Note: Descriptions are shown in the official language in which they were submitted.
CA 02102650 2002-10-17
FIELD OF THE INVENTION
This invention relates to grease compositions. More
particularly, it relates to metal soap thickened base
greases containing certain boron- and phosphorus-containing
property-improving additives.
BACKGROUND OF THE INVENTION
Man's need to reduce friction dates back to ancient
times. As far back as 1400 B.C., both mutton fat and beef
fat (tallow) were used in attempts to reduce axle friction
in chariots.
Until the mid-1800's, lubricants continued to be
primarily mutton and beef fats, with certain types of
vegetable oils playing minor roles. In 1859, however,
Colonel Drake drilled his first oil well. Since that time
most lubricants, including greases, have been based on
petroleum ("mineral") oil, although synthetic oil based
lubricants are used for special applications.
In the NLGI Lubricating Grease Guide, ° 1987,
available from the National Lubricating Grease Institute,
Kansas City, Missouri, USA, is a detailed discussion of
greases, including various types of thickeners. Such
thickeners include metal soaps, complex metal salt-metal
soaps and non-soaps.
Metal soap thickened greases have provided exemplary
performance. Performance of greases may be enhanced by
incorporating therein various types of additives. In A.C.
Witte, Lubrication, Vol. 77, No. 1, Texaco Inc., White
21o2s5~
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Plains, N.Y., (1991), pp 2-3, is a discussion of additives
for greases, including antioxidants, rust and corrosion
inhibitors, EP (extreme pressure) additives, antiwear
additives, lubricity agents, tackifiers and fillers.
Dropping point is one measure of the thermal stability
of a grease. One way to increase the dropping point of
base greases is to convert a simple metal soap grease to a
complex grease by incorporating therein certain acids,
typically carboxylic acids such as acetic acid, alpha-
omega-dicarboxylic acids and certain aromatic acids. This
additional step necessarily consumes considerable time
resulting in reduced production.
Doner et al, in a series of US Patents, specifically,
US Patents
5,084,194 5,068,045 4,961,868
4,828,734 4,828,732 4,781,850
4,780,227 4,743,386 4,655,948
4,600,517 4,582,617
teaches increased thickening of metal salt thickened base
greases is obtained by employing certain boron-containing
compounds. Other additives contemplated by Doner et al for
use with boron-containing compounds are phosphorus- and
sulfur-containing materials, particularly zinc
dithiophosphates.
SUMMARY OF THE INVENTION
This invention relates to improved grease compositions
comprising a major amount of an oil based simple metal soap
thickened base grease and a minor amount of at least one
phosphorus and boron containing composition, said
phosphorus and boron containing composition prepared by
reacting a combination of (A) at least one boron compound
and (B) at least one phospholipid. In one embodiment, the
phosphorus and boron containing composition is present in
amounts sufficient to improve the extreme pressure,
antiwear and lubricity properties of the base grease. In
2'02650
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another embodiment the phosphorus and boron containing
composition is present in amounts sufficient to increase
the dropping point of the base grease, as determined by
ASTM procedure D-2265, by at least 20°C.
The greases of this invention are useful for
lubricating, sealing and protecting mechanical components
such as gears, axles, bearings, shafts, hinges and the
like. Such mechanical components are found in automobiles,
trucks, bicycles, steel mills, mining equipment, railway
equipment including rolling stock, aircraft, boats,
construction equipment and numerous other types of
industrial and consumer machinery.
To meet the requirements of these and other
applications, greases must provide, to varying degrees,
lubricity, extreme pressure and antiwear properties and
depending upon the application, acceptable thermal
stability (heat resistance).
DETAILED DESCRIPTION OF THE INVENTION
Extreme pressure performance of a grease permits the
grease to perform under high load conditions, particularly,
under boundary conditions. Typically, a base grease,
without extreme pressure property improving additives, is
unable to provide acceptable extreme pressure properties.
Likewise, a lubricating grease should provide
protection against undesirable wear of the lubricated
parts. Chemical additives are frequently used to enhance
antiwear performance of a base grease.
Oil-based greases inherently provide a certain degree
of lubricity. Lubricity properties of a base grease may be
enhanced by incorporating therein certain lubricity
improving additives.
These properties are measured by well-known tests such
as the Timken OK Load test (ASTM D-2509), the Shell 4-Ball
test (e. g., ASTM D-2596) and other such tests.
2'o2s5o
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Heat resistance of greases is measured in a number of
ways. One measure of heat resistance is the dropping
point. Grease typically does not have a sharp melting
point but, rather, softens until it no longer functions as
a thickened lubricant. The American Society for Testing
and Materials (1916 Race Street, Philadelphia,
Pennsylvania) has set forth a test procedure, ASTM D-2265,
which provides a means for measuring the dropping point of
greases.
In general, the dropping point of a grease is the
temperature at which the grease passes from a semisolid to
a liquid state under the conditions of the test. The
dropping point is the temperature at which the first drop
of material falls from the test cup employed in the
apparatus used in ASTM procedure D-2265.
For many applications simple metal soap thickened base
greases are entirely satisfactory. However, for some
applications, greater heat resistance manifested by a
dropping point above that obtained employing simple metal
soap thickened greases is desirable.
Complex metal soap greases provide increased dropping
point, but have a number of significant drawbacks. Complex
thickeners have incorporated therein, in addition to a
fatty acid component, a non-fatty acid, e.g., benzoic,
organic dibasic acids, etc. component. The formation of
the complex grease typically involves the additional step
of reaction of the non-fatty acid with the simple metal
soap, and requires extended heating periods, sometimes
several times that required to prepare a simple metal soap
thickened grease. Accordingly, it is desirable to provide
a means for preparing a simple metal soap thickened grease
composition having dropping points approaching or even
exceeding those possessed by complex greases.
Thus, it is an object of this invention to provide
novel grease compositions.
21o2s5o
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It is a further object of this invention to provide
grease compositions having valuable properties.
It is another object of this invention to provide
grease compositions improved with respect to extreme
pressure, antiwear and lubricity properties.
It is another object of this invention to provide
grease compositions having improved thermal (heat)
stability as indicated by an increased dropping point as
measured by ASTM Procedure D-2265.
It is another object of this invention to provide
greases having improved thermal stability without the need
for an additional processing step.
Other objects will become apparent to the skilled
person upon reading the specification and description of
this invention.
In one embodiment, the grease compositions of this
invention display improved extreme pressure properties when
compared to the base grease . In another embodiment, the
grease compositions display improved antiwear properties
and in a still further embodiment, they display improved
lubricity.
The grease compositions of this invention also may
display dropping points at least 20°C greater than the
dropping point of the corresponding oil based simple metal
soap thickened base grease. This benefit is obtained by
incorporating into the simple metal soap thickened base
grease certain boron and phosphorus containing compositions
as described herein in amounts sufficient to increase the
dropping point of the corresponding base grease by at least
about 20°C as measured by ASTM Procedure D-2265.
Frequently, incorporating the boron and phosphorus
compositions described herein into the base grease improves
two or more of the aforementioned properties.
Greases are frequently exposed to water. Thus, it is
desirable that general purpose greases be substantially
CA 02102650 2002-10-17
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free of components that are readily adversely affected by
water.
Many boron-containing compounds are sensitive to
water, either being water-soluble, being subject to
leaching from the grease into water or being readily
hydrolyzed yielding undesirable hydrolysis products or to
hydrolysis products which readily leach out into water.
