Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE: EMULSIFIED BASED LUBRICANTS
TECHNICAL FIELD OF INVENTION
The invention relates to emulsion based lubricants. In particular the
invention
relates to water in oil emulsion lubricants, in particular lubricants that can
be used as
greases.
BACKGROUND OF INVENTION
Lubricating compositions are used to reduce friction between surfaces which
are moving with respect to each other. The lubricant reduces the amount of
intimate
contact between the moving surfaces. The lubricant prevents contact between
the
moving surfaces thus preventing harmful wear to the surfaces. The lubricant
generally
lowers the coefficient of friction. To be effective, the lubricant, in
particular a grease
needs sufficient anti-wear, anti-weld and extreme pressure properties to
prevent metal
to metal contact under high load conditions.
Generally, most lubricants, have been based on petroleum oil although
synthetic based oil lubricants have been used for special applications. Grease
compositions contain an oil of lubricating viscosity and a thickening agent.
Greases
usually include various types of thickeners. Thickeners include simple metal
soaps,
complex metal salt soap and non-soap thickeners, like clays. Greases are
typically
made by thickening an oil with a thickener and the addition of additives for
performance benefits.
Frequently lubricating oils and, greases come into contact with the
environment
through leakage, excretion of old lubricants during reapplication, general
disposal,
mechanical removal, water washout, thermal degradation and the like. The
release of
lubricants and greases pose an environmental concern. The development of
grease-like
materials which contain a majority of water and natural products will lessen
environmental contamination or impact which would result through the use of
currently
used mineral or synthetic oil-based lubricants and greases. It has been
discovered that
an emulsified lubricant can be used in the some of the same applications as
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conventional lubricants and greases and is environmentally friendly, less
expensive,
less toxic and less flammable.
SUMMARY OF THE INVENTION
The invention relates to novel emulsified lubricants such as greases
comprising
(a) a major amount of an aqueous phase, (b) a minor amount of an organic phase
and
(c) a minor but effective amount of at least one emulsifier to emulsify the
aqueous and
organic phase resulting in a water in oil emulsified lubricant.
More particularly the emulsified lubricant comprises (a) a major amount of
water, (b) optionally water soluble additives, (c) optionally alcohols, (d) an
oil of
lubricating viscosity, (e) at least one emulsifier and (f) optionally oil
soluble additives,
resulting in a water in oil emulsified lubricant.
The present invention provides a process for making an emulsified lubricant
comprising:
A. mixing the following components
(a) a major amount of water,
(b) a minor amount of oil of lubricating viscosity,
(c) at least one emulsifier,
(d) optionally, a water soluble additive,
(e) optionally, an oil soluble additive,
(f) optionally, an alcohol,
(g) optionally, a thickener, and
(h) combinations thereof;
B. with sufficient shear to form a water in oil emulsion of a
lubricant, in particular an emulsified grease.
The emulsified lubricant is a stable water in oil emulsion. The emulsified
lubricant can be used as conventional lubricants however, they are
environmentally
friendly.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to emulsified lubricant compositions in
particular
emulsified greases and a process to make it. The emulsion is a water in oil
emulsion
i.e., the oil forms the continuous phase while the water forms the
discontinuous phase
dispersed in the continuous phase. The emulsion has a viscosity in the range
of about
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200 to about greater than 200,000 cps or mm2/sec measured on a Brookfield
Viscometer with a No. 7 spindle at 20 rpm and 25 C. The emulsions can also be
of a
consistency which allows them to be evaluated on a an penotrometer according
to the
ASTM D217 procedure. If measured using the ASTM D217 test, emulsions with
penetrations greater than 85 can be obtained.
Natural oils include animal oils and plant oils (e.g., castor oil, cottonseed
oil,
rapeseed oil, soybean oil, lard oil) as well as liquid petroleum oils and
solvent-treated
or acid-treated mineral lubricating oils of the paraffinic, naphthenic or
mixed
paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal
or shale are
also useful base oils. Synthetic lubricating oils include but are not limited
to
hydrocarbon oils such as polymerized and interpolymerized olefins (e.g.,
polybutylenes, polypropylenes, propylene-isobutylene copolymers, poly(1-
hexenes,
poly(1-octenes), poly(1-decenes), and mixtures thereof); allcylbenzenes (e.g.,
dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, and di(2-ethylhexyl)-
benzenes); polyphenyls (e.g., biphenyls, terphenyls, and alkylated
polyphenyls),
alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives,
analogs,
and homologs thereof.
Alkylene oxide polymers and interpolymers and derivatives thereof where the
terminal hydroxyl groups have been modified by esterification, etherification,
or
similar reaction constitute another class of known synthetic lubricating oils.
