Note: Descriptions are shown in the official language in which they were submitted.
FUNCTIONAL FLUID WITH BORATED EPOXIDES, CARBOXYLIC
SOLUBILIZERS, ZINC S~LTS, AND CALCIUM COMPLEXES
BACKGROUND OF THE INVENTION
A functional fluid is a term which encompasses a
variety of fluids including but not limited to tractor
fluids, automatic~transmission fluids, manual transmission
fluids, hydraulic fluids, power steering fluids, fluids
related to power train components and fluids which have
the ability to act in various different capacities. It
should be noted that within each of these fluids such as,
for example, automatic transmission fluids, there are a
variety of different types of fluids due to the various
transmissions having different designs which have led to
the need for fluids of markedly different functional
characteristics. One type of functional fluid is
generally known as a tractor fluid which can be used in
connection with various types of tractor equipment in
order to provide for the operation of the transmission,
gears, bearings~ hydraulics, power steering, mechanical
power take off and oil immersed brakes of the tractor.
The components included within a functional fluid
such as a tractor fluid must be carefully chosen so that
the final resulting fluid composition will pxovide all the
necessary characteristics required and pass a variety of
different types of tests. In general a tractor fluid must
act as a lubricant, a power transfer means and a heat
transfer means.
Tractor fluids have a number of important specific
characteristics which provide for their ability to operate
within tractor equipment. Such characteristics include
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the ability to provide proper frictional properties for
preventing wet brake chatter of oil immersed brakes while
simultaneously providing the ability to actuate wet brakes
and provide power take-off (PT0) clutch performance. A
tractor fluid must provide sufficient antiwear and extreme
pressure properties as well as water
tolerancetfilterability capabilities.
The extreme pressure (EP) properties of tractor
fluids are demonstrated by the ability of the fluid to
pass a spiral bevel test as well as a straight spur gear
test. The tractor fluid must pass wet brake chatter tests
as well as provide adequate wet brake capacity when used
in oil immersed disk brakes which are comprised of a
bronze, graphitic compositions and asbestos. The tractor
fluid must demonstrate its ability to provide friction
retention for power shift transmission clutches such as
those clutches which include graphitic and bronze
clutches.
U.S. Patent 4,410,438 discloses a lubricant and
liquid fuel composition which includes borated epoxides
which are indicated as being useful in fluids such as heat
~xchange fluids, transmission fluids, and hydraulic
fluids.
U.S. Patent 3,933,659 discloses a functional fluid
for lubricating oil compositions which is comprised of a
major amount of an oil of lubricating viscosity and an
effective amount of an additive. The additive includes
effective amounts of an alkaline succinimide, a group II
metal salt of a dihydrocarbyldithiophosphoric acid, a
basic sulfurized alkaline earth metal alkyl phenate and a
component which is a fatty acid ester, fatty acid amide or
fatty acid amine or mixtures thereof. The patent
indicates that the lubricating compositions are useful as
functional fluids in systems requiring fluid coupling,
hydraulic fluid and/or lubrication of relatively movin~
parts. The lubricating compositions are indicated as
being useful as the functional fluid in automatic
8~
transmissions and particularly in the automatic
transmissions of passenger automobiles.
U.S. Patent 4,116,877 discloses an elastomer
compatible seal swell additive. The additive may be used
in connection with automatic transmission, power trans-
mission fluids and h~draulic steering fluids. The fluid
is a mineral lubricatin~ base oil which includes an
oil-soluble bis(hydrocarbyl) phosphite ester and an
oil-soluble hydrocarbyl substituted phenol wherein a
specific weight ratio is maintained with respect to the
phosphite and phenol. The patent indicates that the
inclusion of these particular additive compounds in the
particularly disclosed ratio provides enhanced elastomer
compatibility to the fluid.
Published European Patent Application 113,199
published ~uly 11, 1984, discloses a tractor hydraulic
fluid which includes oleyl phosphite in a tractor
antifriction hydraulic fluid as well as thioethylocta-
decenylsuccinate containing tractor hydraulic fluids.
British Patent 1,452,513 dated October 13, 1976,
discloses lubricant compositions which include a ~atty
acid and a fatty acid amide in a wet braking system for
trac-tors which was found to be useful in reducing the
amount of noise over a wide temperature range.