Surprisingly, the phosphorus and boron containing
compositions employed in the grease composition of this
invention do not display objectionable water sensitivity.
Greases are typically prepared by thickening an oil
basestock. The greases of this invention are oil-based,
that is, they comprise an oil which has been thickened with
a metal soap thickener.
The grease compositions of this invention employ an
oil of lubricating viscosity, including natural or
synthetic lubricating oils and mixtures thereof. Natural
oils include animal oils, vegetable oils, mineral oils,
solvent or acid treated mineral oils, and oils derived from
coal or shale. Synthetic lubricating oils include
hydrocarbon oils, halo-substituted hydrocarbon oils,
alkylene oxide polymers, esters of carboxylic acids and
polyols, esters of polycarboxylic acids and alcohols,
esters of phosphorus-containing acids, polymeric
tetrahydrofurans, silicone-based oils and mixtures thereof.
Specific examples of oils of lubricating viscosity are
presented in US Patent 4,326,972 and European Patent
Publication 107,282. A basic, brief description of
lubricant base oils appears in an article by D.V. Brock,
"Lubricant Base Oils", Lubricant Engineering, volume 43,
pages 184-185, March 1987. A description of oils of
lubricating viscosity occurs in US Patent 4,582,618 (Davis)
CA 02102650 2002-10-17
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(column 2, line 37 through column 3, line 63, inclusive).
Another source of information regarding oils used to
prepare lubricating greases is NLGI Lubricating Grease
Guide, National Lubricating Grease Institute, Kansas City,
Missouri (1987), pp 1.06-1.09, and A.C. Witte, Lubrication,
Vol. 77, No. 1, Texaco, Inc., White Plans, N.Y. (1991), pg.
2.
The simple metal soap thickeners employed in the
greases of this invention are well-known in the art. These
metal soaps are incorporated into a base oil, typically an
oil of lubricating viscosity, in amounts, typically from
about 1 to about 30% by weight, more often from about 1 to
about 15% by weight, of the base grease composition. In
many cases, the amount of metal soap used to thicken the
base oil constitutes from about 5% to about 25% of the
total by weight of base grease. In other cases from about
2% to about 15% by weight of metal soap is present in the
base grease.
The specific amount of metal soap required often
depends on the metal soap employed. The type and amount of
metal soap employed is frequently dictated by the desired
nature of the grease.
The type and amount of metal soap employed is also
dictated by the desired consistency, which is a measure of
the degree to which the grease resists deformation under
application of force. Consistency is usually indicated by
the ASTM Cone penetration test, ASTM D-217 or ASTM D-1403.
Types and amounts of simple metal soap thickeners to
employ are well-known to those skilled in the grease art.
They are substantially neutral, as defined herein, metal
salts of fatty group containing acids . The aforementioned
CA 02102650 2002-10-17
8
NLGI Lubricating Grease Guide, pp 1.09-1.11 and the
aforementioned article by Witte in Lubrication, pp 1-2, 3-4
and 7, provide descriptions of many simple metal soap
thickeners.
As indicated hereinabove the grease compositions of
this invention are oil based, including both natural and
synthetic oils. Greases are made from these oils by adding
a thickening agent thereto or by forming the thickener
therein. Thickening agents useful in the greases of this
invention are the simple metal soaps. By simple metal
soaps is meant the substantially stoichiometrically neutral
metal salts of fatty acids. By substantially
stoichiometrically neutral is meant that the metal salt
contains from about 90o to about 110% of the metal required
to prepare the stoichiometrically neutral salt, preferably
from about 95o to about 105%, more preferably from about
99o to about 101%.
Fatty acids are defined herein as carboxylic acids
containing from about 8 to about 24, preferably from about
12 to about 18 carbon atoms. The fatty acids are usually
monocarboxylic acids. Examples of useful fatty acids are
capric, palmitic, stearic, oleic and others. Mixtures of
acids are useful. Preferred carboxylic acids are linear;
that is they are substantially free of hydrocarbon
branching. By substantially free of hydrocarbon branching
means that no more than one hydrocarbon substituent (e. g.,
methyl, ethyl, etc.) occurs for each 6 carbon atoms in a
linear chain.
Particularly useful acids are the hydroxy-substituted
fatty acids such as hydroxy stearic acid wherein one or
more hydroxy groups may be located at positions internal to
the carbon chain, such as 12-hydroxy-, 14-hydroxy-etc.
stearic acids.
21026gp
_g_
While the soaps are fatty acid salts, they need not
be, and frequently are not, prepared directly from fatty
acids. The typical grease-making process involves
saponification of a fat which is often a glyceride or of
other esters such as methyl or ethyl esters of fatty acids,
preferably methyl esters, which saponification is generally
conducted in situ in the base oil making up the grease.
Whether the metal soap is prepared from a fatty acid
or an ester such as a fat, greases are often prepared in a
grease kettle, forming a mixture of the base oil, fat,
ester or fatty acid and metal-containing reactant to form
the soap in-situ. Continuous processes are also available.
Additives for use in the grease may be present or added
during base grease manufacture, but are often added
following formation of the base grease.
The metals of the metal soaps are typically alkali
metals, alkaline earth metals and aluminum. For purposes
of cost and ease of processing, the metals are incorporated
into the thickener by reacting the fat, ester or fatty acid
with basic metal containing reactants such as oxides,
hydroxides, carbonates and alkoxides (typically lower
alkoxides, those containing from 1 to 7 carbon atoms in the
alkoxy group). The soap may also be prepared from the
metal itself although many metals are either too reactive
or insufficiently reactive with the fat, ester or fatty
acid to permit convenient processing.
Preferred metals are lithium, sodium, calcium,
magnesium, barium and aluminum. Especially preferred are
lithium, sodium and calcium; lithium is particularly
preferred.
Preferred fatty acids are stearic acid, palmitic acid,
oleic and their corresponding esters, including glycerides
(fats). Hydroxy-substituted acids and the corresponding
esters, including fats, are particularly preferred.
CA 02102650 2002-10-17
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These and other thickening agents are described in US
Patent Nos. 2,197,263; 2,564,561 and 2,999,066, the
aforementioned NLGI Lubricating Grease Guide, and the
aforementioned article by Witte, in Lubrication.
Complex greases, e.g., base greases containing metal
soap-salt complexes such as metal soap-acetates, metal
soap- dicarboxylates, etc. are not simple metal soap
thickened greases as defined herein.
The phosphorus and boron containing compositions
employed in the grease compositions of this invention are
prepared by reacting a combination of (A) boron compounds
and (B) phospholipids. The combination may also include
(C) an amine, (D) an acylated nitrogen compound, (E) a
carboxylic ester, (F) Mannich reaction products, (G) a
basic nitrogen containing polymer, or (H) a basic or
neutral metal salt of an organic acid provided that when
the acylated nitrogen compound (D) has a substituent with
at least an average of forty carbon atoms, then the boron
compound (A) is reacted with the phospholipid (B) to form
an intermediate and the intermediate is reacted with (D).
These reaction products are useful as additives for oil-
based lubricants, including greases. These materials act
as anti-wear, extreme pressure and friction modifying
agents. In simple metal soap thickened oil-based greases
these products, when employed in sufficient amounts in the
grease, also increase the dropping point of the base
grease.