These are
exemplified by the oils prepared through polymerization of ethylene oxide or
propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers
(e.g.,
methylpolyisopropylene glycol ether having an average molecular weight of
1,000
diphenyl ether of polyethylene glycol having a molecular weight of 500-1,000,
diethyl
ether of polypropylene glycol having a molecular weight of 1,000-1,500) or
mono- and
polycarboxylic esters thereof, for example, the acetic acid esters, mixed C3 -
C8 fatty
acid esters, or the C13 Oxo acid diester of tetraethylene glycol.
Another suitable class of synthetic lubricating oils comprises the esters of
dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids
and alkenyl
succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric
acid, adipic
acid, linoleic acid dimer, malonic acid, alkyl malonic acids, and alkenyl
malonic acids)
with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl
alcohol, 2-
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ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, and
propylene
glycol). Specific examples of these esters include but are not limited to
dibutyl adipate,
di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl
azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate,
the 2-
ethylhexyl diester of linoleic acid dimer, and the complex ester formed by
reacting one
mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-
ethylhexanoic acid.
Esters useful as synthetic oils also include but are not limited to those made
from C5 to C12 monocarboxylic acids and polyols and polyol ethers such as
neopentyl
glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and
tripentaerythritol.
Unrefined, refined and rerefined oils (and mixtures of each with each other)
of
the type disclosed hereinabove can be used in the lubricant compositions of
the present
invention. Unrefined oils are those obtained directly from a natural or
synthetic source
without further purification treatment. For example, a shale oil obtained
directly from
retorting operations, a petroleum oil obtained directly from distillation or
ester oil
obtained directly from an esterification process and used without further
treatment
would be an unrefined oil. Refined oils are similar to the unrefined oils
except that they
have been further treated in one or more purification steps to improve one or
more
properties. Many such purification techniques are known to those of skill in
the art such
a solvent extraction, acid or base extraction, filtration, percolation, or
similar
purification techniques. Re-refined oils are obtained by processes similar to
those used
to obtain refined oils. Such rerefined oils are also known as reclaimed or
reprocessed
oils and often are additionally processed by techniques directed to removal of
spent
additives and oil breakdown products.
Petroleum, synthetic and natural waxes and mixtures of the type disclosed
hereinabove can be used in the lubricant compositions of the present
invention.
Petroleum waxes are paraffinic compounds isolated from crude oil via some
refining
process. Examples of petroleum waxes are slack wax and paraffin wax. Synthetic
waxes are waxes derived from petrochemicals, such as ethylene or propylene.
Synthetic waxes include polyethylene, polypropylene, and ethylene-propylene co-
polymers. Natural waxes are waxes produced by plants and /or animals or
insects.
These waxes include bees wax, soy wax andcarnauba wax.
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The emulsified composition contains oil in the range from about 1 % to about
95 %, preferably from about 5 % to about 40 % and more preferably from about 8
% to
about 20 % by weight of the emulsified composition.
The major amount of the emulsified composition is water. The water may be
taken from any source. The water includes but is not limited to tap,
deionized,
demineralized, purified and the like. Combinations of different sources of
water may
be used. The water is present in the range of about 99 % to about 5 %,
preferably 95 %
to about 60 % and more preferably about 92 % to about 80 % of the emulsified
composition.
Conventional thickeners that are either water soluble, oil soluble, or
combinations thereof may optionally be used in the preparation of the
emulsified
composition. Thickeners for the emulsified composition are generally known in
the
art.
The oil phase thickeners include but are not limited to alkali and alkaline
earth
metal soaps of fatty acids and fatty materials, the metals are typified by
sodium,
lithium, calcium and barium, and examples of fatty materials include stearic
acid,
hydroxystearic acid, stearin, oleic acid, palmitic acid, myristic acid,
cottonseed oil
acids, and hydrogenated fish oils. Other thickeners include but are not
limited to salt
and salt-soap complexes, such as calcium stearate-acetate, barium stearate-
acetate,
calcium stearate-caprylate-acetate complexes, calcium salts and soaps of low-
intermediate-and high-molecular weight acids and of nut oil acids, aluminum
stearate,
and aluminum complex thickeners. Useful thickeners include, but are not
limited to,
hydrophilic clays which are treated with an ammonium compound to render them
hydrophobic. Typical ammonium compounds are tetraalkyl ammonium chlorides.
These clays are generally crystalline complex silicates. These clays include
bentonite,
attapulgite, hectorite, illite, saponite, sepiolite, biotite, vermiculite,
zeolite clays and the
like. Combinations of the thickeners may be used.