British Patent 1,440,261 discloses a composition for
- reducing the noise in the wet braking systems of tractors.
The fluid was comprised of a lubricant oil, and a
detergent or dispersant mixed with stearic acid. The
composition indicated that it also included alkylene
polyamine dispersants, calcium and barium sulfonates and
phenates, antiwear-antioxidants and oleic acid.
SUMMARY OF THE IN~EN'rION
_
A functional fluid, especially in the form of a
tractor fluid, is disclosed which is comprised of a major
amount of a hydrocarbon oil and a minor amount, sufficient
to improve characteristics (e.~. lubricant abili~y r power
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transfer means ability, and heat transfer means ability)
of the fluid of an additive. The additive includes four
essential ingredients which are each present in an amount
sufficient to improve characteristics as indicated above
and may include other components to enhance these
characteristics or to provide even further desirable
characteristics to the fluid. The additive necessarily
includes a calcium salt, an EP/antiwear agent in the form
of a zinc dithiophosphate salt, a borated epoxide and a
carboxylic solubilizer preferably in the form of a amine
reaction product of a acylating agent containing a
substituted hydrocarbyl-base substituent containing about
12 to 500 carbon atoms. Specific amounts and ranges with
respect to the ad~itive and the four essential components
are described below. However, since the additive may be
used in a number of different types of ~luids, these
amounts might vary and might also vary somewhat due to
other components and their amounts.
The inventors have found that although there is some
flexibility with respect to the amounts of each of these
four essential components which must be present and the
precise definition oE each of these four components as
generically described above, a useful functional fluid
cannot be obtained if the amount limitations are
completely ignored or if other components are randomly
substituted for these four essential ingredients.
A primary object of this invention is to provide a
functional fluid possessing a wide variety of different
functional characteristics especially when used as a
tractor fluid.
Another object of this invention is to provide a
functional fluid capable of passing a wide variety of
different tests with respect to characteristics such as
EP/antiwear characteristics, water tolerance, brake
capacity and chatter and filterability.
Still another object of the invention is to
simultaneously provide improved performance in the areas
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of improved low temperature fluidity/ilterability,
EP/antiwear performance, friction improving properties,
wet brake chatter suppression, and capacity with respect
to actuating hydraulics, transmissions, power steering and
braking without harming performance in other areas.
Yet another object is to increase per~ormance with
respect to EP/antiwear performance without having an
undesirable effect on corrosion testing and transmission
performance.
Still another object is to provide improved water
tolerance by including surfactants while not limiting EP
performance.
Other objects of this invention include providing a
functional fluid `capable of passing a wide variety of
different tests with respect to characteristics such as
frictional characteristics, low temperature fluidity, seal
swell characteristics, antifoaming characteristics,
antioxidation characteristics and EP protection as
demonstrated by spiral bevel and straight spur gear
testing.
Another object is to provide sufficient power
steering performance while simultaneously providing
sufficient transmission performance as demonstrated in
Turbo Hydra-matic oxidation testing ~a General Motor Corp.
test).
Another object i5 to provide a fluid which provides
sufficient friction retention for power shift transmission
clutches and provides corrosion inhibition particularly
with respect to yellow metal (i.e. copper, brass, bronze~
corrosion while simultaneously providing improved EP
performance, proper frictional properties for wet brake
chatter suppression and simultaneouly providing wet brake
capacity and power take/off clutch performance.
A primary object of this invention is to provide a
functional fluid which includes its essential components
such that the fluid simultaneously provides a variety o~
desirable characteristics.
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These and other objects of the invention will become
apparent to those skilled in the art upon reading this
disclosure.
DETAILED DESCRIPTION OF THE INVEN~ION
The present invention may be produced and sold in the
form of the functional fluid final product which can be
included in various mechanical devices such as tractors.
~owever, the invention is generally produced in the form
of a concentrate which is then substantially diluted
within a hydrocarbon oil to form the final fluid. The
concentrate itself is made up of various components which
are themselves often contained within an oil of some type,
i.e., a diluent or "dil" oil. This should be kept in mind
with respect to the percentage parts by weight of the
components present within the functional fluid. The parts
by weight mentioned with respect to the amount of each of
the components present within the functional fluid is the
parts by wei~ht of the active chemical, and not that
component as it might be added in combination with its
"dil" oil.
