Note: Descriptions are shown in the official language in which they were submitted.
CA 02074308 2003-O1-14
RAILROAD GREASE
CROSS REFERENCE TO RELATEI~,APPLICATIONS
This patent application is a continuation-in-part of the patent application of
John
Andrew Waynick, Ser. No. 07/590,482, filed Sep. 9, 1990, entitled "Aluminum
Soap
Thickened Steel Mill Grease," now U.S. Pat. No. 5,096,605 which is a
continuation-in-part of the patent application of John Andrew Waynick, U.S.
Pat. No.
5,000,862, issued Mar. 19, 1991, Ser. No. 07/332,509, filed Mar. 31, 1989,
entitled
"Process for Protecting Bearings in Steel Mills and Other Metal Processing
Mills."
BACKGROUND OF THE INVENTION
This invention pertains to lubricants and, more particularly, to an adhesive,
friction-reducing grease particularly effective for lubrication of the
interface between
the side of a railroad track and the wheel flanges of trains.
Lubrication of the sides of railroad tracks has been practiced by the railroad
industry for the last 50 years. Until recently, such practice was limited to
areas of the
track where curves existed. It is in such curved track that the wheel flanges
can come
into more direct contact with the track sides. The application of a lubricant
to the track
sides before the curve and the action of the train wheels to spread the
lubricant along
the track through the curved portion provides friction reduction and reduced
track and
wheel wear.
However, numerous studies done within the last ten years have shown that
significant additional benefits can be achieved if the tangent (straight) as
well as
curved track is lubricated. The reasons for this are not completely understood
but are
believed, at least in part, to be due to a less than perfect parallel
alignment of wheels
and track which exists on most if not all trains.
One benefit of increased lubrication of railroad track sides is further
reduction
in frictional drag at the track side/wheel flange interface. Reports from
various
railroads indicate that this additional friction reduction can result in
between 10% and
30% fuel savings. Other benefits of increased lubrication of railroad track
sides
include reduced track and wheel wear, and reduced noise levels in urban
settings.
There are three common methods to apply the lubricant to the railroad track
side. The oldest method is the wayside lubricator. This device comprises a
sealed
reservoir of lubricant near the track. Connected to this reservoir is a length
of piping to
convey the lubricant to some manner of nozzle or other applicator on the track
side.
When a train begins to pass over that
~c.~3i~'
portion of track, a sensor is activated and lubricant from the reservoir is
pumped out the nozzle. Sack set of wheels commonly gets a shot of lubricant
which is then spread down the track. The wayside lubricator was the main
method of application when only curved track was being lubricated. The
disadvantages of wayside lubricators are that they are usually in remote areas
and therefore require special trips by service personnel when malfunctions
occur. Because they are constantly exposed to the elements, malfunctions
occur frequently.
The second method of application of lubricant to the railroad track side
1 0 is by a special mobile applicator. This mobile applicator can be a two-
wheeled trailer type apparatus connected to the back of a rail inspector's
truck.
Sometimes the apparatus is mounted in the payload area of the rail
inspector's truck. In either case, as the rail inspector drives his truck down
the
railroad track inspecting the rails for excessive wear or fatigue failures,
the
1 5 apparatus applies the lubricant to the track sides and also assists in
spreading
it down the track. While this method does not suffer from the disadvantages of
the wayside lubricator, it does require special equipment which is utilized on
trips not made by railroad trains.
The third method of application of lubricant to the railroad track is by
2 0 using equipment that is on board the train locomotive itself. The
components
of the on-board lubricator are in the most general sense similar to that of
the
wayside lubricator: a lubricant reservoir, application noazles, and piping to
convey the lubricant from the reservoir to the nozzles. Each nozzle is
positioned in near proximity to one of the locomotive's wh~el flanges and is
2 5 designed to provide a spray pattern of lubricant to the wheel flange as
the train
is m~ving. The ~rheeB flange spreads the lubricant to the track side and down
the track as the train moves. Most frequently, when the on-board lubrication
system is operating, a metered amount of lubricant is fed to the nozzle per
length of track. Some more advanced on-board lubrication systems also have
3 0 a curve-sensing device. This device detects when the train is traveling
over a
curved portion of track and automatically increases the amount of lubricant
being metered out to provide additions! friction reduction and wear
protection.
A,fthough on-hard lubricators are a capital investment for each locomotiv~,
they have many advantages not realized by other methods and era rapidly
3 5 growing as a method of choice for application of lubricant on railroad
track
sides.
-
Given a particular method of application to the sides of the railroad
track, the level of benefits achieved will depend on the properties of the
lubricant used. Several properties are desirable for a high performance
railroad track/wheel flange lubricant. The lubricant should have sufficient
pumpability and mobility so that it is easily applied by the nozzle. Once
applied the lubricant should transfer from the wheel flange to the rail side
without fling-off. The lubricant should have excellent adherence properties
which allow it to remain on the rail side, ba spread far down the track, and
not
migrate to the top of the rail. Once on the rail, the grease should resist
being
1 0 washed off by water (rain) so that several trains can pass over it before
re-
lubrication is required. This combination of adhesion, spreadability, and
water
resistance as they apply to a railroad track/wheel flange grease is sometimes
referred to as retentivity. The railroad track/wheel flange lubricant should
have
minimal oil separation (bleed) characteristics. It is believed that the
contact
1 S pressure between the rail side and the wheel flange can become as high as
one-half million pounds per square inch. Acxordingly, the railroad track/wheel
flange lubricant should have excellent extreme pressure (EP) and antiwear
(A1M) properties. Th~ lubricant should most desirably provide this EP/AW
characteristic without being corrosive to ferrous metals. Instantaneous
contact
2 0 temperatures at the railroad track/whe~I flange interface have been
estimated
in excess of 350°F. Any lubricant which is corrosive to the rail
surface at such
temperatures may, over many train passes and long periods of lima, promote
corrosive fatigu~ of the rail. This is particularly serious since rail fatigue
is a
major cause of train derailments. Finally, since this lubricant is being
applied
2 S on railroad trades which.network the entire country, the lubricant should
be
environmentally scceptsb!s.
Over th~ years, a vari~ty of lubricants have been used and suggested
for uss~ to lubricate the railroad tracklwheel flange interface. Most of these
lubricants have bg~n greases, due in part to their superiority of application
3 0 without fling-off. Th~se greases are typified by th~ weiB known group of
greases which comprises a thickener of simpl~ fatty acid soap salts of calcium
or lithium and further ~mpris~ graphite andlor molybdenum disulfide as
extreme pressure and antiwear additives. Also suggested are stable mineral
oil (base oil) dispersions of graphit~ and/or molybdenum disulfide such as
3 S those found in V.S. Patent tdo. 4,634,545.
These products, orohile having provided a certain degr~~ of success, do
hav~ shortcomings with respect to the abov~-mentioned properties. In
_3_
particular, greases or mineral oil dispersions which contain graphite are
often
limited in their level of EP/AW performance. This is because the graphite most
commonly used in such products is a material commonly known.as
amorphous graphite. The term amorphous graphite is technically a misnomer
since such material is virtually devoid of the extended laminar, hexagonal
carbon arrays necessary for true graphitic structure. Amorphous graphite is
usually about 75% carbon and about 25% abrasive oxides of silicon,
aluminum, and iron. Instead of providing high levels of EP/AW performance,
amorphous graphite is extremely abrasiv~. The main reason for its
1 0 widespread use in lubricants appears to b~ its very low cost. More
expensive
synthetic graphites or highly pure natural graphites (with true graphitic
structure) are superior to amorphous graphite as lubricity additives. However,
even these mat~rials hav~ significant levels of abrasive oxides of silicon,
aluminum, and iron. Furthermore, although these graphites are fairly effective
1 5 as AW additives under low loads, they are limited in th~ir ability to
perform
under high loads. Another disadvantage of graphites is their corrosivity at
high
temperatur~. The reason for this is most likely due to the presenc~ of
adsorbed, corrosive impuriti~s. !n any event, even purified graphite will
exhibit
this distinct corrosive nature, as easily demonstrated by high temperature
~ 0 copp~r corrosion testing of the corresponding lubricant.
Railroad track/wheel flange lubricants containing molybdenum disulfide
suffer from similar d~ficiencies. Molybdenum disulfide, in its purified form
is
relatively fr~e from abrasive contaminants and is generally superior to
graphite
as a w~ar prevention additive at low loading I~vels. However, at high loads,
2 5 the p~rformance of molybdenum disulfid~ rapidly decreases. The sulfur
cont~nt of molybd~num disulfide makes it quite corrosive in lubricants at
temperatur~s such as 350°F Also, the fundam~ntal presenc~ of the heavy
m~ta9 molybd~snum makes such lubricants increasingly unattractive from an
environm~ntal viewpoint because it can be harmful to plant lif~ and animals.
3 0 Finally, molybd~num disulfide is very expensive, making its us~ in
lubricants
costly.
It is, therefor~, d~sirab!~ to provide an improved railroad track/wheel
flang~ gr~ase which ov~rcomes many, if not all, of the prec~ding problems.
.4.
SUMt~AR~f OF THF IiVVENTinN
An improved adherent, friction-reducing grease is provided which is
particularly useful as a high performance railroad track/wheel flange
lubricant.
The lubricant provides good friction reduction and provides excellent
adherence, the exact amount of which can be controlled by variations in the
levels of the components of its novel composition. The water resistance is
also
excellent, in direct accordance with its adherence properties. The novel
adherent, friction-reducing grease has outstanding extreme pressure and
wear resistance properties which are, advantageously, provided without
1 0 imparting any corrosivity, even when the lubricant is exposed to ferrous
or
non-ferrous metals at high temperatures, e.g., at X50°F for extended
periods
of time. Advantageously, the novel railroad (railway) track grease has
superior
retentivity and mobility qualities and spreads easily down the railroad track
with no substantial fling-off or migration to the top of the railroad track.
1 5 Desirably, the novel grease is non-abrasive, has excellent (low) oil
separation
properties, good pumpability, and is environmentally safe. This latter
characteristic is achieved because the extreme pressure and wear resistance
components of the novel grease are food grade materials. Since none of the
materials in the novel grease have any substantial color, the final grease
will
2 0 be neutral in color unless dyed to a specific color. In any event, the
novel
grease of this invention will not have the unsightly pitch black color of
lubricants which contain graphite or molybdenum disulfide.
In a recent test by an American railroad, using an actual railroad train
equipped with a special instrumentation car, the novel grease provided
2 5 excellent friction-reducing properties when compared with three graphite-
containing lubricants, three molybdenum disulfide-containing lubricants, and
one lubricant containing oil-soluble extreme pressure and wear resistanc~
additives. Further testing showed that all the graphite-containing lubricants
exhibited accelera~t~d wear to the on-board lubricator system. The novel
3 0 grease of this invention did not show any such tendency and substantially
avoids molybdenum disulfide-containing compounds and abrasive oxides of
sili~n, aluminum and iron, as well as substantial amounts of amorphous
graphite, synthetic graphites and (highly pure) natural graphites.
In addition to being used as an effective railroad track~wheel flange
~ 5 lubricant, the novel grease of this invention can also be used as a
lubricant for
the traction motor drive of train locomotives.
.5.
The novel lubricating grease has: (a) a substantial proportion of a base
oil, (b) a thickener, such as polyurea, triurea, biurea, calcium soap
thickener
(simple or complex), aluminum soap thickener (simple or complex), or
combinations thereof, (c) a sufficient amount of an additive package to impart
extreme pressure antiwear properties to the grease, and (d) a sufficient
amount of an adhesive polymer. The polymeric additive cooperates and is
compatible (non-intertering) with the extreme pressure antiwear additive
package to provide the proper balance of railroad track retentivity, friction
reduction, wear reduction, mobility, and pumpability while also maintaining an
1 0 environmentally safe product.
In another form the novel lubricating grease has: (a) a substantial
proportion of a base oil, (b) a sufficient amount of an additive package to
impart extreme pressure antiwear properties to the grease, (c) a sufficient
amount of an adhesive polymer, and (d) a dropping point elevating additive
1 5 comprising a minor amount of polyurea, triurea, biurea, calcium complex
soap,
bentonite or other clay type material, fumed silica or other appropriately
modified silica materials, or combinations thereof. In this form, the
thickener of
the grease is provided by a surprising and unexpected interaction between the
extreme pressure antiwear additive package and the adhesive polymer. The
~ 0 polyurea, triurea, biurea, calcium complex soap, bentonite or clay type
material, silica type material, or combinations thereof are not present in an
amount sufficient to provide significant thickening to the grease structure,
but
do increas~ th~ dropping point of th~ resulting greas~.
In yet another form th~ novel lubricating grease has: (a) a substantial
2 S proportion of a bas~ oil, (b) a sufficient amount of an additive package
to
impart extrem~ pressur~ antiw~ar properties to the grease, end (c) a
sufificient
amount of an adh~sive polymer in th~ absence of any polyurea, triurea,
biurea, or any of the well known fatty acid soap salt thickeners. In this form
the
gr~as~ consistgnc>y and dropping point is provided entirely by the surprising
3 0 and unexpected int~raCtion between the extrem~ pressure antiwear additive
and the adhesive polymer.
In all of th~s~ forms, the novel grease may b~ augmented by addition of
graphit~. Although graphite has significant performance deficiencies, as
discuss~d above, when used in conjunction with the novel compositional
3 ~ aspects of th~ pres~nt inv~ntion, th~ performance of th~ r~sufting
graphite-
containing gr~ases ar~ greatly improved over that of greases containing
graphite as the sole source of EP/AW performance.
_s_
In all of these forms, the novel grease may be further augmented in its
composition by a boron-containing material to further inhibit oil separation.
if
the novel grease is to be used in an application where high temperature
corrosivity is not a problem, then oil-soluble sulfur and phosphorus-
containing
S materials can be used to augment the composition.
The polymeric additive can comprise: polyesters, polyamides,
polyurethanes, polyoxides, polyamines, poiyacrylamides, polyvinyl alcohol,
ethylene vinyl acetate, or polyvinyl pyrrolidone; polyolefins (polyalkylenes),
such as polyethylene, polypropylene, polyisobutylene, ethylene propylene,
1 0 and ethylene butylene; or polyolefin (polyalkylene) arylenes, such as
polymers
of ethylene styrene and styrene isoprene; polyarylene polymers such as
polystyrene; polyacrylate, or polymethacrylate; or combinations, or boronated
analogs (compounds) of the preceding. Preferably, the polymeric additive
comprises: polyolefins (polyalkylenes.), such as polyethylene, polypropylene,
1 S polyisobutylene, ethylene propylen~, and ethylene butylene; or polyolefin
(polyalkylene) arylenes, such as ethylene styrene and styrene isoprene;
polyarylene polymers such as polystyren~,
In one form, the extreme pressure antiwear (wear-resistant) additive
package comprises trica~ium phosphate in the absence of sulfur compounds,
2 0 especially oil-soluble sulfur compounds. Tricalcium phosphate provides
many
unexpected advantages over monocalcium phosphate and dicalcium
phosphate. For example, tricalcium phosphate is water-insoluble and will not
be extracted from the grease if contacted with water. Tricalcium phosphate is
also very nonreactive and non-corrosiv~ to f~rrous and nonferrous metals
2 5 even at very high temperatures. It is also nonreactive and compatible with
most if not all of th~ elastomers in which lubricants may contact.
~n the oth~r hand, monocafcium phosphate and dicalcium phosphate
erg water-soluble. Wh~n water comes into significant contact with
monocadaum or dicaldum phosphate, they have a tendency to leach, run,
3 0 extract, and wash out of the grease. This destroys any significant
antiwear and
extreme pressure qualities of the grease. 9~PonoGa9~ium phosphate and
dicalaum phosphate are also protonated and have acidic hydrogen pr~sent
which can at high temperature adversely react and corrode ferrous and
nonferrous metals as well as degrade many elastomers.