The water phase includes water soluble additives that include but are not
limited to alcohols; water soluble EP antiwear additives; water soluble
additives such
as dihydrogen butyl phosphate, water soluble phosphate salts, water soluble
dithiophosphate salts; water soluble inorganic salts which may give added EP
antiwear
protection such as xanthates, dithiocarbonates, trithiocarbonates, sulfates,
sulfites,
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sulfides, for example sodium sulfide and the like; water soluble phosphate
esters,
phosphites, phosphonates, and the like; water soluble dithiophosphate esters;
water
soluble rust inhibitor such as but not limited to amines like morpholine and
alkanolamines, phosphorous and phosphoric acid derivatives such as mono and
diesters
and amine or metallic salts of phosphoric and phosphorous acid and
combinations
thereof.
The water soluble additives are added to enhance the performance of the
emulsified lubricant. The water soluble additives are preferably present in
the range of
about 0 % to about 50 %, preferably about 0.1 % to about 30 % and more
preferably
about 1 % to about 20 % by weight of the emulsified composition.
The water phase thickeners include but are not limited to surfactant gels
which
are two or more surfactants that associate with each other to form a gel. An
example of
a surfactant gel surfactant combination is lauryl sulfobetaine and cationic
surfactants.
The water phase thickeners further include but are not limited to water-
soluble
polymeric thickeners. Generally, these thickening agents can be
polysaccharides,
synthetic thickening polymers, or mixtures of two or more of these. Among the
polysaccharides that are useful are natural gums such as those disclosed in
"Industrial
Gums" by Whistler and B. Miller, published by Academic Press, 1959. Examples
include but are not limited to gums are gum agar, guar gum, gum arabic, algin,
dextrans, xanthan gum and the like.
Also among the polysaccharides that are useful as thickeners are cellulose
ethers and esters, particularly the hydroxy hydrocarbyl cellulose and
hydrocarbylhydroxy cellulose and its salts. Examples include but are not
limited to are
hydroxethyl cellulose and the sodium salt of carboxymethyl cellulose. Mixtures
of two
or more of any such thickeners are also useful.
The water phase thickeners can also be synthetic thickening polymers. Many
such polymers are known to those of skill in the art. Representative of them
include
but are not limited to polyacrylates, polyacrylamides, hydrolyzed vinyl
esters, water-
soluble homo- and inter-polymers of acrylamidoalkane sulfonates containing 50
mole
per cent at least of acryloamido alkane sulfonate and other comonomers such as
acrylonitrile, styrene and the like. Poly-n-vinyl pyrrolidones and homo- and
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copolymers as well as water-soluble salts of styrene-maleic anhydride
copolymers and
isobutylene-maleic anhydride copolymers can also be used as thickening agents.
The water phase thickeners may also be mineral-based. Many mineral based
thickeners are known. Examples include hydrated silica and hydrated magnesium
aluminum silicates.
The thickener is employed in an amount from about 0 % to about 10 %,
preferably from 0.2 % to about 7 % and more preferably about 0.3 % to about 5
% by
weight of the emulsified composition.
The emulsified composition may contain oil soluble additives in the oil
continuous phase that are conventionally employed in lubricants. The oil
soluble
additives include but are not limited to extreme pressure (EP) anti-wear
additives,
metal deactivators, dispersants, antifoams, corrosion rust inhibitors,
antioxidants,
detergents, polymers and functionalized polymers and others useful additives
for
providing enhanced performance characteristics of the emulsified composition
and are
known in the art. The amount of the organic soluble additive depends on the
specific
performance characteristics designed for the emulsified composition and is
generally in
the range of about 0 % to about 75 %, preferably from about 0.5 % to about 60
% and
more preferably from about 1 % to about 20 % of the emulsified composition.
Extreme pressure anti-wear additives that are soluble in the oil include but
are
not limited to a sulfur or chlorosulphur EP agent, a chlorinated hydrocarbon
EP agent,
or a phosphorus EP agent, or mixtures thereof. Examples of such EP agents are
chlorinated wax, organic sulfides and polysulfides, such as benzyldisulfide,
bis-
(chlorobenzyl) disulfide, dubutyl tetrasulfide, sulfurized sperm oil,
sulfurized vegetable
and or animal oils, sulfurized methyl ester of oleic acid, sulfurized
alkylphenol,
sulfurized dipentene, sulfurized terpene, and sulfurized Diels-Alder adducts;
phosphosulfurized hydrocarbons, such as the reaction product of phosphorus
sulfide
with turpentine or methyl oleate, phosphorus esters such as the dihydrocarbon
and
trihydrocarbon phosphites, i.e., dibutyl phosphite, diheptyl phosphite,
dicyclohexyl
phosphite, pentylphenyl phosphite; dipentylphenyl phosphite, tridecyl
phosphite,
distearyl phosphite and polypropylene substituted phenol phosphite, metal
thiocarbamates, such as zinc dioctyldithiocarbamate and barium heptylphenol
diacid,
such as zinc dicyclohexyl phosphorodithioate and the zinc salts of a
phosphorodithioic
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acid. Additionally, dithiophosphosphate and dithiocarbamate esters and
disulfides,
and mixtures of mono- and dialkylphosphates salted with alkyl amines may also
be
used. . Combinations of the above may be used. The oil soluble EP agents is
present
in the range of about 0 % to about 12 %, preferably from about 0.5 % to about
10 %
and more preferably from about 1 % to about 6 % by weight of the emulsified
composition.