Phospholipids, sometimes referred to as phosphatides
and phospholipins, are lipids which contain a phosphoric
acid or derivative thereof. Glycerophospholipids, have
been referred to as phosphatides and phosphoglycerides, are
any glycerophosphoric acid or derivative thereof with one
or two acyl, alkenyl or alkyl groups attached to a glycerol
.r 21o2s~0
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residue. These materials may be prepared synthetically or
may be derived from natural sources. Natural sources that
produce phospholipids are commonly seeds as well as animal
products such as eggs.
As used herein, the term "hydrocarbyl" or "hydrocarbyl
group" denotes a group having a carbon atom directly
attached to the remainder of the molecule and having
predominantly hydrocarbon character within the context of
this invention. Thus, the term "hydrocarbyl" includes
hydrocarbon, as well as substantially hydrocarbon groups.
Substantially hydrocarbon describes groups, including
hydrocarbon based groups which contain non-hydrocarbon
substituents, or non-carbon atoms in a ring or chain which
do not alter the predominantly hydrocarbon nature of the
group.
Hydrocarbyl groups can contain up to three, preferably
up to two, more preferably up to one, non-hydrocarbon
substituent, or non-carbon heteroatom in a ring or chain,
for every ten carbon atoms provided this non-hydrocarbon
substituent or non-carbon heteroatom does not significantly
alter the predominantly hydrocarbon character of the group.
Those skilled in the art will be aware of such heteroatoms,
such as oxygen, sulfur, phosphorus and nitrogen, or
substituents, which include, for example, hydroxyl, halo
(especially chloro and fluoro), alkyoxyl, alkyl mercapto,
alkyl sulfoxy, etc.
Examples of hydrocarbyl groups include, but are not
necessarily limited to, the following:
(1) hydrocarbon groups, that is, aliphatic (e. g.,
alkyl or alkenyl), alicyclic (e. g., cycloalkyl,
cycloalkenyl) groups, aromatic groups (e. g., phenyl,
naphthyl), aromatic-, aliphatic- and alicyclic-substituted
aromatic groups and the like as well as cyclic groups
wherein the ring is competed through another portion of the
-21o2s~o
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molecule (that is, for example, any two indicated groups
may together form an alicyclic radical);
(2) substituted hydrocarbon groups, that is, those
groups containing non-hydrocarbon containing substituents
or atoms other than carbon attached to the hydrocarbon
group which, in the context of this invention, do not
significantly alter the predominantly hydrocarbon
character; those skilled in the art will be aware of such
groups (e. g., halo (especially chloro and fluoro), hydroxy,
alkoxy, mercapto, alkylmercapto, vitro, nitroso, sulfoxy,
etc.):
(3) hetero atom containing groups, that is, groups
which will, while having a predominantly hydrocarbon
character within the context of this invention, contain
heteroatoms in a ring or chain otherwise composed of carbon
atoms. Suitable heteroatoms will be apparent to those of
ordinary skill in the art and include, for example, sulfur,
oxygen, nitrogen and phosphorus. Such groups as, e.g.,
pyridyl, furyl, thienyl, imidazolyl, etc. are
representative of heteroatom containing cyclic groups.
Typically, no more than about 2, preferably no more
than one, non-hydrocarbon substituent, or heteroatom in a
chain or ring, will be present for every ten carbon atoms
in the hydrocarbyl group. Usually, however, the
hydrocarbyl groups are purely hydrocarbon and are
substantially free of non-hydrocarbon groups, substituents
or heteroatoms.
Unless indicated otherwise, hydrocarbyl groups may be
saturated or unsaturated. Saturated groups include those
which are substantially saturated. By substantially
saturated it is meant that the group contains no more than
one carbon-to-carbon unsaturated bond, olefinic
unsaturation, for every ten carbon-to-carbon bonds present.
Often, they contain no more than one carbon-to-carbon non-
aromatic unsaturated bond for every 50 carbon-to-carbon
- 21o2s5o
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bonds present. Frequently, hydrocarbyl groups are
substantially free of carbon to carbon unsaturation. It is
to be understood that, within the context of this
invention, aromatic unsaturation is not normally considered
to be olefinic unsaturation. That is, aromatic groups are
not considered as having carbon-to-carbon unsaturated
bonds.
(A) Boron Compounds
The grease compositions of this invention comprise
compositions prepared by reacting a combination of (A) a
boron compound and (B) a phospholipid. The boron compounds
include boron oxide, boron oxide hydrate, boron trioxide,
boron trifluoride, boron tribromide, boron trichloride,
boron acids such as boronic acid (i.e., alkyl-B(OH)Z or
aryl-B(OH)2), including methyl boronic acid, phenyl-boronic
acid, cyclohexyl boronic acid, p-heptylphenyl boronic acid
and dodecyl boronic acid, boric acid (i.e., H3B03),
tetraboric acid (i.e. , HZB40~) , metaboric acid (i.e. , HB02) ,
boron anhydrides, boron amides and various esters of such
boron acids. The use of complexes of boron trihalide with
ethers, organic acids, inorganic acids, or hydrocarbons is
a convenient means of introducing the boron reactant into
the reaction mixture. Such complexes are known and are
exemplified by boron-trifluoride-triethyl orthoester, boron
trifluoride-phosphoric acid, boron trichloride-chloroacetic
acid, boron tribromide-dioxane, and boron trifluoride-
methyl ethyl ether complexes.
The boron acid esters include especially mono-, di-,
and tri-organic esters of boric acid with alcohols or
phenols such as, e.g., methanol, ethanol, propanol,
1-octanol, benzyl alcohol, ethylene glycol, glycerol,
Cellosolve, and phenol. Lower alcohols, 1,2-glycols, and
1,3-glycols, i.e., those having less than about 8 carbon
atoms are especially useful for preparing the boric acid
esters for the purpose of this invention. Methods for
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preparing the esters of boron acid are known and disclosed
in the art (such as "Chemical Reviews," pp. 959- 1064, Vol.
56).
(B) Phosoholipids
The phospholipids (B) of the present invention may be
any lipid containing a phosphorus derivative, such as a
phosphoric acid or ester, such as lecithin or cephalin,
preferably lecithin or derivatives thereof. Examples of
phospholipids include phosphatidylcholine, phospha-
tidylserine, phosphatidylinositol, phosphatidyl-
ethanolamine, phosphotidic acid and mixtures thereof.
Preferably, the phospholipids are glycerophos-pholipids,
more preferably, glycero derivatives of the above list of
phospholipids. Typically, the glycerophospholipids have
one or two acyl, alkyl or alkenyl groups on a glycerol
residue. The alkyl or alkenyl groups generally contain
from about 8 to about 30 carbon atoms, preferably 8 to
about 25, more preferably 12 to about 24. Example of these
groups include octyl, dodecyl, hexadecyl, octadecyl,
docosanyl, octenyl, dodecenyl, hexadecenyl and octadecenyl.
The acyl groups on the glycerophospholipids are
generally derived from fatty acids. Fatty acids are acids
having from about 8 to about 30 carbon atoms, preferably
about 12 to about 24, more preferably about 12 to about 18.
Examples of fatty acids include myristic, palmitic,
stearic, oleic, linoleic, linolenic, arachidic, arachidonic
acids, or mixtures thereof, preferably stearic, oleic,
linoleic, and linolenic acids or mixtures thereof.