!n anoth~r farm, the extreme pressure antiwear additive package
~mpdsgs carbonates and phosphates together preferably in the absence of
sulfur compounds including oil-soluble sulfur compounds and insoluble
~. '
~~~ ~E~~
arylene sulfide polymers. The carbonates and phosphates are of a Group 2a
alkaline earth metal, such as beryllium, magnesium, calcium, strontium, and
barium, or of a Group 1 a alkali metal, such as lithium, sodium, potassium,
rubidium, cesium, and francium. Calcium carbonate and tricalcium phosphate
are preferred for best results because they are economical, stable, nontoxic,
water-insoluble, and safe.
The use of both carbonates and phosphates in the additive package
produced unexpected surprisingly good results over the use of greater
amounts of either carbonates alone or phosphates alone. For example, the
1 0 use of both carbonates and phosphates produced superior wear protection in
comparison to a similar grease with a greater amount of carbonates in the
absence of phosphates, or a similar grease with a greater amount of
phosphates in the absence of carbonates. Furthermore, the synergistic
combination of calcium carbonate and tricalcium phosphate can reduce the
1 ~ total additive lav~I over a single additive and still maintain superior
performance over a single additive.
The non-corrosivity of the mixture of phosphates and carbonates at very
high tamparatur~s is also in marked contrast to o,il-solubl~ sulfur-containing
materials. Th~ use of sulfur compounds, such as oil soluble sulfur-containing
2 0 compounds, should generally be avoided in the additive package of railroad
track/wh~el flang~ greases because they are chemically corrosive and
detrimental to th~ metal rail surtace at th~ high temperatures which can
momentarily occur as the train passes. ~il-soluble sulfur compounds, by virtue
of th~ir corrosiv~ natur~, may, and~r high temperature, high mechanical stress
2 5 (loading) ~nditi~ns, acc~larat~ the onset of metal fatigue failure. If
this
process occurs during the long-term use of a railroad track/whaal flange
grass~, the result could ba derailment.
In another form, th~ ~xtrame pressure antiwaar additive package
compris~s sulfates and carbonates together, in th~ abs~ncg of halog~nated
3 0 mat~riais. Tha sulfat~s era of a Group 2a alkaline ~arth metal, such as
beryllium, magnesium, cak;ium, strontium, and barium, or a Group ~a alkali
metaB, such as lithium, sodium, and potassium. Th~ carbonates are of a Group
2a alkaline earth m~tal or of a Group 1a alkali m~tal such as those described
abov~. Calaum sulfate and calcium carbonate ar~ pref~rrad for b~st results
3 5 and bacaus~ they era economical, stable, nontoxic, essentially watar-
insoluble, and saf~.
Anhydrous calcium sulfate is most prefierred over the various hydrated
forms of calcium sulfate since waters of hydration should be avoided in the
final grease. However, if the grease is processed at such temperatures and
pressures so as to remove any water of hydration from the grease, then
hydrated forms of calcium sulfate can be used without adverse effects in the
final grease.
Calcium sulfate and calcium carbonate provide many unexpected
surprisingly good advantages over calcium bisulfate and and calcium
bicarbonate. For example, calcium sulfate is essentially weter-insoluble and
1 0 will not be extracted from the grease if contacted with water. Calcium
sulfate is
also very compatible with elastomers and seals. Similarly, calcium carbonate
is extremely water insoluble and will not b~ extracted from the grease if
contacted with water. Calcium carbonate is also very compatible with
elastomers and seals. .
1 5 On the other hand, calcium bisulfate and calcium bicarbonate are
water-soluble. IeYhen water comes into significant contact with calcium
bisulfate or calcium bicarbonate, they have a tendency to leach, run, extract,
and wash out of the grease. This destroys any significant antiwear and
extreme pressure qualities of the grease. Calcium bisulfate and calcium
2 0 bicarbonate are also protonated and have acidic hydrogen present which can
adversely react, crack, degrade, and corrode seals and elastomers.
The use of both sulfates and carbonates in the additive packages
produced unexpected surprisingly good results over the use of much greater
amounts of either sulfates or carbonates alone. Cdr exampl~, the use of both
2 5 sulfat~s and carbonates produced superior wear protection in comparison to
a
similar grease with a much greater amount of carbonates in the absence of
sulfates, or a similar grease with a much greater amount of sulfates in the
absence of carbonates.
Halogenated materials should be avoided when using the additive
3 0 mixtur~ comprising sulfates and carbonates. HaBogenated materials to be
avoided includ~ ha6ogenated hydrocarbons, particularly chlorinated paraffins.
Such materials exhibit corrosive tendencies at prolonged high temperatures
and th~reby r~su~ in chemical attack t~ fernous and non-ferrous metals. This
corrosivity is greatly accelerated wh~n water is present. Even smaBl levels of
3 5 water such as th~ moisture levels commonly found in air at room
temperatur~
are enough to cause catastrophic ferrous corrosion. Furthermore, the
extremely large synergistic improvement in extreme pressure and antiwear
properties produced by the sulfate/carbonate mixture is decreased when
chlorinated paraffins are also present. Also, the National Toxicology Program
(NTP) has evaluated some chlorinated paraffins and found them to exhibit
clear evidence of carcinogenicity.
S Furthermore, the combination of the above sulfates and carbonates
achieved' unexpected surprisingly good results in copper corrosion protection,
even at 300°F or 350°F, while also achieving compatibility with
elastomers
and seals.
The non-corrosivity of the mixture of calcium sulfate and calcium
1 0 carbonate at very high temperatures is also in marked contrast to oil-
soluble
sulfur-containing materials.
In another form, the additive package comprises sulfates and
carbonates with a minor amount of hydroxides. The preferred hydroxide is
calcium hydroxide. The addition of calcium hydroxide to the suifate/carbonate
1 5 mixture imparts improved wear resistance to the grease and also provides
additional overbasing to neutralize acidic materials which form over long
periods of time as the grease oxidizes.
As used In this application, the term "polymer" means a molecule
comprising one or more types of monomeric units chemically bonded together
2 0 to provide a molecule with at least six total monomeric units. The
monomeric
units incorporated within the polymer may or may not b~ the same. If more
than one type of monomer unit is present in the polymer th~ resulting molecule
may be also referred to as a copolymer.
A more detailed expianatian of the invention is provided in the following
2 5 description and appended claims.
DST I D DID RIPTION c'~F THE PREF RRED EM130~IMENT
~4 high performance adherent, friction-reducing grease is provided
which effectively lubricates the sides of railroad tracks and provides
improved
3 0 benefits of the range described above. The novel grease exhibits
adherence,
spreadabiiity down the rail, resistance to water (rain), lowered fiction at
the
railroad track/wheel flang~ interface, excellent extreme pressure and antiwear
performance, non-corrosivity at high temperatures, low oil separation, good
mobility and pumpability. Most significantly, the novel grease provides these
3 .5 beneficial properties while being completely safe and environmentally
compatible with plant life and animals. The novel grease also avoids most if
not all of the problems associated with prior art lubricant compositions
-10-
containing graphite and/or moiybdenum disulfide and conforms to EPA
guidelines.
The preferred lubricating grease comprises by weight: 45% to 85%
base oil, 4% to 30% extreme pressure enliwaat additives, and 1% to 10% of
adhesive polymer. For best results, the most preferred Lubricating grease
comprises by weight: at least 65% base oil, 8% to 20% extreme pressure
antiwear additives, and 2% to 6% of the adhesive polymer. When the novel
grease is thickened substantially by polyurea, triurea, biurea, calcium soaps
(simple or complex), or aluminum soaps (simple or complex), or combinations
1 0 thereof, the preferred lubricating grease comprises by weight 3% to 14% of
said thickener. For best results, the most preferred lubricating grease
comprises by weight 4% to 8% of said thickener. When the novel grease is
thickened substantially by the interaction of the extreme pressure antiwear
additives and the adhesive polymer, and when the polyurea, triurea, biurea,
1 S calcium complex soap, bentonite, or other clay-type materials, or fumed
silica,
or other appropriate silica materials, or combinations thensof are present as
dropping point elevating additives, then the preferred lubricating grease
comprises by weight 0.1 to 8% of said dropping point elevating additives. For
best results, the most preferred Lubricating grease comprises by weight 0.1 to
2 0 2% of said dropping point elevating additives. It should be noted that
when the
dropping point elevating additives are present at 0°/~ (not present),
the
resulting lubricating grease is thickened entirely by the interaction of the
extreme pressure enliwaat additives and the adhesive polymer.
The polymeric additive cooperates and is ~mpatibls (non-interfering)
2 5 with the extreme pressure antiwear additive pa<,;kage to provide the
proper
balance of railroad track retentivity, friction redaction, wear reduction,
mobility,
and pumpability whiig also maintaining an environmentally safe product.
Sulfide polymers, such as insoluble arylena sulfide polymers, should b8
avoided in the grease becaus~ they: (1 ) corrod~ copper, steel, and other
3 0 metals, especially at high temperatures, (2) degrade, deform, and corrode
silicon seals, (3) significantly diminish the tensile strength and elastomeric
properties of many elastomers, (4) exhibit inferior fretting wear, and (5) are
abrasiv~.
Sulfur compounds, such as oil-soluble sulfur compounds, can be even
3 5 more aggravating, troublesom~, and worse than oil-insoluble sulfur
compounds. Sulfur compounds and especially oil soluble sulfur compounds
should be generally avoided in the grease because they are often chemically
_11-
incompatible and detrimental to silicone, polyester, and other types of
eiastomers and seals. Oil-soluble sulfur compounds can destroy, degrade,
deform, chemically corrode, or otherwise damage elastomers and seals by
significantly diminishing their tensile strength and elasticity.
Furthermore, oil-soluble sulfur compounds are extremely corrosive to
copper, steel and other metals at high temperatures such as 350°F.
Generally, any sulfur-containing organic compounds should be avoided
in the additive composition of the railroad track/wheal flange grease,
especially the sulfurized hydrocarbons and organometallic sulfur salts. Sulfur
1 0 compounds of the type to be avoided in the grease include saturated and
unsaturated aliphatic as well as aromatic derivatives that have from 1 to 32
or
1 to 22 carbon atoms. Included in this group of oil soluble sulfur compounds
to
be avoided in the grease are alkyl sulfides and alkyl polysulfides, aromatic
sulfides and aromatic polysulfides, e.g. benzyl sulfide and dibenzyl
disulfide,
1 5 organometallic salts of sulfur containing acids such as the metal
neutralized
salts of dialkyl dithiophosphoric acid, e.g. zinc dialkyl dithiophosphate, as
well
as phosphosulfurized hydrocarbons and sulfurixed oils and fats. Sulfurized
and phosphosulfurized products of polyolefins are very detrimental and should
b~ avoided in the grease. A particularly detrimental group of sulfurized
olefins
2 0 or polyolefins are those prepared from aliphatic or terpenic olefins
having a
total of 10 to 32 carbon atoms in the molecule and such materials are
generally sulfurized such that they contain from about 10 to about 60 weight
percent sulfur.
The aliphatic olefins to be avoided in the grease include mixed olefins
2 5 such as cracked wax, cracked petrolatum or single olefins such as
tridecene-2,
octadecen~-1, eikosen~-1 as well as polymers of aliphatic olefins having from
2 to 5 carbon atoms per monomer s~rch as ethylene, propylene, butylene,
isobutylene and pentene.
The terp~nic olefins to b~ avoided in the grease include terpenes
(Oto~ts). ses~uiterpenes (O1~M2~) and diterpenes (C2pHs2). Of the terpenes,
the monocyclic terpenes having the gen~r~l formula CI~M~s and their
monpccyclic isomers erg particularly detrimental.
The additive package may be complemented by the addition of small
3 5 amounts of an antioxidant and a corrosion inhibiting agent, as well as
dyes
and pigments to impart a desired color to the composition.
_12_
Antioxidants or oxidation inhibitors prevent varnish and sludge
formation and oxidation of metal parts. Typical antioxidants are organic
compounds containing nitrogen, such as organic amines, sulfides, hydroxy
sulfides, phenols, etc., alone or in combination with metals like zinc, tin,
or
barium, as well as phenyl-alpha-naphthyl amine, bis(alkylphenyl)amine, N,N
diphenyl-p-phenylenediamin~, 2,2,4 trimethyldihydroquinoline oligomer, bis(4
isopropylamlnophenyl)-ether, N-acyl-p-aminophenol, N-acylphenothiazines, N
of ethylenediamine tetraacetic acid, and alkylphenol-formaldehyde-amine
polycondensates.
1 0 Corrosion inhibiting agents or anticorrodants prevent rusting of iron by
water, suppress attack by acidic bodies, and form protective film over metal
surfaces to diminish corrosion of exposed metallic parts. A typical corrosion
inhibiting agent is an alkali mete! nitrite, such as sodium nitrite. Other
ferrous
corrosion inhibitors include metal sulfonate salts, alkyl and aryl succinic
acids,
1 5 and alkyl and aryl succinate esters, amides, and other related
derivatives.
Borated esters, amines, ethers, and alcohols can also be used with varying
success to limit ferrous corrosion. Likewise, substituted amides, imides,
amidines, and imidazolines can b~ used to limit ferrous corrosion. Other
ferrous corrosion inhibitors include certain salts of aromatic acids and
2 0 polyaromatic acids, such as zinc naphthenate.
Metal deactivators can also b~ added to further prevent or diminish
copper corrosion and counteract the effects of mete! on oxidation by forming
catalytically inactive compounds with soluble or insoluble metal ions. Typical
metal deactivators include m~rcaptobenzothiazole, complex organic nitrogen,
2 5 and amines. Although such mete! deactivators can be added to the grease,
their presence is not normally required due to the extreme nonreactive,
noncorrosive nature of the railroad tracWwheel flange grease composition.
The base oi! can b~ naphihenic oil, paraffinic oil, aromatic oil, or a
3 0 synthetic oil such as a polyalphaolefin polyoiester, diester, polyalkyl
ethers,
polyaryl ethers, silicone polymer fluids, or combinations thereof. The
viscosity
of the base oil can range from ~0 to 10,000 ~IJS at 100°F.
Other hydrc~arbon oils can also b~ used, such as: (a) oil derived from
coal products, (b) alkylene polymers, such as polymers of propylene, butylene,
3 5 etc., (c) olefin (alkylene) oxid~-type polymers, such as olefin (alkylene)
oxide
polymers prepared by polymerizing alkylene oxide (e.g., propylene oxide
polymers, etc., in the pr~sence of water or aloahois, e.g., ethyl alcohol),
(d)
_ 13_
carboxylic acid esters, such as those which were prepared by esterifying such
carboxylic acids as adipic acid, azelaic acid, suberic acid, sebacic acid,
alkenyl succinic acid, fumaric acid, malefic acid, etc., with alcohols such as
butyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, etc., (e) liquid asters of
acid
of phosphorus, (f) alkyl benzenes, (g) polyphenols such as biphenols and
terphenols, (h) alkyl biphenol ethers, and (i) polymers of silicon, such as
tetraethyl silicate, tetraisopropyl silicato, tetra(4-methyl-2-tetraethyl)
silicate,
hexyl(4-methol-2-pentoxy) disilicone, poly(methyl)siloxane, and
poly(methyl)phenylsiloxane.
The preferred base oil comprises about 65% by weight of a refined,
solvent-extracted, hydrogenated, dewaxed base oil, preferably 850 SUS oil,
and about 35% by weight of another refined solvent-extracted dewaxed base
oil, preferably 150 SUS oil, for better results.
1 5 Thickener
Thickeners useful in the novel lubricating grease include polyurea,
calcium soaps (simple and complex), and aluminum soaps (simply and
complex), Polyurea thickeners are preferred over other types of thickeners
because they have high dropping points, typically 460°F to
500°F, or higher.
2 0 Polyurea thickeners are also advantageous because they have inherent
antioxidant characteristics, work well with other antioxidants, and are
compatible with all elastomers and seals.