Solid additives in a particle or finely divided form may also be used at
levels of
0% to 20%. These include but are not limited to graphite, molybdenum
disulfide, zinc
oxide, boron nitride, polytetrafluoroethylene, and the like. Mixtures of solid
additives
may be used.
Oil soluble polymers and functionalized polymers include but are not limited
to
polyisobutenes, polymethyacrylate acid esters, polyacrylate acid esters, diene
polymers, polyalkyl styrenes, alkenyl aryl conjugated diene copolymers,
polyolefins
and multifunctional viscosity improvers, including dispersent viscosity
modifiers
(which impart both dispersancy and viscosity improvement). The polymers may
also
be used to provide tackiness to the emulsified lubricant. Combinations may be
used.
The oil soluble polymers including functionalized polymers are present in the
range of about 0 % to about 50 %, preferably, about 0.01 % to about 25 %, and
more
preferably about 0.02 % to about 18 % by weight of emulsified composition.
The antioxidants that are oil soluble are known in the art and include but are
not
limited to phenate sulfides, phosphosulfurized terpenes, sulfurized esters,
aromatic
amines, and hindered phenols. Another example of an antioxidant is a hindered,
ester-
substituted phenol, which can be prepared by heating a 2,6-dialkylphenol with
an
acrylate ester under base catalysis conditions, such as aqueous KOH.
Combinations
may be used. The antioxidants are present in the range of about 0 % to about
10 %,
preferably about 0.25 % to 6 %, and more preferably about 0.5 % to about 3 %
by
weight of the emulsified composition.
Metal deactivators useful in lubricating oil compositions are known in the art
and include but are not limited to benzotriazole, benzimidazole, 2-
alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles, 2-(N,N-
dialkyldithiocarbamoyl)benzothiazoles, 2,5-bis(alkyl-dithio)-1,3,4-
thiadiazoles, and
2,5-bis(N,N-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles. Combinations may be
used.
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The metal deactivators are present in the range of 0 % to about 5 % preferably
about
0.1 % to about 4 % and more preferably about 0.2 % to about 3 % by weight of
the
emulsified composition.
Oil soluble detergents are known in the art and include but are not limited to
overbased materials prepared by reacting an acidic material (typically an
inorganic acid
or lower carboxylic acid, preferably carbon dioxide) with a mixture comprising
an
acidic organic compound, a reaction medium comprising at least one inert,
organic
solvent (mineral oil, naphtha, toluene, xylene, etc.) for said acidic organic
material, a
stoichiometric excess of a metal base, and a promoter. The acidic organic
compounds
useful in making overbased compositions in general can include carboxylic
acids,
sulfonic acids, phosphorus-containing acids, phenols or mixtures of two or
more
thereof.
The metal compounds useful in making the basic metal salts are generally
any Group I or Group II metal compounds (CAS version of the Periodic Table of
the
Elements). The Group I metals of the metal compound include alkali metals
(group
IA: sodium, potassium, lithium, etc.) as well as Group IB metals such as
copper. The
Group I metals are preferably sodium, potassium, lithium and copper, more
preferably sodium or potassium, and more preferably sodium. The Group II
metals
of the metal base include the alkaline earth metals (group IIA: magnesium,
calcium,
barium, etc.) as well as the Group JIB metals such as zinc or cadmium.
Preferably
the Group II metals are magnesium, calcium, or zinc, preferably magnesium or
calcium, more preferably calcium. Generally the metal compounds are delivered
as
metal salts. The anionic portion of the salt can be hydroxyl, oxide,
carbonate, borate,
nitrate, etc.
While overbased metal salts can be prepared by combining an appropriate
amount of metal base and carboxylic acid substrate, the formation of useful
overbased compositions is facilitated by the presence of an additional acidic
material. The acidic material can be a liquid such as formic acid, acetic
acid, nitric
acid, sulfuric acid, etc.