- The four essential components of the present
functional fluid are: (1) calcium salt; (2) antiwear agent
in the form of a group II metal dithiophosphate salt; (3~
borated epoxide; ~4) carboxylic solubilizer. Each of
these four components as well as other components which
are preferably present in the functional fluid of the
invention will now be described in detail. ~t should be
pointed out that none of these components themselves are
per se novel compounds. However, the presence of these
compounds in combination with each other does provide a
novel functional fluid which provides improved
characteristics not before obtainable.
variety of different types of metal salts have been
disclosed and have been indicated as being especially
valuable due to their detergent or dispersant properties
and their ability to neutralize undesirable acid bodies
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37~
formed in lubricants during the operation of the engine or
device in which the lubricant is included. Such metal salts
are generally in the form o~ overbased and/or neutral
complexes with high molecular weight aliphatic carboxylic
acids, sulfonic acids, anhydrides, esters, amides, imides or
salts. These overhased complexes may be used as additives in
lubricating oils, gasoline or other organic fflaterials.
Overbased complexes in general are disclosed within U.S.
Patent 3,714,042 for purposes of disclosing calcium salts and
calcium salt complexes which might be used in connection with
the present invention. The present inventors have found that
although numerous other types of metal salts and metal salt
complexes are generally used in the art, only calcium salts
and calcium salt complexes provide the desirable char-
acteristics o~ the functional fluid of the present invention.Further, it has now been found that it is preferable to
include overbased and/or neutral calcium complexes in the
form of overbased and/or neutral calcium sulfonates,
overbased and/or neutral calcium sulfonate-carboxylates and
overbased calcium carboxylates.
A mixture of overbased carbonate~ calcium complexes
useful in connection with the functional fluid of the present
invention can be formed by carbonating an oil ~oluble sul-
fonic acid (e.g. sulfonic acids of the type comprising
petroleum sulfonates, sulfonated alkyl benzenes, etc.) alone
or in combination with a calcium alkyl phenate, a mixtur2 o~
lower alcohols and an excess of lime. The oil soluble
sulfonic acid or mixture of acids and calcium alkyl phenate
are overbased by the use of the lime. At this point an
overbased carbonated calcium complex has been formed. Such
a complex can be used in connection with the present
invention. However, it might be desirable to take the
solution which has been overbased with lime and then
stabilize it by post treatlng the complex with a
polyisobutene substituted succinic
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anhydride. The overbased calcium complex used in
connection tlith the present invention may be used in
combination with other similar compounds, e.g., including
calcium sulfonates which are combined with calcium
phenates. This component of the invention is likely to
contain a mixture of neutral and overbased salt complexes.
The use of the term "complex" refers to basic metal
salts which contain metal in an amount in excess of that
present in a neutral or normal metal salt. The "metal
ratio" characterizing a complex is thus the ratio of the
total equivalents of metal to the equivalents of metal in
the form of neutral or normal metal. The "base number" of
the complex is the number of milligrams of KOH to which
one gram of the~ complex is equivalent as measured by
titration.
The "base number" of the calcium complexes used in
; connection with the present invention varies over a range
of from about 0 to about 500 TBN. ~s such complex is
present within a diluent oil, the base number of the
calcium complex is preferably in the range of from about
200 to about 400 and more preferably about 300.
In the present invention, the metal salt comple~ must
include some calcium metal salt complex. However, there
may also be present other metal salt complexes and there
may be present calcium salts which are not "overbased."
A useful calcium complex for use in connection with
the present invention could be prepared by the following
procedure:
To 950 grams of a solution of a basic, carbonated
calcium salt of an alkylated benzene sulfonic acid
(average molecular weight 385~ in mineral oil (base number
about 300, calcium--12.0 percent and sulfur-~1.4 percent)
there is added 50 grams polyisobutene (molecular weight
1000)--substituted succinic anhydride post treatment
(having a saponification number of 100) at 25C. Mixture
is stirred for 0~65 hours at 55-57C and then at
152-153C for 0.5 hours and filtered at 150C. The
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filtrate has a base number of about 300 and contains 53
percent of mineral oil.