The polyurea thickener can be prepared, if desired, by reacting an
amine and a poiyamine, with diisocyanate. For example, polyurea can be
2 5 prepared by reacting the following components:
t. A diisocyanate or mixture of diisocyanates having the formula
OCN-R-NCO, wherein R is a hydrocarbylene having from ~ to 30
cartx~ns, preferably from 6 to 15 carbons, and most preferably 7
carbons;
2. A polyamine or mixture of polyamines having a total of 2 to 40
carbons end having the formula:
- 14-
wherein R9 and R2 are the same or different types of
hydrocarbylenes having from 1 to 30 carbons, and preferably
from 2 to 10 carbons, and most preferably from 2 to 4 carbons; Rp
is selected from hydrogen or a C1-C4 alkyl, and preferably
hydrogen; x is an integer from 0 to 4; y is 0 or 1; and z is an
integer equal to 0 when y is 1 and equal to 1 when y is 0.
3. A monofunctional component selected from the group consisting
1 0 of monoisocyanate or a mixture of monoisocyanates having 1 to
30 carbons, preferably from 10 to 2~ carbons, a monoamine or
mixtur~ of monoamines having from 1 to 30 carbons, preferably
from 10 to 24 carbons, and mixtures thereof.
i 5 Th~ reaction can be conducted by contacting the three reactants in a
suitable reaction vessel at a temperature between about 60°F to
320°F.,
preferably from 100°F to 300°F, for a period of 0.5 to 5 hours
and preferably
from 1 to 3 hours. The reaction is usually accomplished in a suitable solvent.
In most cases the solvent is a portion of the base oil to be used in the final
2 0 lubricating grease. The molar ratio of the reactants present can vary from
0.1-
2 molar parts of monoamine or monoisocyanate and 0-2 molar parts of
poiyamine for ~ach molar part of diisacyanate. UVhen the m~noamine is
employed, the molar quantities can be (m+1 ) molar parts of diisocyanat~, (m)
molar parts ~f polyamina and 2 molar parts ~f monoamin~. l~lhen the
2 5 monoisocyanat~ is employed, the molar quantities ran be (m) molar parts of
diisoc~anate, (m+1 ) molar parts ~f polyamine and 2 molar parts of
monoi~ocyanate~ (m is a number from 0.1 to 10, preferably 0.2 t~ 3; and most
prefer~biy 1 ).
Mono- or polyur~a compounds can hav~ structur~s ~~fin~d by th~
~ 0 fol6owing general formula:
- 15-
~~'~~=-~y~~
'0 p 0 0
R~'H~I 't~~R~-PdH-C-PIFI-RS-EdH C-~iH-R!-P~H-C-~1H-R~
r
0 ~ 0 0
R PIH C-IdH-R t~Fi C°~3H-R -L~E3-C°NFI-R -
g ~ 5 N~ c-Nx-R3
(1)
1 5 wherein n is an integer from 0 to 3; R3 is the same or different
hydrocarbyl
having from 1 to 30 carbon atoms, preferably from 10 to 24 carbons; R,~ is the
same or different hydrocarbylana having from 2 to 30 carbon atoms, preferably
from 6 to 15 carbons; and R5 is the same or different hydrocarbylena having
from 1 to 30 carbon atoms, preferably from 2 to i 0 carbons.
2 0 As referred to herein, the hydrocarbyl group is a monovalant organic
radical composed essentially of hydrogen and carbon and may ba aliphatic;
aromatic, alicyciic, or combinations thereof, a.g., aralkyl, alkyl, aryl,
cycloalkyl,
alkylcycloalkyl, atc., and may ba saturated or olafinically unsaturated (one
or
more doubla~bondad carbons, conjugated; or nonconjugated). Tha
2 S hydrocarbylana, as d~fin~d in R~ and R2 above, is a divalent hydrocarbon
radical which may b~ aliphatic, alicyclic, aromatic, or combinations thereof,
a.g., alkylaryl, aralkyi, alkyicycloalkyl, cycloalkylaryl, atc., having its
two free
valances on different carbon atoms.
The mono~ or polyur~as having the structure presented in Formula 1
3 0 shave era prepared by reacting (n+1 ) molar parts of diisocyanate with 2
molar
parts of a monoamina and (n) molar parts of a diamina. (When n equals zero
in the above Formula 1, the diamina is deleted). ~Aono- or polyuraas having
the structure presented in Formula 2 above era prepared by reacting (n) molar
parts of a diisocyanata with (nit) molar parts of a diamina and 2 molar parts
of
3 5 a monoisocyanata. (When n equals zero in the above Formula 2, the
diisocyanata is deleted). ~Aono- or polyuraas having the structure presented
in
Formula 3 above are prepared by reacting (n) molar parts of a diisocyanata
.1
with (n) molar parts of a diamine and 1 molar part of a monoisocyanate and 1
molar part of a monoamine. (When n equals zero in Formula 3, both the
diisocyanate and diamine are deleted).
in preparing the above mono- or polyureas, the desired reactants
(diisocyanate, monoisocyanate, diamine, and monoamine) are mixed in a
vessel as appropriate. The reaction may proceed without the presence of a
catalyst and is initiated by merely contacting the component reactants under
conditions conducive for the reaction. Typical reaction temperatures range
from 70°F to 210°F at atmospheric pressure. The reaction itself
is exothermic
1 0 and, by initiating the reaction at room temperature, elevated temperatures
are
obtained. External heating or cooling may be used.
The monoamine or monoisocyanate used in the formulation of the
mono- or polyurea can form terminal end groups. These terminal end groups
can have from i to 30 carbon atoms, but are preferably from ~ to 28 carbon
1 5 atoms, and mor~ desirably from t 0 to 24 carbon atoms. Illustrative of
various
monoamines are: pentylamine, hexylamine, heptylamine, ociylamine,
decylamine, dodecyiamine, tetradecylamin~, hexadecylamin~,
octalecylamine, eicosylamine, dodecenylamine, hexadacenylamine,
octadecenylamine, octalecxadienylarnine, abietylamine, aniline, toiuidine,
2 0 naphthylamine, cumylamine, bornylamine, fenchylamin~, tertiary butyl
aniline,
benzylamine, beta-phenethylamine, etc. Preferred amines are prepared from
natural fats and oils or fatty acids obtained therefrom. These starting
materials
can be reacted with ammonia to give first amides and then nitrites. The
nitrites
erg reduced to amines by catalytic hydrogenation. Exemplary amines
2 5 prepared by the method include: stearylamine, laurylamin~, palmitylamine,
ofeylamine, petroselinylamine, linoleylamine, linoienylamine,
eleostearylamine, etc. Unsaturated amines are particularly useful.
Illustrative
of monoisocyanates are: hexylisocyanate, decylisocyanate, dodecylisocyante,
tetradecylisocyanate, hexadecylisocyanat~, phenylisocyanate,
3 0 cyclohexylisocyanate, xyleneisocyanate, cumeneisocyanate,
abietylisocyanat~, cyclooctylisocyanate, etc.
Polyamines which form the internal hycJracarbon bridges can contain
from 2 to 40 carbons and preferably from 2 to 30 carbon atoms, more
preferably from 2 to 20 carbon atoms. The polyamine.preferably has from 2 to
3 5 6 amine nitrogens, preferably 2 to 4 amine nitrogens and most preferably 2
amine nitrogens. Such polyamines include: diamines such as
ethylenediamine, propanediamine, butanediamine, hexanediamine,
_ 17_
dodecanediamins, octanediamine, hsxadscanediamine,
cyclohexansdiamine, cyclooctanediamine, phenylenediamine,
tolylensdiamine, xylylsnediamins, dianiline methane, ditoluidinemsthans,
bis(aniline), bis(toluidine), piperazine, etc.; triaminss, such as aminoethyl
pipsraaine, disthylene triamine, dipropylsne triamine, N-methyldisthylene
triamins, etc., and higher polyamines such as tristhylene tetraamine,
tetraethylens pentaamine, pentaethylene hexamine, etc.
Representative examples of diisocyanatss include: hexane
diisocyanat~, decanediisocyanate, octadecanediisocyanats,
1 0 phenylenediisocyanate, tolylenediisocyanate, bis(diphenylisocyanate),
methylene bis(phenylisocyanate), etc. '
Other mono- or polyurea compounds which can be used are:
- ~ B~ Y
i~
2 5 wh~rein n~ is an integer of 1 to 3, R~ is defined supra; % and y are
monovalent
radicals selsoted from 'rabl~ 1 below:
_ 1g _
Table 1
X Y
t~~
)n Tabha 1, Rg is defined supra, Rs is the sam~ as R3 and defined supra,
2 ~ R~ is selected from th~ groups consisting of arylens radicals of 6 to 15
carbon
atoms and alkylsns groups of 2 to 30 carbon atoms, and R~ is selected from
th~ group consisting of alkyl radicals having from 10 to 30 carbon atoms and
aryl radicals having from 6 to 16 Carbon atoms.
lu9pno- or polyurea compounds described by formula ~4) above can be
3 0 characterised as amid~~ and imid~s of mono; di-, and triur~as: Th~ss
mat~rials are formed by rsa~ing, in the selected proportions, suitably
carboxylic acids or internal Garb~xylic anhydrid~s with a dii~ocyanats and a
polyamins with or without a monoamins or monoisocyanate. The mono- or
polyursa compounds ors prepared by bl~nding th~ several reactants together
3 5 in a vassal and heating Them to a tsmperatur~ ranging from ~0°~ to
400°F for a
period sufficient to cause formation of the compound, generally from 5 minutes
to 1 hour. The reactants can b~ added oll of once or sequentially. Usually,
the
1'g _
reactants are mixed and reacted in a solvent to assist in facilitating a
complete
reaction to form the desired polyurea thickener. The solvent can, in
principle,
be any solvent which allows effective dispersion and mixing of the reactants
as
well as dispersion of the resulting polyurea. However, in most cases the
S soleent used is a portion of the base oil to be part of the final
lubricating
grease.
The above mona- or polyureas can be mixtures of compounds having
structures wherein n or n~ varies from 0 to 8, or n or n~ varies from 1 to 8,
existent within the grease composition at the same time. For example, when a
1 0 monoamine, a diisocyanate, and a diamine are all present within the
reaction
zone, as in the preparation of ureas having the structure shown in formula (2)
above, some of the monoamine may react with both sides of the diisocyanate
to form diurea (biurea). In addition to the formulation of diurea,
simultaneous
reactions can occur to farm tri-, tetra-, pants-, hexa-, octa-, and higher
1 S polyureas.
The polyurea comprising the thickener can also b~ prepared in a pot,
kettle, bin, or other vessel by reacting an amine, such as a fatty amine, with
diisocyanate, or a polymerized diisocyanate, and water. In this case the
polyamine-(diamine in this cas~) is formed in situ by hydrolysis of the
2 0 diisocyanate. Therefor~, the chemical structure of the polyamine will be
determined by the choice of diisocyanate used. When this reaction scheme is
used to form the polyurea, the diisocyanates and amines useful are the same
as those already given above. As already described, the reaction to form the
polyurea usually takes place in a soleent. The solvent is usually a portion of
2 5 th~ base oil to be used in the final lubricating grass~.
Blur~a (diur~a) may be used as a thickener, but it is generally not as
stabl~ as polyurea and may shear and lose consistency when pumped. If
desired, triurea can also be included with or used in lieu of polyurea or
biurea.
Calcium soap thickeners may also be used, although experience in the
3 0 IJ.B. has indicated that polyurea thickener systems, as previously
described,
are intrinsically superior. Calcium soap thickeners may ba either simple soaps
or ~mplex soaps.
To make a calcium soap thickener requires a calcium-containing base
and a fatty monocarboxylic acid, ester, amide, anhydride, or other fatty
3 5 monocarboxylic acid derivativ~. When the two materials are reacted
together,
usually while slurried dispersed, or otherwise suspended in a base oil, a
calcium carboxylate sales, or mixture of salts is formed in the base oil. The
_2p_
calcium salt or salts formed thicken the oil, thereby facilitating a grease-
like
texture. During the reaction, water may or may not be present to assist in the
formation of thickener. In earlier calcium grease technology some added
water may be retained in the final calcium soap grease as "tie water." This
water is required to give permanence to the grease consistency. If the greaso
is heated much above 212°F, the tie water is lost, and with it the
grease
consistency. Such hydrous calcium greases are referred to as "cup greases,"
and usually do not perform wall as railroad tracWwheel flange greases where
performance at temperatures of 300°F are encountered.
1 0 Simple calcium soap-thickened greases do not require tie water and
are referred to as anhydrous calcium soap grasses. Anhydrous simple
calcium soap thickeners can be useful for railroad track/wheel flange greases
and can comprise a minor to a substantial portion of monocarboxylic acids or
fatty acid derivatives, preferably with a hydroxyl group on one or more of the
1 5 carbon atoms of the fatty chain for better stability of grease structure.
The
added polarity afforded by this hydroxyl group eliminates the need for tie
water. Anhydrous simple calcium soap-thickened greases are best used at
lower temperatures since their dropping points are usually within the range of
300°F to 390°F.
2 0 The calcium base material used in the thickener can be calcium oxide,
calcium carbonat~, calcium bicarbonate, calcium hydroxide, or any other
calcium containing substance which, when reacted with a monocarboxylic
acid or monocarboxylic acid derivative, provides a calcium carboxylate
thickener.
2 5 Desirably, monocarboxylic fatty acids or their derivatives used in simple
ca~ium soap thickeners hav~ a moderately high molecular weight: 7 to 30
carta~n atoms, preferably 12 to 30 carbon atoms, and most preferably 13 to 22
carbon atoms, such as lau~c, myristic, palmitic, stearic, behenic,
myristoieic,
palmitoleic, of~ic, and linoleic acids. Als~, veg~table or plant oils such as
3 0 rapeseed, sunflow~r, safflow~r, cottons~ed, palm, castor and corn oils and
animal oils such as fish oil, hydragenated fish oil, lard oil, and beef oil
can be
used as a source of monocarboxylic acids in simple calcium soap thickeners.
i/arious nut oils ~r th~ fatty acids derived th~refrom may also be used in
simple
cak~um soap thicken~rs. Mast of thes~ oils are primarily triacylglycerides.
3 5 They may be reacted directly with the calcium-containing base, or the
fatty
ands may be cleaved from the triglyceride backbone, separated, and then
reacted with the ca~ium-containing base as free acids.
_21
Hydroxy-monocarboxylic acids used in simple anhydrous calcium soap
thickeners can include any counterpart to the preceding acids. The most
widely used hydroxy-monocarboxylic acids are 12-hydroxystearic acid, 14-
hydroxystearic acid, 9 6-hydroxystearic acid, 6-hydroxystearic acid and 9,10-
dihydroxystearic acid. Likewise, any fatty acid derivatives containing any of
the hydroxy-carboxylic acids may be used. In general, the monocarboxylic
acids and hydroxy-monocarboxylic acids can be saturated or unsaturated,
straight or branch chained. Esters, amides, anhydrides, or any other
derivative
of these monocarboxylic acids can be used in lieu of the free acids in simple
1 0 anhydrous calcium soap thickeners. The preferred monocarboxylic and
hydroxy-monocarboxylic acid derivative is free carboxylic acid, however, other
derivatives, such as those described above, can be used depending on the
grease processing conditions and the application for which the grease is to be
used.
1 S When preparing simple anhydrous calcium soap thickeners by reacting
the calcium base and the monocarboxylic acid, or mixture of monocarboxylic
acids or derivatives thereof, it is preferred that the calcium base be added
in
an amount sufficient to react with all the acids and/or acid derivatives. It
is also
sometimes advantageous to add an excess of calcium base to more easily
2 0 facilitate a complete reaction. The amount of excess calcium base depends
on the severity of processing which the base grease will experience. The
longer the base grease is heated and the higher the maximum heat treatment
temperature, the less excess calcium base is required. In one railroad
track/wheel flange grease, a tricalcium phosphate and calcium carbonate
2 5 additive system is added as preformed solids during the heal treatment
step,
and less excess calcium base need be added sine both tricalcium phosphate
and calcium carbonate are basic materials capable of reacting with
monocarboxylic acids.
