or composition referred to herein should be interpreted as being
a
commercial grade material which may contain the isomers, by-products, deriva-
tives, and other such materials which are normally understood to be present in
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PCT/US2007/066371
the commercial grade. However, the amount of each chemical component is
presented exclusive of any solvent or diluent oil, which may be customarily
present in the commercial material, unless otherwise indicated. It is to be
understood that the upper and lower amount, range, and ratio limits set forth
herein may be independently combined. Similarly, the ranges and amounts for
each element of the invention 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.
19