A promoter is a chemical employed to facilitate the incorporation of metal
into the basic metal compositions. The promoters are quite diverse and are
well
known in the art, as evidenced by the cited patents. These include but are not
limited
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to the alcoholic and phenolic promoters. The alcoholic promoters include the
alkanols of one to about twelve carbon atoms such as methanol, ethanol, amyl
alcohol, octanol, isopropanol, and mixtures of these and the like. Phenolic
promoters
include a variety of hydroxy-substituted benzenes and naphthalenes. Mixtures
of
various promoters are sometimes used. The promoters are found in U.S. Pat.
Nos.
2,777,874 and 2,616,904.
Combinations of detergents may be used. The detergents are present in the
range of about 0 % to about 8 %, preferably, about 0.1 % to about 6 %, and
more
preferably about 0.3 % to about 5 % by weight of emulsified composition.
Antifoams are known in the art and include but are not limited to organic
silicones such as dimethyl silicone and the like. Combinations may be used.
The
antifoams are present in the range of about 0 % to about 2 %, preferably about
0.01 %
to about 1 %, and more preferably 0.02 % to about 0.7 % by weight of the
emulsified
composition.
Antirust compounds are known in the art and include but are not limited to
alkyl substituted aliphatic dicarboxylic acids such as alkenyl and succinic
acids,
sulfonates relating to the metal detergent, sodium nitrite, calcium salts of
oxidized
paraffin wax, magnesium salts of oxidized paraffin wax, alkali metal salts,
alkaline
earth metal salts or amine salts of beef tallow fatty acids, alkenyl
succinates or alkenyl
succinic acid half esters (whose alkenyl moiety has a molecular weight of
about 100 to
300), glycerol monoesters, nonylphenyl ethoxylate, lanolin fatty acid esters,
and
calcium salts of lanolin fatty acids. Combinations may be used. The antirust
compounds are present in the range of about 0 % to about 10 %, preferably
about 0.1 %
to about 8 %, and more preferably 0.2 % to about 6 % by weight of the
emulsified
composition.
The emulsified composition contains at least one emulsifier. The emulsifier
must be capable of producing a water in oil emulsion to form the emulsified
composition. Examples of suitable emulsifiers include but are not limited to
alkylaryl
sulfonate, lignosulfonate salts, starches and the like. Low hydrophilic
lipophilic
(sometimes called lyophillic) balance (HLB) surfactants are employed within a
range
of less than or equal to BLB 9.0, preferably HLB of 0 to 7, and more
preferably with
an HLB in the range of 4 to 6. Surfactants with HLBs higher than 9 can be used
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provided they are combined with lower HLB surfactants to give a composite
emulsifier
system with an HLB in the range that produces water in oil emulsions. The
procedures
to do this are generally known in the art.
The surfactants include but are not limited to anionic, cationic and non ionic
surfactants. Further, the surfactants include but are not limited to
(polyisobutenyl)
dihydro-2,5-furandione with stearic acid and polyethylenepolyamines ,
(polyisobutenyl) dihydro-2,5-furandione, cyclic dianiines, ethylenamines,
pentaerythritol , 4-polybutenyl(C=20-2000)-2-aminophenol , maleinated
polyisobutenyl succinic acid amine salts, polyolefin aminoester/salt,
polyisobutenylsuccinic anhydride product with diethylethanolamine,
polyisobutenylsuccinic anhydride, product with polyethyleneamines and boric
acid,
polyolefin amide alkeneamine, ' polyolefin aminoester , polyisobutenylsuccinic
anhydride, product with polyethylenepolyamines and carbon disulfide,
(polyisobutenyl) dihydro-2,5-furandione esters with pentaerythritol ,
(polyisobutenyl)
dihydro-2,5-furandione pentaerythritol and polyethylenepolyamines,
polyisobutenylsuccinic anhydride product with diethylethanolamine,
polyisobutenylsuccinic anhydride, product with polyethylene-polyamines pibsa
amines, polyisobutenyl glyoxylate amines, sorbitan mono oleate, sorbitan mono
isosterate and sorbitan sesquioleate, and the like. Combinations of
emulsifiers may be
used and are often preferred since it is known by those skilled in the art
that combining
different emulsifiers often yields more stable emulsions than single
emulsifier systems.
The emulsifier may also be selected from hydroxysubstituted hydrocarbon
amines (particularly mono-, di-, and tri-alkanol amines wherein each allcanol
group
contains 2 to about 10 carbon atoms); hydrocarbyl amines (including mono-, di-
, and
tri-hydrocarbon amines wherein each hydrocarbon group has 1 to about 20 carbon
atoms); polyols of 3 to 8 hydroxyls (including those having 3 to 8 hydroxyl
groups and
3 to 12 aliphatic carbon atoms and analogous materials made by treating such
polyols
with alkylene oxides of 2 to 8 carbon atoms); alkylene glycols (including
those wherein
the alkylene group has 2 to 4 carbon atoms); polyalkylene glycols (including
those
wherein each alkylene group is of 2 to 4 carbon atoms and the polyalkylene
glycol has
molecular weights ranging from 50 to about 1500) and sulfonated materials such
as
sulfonated hydrocarbon and amine-neutralized salts thereof. Among the
sulfonated
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materials are included the sulfonamidcarboxylic acids and neutralized
derivatives
thereof.