!n simple anhydrous calcium-soap thickened greases, the thickener
3 0 forming reaction is usually carried out at somewhat elevated temperatures,
150°F to 320°F YVater may or may not b~ added to facilitate a
better or more
complete reaction. Preferably, any water added at the beginning of the
processing as well as water formed from the thickener reaction is evaporated
by heat, vacuum, or both. Th~ thickener reaction is generally carried out
after
3 5 the addition of some bas~ oil as previously described. After the thickener
has
b~en formed and any water removed, additional base oif can be added to the
anhydrous base grass~. During preparation, the base grease ,can be heat
-22-
treated to a temperature ranging from about 250°F to about 320°F
The
concentration of base grease can be reduced with more base oil, additives,
and other ingredients used to produce the finished grease product.
In addition to simple calcium soap thickener, calcium complex soap
S thickener can be used. Calcium complex soap thickener comprises the same
two ingredients described in the simple calcium soap case, namely, a calcium-
containing base and monocarboxylic acids, at least part of which should
preferably be hydroxy-monocarboxylic acids. Additionally, calcium complex
soap thickeners eompris~ a shorter chain monoearboxylic acid. Esters,
f 0 amides, anhydrides, or other carboxylic acid derivatives can also be used.
The short chain fatty acid in calcium complex soap greases can have from 2 to
12 carbons, preferably 2 to 10, and most preferably 2 to 6. While the short
chain acid in calcium complex soap thickener can be alkyl or aryl, unsaturated
or saturated, straight chain or branched, alkyl, straight chain, saturated
acids
1 5 are preferred, such as ac~tic acid, due to its low cost and availability.
Propionic acid can also be used with similar results. Butyric, valeric, and
caproic acids can be used, but are not preferred in part because of their
offensive odors.
In calcium complex soap thickeners, the ratio of short chain acids to
2 0 long chain acids can vary widely depending on the desired grease yield and
dropping point. The lower the ratio of short chain acids to long chain acids,
the
less will be the dropping point elevation above that of a simple, anhydrous
calcium soap gr~ase. The larger the ratio of short chain acid to long chain
acid, however, the poorer the grease yield because of the less effective
2 S thickening power of the calcium salt of the short chain carboxylic acid.
Processing conditions for manufacture of calcium complex greases are
similar to those described for simpl~ calcium greases. An amount of the
calaum base is slurried in some of the base oil. Then the long chain
monocarboxylic acids and short chain cartoxylic acids ar~ added. They may
3 0 be added together or separately. tNater may or may not also be added. If
water is added to the thickener, then the weter is preferably vaporized or
otherwise removed after the thickener has been formed. 'This can be
accomplished by heat, vacuum, or both. ~nce formed and dried, the calcium
complex base grease can b~ condition~d with a heat treatment step, such as
3 5 by heating the grease to a temperature ranging from about 250°F to
about
a00°F, preferably, t~ at least about 300°F.
_23_
~~'~p~il~
Other types of thickener systems which may be of utility include
aluminum soap thickeners. As with the previously described calcium soap
thickeners, aluminum soap thickeners may be simple or complex.
The major difference between the previously described calcium soap
thickeners and the aluminum soap thickeners is the basic metallic source
used. Aluminum soap thickeners are generally made using basic aluminum
sources such as aluminum alkoxides. One particularly useful material is
aluminum isopropoxide. In theory, aluminum hydroxide and aluminum oxide
are applicable. However, in practice, it has generally been found that these
1 0 materials are less reactive towards acids and accordingly are usually not
used. Other aluminum sources include specialty chemicals designed to react
with acids and/or water to produce the desired aluminum soap thickeners.
Such materials include a mate~al sold under the brand name of Tri-XL by R. T.
Vanderbilt Co. Other aluminum-containing sources can also be used. The
1 5 only requirement is that the source of aluminum react with the other
involved
reagents to form the desired aluminum soap thickener. For instance, a more
reactive metal base such as sodium hydroxide can be reacted with the proper
aliphatic monocarboxylic acid to produce the sodium aliphatic monocarboxylic
acid salt. Then metathesis with an aluminum salt such as aluminum nitrate or
2 0 aluminum sulfate will produce the desired aluminum soap thickener.
The relative stoichiometric amount of aluminum base to monocarboxylic
acid can vary depending on the rheological properties desired in the final
thickener. Generally, aluminum monocarboxylates will give superior
thickening and gel strengths compared to aluminum tricarboxylates.
2 5 Aluminum dicarboxylates have been found to be intermediate in such
respects.
The aliphatic monocarboxylic acids used to manufacture simple
aluminum soap thickeners are the same as those described above for calcium
soap thickeners and their description shall not b~ repeated here.
3 0 The additional acids used to produce aluminum complex thickeners, the
so-called complexing acids, can be selected from the same group described
above in the section on cak,ium complex soap thicken~rs. I~owever, the
preferred acids are, in common practic~, somewhat different than those
described in the previous section on calcium ~mplex soap thickeners.
3 5 Preferably, the complexing acids used to form aluminum complex soap
thickeners are acids which contain at least one aryl ring. Most preferably,
the
complexing acids used have one to three carbon atoms not included in the
2~ .
aryl ring. While these aryl acids may contain more than one carboxylic acid
group per molecule, one carboxylic acid group per molecule is most preferred.
The acidic group in the complexing acid need not be carboxylic. Sulfonic
acids groups and acidic phenol groups may also be used.
When forming aluminum complex soap thickeners, at least two of the
three valences of the aluminum should be satisfied by the acid moieties, at
least one of which should be the derived from the complexing acid. Most
preferably, two of the three aluminum valences are satisfied by one each of
monoaliphatic carboxylate and aryl carboxylate with the third valence
satisfied
1 0 by hydroxide.
Aluminum soap thickeners, both simple and complex are formed by
processes similar to those described above for calcium soap thickeners. Water
is generally present as a reaction media, and if aluminum alkoxides are used,
the water is also a reactant. Reaction by-products such as water and alkyl
1 5 alcohols are volatiliz~d off by heat, vacuum, or both heat and vacuum.
Reaction conditions are similar to those described above for simple and
complex calcium soap thickeners.
Combir~atlons of polyurea with one or more of the soap thickeners
previously described may also be used.
In order to attain extreme pressure properties, antiwear ualities n
q ,a d
friction reduction properties, as well as any elastomeric compatibility which
may be required, th~ additives in th~ additive package comprise, in one form,
Z S tricalcium phosphat~ and calcium Carbonate, preferably in the abs~nce of
sulfur compounds,
Preferably, the tricalcium phosphate and the calcium carbonate are
each present in th~ additiv~ packag~ in an amount ranging from 2°/~ to
15% by
weight of tha grass~. 1°or ease of handling and rn~nufac~i;ure, the
tricalcium
3 0 phosphat~ and calaum carbonate are each most preferably present in the
additive packag~ in an amount ranging from 4% to 10°/~ by weight of the
grease.
Desirably, the maximum particle sizes of the tricalcium phosphate and
the ~Icium ~~,nate are t 00 microns and th~ tricalcium phosphate and the
calcium carbonate are of food-grade quality to minimiz~ abrasive
contaminants and promote homogenization. Calcium carbonate can be
-25-
provided in dry solid form as CaC03. Tricalcium phosphate can be provided
in dry solid form as Ca3(POa)2 or 3Ca3(i'O~)2 ~Ca(OH)2.
If desired, the calcium carbonate and/or tricalcium phosphate can be
added, formed, or created in situ in the grease as by-products of chemical
reactions. For exampl~, calcium carbonate can be produced by bubbling
carbon dioxide through calcium hydroxide in the grease. Tricalcium
phosphate can be produced by reacting phosphoric acid with calcium oxide or
calcium hydroxide in the grease. tether methods for forming calcium
carbonate and/or tricalcium phosphate can also be used.
1 0 The preferred phosphate additive is tricalcium phosphate for best
results. While tricalcium phosphate is preferred, other phosphate additives
can be used, if desired, in conjunction with or in lieu of tricalcium
phosphate,
such as the phosphates of a Group 2a alkaline earth metal, such as beryllium,
magnesium, calcium, strontium, and barium, or the phosphates of a Group 1 a
1 ~ alkali metal, such as lithium, sodium, and potassium.
Desirably, tricalcium phosphate is less expensive, less toxic, more
readily available, safer, and more stable than other phosphates. Tricalcium
phosphate is also superior to monocalcium phosphate and dicalcium
phosphate. Tricalcium phosphate has unexpectedly b~en found to be
2 0 noncorrosive to metals and compatible with elastomers and seals.
Tricalcium
phosphate is also water-insoluble and will not wash out of the grease when
contamination by water occurs. AAonocalcium phosphate and dicalcium
phosphat~, however, have acidic protons which at high temperatures can
corrosively attack metal surfaces. Monocalcium phosphate and dicalcium
2 5 phosphate wer~ else found to corrode, crack, and/or degrade some
elastom~rs and seals. Monocalcium phosphate and dicalcium phosphate
were also undesirably found to be water soluble and can wash out of the
grease when exposed to water, which would significantly decrease the
antiwear and extreme pressure qualities of the grease.
3 0 The preferred carbonate additive is calcium carbonate for best results.
While calacium carbonate is preferred, other carbonate additives can be used,
if
desired, in conjunction with or in lieu of calcium carbonate, such as the
carbonates of Group 2a alkaline earth metal, such as beryllium, magnesium,
cakrium, strontium, and barium, or the carbonates of a Group 1 a alkali metal,
~ S such as lithium, sodium, and potassium.
. 2~ .
Desirably, calcium carbonate is less expensive, less toxic, more readily
available, safer, and more stable than other carbonates. Calcium carbonate is
also superior to calcium bicarbonate. Calcium carbonate has been
unexpectedly found to be non-corrosive to metals and compatible to
elastomers and seals. Calcium carbonate is also water insoluble. Calcium
bicarbonate, however, has an acidic proton which at high temperatures can
corrosively attack metal surfaces. Also, calcium bicarbonate has been found
to corrode, crack, and/or degrade many elastomers and seals. Calcium
bicarbonate has also b~en undesirably found to be water soluble and
1 0 experiences many of the same problems as monocalcium phosphate and
dicalcium phosphate discussed above.
The use of both tricalcium phosphate and calcium carbonate together in
the extreme pressure antiwear (wear-resistant) additive package of the novel
grease was found to produce unexpected superior results.
1 S If desired, in lieu of tricalcium phosphate, calcium sulfate can be used
in
combination with calcium carbonat~. Preferably, the calcium sulfate and
calcium carbonate are each present in the additive package in an amount
ranging from 2% to 15% by weight of the grease. For ease of handling and
manufacture, the calcium sulfate and calcium carbonate are each most
2 0 preferably pr~sent in the additive package in an amount ranging from 4% to
10% by weight o9 the grease.
If desired, ih~ calcium carbonate and/or calcium sulfate can b~ added,
formed, or created in situ in the grease as by-products of chemical reactions.
For exampl~, calcium carbonate can b~ produc~d by bubbling carbon dioxide
2 5 through calcium hydroxide in the grease. Calcium sulfate can be produced
by
reacting sulfuric acid with calcium oxide or calcium hydroxid~ in the grease.
Oth~r methods for forming calcium carbonate and/or calcium sulfate can also
be used.
The pref~rred sulfate additive is anhydrous calcium sulfate for best
3 0 results. Y~lhile calc9um sulfate is the prgf~rred, other sulfat~ additives
can be
used, if desired, in conjunction with or in li~u of calcium sulfate, such as
the
sulfates of Group 2a alkaline earth metal, such as beryllium, magnesium,
calaum, strontium, and barium, or the sulfates of a Caroup a1 alkali metal,
such
as lithium, sodium, and potassium.
3 5 D~sirably, calcium sulfate is less exp~nsivg, less toxic, more readily
available, and safer. Calcium sulfate is also sup~rior to calcium bisulfate.
_ 27 .
Calcium sulfate is also essentially water insoluble and will not wash out of
the
grease when contamination by water occurs.
The calcium sulfate and calcium carbonate additive package can further
comprise calcium hydroxide. It has been found that a relatively minor level of
calcium hydroxide, when added to the greas~, improves the wear resistance
properties. Also, the calcium hydroxide provides additional excess alkaline
reserve which can be useful to help neutralize any acidic products which may
result from high temperature oxidation of the grease over long periods of
time.
Preferably, the calcium hydroxide, when present, should be present at 0.01
t 0 to 5% by weight of the grease. For best results, the calcium hydroxide,
when
present, should b~ present at 0.1 % to 2% by weight of the grease. Calcium
hydroxide may be provided as Ca(OH)2. If desired, the calcium hydroxide can
b~ produced, formed, or crested in situ in the grease as by-products of
chemical reactions designed to produce calcium hydroxide.
1 5 The use of both calcium sulfate and calcium carbonate together in the
additive package of the grease was found to produce unexpected superior
results in comparison to a similar grease with greater amount by weight of:
(a) calcium sulfate alone in the absence of calcium carbonate, or (b) calcium
carbonate alone in the absence of calcium sulfat~.
2 0 Poly,~ers
It has been unexpectedly and surprisingly found that the polymeric
additives comprising the polymers described below, in the absence of
organically bonded sulfur, when used in the presence of and in combination
and conjunction with the above described extreme pressure antiwear
2 5 additives and preferably with the below described boron-containing
material,
imparts requisite retentivity-related properties i.e. adhesion to the rail
side,
sprsadability down the rail, effectiveness during the passing of several
trains,
resistanc~ to removal by water as well as preserving the extreme pressure
antiwear and friction reducing properties of the grease. Furthermore, is has
3 0 been most unexpectedly and surprisingly found that permanent and stable
greases can b~ formed when only a minor portion or even zero thickener is
present. This is apparently due to an interaction betw~en the extreme
pressure antiwear additives and polymeric additives. Advantageously, such
potymePS are hydrophobic to assist in imparting resistance to removal by
3 5 exposure to rain water once applied to to the rail. The polymers should
have
reasonably good thermal and ~xidative stability so as to not degrade during
the transient high temperatures encountered on the rail side during passage of
a train. Polymers containing organically bonded sulfur should be avoided due
to their high temperature corrosive nature.
Polymers which are applicable for use in railroad track/wheel flange
greases to attain the desired characteristics described above desirably have
molecular weights in the range from about 1,000 to about 25,000,000 or more.
Preferably, at least a substantial portion of polymer should have a molecular
weight between 10,000 and 5,000,000. For best results, a substantial portion
of the polymer should have a molecular weight between 50,000 and 200,000.
Acceptable polymers far attaining many of the grease characteristics
1 0 described above include: polyolesters (polyesters), polyamides,
polyurethanes, polyoxides, polyamines, polyacrylamide, polyvinyl alcohol,
ethylene vinyl acetate, and polyvinyl pyrrolidone. Other acceptable polymers
include: polyolefins (polyaikylenes), such as polyethylene, polypropylene,
polyisobutylen~, ethylene propylene copolymers, or ethylene butylene
1 5 copolymers; or polyolefin (polyalkylene) arylene copolymers, such as
ethylene
styrene copolymers and styrene isoprene copolymers; polyarylene polymers,
such as polystyren~; acrylate or methacrylate polymers or copolymers.
Copolymers with monomeric units comprising the monomeric units of the
preceding polymers and combinations thereof may also be used. Also,
2 0 boronated polymers or boronated compounds comprising the borated or
boronated analogs of the preceding polymers (i.e., any of the preceding
polymers reacted with boric acid, boric oxides, or boron inorganic oxygenated
material) may also be used when nucleophilic sites are available for boration.
For batter results, the preferred polymers include at least a substantial
2 5 portion of a polymer containing as a monomeric unit an alkenyl substituted
aryl
group such as styrene.
For best results, the most preferred polymers include at least a
substaniai portion of a polymer containing as monomeric units an aryl
substituted alkenyl group such as styrene as well as a non-aryl substituted
3 0 alkenyl group such as ethylene, propylene, butane, butadiene, or isoprene.
ParticularBy preferred among this group is the styren~-isoprene copolymer
Shellvis 40, having a molecular weight of about 150,000 and sold by Shell
Chemical Company.