In the present invention, derivatives of phospholipids
may also be used. Derivatives of phospholipids may be
acylated or hydroxylated phospholipids. For instance,
lecithin as well as acylated and hydroxylated lecithins may
be used in the present invention. Acylated lecithins may
be prepared by reacting an acylating agent with a lecithin.
Acylating agents include acetic acid. An example of an
CA 02102650 2002-10-17
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acylated lecithin is Thermole ~ 200 acylated Soya lecithin
available from Ross & Rowe, Inc. of Decatur, Illinois.
Hydroxylated lecithins may also be used. Hydroxylated
lecithins may be prepared by acidic or enzymatic
hydrolysis. An example of hydroxylated lecithins is
Thermole ~1018 hydroxylated lecithin available from Ross &
Rowe, Inc.
Phospholipids may be prepared synthetically or derived
from natural sources. Synthetic phospholipids may be
prepared by methods known to those in the art. Naturally
derived phospholipids are extracted by procedures known to
those in the art. Phospholipids may be derived from animal
or vegetable sources. The animal sources include fish,
fish oil, shellfish, bovine brain or any egg, preferably
chicken eggs. Vegetable sources include rapeseed,
sunflower seed, peanut, palm kernel, cucurbit seed, wheat,
barley, rice, olive, mango, avocado, palash, papaya,
jangli, bodani, carrot, soybean, corn, and cottonseed, more
preferably soybean, corn, sunflower and cottonseed.
Phospholipids may be derived from microorganisms, including
blue-green algae, green algae, bacteria grown on methanol
or methane and yeasts grown on alkanes.
A useful phospholipid is derived from sunflower seeds.
The phospholipid typically contains from about 35 to about
60% phosphatidylcholine, from about 20 to about 35%
phosphatidylinositol, from about 1 to about 25%
phosphatidic acid and from about 10 to about 25%
phosphatidylethanolamine, wherein the percentages are by
weight based on the total phospholipids. The fatty acid
content is typically about 20-30% by weight palmitic acid,
from about 2-10% by weight stearic acid, from about 15-25%
by weight oleic acid and from about 40-55% by weight
linoleic acid. In one embodiment, the phospholipid is
derived from high oleic content sunflower seeds. These
seeds typically produce phospholipids having oleic content
CA 02102650 2002-10-17
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greater than about 75%, preferably about 80%, more
preferably about 85%. The fatty acid content of
phospholipids derived from high oleic sunflower seeds
generally range from about 3.5-4.5% palmitic acid, about
3.0-5.5% stearic acid, about 75-95% oleic acid and about 5-
15% linoleic acid. Generally, the phospholipid is derived
from a meal produced from high oleic content sunflower
seeds. The meal is available commercially under the
tradename TRISUN~ high oleic sunflower meal available from
SVO Enterprises, 35585-B Curtis Boulevard, Eastlake, Ohio
44095.
In one embodiment, phospholipids included in the
present invention are represented by one of the formulae
H2C-O-C ( O ) -R~ HZc-o-c ( o ) -R~
HC-O-C(O)-R~ HC-O-C(0)-R~
H2 -OP ( 0 ) -0' HZC-OP ( O ) -OR3
~ i
ORZ and OH
or mixtures thereof, wherein each R~ is independently a
hydrocarbyl group and each RZ is independently selected from
-CHZCH2N+(CH3)3, -CH2CHZN'H3, -CHZCH(N+H3)COOH, or, mixtures
thereof, and each R3 is independently -C6H6 (OH) 6, hydrogen or
mixtures thereof. Preferably each R is independently an
alkyl, alkenyl or acyl group which have been described
above.
Phospholipids and lecithins are described in detail in
Encyclopedia of Chemical Technology, Kirk and Othmer, 3rd
Edition, in "Fats and Fatty Oils", Volume 9, pages 795-831
and in "Lecithins", Volume 14, pages 250-269. -
21o2s50
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In one embodiment, the combination, used to prepare
the compositions of the present invention, further
comprises (C) at least one amine, (D) an acylated nitrogen-
containing compound, (E) a carboxylic ester, (F) a Mannich
reaction product or (G) a neutral or basic metal salt of an
organic acid provided that when the acylated nitrogen
compound (D) has a substituent with at least an average of
forty carbon atoms, then the boron compound (A) is reacted
with the phospholipid (B) to form an intermediate and the
intermediate is reacted with (D).
(C) Amines
The amines include ammonia, monoamines or polyamines.
The monoamines generally contain from 1 to about 24 carbon
atoms, preferably 1 to about 12, and more preferably 1 to
about 6. Examples of monoamines useful in the present
invention are substantially hydrocarbon-based amines which
may be primary amines, secondary amines and tertiary
amines.
In another embodiment, the monoamine may be a hydroxy
hydrocarbyl amine. Typically, the hydroxyhydrocarbylamines
are primary, secondary or tertiary alkanolamines or
mixtures thereof . Such amines can be represented by the
formulae:
HZN-R' OH,
H
N R'- OH ,
R4~
and
R4
\ N R'- OH
3 5 R4~
210265p
-18-
wherein each R4 is independently a hydrocarbyl group of one
to about eight carbon atoms or hydroxyhydrocarbyl group of
two to about eight carbon atoms, preferably one to about
four, and R' is a divalent hydrocarbyl group of about two
to about 18 carbon atoms, preferably two to about four.
The group -R'-OH in such formulae represents the
hydroxyhydrocarbyl group. R' can be an acyclic, alicyclic
or aromatic group. Typically, R' is an acyclic straight or
branched alkylene group. Where two R groups are present in
the same molecule they can be joined by a direct
carbon-to-carbon bond or through a heteroatom (e. g.,
oxygen, nitrogen or sulfur) to form a 5-, 6-, 7- or
8-membered heterocyclic ring structure. Typically,
however, each R group is independently a methyl, ethyl,
propyl, butyl, pentyl or hexyl group.
The hydroxyhydrocarbylamines can also be an ether N-
(hydroxyhydrocarbyl)amine. These are hydroxypoly(hydro-
carbyloxy) analogs of the above-described hydroxy amines
(these analogs also include hydroxyl-substituted
oxyalkylene analogs). Such N-(hydroxyhydrocarbyl)amines
can be conveniently prepared by reaction of epoxides with
the aforedescribed amines and can be represented by the
formulae:
HzN-(R'O)X H,
H
\ N (R'O)X H,
R4~
and
R4
\/ N (R'O)X H
3 5 R4/
i
21o2s50
-19-
wherein x is a number from about 2 to about 15 and R4 and R'
are as described above. R4 may also be a hydroxypoly(hydro-
carbyloxy) group.
The amine may also be a polyamine. The polyamine may
be aliphatic, cycloaliphatic, heterocyclic or aromatic.
Examples of the polyamines include alkylene polyamines,
hydroxy containing polyamines, arylpolyamines, and
heterocyclic polyamines.
Alkylene polyamines are represented by the formula
HN-(Alkylene-N)~RS
R5
wherein n has an average value between about 1 and about
10, preferably about 2 to about 7, more preferably about 2
to about 5, and the "Alkylene" group has from 1 to about 10
carbon atoms, preferably about 2 to about 6, more
preferably about 2 to about 4. R5 is independently
preferably hydrogen; or an aliphatic or hydroxy-substituted
aliphatic group of up to about 30 carbon atoms. Preferably
RS is defined the same as R4.