The calcium salts complexes preferable used in
connection with the present invention are useful in providing
improved characteristics in areas such as dispersancy and
~ntirust and as used in a tractor fluid is present in an
amount of about 0.5 to about 5.5 parts by weight based on the
weight of the fluid.
The EP/antiwear agent used in connection with the
present invention is in the form of a zinc dithiophosphate.
Although there are an extremely large number o differsnt
types of antiwear agents which might be utilized in
connection with such functional fluids, the present inventors
have found that zinc dithiophosphate type antiwear agents
work particularly well in connection with the other
components to obtain the desired characteristics.
Particularly useful zinc dithiophosphate antiwear agents are
disclosed within U.S. Patent 4,263,150.
It has been found that salts of dialkylphosphorodithioic
acids which are treated with phosphites and/or olefins work
particularly ~ell in connection with the present invention.
More specifically, treating such salts or their acid
precursors with a triaryl phosphite, and specifically,
trip~enyl phosphite, provide results which work particularly
well in connection with the functional fluid and particularly
the tractor fluid of the present invention. By treating
these zinc salts or their acid precursors with triaryl
phosphite compounds, the treated zinc salts have a reduced
tendency to stain and corrode the metal parts that they are
used in connection with. Specifically, such treated zinc
salts or acid precursors are much less likely to stain or
corrode copper parts~
~ he salts of dialkylphosphorodithioic acids are known
to be useful with respect to thair antiwear properties as
used within lubricating compositions~ However, the
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antiwear agents used in connection with the present
invention have removed the sulfur activity o~ such zinc
salts by some means. One means for removing the sulfur
activity involves treating the salt or their acid
precursors with phosphites. For example, an antiwear
agent useful in connection with the present invention can
be prepared by the following method:
Triphenylphosphite is heated with a zinc
dialkylphosphorodithioate or a mixed zinc salt of a
dialkylphosphorodithioic acid and a carboxylic acid. The
dialkylphosphorodithioic acid used in the preparation of
the zinc salt i5 itself prepared by the reaction of at
least one alcohol with phosphorus pentasulfide which
contains a stoichiometric excess of sulfur.
The zinc dithiophosphate component of the present
invention is added in an amount su~ficient to improve
antiwear properties o~ the fluid and as used in a tractor
fluid is present in an amount of about 1 percent to about
4 percent by weight based on the weight of the fluid.
Various boron containing compounds are known to be
useful in connection with functional fluids. lt has now
been found that borated epoxides work particularly well in
combination with the other components described herein to
provide a functional fluid with improved characteristics.
Such borated epoxides are obtained by reacting an epoxide
of the general structural formula:
R - C / \ C R'
R2 R3
wherein R, R', R and R3 are hydrogen or a C8 30 hydro-
caxbyl group, at least one of which is hydrocarbyl, with
boric acid, boric oxide or an alkyl borate o~ the formula
~RO)xB(GH~y wherein x is 1 to 3 and y is O to 2, there sum
being 3, or boric oxide and R is an alkyl group contairling
1 to 6 carbon atoms. Such borated epoxide compounds are
: :.
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~2~
disclosed within U.S. Patent ~,410,438 incorporated herein
by reference for purposes of disclosing the borated epoxide
component used in connection with the present functional
fluid.
one preferred borated epoxide is obtained as the result
of reacting boric acid with a 1,2-epoxide mixture with the
epoxide containing about 16 carbon atoms.
It is possible to prepare a borated epoxide useful in
connection with the present invention by including 1,2~
- 10 epoxide hexadecane in combination with boric acid. The
mixture is heated to about 180 C in the presence of water
ahd toluene. The reaction may be carried out in the presence
of a diluent oil. The resulting product is a borated epoxide
compound which is useful in connection with the ~unctional
fluid of the present invention.
The borated epoxide is present in an amount sufficient
to provide the fluid with an ability to pass fluid related
tests and for a tractor fluid ie present in an amount of
about 0.1 percent to about 1.5 percent by weight based on
the weight of the fluid.