3 5 In any of the above described forms of the novel lubricating grease,
boron-containing oil separation inhibitors can be optionally added. It was
found that borates or boron-containing materials such as borated amine, when
29 -
used in polyurea greases in the presence of calcium phosphates and calcium
carbonates, act as an oi! separation inhibitor, which is especially useful at
high
temperatures.
Such useful borated additives and inhibitors include: (1 ) borated amine,
such as is sold enter the brand name of Lubrizol 5391 by the Lubrizol Corp.,
and (2) potassium triborat~, such as a microdispersion of potassium triborate
in mineral oil sold under the brand name of OLOA 9750 by the Oronite
Additive Division of Chevron Company.
Other useful borates include borates of Group 1 a alkali metals, borates
1 0 of Group 2a alkaline earth metals, stable borates of transition metals
(elements), such as zinc, copper, and tin, boric oxide, and combinations of
the
above.
These borated materials may also b~ used when soap thickeners or
mixtures of polyurea and soap thickeners are used.
1 5 When boron-containing oil separation inhibitors are used in the novel
grease they should b~ present at 0.01 % to 10%, preferably 0.1 % to 5%, and
most preferably 0.25% to 2.5%, by weight of the boron-containing material in
the total grease.
It was also found that borated inhibitors minimized oil separation even
2 0 when temperatures were increased from 210°F to 300°F or
350°F
Advantageously, borated inhibitors restrict oil separation over a wide
temperature range. This is in direct contrast to the traditions! oil
separation
inhibitors, such as high molecular weight polymer inhibitors such as that sold
under the brand name of Paratac by Exxon Chemical Company U.S.A. As
2 5 already discussed abov~, polymeric additives can impart an adhesive,
stringy,
or tacky texture to the lubricating grease because of the extremely high
viscosity and long length of their molecules. As the temperature of the grease
is raised, the viscosity of the polymeric additive within the grease is
substantially reduced as is its tackiness. Tackiness restricts oil bleed. As
the
3 0 taCklneSS 1~ PedlJ, th~ beneficial effect on oil separation is also
reduced.
Borated amin~ additives do not behave in this way since their effectiveness
does not depend on imparted tackiness. Borated amines do not cause the
lubricating grease to become adhesive, tacky, or stringy. This is desirable
sinc~ it provides the lubricant formulator with the means to separately
control
3 5 the high temperature oil separation properties and the adhesive, tacky
texture.
It is b~lieved that borated amines chemically interact with the tricalcium
phosphate and/or calcium carbonate in the grease. The resulting species then
interacts with the polyurea thickener system in the grease to form an
intricate,
complex system which effectively binds the lubricating oil.
Inorganic borate salts, such as potassium triborate, provide an oil
separation inhibiting effect similar to borated amines when used in polyurea
greases in which calcium phosphate and calcium carbonate are also present.
It is believed that the physio-chemical reason for this oil separation
inhibiting
efifect is similar to that for borated amines.
1 0 The following Examples are for purposes of illustrating the novel
adhesive, friction reducing greases and should not be used for purposes of
limiting the scope of the invention as provided in the appended claims.
Example 1 below describes the preparation of a polyurea base greas~.
1 5 To a laboratory grease kettle was charged 34.00 pounds of a solvent -
extracted, hydrotreated, paraffinic mineral oil having a viscosity of about
850
SUS at 100°F. The oil was stirred and heated until the temperature
reached
170°F. Then 7.49 pounds of fatty amine sold under the brand name of
Armeen
T by Akzo Chemicals, Inc. was added to the kettle where it melted and mixed
2 0 well with the 850 SUS oil. Then 3,500 milliliters of water was added to
the
kettle and the contents stirred well while heating back to 170°F. A
8.51 pound
charge of Isonate 143L, a diisocyanate blend sold by Dow Chemical
Company and containing predominantly 4,4'-diphenylmethane diisocyanate,
was added and the kettle was closed.
2 5 The contents of the kettle were stirred for 90~ misiutes while maintaining
the temperature around 190°F. The hot heat transfer fluid was
circulated
through the kettle jacket to provide heating to the kettle contents. The
polyurea
base grease in the kettle was heated to 307°F ander sealed and
pressurized
conditions. During the heating step, the internal pressure was parkially
vented
3 0 several times to maintain a pressure of 75 to 82 psi. Venting was
accomplished via a valued port in the top of the kettle lid. then 307°F
was
reached, the pressure was vented to atmospheric and the kettle was opened.
During final venting, the temperature of the grease dropped to
230°F.
Upon inspection, the grease appeared to still contain some water, so
3 5 the kettle was closed and the contents were heated under vacuum back to
309°F. The vacuum was then released, the kettle was opened, and 25.00
pounds were removed and stored for other uses. The remaining polyurea
-31 -
base grease was heated to 395°F while maintaining a nitrogen blanket
over it.
During this heating step, 11.37 pounds of a solvent-extracted, hydrotreated,
paraffinic mineral oil having a viscosity of 350 SUS at 100°F was
slowly added
to base grease while continually stirring. The polyurea base grease was held
at 395°F for 15 minutes, cooled to 200°F, and removed and stored
for later
us~. The final composition of the polyurea base greasy was:
Component %(wt)
850 SUS Oil 46.74
350 SUS Oil 31,26
Polyurea 22.00
The following Example 2 illustrates the preparation of a typical calcium
complex base grease.
To a laboratory grease kettle was added 16.13 pounds an 850 SUS oil
1 5 similar to that used in Example 1. Then 1,013.7 grams of hydrated lime
(calcium hydroxide) was added and stirred well to produce a smooth slurry.
The slurry was then heated to 140°F by addition of steam to the kettle
jacket.
When 140° F was reached, 616.85 grams of 12-hydroxystearic acid
and
1,822.61 grams of hydrogenated fatty acids were added and the temperature
2 0 was increased to 170°F. The kettle contents were stirred for 30
minutes during
which time a gra~ase structure formed. Then 1,038.14 grams of glacial acetic
acid was added and allowed to react without additional applied heat for 30
minutes. The kettle was then heated with full jacket steam while continuing to
stir the calcium complex base grease.
2 5 Wh~n the t~mperature reached 240°F, electrical heating units in the
kettle walls wer~ energized with 40 amperes and heating was continued until
th~ temperature reached 280°F. The kettle was then sealed and a vacuum
was applied. The electrical heaters wer~ boosted to 90 amper~s and the
kettle contents were stirred for on~-half hour. Then the vacuum was released
3 0 and the kettle was opened. The temperatur~ of the calcium complex grease
was 310°F ~4dditional 850 SUS oil was slowly admixed to the calcium
comp!~x bas~ greys~. When all the oil was in and well mixed, the grease was
heated to 390°F and~r a nitrogen blanket, remov~d, and stored. The
final
imposition of the calcium complex bas~ grease was:
-32-
Com onent %(wt)
850 SUS Oil 75.86
Calcium Complex Soap 24.00
Excess Calcium Hydroxide 0.14
The following Example 3 illustrates the preparation of a typical
aluminum complex base grease.
An aluminum complex base grease was made by the following
1 0 procedure. To a 4,000 ml Pyrex beaker was added 850.0 grams of 850 SUS
Oil. The Oil was stirred by an overhead rotary paddle stirrer and heated by an
electric laboratory hot plate. The temperature of the oil was maintained at
180°F. Stearic acid in an amount of 95.14 grams was added to the oil
and
stirred until it had melted. To the resulting homogenous mixture was then
1 5 added 40.82 grams of benzoic acid. The mixture was then stirred for 35
minutes until the benzoic acid had dissolved. Care was taken to keep the
temperature near 180°F, thereby preventing significant sublimation of
the
benzoic acid. Once a homogenous mixture was obtained, 68.32 grams of
reagent grade aluminum isopropoxide was added and the reaction was
2 0 allowed to pros~ed for 40 minutes while maintaining the temperature near
180°F. When no further isopropyl alcohol was being evolved, 15 ml of
distilled
water was ailed and the mixture was allowed to further react at 196°F.
In the
following 3-5 minutes the mixture changed from a soft, grease-like fluid to a
very firm, transius~nt grease. To increase the pliability of the grease 153.85
2 5 grams of 850 SUS oil was added and allowed to mix into the grease. This
reduced the thiraeener content from 15% to 13°/~. The resulting base
grease
was then stirred and heated to 300°'~ to assure compl~te reaction of
thickener
components and votatiliaing of reaction by-products. The base grease was
then removed and stored. ,
3 0 The following Examples 4-14 illustrate the surprising and unexpected
performance of tridaicium phosphate and calcium carbonate as an extreme
pressure antiwear additive package.
This test served as the control for subsequent tests. A base grease was
3 5 formulated with about 15°1o by weight poiyurea thickener and about
85% by
33
weight paraffinic solvent extracted base oil. The polyurea thickener was
prepared in a vessel in a manner similar to Example 1. The paraffinic solvent
extracted base oil was mixed with the polyurea thickener until a homogeneous
base grease was obtained. No additive package was added to the base
grease. Neither tr7calcium phosphate nor calcium carbonate were present in
the base grease. The EP (extreme pressure)/antiwear properties of the base
greas~, comprising the last nonseizure load, weld load, and load wear index
were measured using the Four Ball EP method as described in ASTM D2596.
The results were as follows:
1 0 Last nonseixure load, kg 32
Weld load, kg 100
Load wear index 16.8
Exam Ig ~ 5
A grease was prepared in a manner similar to Example 4, except that
1 5 about 5% by weight of finely divided, precipitated tricalcium phosphate
with an
average mean diameter of less than 2 microns was added to the base grease.
The resultant mixture was mixed and milled in a roil mill until a homogeneous
grease was produced. The Four Ball EP Test showed that the EP/antiwear
properties of the grease w~r~ significantly increased with tricalcium
2 0 phosphate.
Last nonseizure load, kg 63
Weld load, kg 160
Load wear index 33.1
2 5 A greas~ was prepared in a mangier similar to Example 5, except that
about 10°!~ by weight tricafcium phosphate was added to the base
grease. The
Four Sall EP Test showed that the EP/antiwear properties were further
increased ~rith more tricalcium phosphat~.
Last nonseizure load, kg 80
3 0 Weld load, kg 250
Load wear index 4A.4
Exam I~e 7
A grease was prepared in a manner similar to Example 6, except that
about 20% by weight tricalcium phosphate was added to the base grease. The
Four Ball EP Test showed that the EP/antiwear properties of the grease were
somewhat better than the 5% tricalcium phosphate grease of Example 5, but
not as good as the 10% tricalcium phosphate grease of Example 6.
Last nonseizura load, kg 63
Weld load, kg 250
1 0 Load wear index 36.8
amble
A grease was prepared in a manner similar to Exempla 4, except that
about 5% by weight of finely divided precipitated tricalcium phosphate and
1 5 about 5% by weight of finely divided calcium carbonate were added to the
bas~ grease. The tricalcium phosphate and calcium carbonate had an
average mean particle diameter of lass than 2 microns. The resultant grease
was mixed and milled until it was homogeneous. The Four Ball EP Test
showed that the EP/antiwear properties of the grease were surprisingly better
2 0 than the bas~ grease of Example 2 and the tricalcium phosphate greases of
Examples 5-7.
Last nonseizure load, kg 80
W~Id load, kg 400
Load wear index 52.9
A grease was pr~pared in a manner similar to Exempla 8, except that
10% by weight tricalcium phosphate and l0% by weight calcium carbonate
wer~ added to th~ base grease. The Four Bal! EP Test showed that the weld
load was slightly low~r and the load wear index was slightly better than the
3 0 graas~ of Exempla 8.
Last nuns~izura load, kg 80
W~Id toad, kg 315
Load wear index 55.7
35 .
~~p~r,~
Ie~l O
A grease was prepared in a manner similar to Example 9, except that
20% by weight tricalcium phosphate and 20% calcium carbonate were
blended into the base grease. The Four Ball EP Test showed that the
EP/antiwear properties of the groase were batter than greases of Examples 8
and 9.
Last nonseizure load, kg 100
Weld load, kg 500
Load wear index 85.6
A grease was prepared in a manner similar to Exampi~ 4, except that
about 10% by weight of finely divided calcium carbonate with a mean particle
diameter of less than 2 microns was added to the base greas~. The resultant
grease was mixed and milled until it was homogeneous. The Four Ball EP
1 5 Test showed that the weld load and load wear index of the calcium
carbonate
grease were better than the base grease of Example 4.
Last nonseizure load, kg 80
Weld load, kg 400
Load wear index 57
A grease was prepared in a manner similar to Example 8, except that
about 3% by weight tricalcium phosphate and about 5% by weight calcium
carbonate were added to the base grease. The Four Bal! EP Test showed that
the weld load and load wear index of the grease were better than the greases
2 5 of Exannple 6 (10% trica~ium phosphate alone) and Example 11 (10%
caDeaum carbonate alone), even though the total combined level ~f additives
was only 8%. This result is most surprising and unexpected. It illustrates how
the two additives can work together to give the surprising improvements and
beneficial resutts.
3 0 Last nonseizure load, kg 80
Weld load; kg 500
Load wear index 61.8
Exam, Ip ~ 13
The grease of Exempla 8 (5% by weight tricalcium phosphate and 5%
by weight calcium carbonate) was subjected to the ASTM D4048 Copper
Corrosion Tast at a temperature of 300°F for 24 hours. No
significant
S corrosion appeared. The copper tost sample remained bright and shiny. The
copper strip was rated 1 a.
Example 14
Tha grease of Example 12 (3% by weight tricalcium phosphate and
about 5% by weight calcium carbonate) was subjected to the ASTM D4048
1 0 Copper Corrosion Test at a temperature of 300°F for 24 hours. The
results
were similar to Exempla 13.
Tha following Examples 15-32 illustrate the surprising and unexpected
performance of calcium sulfate and calcium carbonate as an extreme pressure
antiwear additive package.
A grease was prepared in a manner similar to the control grease of
Example 4, except that about 2% by weight of finely divided calcium sulfate
with an average mean diameter of less than 3.75-4.40 microns was added to
the base grass~. The resultant mixture was mixed and milled in a roll mill
until
2 0 a homogeneous grease was produced. The Four Ball EP Test showed that
the EP/antiwear properties of the grease were significantly increased with
calcium sulfate.
Last nonseizure load, kg 40
Weld load, kg 200
2 S Load wear index 31.0
J xa I 18
A grease was prepared in a manner similar to Exempla 15, except that
about 5°!~ by weight of finely divided, calcium sulfate was added to
the base
graas~. The resultant mixtur~ was mixed and milled in a roll mill anti! a
3 0 homogango~s grease was produced. Th~ Four Eall EP Test showed that the
EP/antiwear properties of the grease ware further increased with calcium
sulfat~.
_37_
2~'~~~~
Last nonseizure load, kg 80
Weld load, kg 250
Load wear index 42.5
Exam In a 17
A grease was prepared in a manner similar to Example 16, except that
about 10% by weight calcium sulfate was added to the base grease. The Four
Ball EP Test showed that the EP/antiwear properties were further increased
with more calcium sulfate.
Last nonseizure load, kg 63
1 0 Meld load, kg 315
Lead wear index 48.6
Example 18
A grease was prepared in a manner similar to Example 17, except that
about 15% by weight calcium sulfate was added to the base grease. The Four
1 5 Ball EP Test showed that the EP/antiwear properties of the grease were
further
increased.
Last nonseizure load, kg 63
Weld load, kg 400
Load wear index 63.6
~x,amole~ 79
A grease was prepared in a manner similar to Example 18, except that
about 20% by weight calcium sulfate was added to the base grease. The Four
Ball EP Test showed that the load wear index of the grease was somewhat
2 5 better than the 159'o calcium sulfate grease of Example 18, but the last
nonseizure load had dropped significantly.
Last nonseizure load, kg 20
lAield load, kg 4015
Load wear index 65.3
3 0 Exarr~, a 20
A grease was prepared in a manner similar to Example i 8, except that
about 15% by weight of finely divided calcium carbonate was added to the
base grease. The resultant grease was mixed and milled until it was
homogeneous. The Four Ball EP Test showed little improvement over the
grease of Example 18.