Higher homologs obtained by condensing two or more of
the alkylene amines are similarly useful as are mixtures of
two or more of the polyamines.
Ethylene polyamines, such as some of those mentioned
above, are useful. Such polyamines are described in detail
under the heading Ethylene Amines in Kirk Othmer's
"Encyclopedia of Chemical Technology", 2d Edition, Vol. 7,
pages 22-37, Interscience Publishers, New York (1965). Such
polyamines are most conveniently prepared by the reaction
of ethylene dichloride with ammonia or by reaction of an
ethylene imine with a ring opening reagent such as water,
ammonia, etc. These reactions result in the production of
a complex mixture of polyalkylenepolyamines including
CA 02102650 2002-10-17
-20-
cyclic condensation products such as the aforedescribed
piperazines. Ethylene polyamine mixtures are useful.
Other useful types of polyamine mixtures are those
resulting from stripping of the above-described polyamine
mixtures to leave as residue what is often termed
"polyamine bottoms". In general, alkylene polyamine
bottoms can be characterized as having less than 2%,
usually less than 1% (by weight) material boiling below
about 200°C. A typical sample of such ethylene polyamine
bottoms obtained from the Dow Chemical Company of Freeport,
Texas designated "E-100" has a specific gravity at 15.6°C
of 1.0168, a percent nitrogen by weight of 33.15 and a
viscosity at 40°C of 121 centistokes. Gas chromatography
analysis of such a sample contains about 0.93% "Light Ends"
(most probably diethylenetriamine), 0.72% triethylene
tetraamine, 21.74% tetraethylene pentaamine and 76.61%
pentaethylene hexamine and higher (by weight). These
alkylene polyamine bottoms include cyclic condensation
products such as piperazine and higher analogs of
diethylenetriamine, triethylenetetramine and the like.
Another useful polyamine is a condensation reaction
product between at least one hydroxy compound with at least
one polyamine reactant containing at least one primary or
secondary amino group. The hydroxy compounds are prefera-
bly polyhydric alcohols and amines. Polyamine reactants,
which react with the polyhydric alcohol or amine to form
the condensation products or condensed amines, are
described above. Preferably the hydroxy compounds are
polyhydric amines.
The amine condensates and methods of making the same
are described in US Patent 5,053,152.
In another embodiment, the amine is a polyalkene-
substituted amine. These polyalkene-substituted amines are
CA 02102650 2002-10-17
-21-
well known to those skilled in the art. These amines are
disclosed in U.S. patents 3,275,554; 3,438,757; 3,454,555;
3,565,804; 3,755,433; and 3,822,289.
SDL Ac~lated Nitro4en-Containincr Compounds
The combination may also include an acylated nitrogen-
containing compound. The acylated nitrogen-containing
compounds include reaction products of hydrocarbyl-
substituted carboxylic acylating agents such as substituted
carboxylic acids or derivatives thereof. These compounds
include imides, amides, amidic acid or salts, heterocycles
(imidazolines, oxazolines, etc.), and mixtures thereof. In
one embodiment, these compounds are useful as dispersants
in lubricating compositions and have been referred to as
nitrogen-containing carboxylic dispersants.
The conditions, i.e., temperature, agitation,
solvents, and the like, for reacting an acid reactant with
a polyalkene, are known to those in the art. Examples of
patents describing various procedures for preparing useful
acylating agents include U.S. Patents 3,215,707 (Rense):
3,219,666 (Norman et al); 3,231,587 (Rense): 3,912,764
(Palmer); 4,110,349 (Cohenl: and 4,234,435 (Meinhardt et
al); and U.K. 1,440,219.
EEL Carboxylic Ester
In another embodiment, the combination, which forms
the compositions employed in the grease compositions of the
present invention, may also include a carboxylic ester.
These compounds are prepared by reacting at least one of
the above described hydrocarbyl-substituted carboxylic
acylating agents with at least one organic hydroxy
compound. In another embodiment, the ester dispersant is
prepared by reacting the acylating agent with the above-
CA 02102650 2002-10-17
-22-
described hydroxyamine. The carboxylic ester may be
further reacted with any of the above-described amines.
The preparation of useful carboxylic ester dispersant
is described in U.S. Patents 3,522,179 and 4,234,435.
The carboxylic esters may be further reacted with at
least one of the above described amines and preferably at
least one of the above described polyamines. These
nitrogen-containing carboxylic ester dispersant
compositions are known in the art, and the preparation of
a number of these derivatives is described in, for example,
U.S. Patents 3,957,854 and 4,234,435.
The carboxylic esters and methods of making the same
are known in the art and are disclosed in U.S. Patents
3,219,666, 3,381,022, 3,522,179 and 4,234,435.
(F~ Mannich Reaction Products
The combination may also include a Mannich product.
Mannich products are formed by the reaction of at least one
aldehyde, at least one of the above described amine and at
least one hydroxyaromatic compound. The reaction may occur
from room temperature to 225°C, usually from 50° to about
200°C (75°C-125°C most preferred), with the amounts of
the
reagents being such that the molar ratio of hydroxyaromatic
compound to aldehyde to amine is in the range from about
(1:1:1) to about (1:3:3).
Mannich products are described in the following
patents: U.S. Patent 3,980,569; U.S. Patent 3,877,899; and
U.S. Patent 4,454,059.
(G) Basic Nitrogen Containing Polymers
The reaction product may also include a basic
nitrogen-containing polymer. These polymers include
polymer backbones which are functionalized by reacting with
CA 02102650 2002-10-17
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an amine source. A true or normal block copolymer or a
random block copolymer, or combinations of both are
utilized.
It is often preferred that these block copolymers, for
reasons of oxidative stability, contain no more than about
5 percent and preferably no more than about 0.5 percent
residual olefinic unsaturation on the basis of the total
number of carbon-to-carbon covalent linkages within the
average molecule. Such unsaturation can be measured by a
number of means well known to those of skill in the art,
such as infrared, NMR, etc. Most preferably, these
copolymers contain no discernible unsaturation, as
determined by the aforementioned analytical techniques.
The amine source may be an unsaturated amine compound
or an unsaturated carboxylic reagent which is capable of
reacting with an amine. The unsaturated carboxylic
reagents and amines are described above.
Examples of the basic nitrogen-containing polymers are
given in the following references:
EP 171,16? 3,687,905
3,687,849 4,670,173
3,756,954 4,320,012
4,320,019
SH)~ A Neutral or Basic Metal Salt
The combination may also include neutral, or basic
metal salts. Preferably, the salts include alkali,
alkaline earth or transition metal salts. Examples of
metals of the salts include sodium, potassium, magnesium,
calcium, barium, titanium, manganese, cobalt, nickel,
copper, zinc, preferably sodium, potassium, calcium,
magnesium, copper and zinc, more preferably- zinc or
magnesium cation, most preferably zinc.
In one embodiment, the salts are formed from metal
compounds which are generally basic salts of metals.
.. _ 21o2s~0
-24-
Generally, the metal compounds are oxides, hydroxides,
chlorides, carbonates, phosphorus acid (phosphonic or
phosphoric) salts, and sulfur acid (sulfuric or sulfonic)
salts of the metal cations listed above.
Neutral salts are those wherein the number of
equivalents of metal and acidic compound are substantially
the same. By substantially the same is meant that the
amount of metal present ranges from about 0.9 to about 1.1
equivalents of metal per equivalent of acid, preferably
from about 0.95 to about 1.05 equivalents of metal per
equivalent of acid, more preferably from about 0.99 to
about 1.01 equivalents of metal per equivalent of acid.