The fourth essential component of the present functional
fluid is a carboxylic solubilizer. This component is capable
of interacting with other components i~ such a manner so ~s
to provide a microemulsion of water particles so as to
provide improved water tolerance and filterability. The
carboxylic solu~ilizer component i6 present in sufficient
amount so as to provide these characteristics, i.e., improv~d
water toleranca and filterability, and for a tractor fluid is
about 0.1 percent to about 1 percent by weight based on the
weight of the ~luid. Preferred examples of such car~oxylic
solubilizers are disclosed within U.S. Pa~ent 4,435,297.
The carboxylic solubilizers used in connection wlth
the present functional fluid are nitrogen-containing
",~.~,
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phosphorus-free carboxylic acid derivatives. These
derivatives are made by reacting an acylating agent with
an alkanol tertiary monoamine. It has now been found that
particular solubilizing agents work particularly well in
connection with functional fluids and especially those
functional fluids useful as tractor fluids. The most
preferred carboxylic solubilizer found by the inventor is
the product of a reaction of polybutylene succinic
anhydride with N,N-diethylethanolamine at a molar ratio of
1:2. The resulting product is predominantly an ester-salt
and contains a small amount of diester. Further, the
product may contain small amounts of free unreacted
polybutylene and trace amounts of maleic anhydride reacted
with N,N-diethylethanolamine.
The carboxylic solubilizer most preferably used in
connection with the present invention is a
nitrogen-containincJ, phosphorous-free carboxylic acid
derivative which is obtained by the reaction at a
temperature in the range of about 30C to the
decomposition temperature of one or more of the reacting
components of (A) a carboxylic acid acylating agent with
(B) an alkanol tertiary monoamine. The acylating agent
has at least one hydrocarbyl substitutent containing about
20 to about 500 carbon atoms and the monoamine (B) has one
hydroxyl group and a total of up to about 40 carbon atoms.
In addition to the four essential components
described above, the present functional fluid preferably
includes a viscosity improving agent and an antifoaming
agent. The type and amount of each component is adjusted
depending on factors such as the temperature of operation,
the desired viscosity and amount of aggitation the fluid
is subjected to and the amount of foaming permitted.
Since a functional fluid is likely to be utilized in
equipment over a wide temperature range, the inclusion of
the viscosity improqing agent in order to aid in the
regulation of the viscosity of the fluid is highly
desirable. The viscosity improver is generally present in
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an amount of about 0.5 to about 8 percent by weight based
on the weight of the fluid. Further, since the fluid is
generally subjected to substantial mechanical agitation
and pressure, the inclusion of an antifoaming aaent is
highly desirable in or~er to reduce and/or eliminate
foaming which could create problems with the mechanical
operation of the device the fluid is used in connection
with. The antifoaming agent is generally present in an
amount of about 0.005 to about 0.08 parts by weight based
on the weight of the fluid.
Some useful viscosity index improvers include
well-known polymethacrylate compounds, hydrogenated
styrene-butydiene viscosity improvers and styrene-malan
copolymers. A ~useful antifoamin~ agent includes a
combination of about 90 percent by weight of kerosene and
about 10 percent by weight of a silicone agent (DC 200,
V~S 30,000 cSt at 25C).
The functional fluid of the present invention can be
in the form of various specific types of functional fluids
such as hydraulic/transmission fluids, brake fluids, power
steering fluids and tractor fluids, the precise
composition of which might vary slightly. The precise
composition of such fluids can be formulated by those
skilled in the art upon reading the present disclosure and
considering the characteristics of the fluid which are
effected by the components and the amount ranges
disclosed. In order to provide the present invention in
the form of a final product it is necessary to include the
four essential components within a hydrocarbon oil. The
four essential components in the form of active chemicals
are present within the hydrocarbon oil in an amount in the
range of about 0.5 percent to about 19.5 percent by weight
based on the total weight of the functional fluid of the
invention. Accordingly, the hydrocarbon oil is present in
the amount in the range of about 81.5 percent to about
99.5 percent based on the total weight of the functional
fluid.
~1 2~8~6~
14 -
The four essential components of the present
invention could be included by themselves or in
combination with other co~ponents within a concentrate.
The concentrate could contain from about 1 percent to
about 99 weight percent of the active chemical with the
remainder of the concentrate being comprised of a
hydrocarbon oil.