Last nonseizure load, kg 80
Weld load, kg 400
Load wear index 66.9
~xamale 21
A grease was prepared in a manner similar to Example 20, except that
about 20% by weight of finely divided calcium carbonate was added to the
base grease. The resultant grease was mixed and milled until it was
t 0 homogeneous. The Four Eall EP Test showed little improvement over the
grease of Example 20.
last nonseizure load, kg 80
Weld load, kg ~ 400
Load wear index 67.1
A greas~ was prepared in a manner similar to Example 4, except that
about 5% by weight of finely divided calcium sulfate and about 5% by weight
of finely divided calcium carbonate were added t~ the base grease. The
calcium sulfate had a mean particle diameter of 3.75-4.40 microns and the
2 0 calcium carbonate had an average mean particle diameter less than 2
microns. The r~eo1tanf greasd was mixed arid milled until it was
homog~n~ous. ~ Th~ F~ur Eall EP Test showed that the EP/antiwear prop~rties
of th~ greas~ w~r~ surprisingly batter than the ba~~ greas~ of Example 4, the
grease of Exempla 17, and the greases of Examples 15-21.
2 S last nonseiaur~ load, kg 84
Wed toad, kg 800
Load wear index 133.4
Th~ results of Exaanpla 22 are ~xtremely surprasing and unexpected. Even
though th~ flrea~e of Examp9~ 2~ had 5% each o9 calcium sulfat~ and calcium
3 0 carbonate, it d~monstrated far sup~rior ~P/antiw~ar properties than
greases
with t 0~m, or 15%, or even 20°/~ of either calcium sul9~tt~ aidn~ or
calcaum
carbonat~ along.
.. 39 .
Weld load, kg 250
Load
The grease of Example 22 was subjected to a steel strip corrosion test.
This test is similar to the ASTM D4048 Copper Strip Corrosion Test except that
a polished steel strip is used instead of a polished copper strip. The test
was
performed at 300°F for 24 hours after which time the jar of grease with
the
immersed steel slrip was removed and allowed to cool. Then the steel strip
was removed from the jar and the excess grease was removed from the steel
strip by gentle blotting with a laboratory tissue paper followed by washing
with
a stream of heptane from a plastic squirt bottle. The steel strip had not
changed its appearance. It was still shiny and polished. The steel strip was
t 0 was placed on a clean laboratory tissue paper and allowed to sit over
night for
16 hours in the laboratory. The next morning it was still shiny and polished
with no change in its appearance.
Exam~lp,~ 2s 3-25
To further determine the magnitude of this synergism, three more
1 5 greases were made in a manner similar to Example 22 but with lower levels
of
both calcium sulfate and calcium carbonate than that of Example 22.
Compositions and Four Ball EP Test results are tabulated below.
Example Number 23 24 25
Calcium sulfate, % wt 4.0 3.0 2.0
2 0 Calcium carbonate, % wt 4.0 3.0 2.0
Last nonseiaure load, kg 63 32 80
Weld load, kg 800 800 500
Load wear index 97.0 100.4 59.3
These results are even more surprising and unexpected than those of
Exampl~ 22. Even when only 2% each of calcium sulfat~ and calcium
carbonate was used, test results were superior to that obtained with test
greases containing 10% of calcium sulfate alone or i 0% of calcium carbonate
3 0 alone. When 3°/~ each of calcium sulfate and calcium carbonate was
used,
test results were superior to that obdained with test greases containing 10%,
or
15%, or even 20% of either calcium sulfate alone or calcium carbonate alone.
Examples 26-29
To further define the remarkable synergism of calcium sulfate and
~ 5 calcium carbonate, several more samples were made in a manner similar to
-40-
that of Example 22. The combined levels of calcium sulfate and calcium
carbonate were maintained at 10% for all these samples. Compositions and
Four Ball EP Test data are tabulated below:
Example Number 26 27 28 29
Calcium sulfate, % wt 8.0 6.0 4.0 2.0
Calcium carbonate, % wt 2.0 4.0 6.0 8.0
Last nonseizure load, kg 80 80 80 80
lNeld load, kg 500 800 620 620
1 0 Load wear index 67.7 100.5 86.1 83.7
The test data of Examples 26-29 as well as the test data of Examples 11, 17,
and 22 define the synergistic interaction of calcium sulfate and calcium
carbonate with respect to EP/antiwear properties.
EYam
1 5 Two greases were made in a manner similar to that of Example 24
except that 1.0% Nasul BSN by weight of the grease and 0.2% Vanlube 848
by weight of the grease were added to each of the two greases. Nasul BSN is
a barium dinonylnaphthalenesulfonate additive and is available from King
Industries, inc. Vanlube 848 is an octylated diphenylamine antioxidant
2 0 available from R. T. Vanderbilt Company, Inc. The second grease also had
0.5°/~ calcium hydroxide by weight of the grease. The greases were
subjected
to the ASTNI D2266 Four Ball Wear Test. The second grease which contained
the additional minor amount of calcium hydroxide gave results superior to that
of the first grease which contained no added calcium hydroxide.
2 5 Example Number 30 31
Calcium Hydroxide, °/~ (wt~ 0 0.5
Four sell ih4ear, ASTPN D2266 at
40 kg, 1200 rpm for 1 hr 0.53 0.44
~2
3 0 A grease was prepared in a manner similar to Example 22 (containing
5°/~ caPcium sulfate and 5% calcium carbonate) except that 1 °>~
of Cereclor
63L, a chlorinated paraffin containing 63°/~ chlorine, was also added
to the
grease. Th~ resulting greas~ was subjected to the Four Ball EP Test and gave
a load wear index lower than that of Example 22.
_ 47 _
Last nonseizure load, kg 80
Weld load, kg 800
Load wear index 107.7
The grease of Example 22 was subjected to a steel strip corrosion test
described in Example 22. The steel strip showed very obvious signs of
chemical attack. Etching pitting and a dark brown deposition covered the steel
strip. The strip was placed on a clean laboratory tissue paper and allowed to
sit over night for 16 hours in the laboratory. The next morning the steel
strip
was covered with a thick layer of rust. This rusting had occurred from the
I 0 moisture content of the air and was catalyzed by residual iron chloride
which
had formed on the steel strip surface. This residual iron chloride had formed
during the #est from the dehydrohalogenation and/or dechlorination of the
chlorinated paraffin additive and concomitant reaction of hydrogen chloride
and/or chloe~ne with the steel surface.
I 5 Ex~umrales 33-34
Two railroad track/wheel flange greases are prepared as follows. A
polyurea base grease was prepared in a manner similar to that of Example 1.
Two portions of the base grease were separately processed in a grease kettle
by heating and stirring to 300°F and adding the following additives:
tricalcium
2 0 phosphate; calcium carbonate; Shellvis 40, a styrene-isoprene copolymer
available from Shsil Chemical Company. Each of the two additized greases
were then cyclically milled at 280°F using a rotating knife blade mill.
Each of
the two additized greases were then cooled to 180°F and finished with
additional 550 SUS oil, 350 SUS oil, and the following additives: Lubrizol
2 5 5391, a borated amine available from the Lubrizol Corporation; Vanlube
!34$,
an octylated diphenylamine antioxidant available from Fi. T. l/anderbilt
Company, Inc; Nasul ISSN, a barium dinonylnaphthenate additive available
from king Industries, lnc. Finally, each of the two greases were milled at
7,000
psi using a Caaulin homogenizer. The two greases had the following
3 0 compositions:
-42-
Test Grease Ex~33 ~x~34
Component, % (wt)
850 SUS Oil 56.39 54.46
350 SUS Oil 28.41 27.44
Polyurea Thickener 8.00 8.00
Tricalcium Phosphate 2.00 3.20
Calcium Carbonate 2.00 3.20
Shellvis 40 2.00 3.20
1 0 Nasul BSN 1.00 ----
Lubrizol5391 ---- 0.30
Vanlube 848 0.20 0.20
-43-
~~'~r ~,~~
The grease was tested and had the following performance properties:
Worked Penetration, ASTM D217 391 ' 357
Dropping Point, F, ASTM D2265 503 520
Four Ball Wear, ASTM D2266 at
40 kg, 1200 rpm for 1 hr. 0.49 0.40
Four Ball EP, ASTM D2596
last nonseizure load, kg 63 40
weld load, kg 315 315
1 load wear index 38.1 41.9
0
Optimol SRV Stepioad Test, 80C
Maximum Passing Load, Newtans 900 900
Optimol SRV Wear Test, 200 N,
1 hr,
80C, scar depth, micro-inches 40 17
1 scar width, inches 0.014 0.018
5
U.S. Steel Grease
Mobility Test, S-75,
at -20F, grams/minute
50 PSI 0.20 ---
20 100 PSI 1,36 ---
150 PSI 2.63 ___
Results were very good. Optimol SRV stepload and wear test results in
particular indicate the superior extreme pressure antiwear performance of the.
2 5 two test greases. The Optimol SRV stepload test is the procedure
recommended by Optimol Lubricants, inc. and used by Automotive
Manufacturers such as General Motors for lubricant evaluation. This meth
was also specified by the U.S. Air Force Laboratories Test Procedure of March
6, 1985. In the t~st, a 10 mm st~el ball is oscillated under load increments
of
3 0 100 newtons on a lapped steel disc lubricated with the grease being tested
until seizure ocxurs.
The Optimol SRV wear test is a similar procedure in which the load is
maintained at the specified level for the specified time and temperature
conditions. At the conclusion of the time interval the bottom disk is cleaned
3 5 with heptane and the west scar is measured using a profilometer. Both scar
-44-
~~~~~a~~
depth and width measurements are recorded as an indication of the wear that
occurred during the test.
It can be s~en that both greases are of softer consistencies generally
desired for use as railroad track/wheel flange greases. The grease of
Example 33 is nearly an NLGI 00 grade; the grease of Example 34 is an NLGI
0 grade. Both greases exhibited distinct adherence properties in that when a
layer or film of either grease was applied to a flat, steel surface, the
grease
could not be entirely removed by manual wiping, regardless of the farce used
or the number of repetitions. The only way that either of the greases could be
1 0 removed from the flat, steel surface was to wash it off using heptane
solvent.
The grease of Example 34 appeared to be the most adherent, in keeping with
its higher level of Shellvis 40 polymer.
Ex~,m_ples 35-36
Another polyurea base grease was prepared in a manner similar to that
1 S of Example 1, except that a paraffinic, solvent-extracted base oil having
a
viscosity of 150 SUS at 100°F was used instead of the 350 SUS oil. Two
rail
track/wheel flange greases were prepared from portions of that polyurea base
grease using a procedure similar to that of Examples 33-34. The two greases
had the following compositions:
Component, % (wt)
550 SUS fail 54.73 54.06
150 SUS Gii 27:57 27.24
2 S Polyurea Thickener 5.00 5.00
Tricalcium Phosphate 5.00 5.00
Calciurre Carbonate 5.00 5.00
Shellvis 40 2.00 3.00
Lubrizol5391 0.50 0.50
3 0 Vanlub~ 84~ 0.20 0.20
The grease was tested and had the fallowing performance properties:
_ 45 -
Worked Penetration, ASTM D217 441
431
Dropping Point, F, ASTM D2265 471
480
Four Ball Wear, ASTM D2266 at
40 kg, 1200 rpm for 1 hr 0.45 0
45
Four Ball EP, ASTM D2596 .
last nonseizure load, kg 63
63
weld load, kg
620 400
oad wear index 59.6 46
7
Optimol SRV Stepload Test, 80C .
I 0 Maximum Passing Load, Newtons 1,000 900
.
Optimol SRV Stepload Test, 150C
Maximum Passing load, Newtons 900 900
Optimol SRV Wear Test, 200 N, 1 hr,
80C, scar depth, micro-inches 25 22
I S scar width, inches 0.018 0.016
U.S. Steel Greasy
Mobility Test, S-75,
at -20F, grams/minute
50 PSI 1.05 0
25
100 PSI 3.42 .
1.15
150 PSI 5.62 2.02
Copper Strip Corrosion,
ASTM D4048, 300F, 24 hr. 1 A 1 A
2 5 As can b~ seen, resuPts were excellent. The higher level of tricalcium
phosphate and calcium carbonate produced generally higher levels of
extr~me pressure antiwear pert~rmance when compared to tha grass~s of
Exampl~s 33-34. The Optimol SRV stepload test results at 150°C
indibate that
the ex;r~me pressure antiurear performance is maintained at greatly elevated
3 0 temperatures. The Copper Strip Corrosion test result indicates that
despite the
excellent extreme pressur~ antiwear performanc~, the grease is not
chemically corrosive at high temperatures. As with the greases of Examples
33-34, both greyses appeared quite adherent when applied t~ metal surfaces,
with the grease of Exampi~ 36 being the more adherent of the two. The
3 5 greater adherence of the Example 36 grease an also be seen by its reduced
mobility, compared with the Example 35 grease. However, the grease of
Example 36 had similar mobility to the grease of Example 33.
-46-
~~'~ ~, j ~!~;
Exams la a 37
A railroad track/wheel flange grease was prepared in a manner similar
to that of Examples 35-36, except that the final milling was done using a
Gaulin Homogenizer at 5,000 psi. The grease also contained blue dye for
cosmetic purposes. The grease had the following composition:
Component % (wt
850 SUS Oil 53.81
150 SUS Oil 27.11
Polyurea Thickener 6.00
1 0 Tricalcium Phosphate 5.14
Calcium Carbonate 5.14
Shellvis 40 2.06
Lubrizol 5391 0.50
Vanluba 848 0.20
1 5 Blue Dya 0.04
The grease was tasted and had the following performance properties:
Worked Penetration, ASTM D217 396
Dropping Point, F, ASTM D2265 463
Oil Separations, SDM 433,
2 0 24 hr, 212F 0.5
24 hr, 300F 2,6
24 hr, 350F 26.5
Four Ball Waar, ASTM D2266 at
40 kg, 1200 rpm fbr 1 hr 0.45
2 5 Four Ball A=P, ASTM D2596
last nonsaizura load, kg 80
weld load, kg 400
load wear index 50.6
Optimol SRV Stapload Test, 80C
~ 0 Maximum Passing Load, Newtons 900
Optimol SRV Stepload Tast, 150C
Maximum Passing Load, IVawtons 900
Test results ware good. Oil separation
was measured by the oif
3 5 separation cone fast (bleed test),
SDM 433 standard test of the Saginaw
_ 47 _
~~~~~1>J
Steering Gear Division of General Motors. In the test, the grease was placed
on a 60 mesh nickel screen cone. The cone was heated in an oven for the
indicated time at the listed temperature. The percentage decrease in the
weight of the grease was measured. Oil separation is very good for
212°F and
300°F, but increased dramatically at 350°F. The extremely
adherent texture
demonstrated in Examples 33-36 was present in this grease as well. The
consistency of the grease was between NLGI grades 0 and 00.
Example 38
Another railroad track/wheel flange grease was prepared in a manner
1 0 similar to that of Example 37. The grease had the following composition:
C~gonent
850 SUS Oil ~ 53.45
150 SUS Oil 26.93
Polyurea Thickener 6,88
1 5 Tricalcium Phosphate 5.00
Calcium Carbonate 5.00
Shellvis 40 2.00
Lubrizol 5391 0,50
Vanlube 848 0.20
2 0 Blue Dye 0.04
The grease was tested and had the following performance properties:
Worked Penetration, ASTN1 D217 378
Dropping Point, f=, ASTNI D2265 497
2 5 Oil Separations, SDM 433,
24 hr, 212F 0.5
24 hr, 300F 0.3
24 hr, 350F' S.5
Four Ball Wear, AST~1 D2266 at
3 0 40 kg, 1200 rpm for 9 hr 0.44
Four Ball EP, ASTAA D2596
last nonseizur~ load, kg 63
weld load, kg 620
load wear index 60.6
3 5 Optimal SRV Stepload Test, 80C.,
, ,
Maximum Passing Load, Newtons 800
Optimol SRV Stepload Test, 150C
Maximum Passing Load, Newtons 900
U.S. Steel Greasy
Mobility Test, S-75,
at -20F, grams/minute
50 PSI 0.80
100 PSI 1.91
150 PSI 2.54
The resulting grease had a consistency of NLGI grade 0. Oil separation
at 350°F was greatly improved over that of Example 37.