In another embodiment, the salts are basic salts,
generally referred to as overbased salts. Overbased
materials are single phase, homogeneous Newtonian systems
characterized by a metal content in excess of that which
would be present according to the stoichiometry of the
metal and the particular organic compound reacted with the
metal.
The amount of excess metal is commonly expressed in
metal ratio. The term "metal ratio" is the ratio of the
total equivalents of the metal to the equivalents of the
acidic organic compound. A neutral metal salt has a metal
ratio of one. A salt having 4.5 times as much metal as
present in a normal salt will have metal excess of 3.5
equivalents, or a ratio of 4.5. The basic salts of the
present invention have a metal ratio greater than about
1.1, preferably about 1.5, more preferably about 3 up to
about 40, preferably up to about 30, more preferably up to
about 20.
The methods for preparing the overbased materials as
well as an extremely diverse group of overbased materials
are well known in the prior art and are disclosed, for
example, in the following U.S. Patent Nos.: 2,616,904;
2,616,905; 2,616,906; 3,242,080; 3,250,710; 3,256,186:
CA 02102650 2002-10-17
-25-
3,274,135; 3,492,231; and 4,230,586. These patents
disclose processes, materials which can be overbased,
suitable metal bases, promoters, and acidic materials, as
well as a variety of specific overbased products useful in
producing the disperse systems of this invention.
The above (D) acylated nitrogen compounds, (E)
carboxylic esters, (F) Mannich products and (G) basic
nitrogen-containing polymers may be post-treated with one
or more post-treating reagents selected from the group
consisting of boron compounds (discussed above), carbon
disulfide, hydrogen sulfide, sulfur, sulfur chlorides,
alkenyl cyanides, carboxylic acid acylating agents,
aldehydes, ketones, urea, thiourea, guanidine,
dicyanodiamide, hydrocarbyl phosphates, hydrocarbyl
phosphites, hydrocarbyl thiophosphates, hydrocarbyl
thiophosphites, phosphorus sulfides, phosphorus oxides,
phosphoric acid, hydrocarbyl thiocyanates, hydrocarbyl
isocyanates, hydrocarbyl isothiocyanates, epoxides,
episulfides, formaldehyde or formaldehyde-producing
compounds with phenols, and sulfur with phenols.
The following U.S. Patents disclose posttreating
processes and posttreating reagents applicable to the
carboxylic derivative compositions of this invention: U.S.
Patent Nos. 3,087,936; 3,254,025; 3,256,185; 3,278,550;
3,282,955; 3,284,410; 3,338,832; 3,533,945; 3,639,242;
3,708,522; 3,859,318; 3,865,813; etc. U.K. Patent Nos.
1,085,903 and 1,162,436 also describe such processes.
In one embodiment, (D) through (G) are posttreated
with at least one boron compound described above. The
reaction of the compound with the boron compounds can be
effected simply by mixing the reactants at the desired
temperature, preferably between about 50°C and about 250°
C.
21o2s50
-26-
In some instances it may be 25°C or even lower. The upper
limit of the temperature is the decomposition point of the
particular reaction mixture and/or product.
The amount of boron compound used to post-treat (D)
(G) generally is sufficient to provide from about 0.1 to
about 10 atomic proportions of boron for each equivalent of
(D) through (G) such as the atomic proportion of nitrogen
or hydroxyl group. The preferred amounts of reactants are
such as to provide from about 0.5 to about 2 atomic
proportions of boron for each equivalent of nitrogen or
hydroxyl group. To illustrate, the amount of a boron
compound having one boron atom per molecule to be used with
one mole of a acylated nitrogen compound having five
nitrogen atoms per molecule is within the range from about
0.1 mole to about 50 moles, preferably from about 0.5 mole
to about 10 moles.
The phosphorus and boron containing compositions
employed in the grease compositions of the present
invention may be prepared by reacting (A) a boron compound
and (B) a phospholipid. Further, the composition may be
prepared by reacting (A) a boron compound with a mixture of
(B) a phospholipid and one of the above-described (C) an
amine, (D) an acylated nitrogen compound, (E) a carboxylic
ester, (F) a Mannich reaction product and (G) a basic
nitrogen-containing polymer or derivatives thereof. The
mixture may be simply a mixture of these components or may
be a salt or partial salt of these components. In another
embodiment, the boron and phosphorus containing composition
may be prepared by reacting (A) a boron compound with (B)
a phospholipid to form an intermediate reaction product.
The intermediate product is then reacted with one of the
above-described (C) through (H).
The boron and phosphorus containing compositions of
the present invention may be prepared by reacting (A) a
boron compound with one of the above-described (C) through
,_ ~. -- 21o2s50
-27-
(H) to form an intermediate. The intermediate is then
reacted with (B) a phospholipid provided that when the
acylated nitrogen compound (D) has a substituent with at
least an average of 40 carbon atoms, then the boron
compound (A) is reacted with the phospholipid (B) to form
an intermediate and the intermediate is reacted with (D).
When the acylated nitrogen-containing compound contains a
substituent with no more than an average of about 40 carbon
atoms, it must be understood that the acylated nitrogen-
containing compound does not have to have a substituent
with an average number of carbon atoms. The substituent
may have a specific single number of carbon atoms, e.g. 18
carbon atoms. In one embodiment, the substituent of the
acylated nitrogen compound has no more than an average of
about 30 carbon atoms. The average number of carbon atoms
is based on number average molecular weight.
The reactions usually occurs at a temperature from
about 60°C to about 200°C, about 90°C to about
150°C. The
reaction is typically accomplished in about 0.5 to about 10
hours, preferably about 2 to about 6, more preferably 4.
An inert organic diluent, such as benzene, toluene, xylene,
or mineral oil may be used.
The boron compound (A) and phospholipid (B) are
reacted at an atomic proportion of boron to phosphorus of
about (1:1) up to about (6:1), preferably about (2:1) up to
about (4:1), more preferably about (3:1).
The boron compound (A) is reacted with the mixture of
the phospholipid (B) and one or more of (C) through (H) in
an amount of one atomic proportion of boron to equivalent
of the mixture from about (1:1) to about (6:1), preferably
about (2:1) to about (4:1), more preferably (3:1). The
equivalents of the mixture are based on the combined
equivalents of phospholipid (B) based on phosphorus and
equivalents of.(C) through (H). The equivalents of (C)
through (G) are determined by the number of nitrogen atoms
x'02650
-28-
or hydroxyl groups. The equivalents of (H) are based on
base number. Base number is the amount of hydrochloric
acid expressed in terms of equivalent milligrams of
potassium hydroxide per gram of sample, required to titrate
a sample to a defined endpoint. The base number is
converted to equivalent weight by the equation: equivalent
weight = (56100/base number).
When the phospholipid (B) is reacted with a post
treated product of (C)-(H), then the phospholipid is
reacted with the post-treated product at equivalent ratio
of about (1:1) up to about (6:1), preferably about (2:1) up
to about (4:1), more preferably about (3:1). The
equivalents of the post-treated product are based on boron
atoms.
The following examples illustrate the preparation of
reaction products of a boron compound and a phospholipid.
In the following examples as well as in the claims and
specification, parts are parts by weight, temperatures are
degrees Celsius and pressure is atmospheric pressure unless
otherwise indicated.