Other emulsifiers include, but are not limited to di- and tri-ethanol and
propanol
amine, polypropylene glycols, particularly those having an average molecular
weight
of about 700 to about 1200 and solubility of at least about 20 grams per liter
in water at
20 C, glycerin, liquid sugar alcohols, alkali and alkaline earth metal,
dodecylbenzene
sulfonates, alkali metal laurylsulfonates, and the like. Many other such
dispersing
agents are known to those of skill in the art. See, for example, the list
beginning at
page 52 entitled "Coupling Agents" in "McCutcheon's Publications - Combined
Edition, Book III - Functional Materials," published by the McCutcheon's
Division,
M.C. Publishing Co., Ridgwood, N.J., U.S.A., 1976.
The emulsifier is present in the range of about 20 % to about 0.25 %,
preferably about 5 % to about 1 % and more preferably about 2 % to about 1.5 %
by
weight of the emulsified composition.
Optionally, an alcohol may be employed in the emulsified composition.
Typical alcohols include but are not limited to polyol-, ethylene glycol,
propylene
glycol, methanol, ethanol, glycerols and mixtures thereof. The alcohol may be
present
in the range of about 0% to about 30 % preferably about 1 % to about 20 %, and
more
preferably about 2 % to about 10 %by weight of the emulsified composition.
In the practice of the present invention the process to make the emulsified
composition is carried out as a batch; semi-batch, continuous process, or a
combination. The emulsified composition formed is a stable macro emulsion in
which
the water components are suspended in a continuous phase of oil components.
The
emulsified composition can be used first made in a concentrated form and then
diluted
either immediately or later which ever is more suitable for efficient delivery
of the
product.
In the practice of the present invention the process is capable of monitoring
or
adjusting the amount of the oil, the oil soluble additives, water, emulsifier,
alcohol
and/or water soluble additives to form a stable emulsion with the desired
water droplet
size. The batch processes described herein depicts one embodiment of the
invention.
The components are all added to a vessel and mixed or in the alternative the
oil soluble
components are mixed separately from the separately mixed water soluble
components
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and then both mixtures are added together and emulsified. The components may
be
introduced into the vessel as discreet components or combinations of the
discreet
components.
The mixture is emulsified using an emulsification device in the vessel,
alternatively the mixture flows from the vessel via a circular line to an
emulsification
device which is external to the vessel, for about one to about 20 tank
turnovers. The
temperature of the process is in the range of about 0 C to about 200 C,
preferably in
the range of about 8 C to about 150 C and most preferably about 15 C to about
90 C,
and a pressure in the range of about atmosphere pressure to about 300 psi,
preferably
about atmosphere pressure to about 75 psi and more preferably in the range of
about
atmospheric pressure to about 50 psi resulting in a stable emulsified
composition.
In another embodiment a continuous process is used to make the emulsified
composition. The feeds of the oil, the emulsifier, the oil soluble additives,
the water,
the alcohol and the water soluble additives are introduced as discreet feeds
or in the
alternative as combinations of the discreet feeds, depending on the components
solubility, to form a stable emulsified composition. More than one
emulsification
device may be employed. The continuous process generally occurs under ambient
conditions and at a pressure in the range of atmospheric pressure to about
20,000 psi,
preferably atmospheric pressure to about 5000 psi, and more preferably about
atmospheric pressure to about 4000 psi and with a temperature in the range of
0 C to
about 200 C, preferably about 5 C to about 150 C and more preferably from
about
10 C to 100 C.
The emulsification occurs by methods known in the art including but not
limited to mixing, mechanical mixture agitation, static mixers, shear mixers,
sonic
mixers, high pressure mixture, jet mixers, homogenizers, pin mills, rotor-
stator mills,
microfluidizers and the like.
A programmable logical controller is optionally employed for governing the
flow of components in the batch, semi-batch or continuous process, thereby
controlling
the flow rates and mixing ratio in accordance with the desired blending rates.
The emulsification provides for the desired particles size and a uniform
dispersion of the water in the oil. The emulsification results in a uniform
dispersion of
an emulsified composition having a mean particle droplet size in the range of
0.01
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micron to about 20 micron, in another embodiment in the range of about 0.5
micron
to about 10 micron, and in another embodiment of the range of about 1 micron
to
about 5 micron.