Exam,
Another railroad track/wheel flange grease was prepared in a manner
1 5 similar to Example 38 except that the final milling was done at 7,000 psi
using
a Gaulin Homogenizer. The grease had the following composition:
Coma neat % (wt)
850 SUS Oil 56.03
150 SUS Oil 28.23
2 0 Polyurea Thickener 3.00
Tricalcium Phosphate 5.00
Calcium Carbonate 5.00
Shellvis 40 2.00
Lubrizol 5391 0.50
2 5 Vaniube 848 0.20
Blue Dye 0.04
The grease was tested and had the following per#ormanc~ properties:
ll~o~ed Penetration, ASTM D217 449
Dropping Point, F, ASTM D2265 458
3 0 Four Bail dear, ASTM D2266 at
. 40 kg, 1200 rpm for 1 hr 0.49
Four Ball EP, ASTM D2596
last nOnSelzUre goad, kg 63
weld IoacJ, kg 400
3 5 load wear index 50.0
_4g_
Optimol SRV Stepload Test, 80°C
Maximum Passing Load, Newtons 900
Optimol SRV Stepload Test, 150°C
Maximum Passing Load, Newtons 800
U.S. Steel Grease
Mobility Test, S-75,
at -20°F, grams/minute
50 PSI 1.1p
100 PSI 3.82
1 0 150 PSI 6.17
The resulting grease was essentially an NLGI grade 000 in consistency.
Despite its very soft consistency, the texture was quite adherent. Like
earlier
examples, when the grease was applied as a layer or film to a flat, steel
1 5 surface, the only m~thod which could completely remove it was to use a
solvent such as heptane.
Exams s 40-42
A polyurea base grease was prepared in a manner similar to Example
1, except that a paraffinic, solvent-extracted base oil with a viscosity of
150
2 0 SUS at 100°F was used instead of the paraffinic, solvent extracted
850 SUS
oil. This base grease was stirred and heated to 300°F and Shelivis 40
was
added. The gP~ase was allowed to mix while cooling to 250°F. Then the
grease was cyclically millod with a rotating knife mill to insure complete
disp~rsion of th~ Sheilvis 40 polymer in the base grease. The final
2 5 composition of the polymer-additiaed polyurea base grease was:
Component %% (w:)
850 SUS ~i1 64.59
150 SUS C~ii 16.6f
3 0 P~lyurea Thickener 15.00
Shellvis 40 3.75
Three portions of the p~lymer-additized polyurea base grease were
separately finished in ~ greaso kettle by addition of (dasul BSN, Va~lube 848,
3 5 and graphite. Each of the three finished greases c~ntained a different
type of
graphite. The three graphites used were: Superior Graphite No. 9039, a
synthetic graphite (graphitic carbon) with a mean particle sire of about 3.5
50 _
microns and comprising about 90% graphite structure; Superior Graphite No.
4939, a high temperature purified natural graphite with a mean particle size
of
about 3.5 microns and comprising nearly 100% graphite structure; Superior
Graphite No. 3226, an "amorphous graphite" comprising about 75% carbon by
S weight with the remaining material comprising oxides of iron, aluminum, and
silicon. The Superior Graphite No. 3226 comprised virtually no extended
graphite structure. All three graphites are available from Superior Graphite
Company. The three greases had the following compositions:
Te~L~~ease Ex~40 Ex~41 Ex~42
Component, % (wt)
850 SUS ~i1 ~ 53.23 53.23 53.23
150 SUS Oil 26.82 26.82 26.82
1 S Polyuraa Thickener 7.00 7.00 7.00
Superior Graphite No. 9030 10.00 ---- ____
Superior Graphite No. 3226 ---- 10.00 ----
Superior Graphite No. 4939 ---- ---- 10.00
Shallvis 40 1.75 1.75 1.75
2 0 Nasul BSN 1.00 1.00 1.00
Vanlube 848 0.20 0.20 0.20
Th~ greases were tested and had the following performance
properties:
25
,
Worked Penetration, ASTAA D217364 376 382
Dropping Point, F, ASTM D2265 500+ 509 508
Four Ball Wear, ASTP~9 D2266
at
40 kg, 1200 rpm for 1 hr. 0.66 0.63 0.61
3 0 Four Ball EP, ASTAA D2596
last nonseizure load, kg 40 40 32
weld load, kg 250 160 200
load wear index 32.4 29.6 27.8
~ptimol SRV Stapload Tast,
80C
3 5 PUlaximum Passing Load, 200 400 ----
Nawtons
Optimol SRV Stapload Test,
150C
PAaximum Passing Load, Nevvtons-- - 400 _-__
~
. 51 _
Optimol SRV Wear Test, 200
N, 1 hr.,
80C, scar depth, micro-inches 200 252 146
scar width, inches 0.026 0.028 0.026
U.S. Steel Grease
Mobility Test, S-75,
at -20F, grams/minute
50 PSI 0.23 ---- ----
100 PSI 0.85 ---- ----
150 P.SI 1.37 ---- ----
1 0 Copper Strip Corrosion,
ASTM D4048, 300F, 24 hr. 2C 2C 2C
Although all three greases exhibited an adhesive texture, the overall
test results on all three greases were poor. Extreme pressure antiwear
1 5 performance of all three graphite greases was generaAy inferior to the
greases
of Examples 33-36. Optimol SRV stepload and wear test data was particularly
poor, with the amorphous graphite grease of Example 41 being the worst.
This is undoubtedly due to the high level of abrasive oxides of iron,
aluminum,
and silicon prosent in that graphite. The least abrasive graphite grease was
2 0 Example 42, containing the purified natural graphite. However, even that
grease gave far more SRV wear depth than the novel railroad track/wheel
flange greases of Examples 33-36. Also, all three graphite greases were
highly corrosive at 300°F as evidenc~d by the Copper Strip test
results. The
reason for this is not clear, but may be due to corrosive impurities adsorbed
on
2 5 the surface of graphites:
Exam X43
A sample of a stable graphite dispersion in mineral oil sold under the
name of Rail Lube No. 32 by Superior Graphite was evaluated. Rail Lube No.
3 0 32 is a high graphite content material marketed as a railroad tra~k/wheel
flange Iubricant.The sample of Rail Lube No. 32 was tested and had the
following performance prop~rcies.
Four Sell Wear, ASTM D2266 at
3 5 40 kg, 1200 rpm for 1 hr 1.00
Four Sali EP, ASTM D2596
last nonseizure load, kg 50
-52-
weld load, kg 500
load wear index g7, ~
Optimol SRV Stepload Test, 80C
Maximum Passing Load, Newtons 300
Optimol SRV Stepload Test, 150C
Maximum Passing Load, Newtons 300
Optimol SRV Wear Test, 200 N, 1 hr,
80C, scar depth, micro-inches 420
scar width, inches 0.040
1 0 Copper Strip Corrosion,
ASTM D4048, 300F, 24 hr. 4~a
Although th~ Rail Lube No. 32 gave good Four Ball EP test results, it
gave extremely bad results on all other extreme pressure antiwear tests. The
1 5 Four Salt Wear and Optimol SRV Wear results were particularly bad
,indicating
the highly abrasive nature of this high graphite dispersion. As with the
previous three graphite greases, this graphite dispersion was also very
corrosive as indicated by the 300°F Copper Strip Corrosion Test.
scam I~,e 44
A lithium 12-hydroxystearate thickened rail track/wheel flange gr~as~
using molybdenum disulfide was made as follows. A 27.91 pound portion of
850 SUS oil was added to a grease kettle. The oil was heated using a hot
heat transfer oil recirculating through the kettle jacket. While heating and
~ 5 stirring, 3,261.92 grams of methyl 12-hydroxystea~at~ were added. The
mixture was stirred at 177°F until all the ester had melted and mixed
with the
oil. Than 503.24 grams of lithium hydroxide monohydrate arid 300 ml of water
were added and the gr~ase kettle was sealed shut. The kettl~ was then
heated until the internal temperature was 220°F: The contents were
stirred for
3.0 one hour at that temperature under sealed conditions. The contents were
then
further heated to 340°F while continuing to stir under sealed
conditions. When
the internal pressure of the kettle reached 105 psi, the kettle was vented
through a port located at the top of the kettle i'sd. When the internal
pressure
had been completely bled off, the kettle ayes op~ned to reveal a heavy, dry
3 5 base grease. To the base grease was added 1,589 grams of Sh~ilvis 40 and
105.93 grams of Vanlube 848. The grease was then stirred and heated to
410°F while slowly adding 3,602 grams of 850 SIDS oil. An additional
3.5
-53-
pounds of 850 SUS oil and 19.82 pounds of 150 SUS oil were slowly added.
When 410°F was reached, the melted grease was cyclically milled
using a
rotating knife blade mill while slowly cooling. The cyclic milling was stopped
when the grease temperature cooled to 376°F. When the grease was cooled
S to 250°F, a portion was removed and stored for other use. The
remainder was
finished with Lubrizol 5391, molybdenum disulfide and additional 850 SUS oil
and 150 SUS oil. The finished grease was milled with a rotor-stator mill using
a gap setting of 0.005 inches. The final grease had the following composition:
ComDOnen_t
850 SUS Oil 59.34
150 SUS Oil 29.90
Lithium 12-hydroxystearate 5.00
1 5 Excess Lithium hydroxide 0.06
Shellvis 40 2.50
Molybdenum disulfide 2.50
Lubrizol 5391 0.50
Vanlube 848 0.20
The grease was tested and had the following performance
properties:
Worked Penetration, ASTM D217 318
2 5 Dropping Point, F, ASTM D2265 414
~i1 Separations, SDM 433,
24 hr, 212F , 0.4
24 hr, 300F 5.0
24 hr, 350F 20.6
3 0 Four Sall W~ar, ASTM D2266 at
40 kg, 1200 rpm for 1 hr 0.48
Four Bali EP, ASTM D2596
last nonseizure load, kg 63
weld load, kg 250
3 5 load enrear index 32.0
Optimol SRV Stepload Test, 80C
Maximum Passing Load, Newtons 300
-54-
tJ.S. Steel Grease
Mobility Test, S-75,
at -20°F, grams/minute
50 PSI 1.05
100 PSI 4.81
150 PSI 7.64
Copper Strip Corrosion,
ASTM D4048, 300°F, 24 hr. 4A
1 0 The grease of Example 44 generally gave better extreme pressure
antiwear performance than the preceding graphit~-containing compositions.
However, it was not as good as the extreme pressure antiwear performance of
the railroad track/wheel flange greases of Examples 33-39. Like the
preceding graphite-containing compositions, th~ molybdenum disulfide
1 5 grease of Example 44 showed corrosive properties as ndicated by the
300°F
Copper Strip Corrosion Test. This is attributable to the inorganic sulfur
present
in molybdenum disulfide.
Exam I
2 0 A sample of another commercially available rail track/wheel flange
greas~ sold by Mobii OiI Company and~r the brand name of Mobil Curve
Grease 213 was obtained and evaluated. Mobil Rail Curve Gr~ase 213 is a
lithium 12-hydroxystearate thickened grease containing 3%(wt) molybdenum
disulfide. The consistency of this product is N~G9 grad~a i . An IVLG! grade
000
2 5 product essentially equivalent to this product (~xc~pt for consistency) is
also
available from Mobi! under the brand name of Mobil Curve Grease 213-000.
The s~mpl~ of Mobil Curv~ Grease 213 was tested and had the following per
formance properties:
Worked Penetration, ASTM D217 317
Dropping Point, F, ASTM D2265 363
Oil Separations, SDM 433,
24 hr, 212F 2.2
24 hr, 300F 7.0
3 5 24 hr, 350F 17.3
Four SaiB Wear, ASTM D2266 at
40 kg, 1200 rpm for i hr 0.50
-55-
Four Ball EP, ASTM D2596
last nonseizure load, kg 63
weld load, kg 250
load wear index 32.6
Optimoi SRV Stepload Test, 80C
Maximum Passing Load, Newtons 300
Optimal SRV Stepload Test, 150C
Maximum Passing Load, Newtons 200
Optimol SRV Wear Test, 200 N, 1 hr,
1 0 80C, scar depth, micro-inches 120
scar width, inches 0.020
U.S. Steel Grease
Mobility Test, S-75,
at -20F, grams/minute
1 S 50 PSI 0.92
100 PSI 3.35
150 PSI 4.97
Copper Strip Corrosion,
ASTM D4048, 300F, 24 hr. 4B
2 0 Test results for the Mobil Curve Grease 213 are generally similar to to
thos~ of Exampl~ 44. Optimol SRV Wear Test results ar~ significantly inferior
to the rail traclc/wheel flange greases of Exampl~s 33-36.
Exam Ip a 46,
2 5 The rail track/wheel flange greas~ of Example 39 was evaluated by a
major eastern U.S. railroad. Eight other lubricants were also evaluated
including: three lubricants comprising graphite; three lubricants cbmprising
molybdenum disulfide; one lubricant comprising an oiB-soluble extreme
pressure antiwear additive package; one lubricant having no extreme
3 0 pressure antiwear additive. Among thos~ eight lubricants w~re the graphite
dispersion of Exampl~ 43 and th~ molybdenum disulfid~ lubricant Mbbil Curve
Grease 213-000 mentioned in Exampl~ 45.
Th~ evaluation was done at a specie! test track facility in Pueblo,
Colorado using a train consisting of a locomotive, twenty-four loaded 100 ton
3 5 hopper cars, and a special instrumentation car. The instrum~ntation car
was
designed specifically to measure the work done by the locomotive to pull the
train around the test track: This parameter way used to compare th~
:~-
effectiveness of rail tracWwheel flange lubricants to reduce friction at the
rail/flange interface thereby increasing fuel economy. The grease of Example
39 performed well, providing work reductions equal to or exceeding all other
greases tested. Also, the grease of Example 39 was the only extreme
pressure antiwear lubricant tested which did not contain components
corrosive at high temperatures such as 300°F or higher.
Further work done by the railroad company indicated that all the
graphite-containing lubricants promoted abrasive wear to on-board lubricator
equipment. The rail tracWwheel flange lubricant grease of Example 39 used a
1 0 food grade extreme pressure antiwear additive package.
JE~,;~m~l
Although graphite-containing lubricants can be abrasiv~ and of inferior
antiwear performance, the performance of such lubricants can be significantly
1 5 improved by incorporating the novel technology illustrated by Examples 33-
39.
A lubricating grease was made by a procedure similar to that of the polyurea-
thickened graphite grease of Example 40, except that tricalcium phosphate
and calcium carbonate were also added. The grease had the following
composition:
Comb
850 SUS Oil 52.27
150 SUS Oil 26.33
2 5 Superior Graphite No. 9039 10.00
Polyurea Thickener 5.00
Tricalcium Phosphate 2.00
Calcium Carbonate 2.00
Shellvis 40 2.00
3 0 Lubrizol 5391 0.20
Vanlube 848 0.20
_57_
The grease was tested and had the following pertormance properties:
Worked Penetration, ASTM D217 441
Dropping Point, F, ASTM D2265 473
Four Bail Wear, ASTM D2266 at
40 kg, 1200 rpm for 1 hr 0.50
Four Ball EP, ASTM D2596
last nonseizure load, kg 50
weld load, kg 400
load wear index 46,7
1 0 Optimol SRV Stepload Test, 80C
Maximum Passing Load, Newtons 400
Optimol SRV Stepload Test, 150C
Maximum Passing Load, Newtons 600
Optimol SRV Wear Test, 200 (J, 1 hr,
1 5 80C, scar depth, micro-inches 50
scar width, inches ~ 0.016
U.S. Steel Grease
Mobility Test, S-75,
at -20F, grams/minute
2 0 50 PSI 0.65
100 PSi 2.42
150 PSI 3.66
r3oth this grgasa and the grease of Example 40 exhibited significant
adhesive textur~. However, significant different~s between this grease and
2 5 the Example 40 grease exist. Sy comparing the r~sults of this grease with
that
of Example 40, one can see that the extreme pressure antiwear properties
have significantly improved by incorporating the tricalcium phospt~at~ and
cahium carbonate into the graphite grass~, The Optimol SRV Wbar
improvement is especially surprising since the poor SRV Waar pertormance of
3 0 the Example 40 grease was most likely due to abrasive contaminants.