When formulating a tractor fluid the hydrocarbon oil
is generally present in an amount in the range of about
81.5 weight percent to about 99.5 weight percent. The
individual essential components of the tractor fluid are
present in the following amounts: the calcium salt is
present in an amount of about 0.5 weight percent to about
5.5 weight percent; the EP/antiwear agent i5 present in an
amount of about 1 percent to about ~ wei~ht percent; the
borated epoxide is present in amount of about 0.1 percent
to about 1.5 weight percent and the carboxylic solubilizer
is present in the amount of about 0.1 percent to about 1
weight percent, with all of the amounts being based on
parts by weight of the active chemical in the tractor
fluid as a whole.
In a particularly preferred embodiment of the present
vention the calcium salt is present in an amount of
about 1.41 weight percent or about 3 percent with its
diluent oil. The EP/antiwear agent is present in an
amount of about 1.7 weight percent; the borated epoxide i9
; present in an amount of about ~.5 weight percent and the
carhoxylic solubilizer is present in an amount of about
0.25 weight percent of active chemical based on the weight
of the tractor fluid as a whole.
EXAMPLE I
A formulation containing 2.82 percent by weight of an
overbased calcium sulfonate salt complex; 3.38 percent by
weight of a zinc dithiophosphate; 1 percent by weight of a
borated epoxide and 0.5 percent by weight of a carboxylic
solubilizer; 1.93 percent by weight of styrene/maleic
anhydride VI improver and 0.02 percent by weight of a
silicon anti-foam agent dissolved in hydrocarbon oil.
EXAMPLE II
A formulation containing 1.76 percent by weight of an
overbased calcium sulfonate salt complex; 2.14 percent by
weight of a zinc dithiophosphate treated with
triphenylphosphite; 0.63 percent by weight of a borated
epoxide and 0.31 percent by weight of a carboxylic
solubilizer as the essential components and including 1.93
percent by weight of a styrene/maleic anhydride VI
improver; and 0.02 percent by weight of a silicon
anti-foaming agent dissolved in hydrocarbon oil.
-
EXAMPLE III
A formulation containing 1.41 percent by weight of an15 overbased calcium sulfonate salt complex; 1.71 percent by
weight of a zinc dithiophosphate treated with an olefin;
0.5 percent ~y weight of a borated epoxide and 0.25
percent by weight of a carboxylic solubilizer as the
essential components and 1.93 percent by weight of a
styrene/maleic anhydride VI improver; and 0.02 percent by
weight of a silicon anti-foaming agent dissolved in
hydrocarbon oil.
With respect to each of the examples referred to
above some variation is possible with respect to what each
of the actual components will be. For example, with
xespect to the use of an overbased calcium sulfonate salt
complex, the actual component utilized might be a calcium
sulfonate complex which has been overbased with a calcium
compound and then treated with polyisobutylene succinic
acid or anhydride having a molecular weight in the range
of from about 700 to ahout 5,000. With respect to the
- zinc dithiophosphate this component might be a mixture of
zinc salts of bis(2-ethylhexyl)dithiophosphate and
2-ethylhexyl carboxylic acid treated with
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- 16 -
triphenylphosphite. This salt is preferably combined with
a stoichiometric excess of zinc, i.e., the salt is
preferably over-zinced including about 1.2 to about 1.4
stoichiometric equivalents of zinc. The borated epoxide
may be a product obtained as a result of the reaction of
boric acid with 1,2-epoxide containing about 16 carbon
atoms. The carboxylic solubilizer may be the product
obtained as a result of a reaction of polybutenyl succinic
anhydride with N,N-diethylethanolamine at a molar ratio of
about 1:2. In addition, these formulations may include
other components depending upon its desired end use. The
actual specific chemical compound used for each of the
essential components, their amounts, as well as other
additional activ~ chemicals will be chosen by those
skilled in the art depending upon the specific
requirements of the functional fluid being produced.
Variations in the amounts and the actual specific type of
chemical component will be deducible by those of ordinary
skill in the art upon consideration of their needs and a
reading of the present description.
The present invention has been disclosed and
described here in what is believed to be its most
preferred embodiments. However, it is recognized that
those skilled in the art, upon reading this disclosure,
will recognize certain variations thereof which are
considered to be encompassed by the scope of the present
invention.
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