The emulsified composition is used as an emulsifier lubricant and more
particularly an emulsifier grease. The emulsified composition has a major
portion
of water and natural products compared to conventional lubricants and is less
harmful to the environment. Further, the emulsified grease is used for the
same or
similar application as are conventional greases.
SPECIFIC EMBODIMENT
The following examples demonstrate the process to produce an emulsified
lubricant of the invention.
Example I
A 3-speed HobartTM mixture was used as the reaction vessel for
emulsifying the grease. An 8-qt mixing bowl was charged with about 285g of
soybean oil, about 150g of a multifunctional performance additive package
containing a zinc dialkyldithiophosphate an olefin polysulfide, an amine
corrosion
inhibitor, a triazole metal deactivator, soybean oil, an antiwear agent
composed of a
complex mixture of mono and diesters of phosphoric acid, C12-14 alkylamine
salt
and 15 % by weight diluent oil, about 30g of an olefin sulfide containing
about 40
% sulfur, about 60g of a surfactant system comprised of a mixture of
polyisobutenylsuccinyl aminoester and polyisobutenylsuccinic acid dimethyl
ethanolamine salt and 45% diluent oil, and about 82.5g of 2000 number average
molecular weight polyisobutylene. The components were heated to about 75-85 C
while stirring the mixture with a hip stirrer at the mixer's fastest setting.
A solution
of 450g of glycerol and about 1950g of water was heated to about 65 C.
The water solution was added dropwise to the mixing bowl in 4 increments
during which the mixture was constantly heated. The first 600 ml solution was
added over a period of 30 min. The second 600 ml solution was added over the
next 35 min, the third 600 ml solution was added over the next 20 min and the
last
addition was added over the next 25 min. The final temperature of the emulsion
was about 57 C. The final milky white emulsion was weighed and was found to be
640g. The product was collected as a viscous grease like emulsion.
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Example 2
In Table 1, all of the emulsions contained 5 % by weight of the additive
package from example 1, 1% by weight of a olefin sulfide extreme pressure
agent and
2 % by weight of the surfactant package of example 1. Three types of emulsions
were
made by the same method (as in example 1) but with different mixtures of water
and
alcohols. The ASTM D217 (penetration) test was used to determine the
consistency of
the products. The unit of measurement for this test is 1/10th mm. Item 1 was
prepared
with the least amount of water, 32 % wt, and had the highest penetration
result of
Po=355 which correlates to a NLGI "grade 0" grease. When propylene glycol
(PRG)
replaced the ETG (ethylene glycol) and with an increase in water to 65 %wt.
The
emulsion became stiffer as seen by the penetration result with Po=309 was
measured
(item 2.) For item 3 the ethylene glycol was changed to glycerol while the
water
content remained at 65 %wt, yielding an emulsion. This emulsion had a
penetration
Po=262 which corresponds to a "Grade 2" grease, the most commonly used grease
in
the industry. Item 4 and 5 showed the influence that increased levels of water
have on
the emulsion's penetration result. The emulsion product became softer in these
examples with additional water as can be seen with penetration results of
Po=327 and
326, respectively.
Table 1 Penetration Results Resulting from Polar Changes
Item 1 2 3 4 5
Additives % % % % %
Water 32 65 65 70 75
Ethylene glycol 48
Propylene glycol 15
Glycerol 15 10 5
Citgo 150 bright stock 10.4 9.5 9.5 10.4 10.4
2,000 Mn 1.6 2.5 2.5 1.6 1.6
Polyisobutylene
Tests
D217 Penetration 355 /309 262 327 326
(1/10th MM)
D2509 Timken (lbs) 25# not run 30# 30# 35#
D2266 Four Ball Wear 0.57 0.57 0.54 0.63 0.48
(MM)
D2596 Four Ball (kg) 160 126 126 126 126
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A lubricant must meet certain test requirements in order for it to be
considered
acceptable for use in an application. Commonly available greases will have
Timken
(ASTM D2509) results between 20-40 pounds, a 4-ball wear (ASTM D2266) of
<0.60mm, a 4-ball EP (ASTM D2596) that is >250kg and a pass in the ASTM D
1743B
rust test.
The performance results for these emulsions are shown in Table 1. Item 1 had a
result in the ASTM D2509 Timken test of 25 lbs. and wear result in the ASTM
D2266
Four-Ball Wear test result of 0.57 mm. Likewise, items 3 and 4 gave Timken
results
of 30 lbs. when glycerol replaced ethylene glycol, and the wear results still
remained
approximately the same at 0.57 and 0.63 mm. Item 5 had the highest amount of
water
with the least amount of glycerol and a good Timken test result of 35 lbs and
wear scar
of 0.48 mm in the fourball wear test. The ASTM D2596 four-ball EP test result
was
160 kg weld for item 1 with the remaining items giving results of 126 kg.