Example 1
A reaction vessel is charged with 2195 parts (1.40
equivalents) of lecithin (a mixed phospholipid product from
Central Soya Company of Fort Wayne, Indiana, available
commercially under the tradename Centrophase (typical
analyses: %P - 1.97, %N - 0.75)), 396 parts of a 100
neutral mineral oil, and 260 parts (4.20 moles) of boric
acid. The mixture is heated to 90°C and the temperature is
maintained at 90-95°C for 0.75 hour. A vacuum is applied
and maintained at 160 millimeters of mercury for 2.25 hours
during which time the reaction temperature rises from 95°C
to 120°C and distillate is collected. The vacuum is
decreased to 50 millimeters of mercury and the reaction
temperature is held for an additional 1.25 hours at 120-
125°C (total reaction time equals 3.5 hours), while
~.~102650
-29-
collecting 151 parts of distillate. A 100 neutral mineral
oil (10 parts) is added to the residue and the residue is
cooled to 55°C and filtered through cloth. The filtrate
has 1.52% phosphorus, 0.53% nitrogen, 1.78% boron and 15%
oil.
Example 2
A reaction vessel is charged with a mixture of 2600
parts (1.66 equivalent) of lecithin and 600 parts of
toluene. Boric acid (307 parts, 4.97 moles) is added to
the mixture over 0.5 hour at 40°-60°C under nitrogen
atmosphere. The reaction mixture is heated to reflux
(130°C) while removing 180 parts of water over 4 hours. A
vacuum is applied (20 millimeters of mercury) and toluene
solvent removed while raising the reaction temperature to
110°C. The residue is filtered through diatomaceous earth.
The filtrate contains 1.78% P (1.88% theory), 0.71% N
(0.72% theory) and 2.05% B (2.10% theory).
Example 3
A reaction vessel is charged with a mixture of 800
parts (0.5 equivalent) corn lecithin (available as Corn
Goodness UB from ADM Ross and Rowe), 150 parts toluene and
141 parts of a 100 neutral mineral oil. Boric acid (104
parts (1.68 moles)) is added over 0.5 hour at 40°-60°C to
the mixture. The reaction mixture is heated to reflux
(125°-127°C) for 4 hours while removing 63 parts
distillate.
A vacuum is applied (20 millimeters of mercury) and
toluene solvent removed while raising the temperature to
120°C. The residue is filtered through diatomaceous earth.
The filtrate contains 1.55% P, 0.62% N, 1.1% B and 15% oil.
example 4
A reaction vessel is charged with 1562 parts (1
equivalent) of a lecithin of Example 1, 200 parts toluene
and 560 parts (1 equivalent) of a 40% oil solution of a
succinimide, which has 2.5% nitrogen and a total base
__ 21o2s5o
-30-
number of 65 and is prepared by reacting a polyamine with
a polyalkene succinic anhydride wherein the polyalkene has
a number average molecular weight of approximately 1000.
The mixture is heated to 50°C with nitrogen sparging at 1
scfh where 247 parts (4 moles) of boric acid are added to
the mixture over 0.25 hour. The mixture is heated to 120°C
where 25 parts of water are removed over 1.5 hours. The
reaction is held at 120°-125°C for 4.5 hours while 115
milliliters of distillate are obtained. The product is a
clear, bright, deep red color. The mixture is vacuum
stripped to 80°C and 25 millimeters of mercury. The
residue is a product which has 1.3% phosphorus (1.37%
theory), 1.07% nitrogen (1.14% theory), 1.86% boron (1.95%
theory), and 15% 100 neutral mineral oil.
Example 5
A reaction vessel is charged with 1568 parts (1
equivalent) of the lecithin of Example 1 and 200 parts of
textile spirits. The mixture is heated to 60°C where 525
parts (3 equivalents) of a borated sodium sulfonate
prepared by reacting 1 equivalent of boron with 1
equivalent of a sodium overbased alkylated benzene
sulfonate having a metal ratio of 20 and containing 36%
diluent (including 100 neutral mineral and unreacted
alkylated benzene sulfonate) is added to the mixture. The
reaction temperature is maintained at 60-70°C for 3 hours.
The reaction mixture is vacuum stripped to 80°C and 25
millimeters of mercury. The product contains 1.47%
phosphorus (1.49% theory), 3.51% sodium (2.87% theory),
1.52% boron (1.57% theory) and a specific gravity of 1.04.
Example 6
A reaction vessel is charged with 784 parts (0.5
equivalent) of the lecithin of Example 1, 124 parts (2.1
equivalents) of boric acid and 449 parts (1 equivalent) of
a calcium overbased tall oil fatty acid having a metal
ratio of 2, 58% 100 neutral mineral oil and a base number
?102650
-31-
of 125. The mixture is heated to 90°C and held for 1 hour.
The reaction mixture is heated to 120°C under 140
millimeters of mercury and the reaction is maintained at
120°C for 1 hour. The reaction mixture is cooled to 60°C
and vacuum stripped at 60°C and 40 millimeters of mercury.
The residue has 1.12% phosphorus (1.19% theory), 1.63%
calcium (1.60% theory), 1.97% boron (1.79% theory) and
specific gravity of 1.02.
Example 7
(A) A reaction vessel is charged with 389 parts (1
equivalent) of a sulfur-coupled tetrapropenyl phenol having
5% sulfur and 42% diluent as mineral oil, 200 parts of
toluene and 20 parts (0.25 equivalent) of a 50% aqueous
solution of sodium hydroxide. The mixture is stirred and
heated to 80°C where 33 parts (1.0 equivalent) of
paraformaldehyde are added to the reaction vessel over 2
minutes and held for one-fourth hour.
(B) A reaction vessel is then charged with 1569 parts
(1 equivalent) of the lecithin of Example 1 and 200 parts
of toluene., The mixture is warmed to 40°C where 185 parts
(3 equivalents) of boric acid is added to the vessel over
one-half hour with stirring. The reaction temperature is
increased to 100°C and maintained for three-fourths of an
hour. The product contains 0.63% sulfur (0.67% theory),
1.31% phosphorus (1.37% theory), 1.34% boron (1.45% theory)
and 10% 100 neutral mineral oil.
Lubricants
As previously indicated, the reaction products of a
boron compound and a phospholipid as described herein are
useful as additives for lubricants, including greases, in
which they can function as antiwear, extreme pressure
and/or friction modifying agents. Additionally, when
employed in sufficient amounts, they increase the dropping
point of oil based, simple metal soap thickened, base
greases. They can be employed in such greases based on
CA 02102650 2002-10-17
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diverse oils of lubricating viscosity, including natural
and synthetic lubricating oils and mixtures thereof.
The borated phospholipid may be incorporated into the
base grease directly or as a component of additive
concentrates, by itself or in combination with any other
known additives for oil based simple metal soap thickened
base greases which include, but are not limited to,
antioxidants, anti-wear agents, extreme pressure agents,
friction modifiers, anti-rust agents, corrosion inhibitors,
and dyes.
Antioxidants, corrosion inhibitors, extreme pressure
and anti-wear agents include but are not limited to metal
salts of a phosphorus acid, metal salts of a thiophosphorus
acid or dithiophosphorus acid; organic sulfides and
polysulfides; chlorinated aliphatic hydrocarbons;
phosphorus esters including dihydrocarbyl and
trihydrocarbyl phosphites; and molybdenum compounds.
Viscosity improvers and pour point depressants are
sometimes employed to improve the properties of the oil
from which the base grease is derived.
Viscosity improvers include but are not limited to
polyisobutenes, polymethyacrylate acid esters, polyacrylate
acid esters, diene polymers, polyalkyl styrenes, alkenyl
aryl conjugated dime copolymers, polyolefins and
multifunctional viscosity improvers.
For some very low temperature applications, the pour
point of the oil component of the base grease may be an
important consideration. Pour point depressants are
sometimes included in the lubricating oils described
herein. See for example, page 8 of "Lubricant Additives"
by C. V. Smalheer and R. Kennedy Smith (Lesius-Hiles
Company Publishers, Cleveland, Ohio, 1967).
These and other additives are described in greater
detail in U.S. Patent 4,582,618 (column 14, line 52 through
column 17, line 16, inclusive
CA 02102650 2002-10-17
-33-
The additive concentrate might contain 0.01 to 90% by
weight of the phosphorus and boron containing compositions
employed in the grease compositions of the present
invention. The boron and phosphorus containing
compositions may be present in the grease compositions of
this invention in amounts effective to provide extreme
pressure, or antiwear or lubricity properties, preferably
in amounts ranging from about 0.1% to about 20%, preferably
0.25% to about 10% by weight, most preferably about 0.5% to
about 5%. When the compositions of the present invention
are used to increase the dropping point of the base
greases, they are used in minor amounts, preferably in
amounts ranging from about 0.25% to about 10%, most
preferably from about 0.5% up to about 5% by weight of the
total grease composition.
As mentioned hereinabove, the boron- and phosphorus
containing compounds which provide increased dropping
points of metal soap thickened greases are used in minor
amounts effective to increase the dropping point of the
base grease by at least 20°C.
Preferred minimum amounts of boron and phosphorus
containing compound to employ depend to some extent upon
the additive, for example, some higher molecular weight
compounds may be needed in somewhat larger amounts to
obtain the desired effect.
It generally is not necessary to use more than about
10% by weight of the boron and phosphorus containing
compound since usually no additional benefit is obtained
and often, deteriorating performance with respect to the
dropping point or other characteristics of the grease is
observed above this treating level. More often no more
than about 5%, frequently no more than about 2% of the
boron and phosphorus containing compound is employed.
21o2s5o
-34-
Often 1% by weight is sufficient to provide a 20°C increase
in dropping point.
Thus, it is preferred to use the minimum amount of
boron and phosphorus containing additive consistent with
attaining the desired effect such as extreme pressure,
antiwear, etc. or dropping point elevation of at least
20°C.
The boron- and phosphorus- containing composition may
be present during grease formation, i.e., during formation
of the soap thickener in the oil of lubricating viscosity,
or may be added after the base grease has been prepared.
In many cases it is preferred to add the boron and
phosphorus containing composition to the preformed base
grease.
Other additives may be incorporated into the base
grease to improve performance of the grease as a lubricant.
Such other additives, including corrosion inhibitors,
antioxidants, extreme pressure additives and others useful
for improving specific performance characteristics of a
base grease, are well-known and will readily occur to those
skilled in the art.
The following examples illustrate grease compositions
of this invention. It is to be understood that these
examples are intended to illustrate the invention and are
not intended to be limiting in any way. Dropping points
are determined using ASTM Procedure D-2265. All amounts
are, unless indicated otherwise, on an oil free basis and
are by weight.
Example A
A lithium 12-hydroxystearate thickened base grease
shows a dropping point of 206°C. This is a typical simple
lithium salt thickened base grease.
Example B
A base grease is prepared by mixing 92 parts of the
base grease of Example A and 8 parts of mineral oil having
CA 02102650 2002-10-17
-35-
a kinematic viscosity of 800 Saybolt Universal Seconds
(172.6 centistokes) measured at 100°F (37.8°C). The
dropping point of this grease is 204°C.
Example C
A grease composition is prepared by blending 4% by
weight of the product of Example 1 into the grease
composition of Example B. This grease has a dropping point
of 277°C.
Example D
A grease composition is prepared by blending 2% by
weight of the product of Example 1 into the base grease of
Example B. This grease composition has a dropping point of
267°C.
Example E
A grease composition is prepared by adding to the base
grease of Example B 1% by weight of a composition prepared
according to the procedure of Example 1 and 1% by weight of
a product obtained by reacting 1000 parts of O,O' (di)-
methylamyl dithiophosphoric acid prepared by reacting about
4 moles methylamyl alcohol with 1 mole of PISS with 183
parts of propylene oxide, reacting the product obtained
thereby with 144 parts of P205 and neutralizing the acidic
product thereby with 584 parts of a tertiary alkyl primary
amine having from 11-14 carbon atoms in the tertiary alkyl
group (Primene~ 81-R, Rohm and Haas). This grease
composition has a dropping point of 272°C.
Example F
A grease composition is prepared by adding to the base
grease of Example B 1% by weight of a sulfurized
isobutylene containing about 45% sulfur and 2% by weight of
the product of Example 1. The dropping point of this
grease composition is 228.5°C.
Example G
To the grease composition of Example F is added 0.1%
by weight of Reomet 39, an oil-soluble benzotriazole
21o2s50
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derivative marketed by Ciba-Geigy. The dropping point of
this grease composition is 231°C.
Examples H-M are comparative Examples employing a
phophorus containing additive that is free of boron.
Example H-I
Grease compositions are prepared by blending into a
lithium 12-hydroxystearate base grease having a dropping
point of 207°C the indicated percentages of a mixed
phosphoric acid salt prepared by reacting 3 moles (based on
OH) of C01418 alcohol (a primary alcohol containing a
mixture of C~4, C~6 and C~8 carbon chains) with 1 mole Pz05
then reacting the acidic product obtained with 1.13
equivalents of Primene 81-R per equivalent of strong acid.
Example % by weight additive DroppinctPoint (°CZ
H 1.0 204°C
I 1.4 198°C
Examples J-L
Grease compositions are prepared by blending into a
lithium 12-hydroxystearate base grease the indicated
percentages of dibutylhydrogen phosphite ((Butyl-0)ZPHO).
Example % by weight additive Dropping Point ~(°C)
J 0.35 200°C
K 0.45 202°C
L 0.55 197°C
Example M
A grease composition is prepared by blending into the
grease of Example B, 4% by weight of the lecithin described
in Example 1. The dropping point of this grease
composition is 194°C.
21o2s5a
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Examples N-R
Examples C-G are repeated replacing the lithium 12-
hydroxy stearate base grease with the corresponding calcium
soap thickened base grease.
Examples S-T
Examples C and G are repeated replacing the lithium
12-hydroxy stearate base grease with a sodium tallowate
thickened base grease.
From the foregoing Examples it is apparent that the
use of certain boron and phosphorus containing compositions
at minimum levels provides enhanced thermal stability as
evidenced by increased dropping points compared to the base
greases without additive. It is also apparent that
phosphorus containing compounds that are substantially free
of boron do not provide any significant increase in
dropping point.
While the invention has been explained in relation to
its preferred embodiments, it is to be understood that
various modifications thereof will become apparent to those
skilled in the art upon reading the specification.
Therefore, it is to be understood that the invention
disclosed herein is intended to cover such modifications as
fall within the scope of the appended claims.