These
favorable test results in traditional grease tests are surprising in view of
these novel
emulsified lubricant compositions containing high levels of water.
Example 3
The results in Table 2 were made with Citgo 150 bright stock (items 6 and 7)
and contained 5 % by weight of the additive package from example 1, 1% by
weight of
a olefin sulfide extreme pressure agent and 2 % by weight of the surfactant
package of
example 1.
Table 2. Effects on the Penetration Due to Oils Types
Item 6 7
delete delete delete
Water 67.5 57.5
Citgo 150 bright stock 9.5 9.5
delete delete delete
Propylene Glycol 15 25
2000 Mn of isobut lene 2 2
Tests
D217 (1/10 mm) 287 347
D2509 (load) 35# 40#
D2596 (weld) 126kg 126kg
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The Timken results for the stable emulsions, items 6 and 7 were very good with
35-40
lb Timken OK load results.
Example 4
About 69 parts of water, about 12 parts of a lithium 12-hydroxystearate
thickened grease made in about a 750 SUS naphthenic base oil and having a ASTM
D-
217 Cone Penetration of 254, and about 5 parts of sorbitan monooleate, about 8
parts of
soybean oil, about 4 parts of additives of Example 1, an overbased calcium
sulfonate,
and about 2 parts olefin sulfide are stirred using a Model 89 dispersator
rated at one
horsepower and manufactured by Premier Mill Corporation for about 5 minutes.
The
mixture was transferred to the bowl of a Hobart mixer fitted with a wick. The
mixture
was processed for about 5 additional minutes in a Hobart mixer until a smooth
and stiff
product formed. The product obtained gave an unworked ASTM D217 cone
penetration result of 280 and an ASTM D2266 four ball wear result of 0.64 mm.
The
material gave a pass result in the ASTM D1743B demonstrating good rust
performance
as an emulsified lubricant containing high levels of water.
Example 5
About 70 parts of water, about 4 parts of a 42 % aqueous solution of NaH2PO4,
about 10 parts of a lithium 12-hydroxystearate thickened grease made in a 750
SUS
naphthenic base oil and having a ASTM D-217 Cone Penetration of 254, and about
5
parts of sorbitan monooleate, about 5 parts of soybean oil, about 5 parts of
additives
1from Example 1, a sulfur-phosphorous-containing additive package are stirred
using a
paint mixer for 5 minutes. The mixture was transferred to the bowl of a Hobart
mixer
fitted a wisk. The mixture was processed for about 5 additional minutes in a
Hobart
mixer until a smooth and stiff product formed. The product obtained gave an
unworked ASTM D-217 cone penetration result of 299 and an ASTM D-2266 four
ball
wear result of 0.90 mm. The material gave a result of 315 kg in the ASTM D-
2596
four ball weld test. This example demonstrates the use of water soluble
additives, like
NaH2PO4 improve the performance of the composition that would otherwise be
insoluble in traditional oil-based lubricants.
Example 6
About 66.5 parts of water, about 20 parts of a lithium 12-hydroxystearate
thickened grease made in a 750 SUS naphthenic base oil and having a ASTM D-217
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Cone Penetration of 254, about 5 parts of sorbitan monooleate, about 2 parts
of corn
starch, about 5 parts of an overbased calcium sulfonate, about 2 parts of an
alkyl
sulfide, and about 0.5 parts of a mixture of mono and dialkyl substituted
phosphoric
acids salted with an alkyamine are stirred using a dispersator for 5 minutes.
The
mixture was transferred to the bowl of a Hobart mixer fitted with a wisk. The
mixture
was processed for about 5 additional minutes until a smooth and stiff product
formed
The product obtained gave an unworked ASTM D-217 cone penetration result of
316
and an ASTM D-2266 four ball wear result of 0.57 mm.
Example 7
About 0.25 parts of a water-thickening product available from RT Vanderbilt
known as Veegum-D and about 0.25 parts of Na2HPO4 are dissolved in 68.5 parts
of
water. To this solution is added 15 parts of a lithium 12-hydroxystearate
thickened
grease made in a 750 SUS naphthenic base oil and having a ASTM D-217 Cone
Penetration of 254, about 5 parts of sorbitan monooleate, about 5 parts of an
overbased
calcium sulfonate, and about 0.5 parts of a mixture of mono and dialkyl
substituted
phosphoric acids salted with an alkyamine. The mixture is stirred using a
dispersator
mixer for 5 minutes. The mixture is transferred to the bowl of a Hobart mixer
fitted a
wick and processed for an additional 5 minutes in until a smooth and stiff
product
formed. The product obtained gave an unworked ASTM D-217 cone penetration
result
of 308 and an ASTM D-2266 four ball wear result of 0.60 mm.
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