Abrasive wear cannot generally be reduced by complementary inclusion of
other extreme pr~ssure antiwear additives: Therefore, the improved overall
extreme pressure antiv~ear performance of the grease of Example 47 is a
surprising and unexpected benefit of the novel technology described herein.
. 56 .
Exam~'~e 48
The grease of Example 39 contained only 3%(wt) of polyurea thickener,
a level far belaw thickener levels typical of polyurea-thickened lubricating
greases. Even so, the resulting Example 39 grease retained a stable grease
structure.This suggests that it may be possible to reduce the polyurea
thickener even further or even eliminate it while still retaining a stable
grease
structure. To investigate that possibility the following composition was made.
To a grease kettle was added 24.8 pounds of 850 SUS oil, 12.5 pounds of 150
SUS oil, 5.0 pounds of tricalcium phosphate, 5.0 pounds of calcium carbonate,
1 0 90.8 grams of Vanlube 848, 908.0 grams of Shellvis 40, and 9.08 grams of
blue dye. The mixture was stirred and heated to 300°F by circulating
hot heat
exchange fluid through the kettle jacket. At 300°F the mixture was
cyclically
milled using a rotating knife blade mill. The mixture took on a distinctly
adhesive grass~-like textur~. The grease was cooled to 200°F and 227.0
1 5 grams of bubrizol 5391 was mixed into the grease. The grease was cooled to
152°F and then milled out into a storage container, using the rotating
knife
blade mill. The resulting composition had a very adhesive grease texture
which was stable. No visible separation of components occurred even after
one year of room temperature storage. The grease had the following
2 0 composition:
component
850 SUS Oil 49.58
2 5 150 SUS Oil 24.98
Tricalcium Phosphate 10.00
Calcium Carbonate 10.00
Shellvis 40 4.00
t_ubrizo! 5391 1.00
3 0 Vanlube 848 0.40
Blue Dye 0.04
-5g-
The grease was tested and had the following performance properties:
Worked Penetration, ASTM D217
S Worked 60 strokes 400
Worked 10,000 strokes 406
Worked 100,000 strokes 411
Dropping Point, F, ASTM D2265 302
Four Ball Wear, ASTM D2266 at
1 0 40 kg, 1200 rpm for 1 hr 0.68
Four Ball EP, ASTM D2596
last nonseizure load, kg 63
weld load, kg 800
load wear index ' 89.7
1 5 ~ptimol SRV Stepload Test, 80C
Maximum Passing Load, Newtons 700
Optimol SRV Stepload Test, 150C
Maximum Passing Load, Plewtons 700
2 0 The gre~sa was extremely adhesive. Removal from a flat, steel surface
was accomplished only with repeated application of a solvent such as
heptane. The grease had excellent shear stability as indicated by the very
small change in penetration upon 100,000 strokes of working. Even after such
shearing, the extreme adhesive texture remained unaltered. Extrem~
2 5 pressure antiwear properties were generally good although the Four Ball
Wear was higher than the greases of Examples 33-39.
-s~-
Examples 49-50
Two compositions were made by adding 850 SUS oil and Shalvis 40 to
a grease kettle, and than heating, mixing, and milling in a manner similar to
that of Example 48. Final compositions are given below:
Ted jybricant Ex~"49 Ex~50
Component, % (wt)
850 SUS Oil 96.00 94.00
Shellvis 40 4.00 6.00
1 0 Both products were viscous mineral oil solutions of the polymeric
additive but did not have any grease structure.
~xamcaie 51
A lubricant composition was made by adding 850 SUS oil, tricalcium
1 5 phosphate, and calcium carbonate to a grease kettle, and then heating,
mixing, and milling in a manner similar to that of Example 48. Final
compositions are given below:
Com onent % (wt1
850 SUS Oil 80.00
Tricaloium Phosphate 10.00
Calcium Carbonate 10.00
2 5 The composition was, as expected, unstable. As soon as the mixture
was milled out into a five gallon container, the solid tricalcium phosphate
and
calcium carbonate quickly and completely settled out. Pdo grease structure
could be obtained. The results of Examples 48-51 show that th~ polymeric
additiv~, iricalcium phosphate; and calcium carbonate intee~ct to form a
3 0 greasy structure, even when conventional greas~ thickeners such as
polyurea, or metal fatty acid salts are not present. Furthermore, Examples 49-
51 Shaw that this interactian could not hav~ been anticipated from th~
prop~rti~s of either th~ poiym~r or the tricalcium phosphat~ and calcium
carbonate alone.
. 61 _
~~~~~~a
Exam, IQ a 52,
Another composition was made in a manner similar to Example 51.
Calcium sulfate and calcium hydroxide were used instead of tricalcium
phosphate and a blend of 850 SUS oil and 150 SUS oil was used instead of
850 SUS oil alone. The oil soluble additives Vanlube 848 and Lubrizol 5391
were also used. The final blend composition was as follows:
Comi o~ nent % (wt)
850 SUS Oil 50.00
1 0 150 SUS Oil 25.52
Calcium Sulfate ~ 10.42
Calcium Carbonate 10.42
Calcium Hydroxide 2.08
Lubrizol 5391 1.04
1 5 Vanlube 848 0.52
Just as with the composition of Example 51, this composition did not
exhibit any grease structure. The solid calcium sulfate, calcium carbonate,
and calcium hydroxide quickly and completely settled out of the oil.
2 0 Examples 53-55
Thre~ lubricating greases were made in a manner similar to Example
52, except that they also comprised the polymeric additive Shellvis 40. The
three greases had th~ following compositions:
2 5 T~st Grease , x, 54
Component, % (wt)
850 SUS Oil 48.00 40.71 39.39
150 SUS Oil 24.50 29.79 20.11
Calcium Sulfate 10.00 15.00 15.00
3 0 Calcium Carbonate 10.00 15.00 15.00
Calcium Hyt~roxide 2.00 3.00 3.00
Shsllvis 40 4.00 4.00 6.00
Lubrizol 5391 1.00 1.00 1.00
vanlub~ 84~ 0.50 0.50 0.50
. 62 -
The greases were tested and had the
following performance properties:
Worked Penetration, ASTM D217 -- -- 344
Dropping Point, F, ASTM D2265 -- -- 350
Four Ball Wear, ASTM D2266 at
S 40 kg, 1200 rpm far 1 hr -- -- 0.55
Four Ball EP, ASTM D2596
last nonseizure load, kg -- -- 50
weld load, kg -- -- 500
load wear index - , -- 65.1
1 0 Optimol SRV Stepload Test, 80C
Maximum Passing Load, Newtons 800 700 600
Optimol SRV Stepload Test, 150C
Maximum Passing Load, Newtons -- 800 600
All thre~ compositions were stable having an extremely
greases
1 5 adhesive texture.
Fxarryc~l~a6
A lubricating grease was made in a manner similar to that to Examples
53-55, except that low~r levels of the calcium sulfate, calcium carbonate,
calcium hydroxide, and Shellvis 40 were used. Also, an additional sthylene-
2 0 propyl~na copolymer Functional V-188, available from Functional Products,
Inc. was used. The grease had the following composition:
C,~~~on~nt °70 (wtl
2 5 850 SUS Oil 50.87
150 SUS Oii 25.63
Calcium Sulfate 8.00
Calcium Carbonate 8.00
Calcium Hydroxid~ 1.50
3 0 Shgltvis 40 2.00
Functi~nal V-188 2.50
Lubrizol 5391 1.00
Vanlube 848 0.50
_ 63 .
The grease was tested and had the fiollowing performance properties:
iNorked Penetration, ASTM D217 605.
Four Ball Wear, ASTM D2266 at
40 kg, 1200 rpm for 1 hr 0.42
Four Ball EP, ASTM D2596
last nonseizure load, kg 80
weld toad, kg 800+
load wear index 100+
1 0 Copper Strip Corrosion,
ASTM D4048, 300F, 24 hr 1 A
The resulting composition was a very soft, semi-fluid grease with an
adhesive and somewhat stringy texture. Upon standing at room temperature
1 5 for five months, syneresis had occurred. Simple stirring with a ste~!
spatula
restored the original appearance and texture.
Exam leis 57-61
Five portions of the grease of Example 48 were augmented with varying
2 0 amounts of several oil soluble antiwear additives. The additives used
were:
Durad 150, a triaryl phosphate available from FMC Corporation; Amoco 198, a
zinc diaikyidithiophosphate available from Amoco Petroleum Additives
Company; Lubrizol 606~A, a sulfur-phosphorus industrial gear oil additive
package; Vanlube 7723, a 4,4'-methylene bis(dibutyldithiocarbamate) additive
2 5 available from Fd. T. Vanderbiit Company, Inc. The five greases had the
following compositions:
T,~ar,~ eas~ Ex~Sg ~x 60 Ex 61
Component, % (wt)
Example 48 Grease 98.50 99.50 96.00 94.00 96.00
Durad 150 1.50 -- -- 3.00 --
Amoco 198 - 0.50 -- -_ __
Vaniube 7723 -- -- 4.00 3.00 --
Lubrizol6063A -_ __ -_ ._ 4.00
The greases were tested and had the following performance properties:
-64-
Four Bafl Wear, ASTM D2266 at
40 kg, 1200 rpm ''
for 1 hr. 0.63 0.53 0.72 0.48 0.46
By comparing the above Four Ball Wear test results with those of
Example 48, one can see the level of improvement afforded by the additives.
Durad 150 gave little improvement; Vanlube 7723 gave none. Their combined
use gave significant improvement. Amoco 198 gave only modest
1 0 improvement in enliwaat performance. Lubrizol 6063A gave good
improvement. The use of sulfur-containing organic additives such as Vanlube
7723, Amoco 198, or Lubrizol 6063A will result in increased corrosivity at
high
temperatures. However, for applications where such properties are not
important, then compositions such as those in Examples 57-61 can be used.
Examples 62-63
A polyurea bass grease is made in a manner similar to Example 1,
except that all the base oil used was 850 SUS oil. The final composition was
as follows:
zo
ysZm_ponent
850 SUS Oil 78.00
F'olyurea 22.00
Two lubricating greases were made in a manner similar to Examples
53-55, except that very minor amounts of polyurea were also incorporated into
the grasses. The 22 %(wt) polyurea base grease in 850 SUS oil was used as
the sourc~ of polyurea. Also, a paraffinic, solvent-extracted 350 SUS base oil
3 0 similar to that used in Example 1 was used instead of 850 SUS oil. The two
greases had the following compositions:
_65_
~~gst Gr_eas~ Ex~62
Component, % (wt)
350 SUS Oii 69.64 63.37
850 SUS Oil 2.36 3.53
S Calcium Sulfate 10.00 12.00
Calcium Carbonate 10.00 12.00
Calcium Hydroxide 2.00 2.40
Shellvis 40 4.00 4.00
Polyurea 0.67 1.00
Lubrizol5391' 1.00 1.20
Vanlube 848 0.33 0.50
The grease was tested and had the following performance properties:
1 5 Worked Penetration, ASTM D217
Worked 60 strokes 322 328
Worked 100,000 strokes 323 327
Oil Separations, SDM 433, !
24 hr, 212F 0 0
2 0 24 hr, 300F 0.1 ~ 0
24 hr, 350F 0.5 3.2
Dropping Point, F, ASTM D2265 403 397
Four Ball VIIear, ASTM D2266
at
40 kg, 1200 rpm for 1 hr 0.40 0.60
2 5 Four Ball EP, ASTM D2596 .
last nonseizure load, kg 80 ao
weld had, kg aoo~. s2o
had wear index 110. 80.0
Optimol SI~V Stepload Test, 80C
3 0 AAaximum Passing Load, Newtons 1,000 900
By comparing the results of these tyro greases with pr~vious Examples,
one can see that even very small levels of polyurea are enough t~ raise the
dropping point and improve high temperature oil separation significantly. As
3 5 with earlier greases, th~ two greases of Examples 62-63 had an extremely
adhesiv~ texture.
-66-
Examc~les 64-67
The dropping point of greases similar to those of Example 48 and
Examples 53-56 can also be increased by addition of very minor levels of
materials such as clays and fumed silica, or other similar materials. Several
portions of the grease of Example 55 were augmented with amounts of the
following materials: Bentone 34, a bentonite clay material available from N.
L.
Industries; Cab-0-Sil, a fumed silica available from Cabot Corporation having
a 0.2 micron mean aggregate length. Although silica (silicon dioxide) is
1 0 usually quite abrasive and should be avoided in high performance
lubricants,
fumed silica of this type can be satisfactorily used. The reason for this is
the
extremely small particle size of the fumed silica in the final grease and
nature
of the surface of those particles. The gentone 34 and Cab-O-Sil were added
to the Example 55 grease, stirred with a steel spatula and heated to about
1 5 300°F. The greases were then milled with a three-roll mill to
achieve a
homogenous grease. Four such greases were prepared and had the
following compositions:
Test Grease Ex. 64 Ex. 65 Ex. 66 Ex. 67
2 0 Component, % (wt)
Example 55 Grease 97.00 97.00 99.00 99.00
Bentone 34 3.00 --- 1,00 ---
Cab-O-Sil _-_ 3.00 __- 1.00
2 5 The greases were tested and had the following dropping points:
Dropping Point, °F,
ASTlv) D2265 532 560+ 393 386
3 0 All of the above four greases had dropping points which had been
significantly increased compared to that of the Example 55 grass~.
Eoeam I
To a portion of the grease of Example 62 was added a polyalkylene
3 5 polymer having a molecular weight greater than 20,000,000, sold under the
brand nam~ of CDR-102, and available from Conoco Specially Products, Inc.
The grease was mixed well at about 300°F and then mill~d using a
three-roll
_67_
mill to obtain a homogenous grease. The resulting grease had the following
composition:
Cod, onent °(~(wt1
Example 62 Grease 97.00
CDR-102 3.00
The grease had the same adherent texture as the original Example 62
grease but also had an additional extreme stringy or gutty textur~. This added
1 0 texture! feature was imparted by the extremely high molecular weight CDR-
102. Even after the shearing conditions impareed during milling, the molecular
weight of the CDR-102 was high enough to give the stringy texture. The ability
of the grease to string-out when touched by and pulled apart from two surfaces
is actually more a measure of cohesion and not adhesion. Such cohesive
1 5 properties~are not necessarily beneficial in applications such as railroad
track/wheel flange greases unless good adhesive properties also exist.
However, many potential customers of such greases believe that a stringy
texture is an indication of good adhesive properties. Therefore, if such a
property is included in the grease while also insuring good adhesive
2 0 properties, the grease becomes more attractive. Applicant's use of an
adhesive poiym~r such as styrene-isopren~ copolymer complemented by a
stringy polymer is an excellent way to provide a high pe~formanc~ product
from an environmental and marketing viewpoint.
-6~-
~Q~~ ~z~~
Among the many advantages of the novel adherent, low friction grease are:
1. Superior performance as a railroad track/wheel flange lubricant.
2. , Outstanding friction reduction with associated train fuel economy.
3. Superior retentivity on the railroad track side.
4. Lower fling-off when applied as a railroad track/wheel flange lubricant.
5. Excellent resistance to displacement by water (rain).
6. Non-corrosivity to copper, iron, and steel at prolonged high
temperatures.
1 0 7. Impressive extreme pressure and wear resistance properties.
8. Non-abrasive to railraad track/wheel flange lubricators.
9. Oxidatively and thermally stable at high temperatures and at lower
temperatures.
1 Q. Prevention of lacquer-like deposits.
1 S 11. Good pumpability and mobility.
1 Z. Remarkable compatibility and protection of elastomers and seals.
13. Excellent oil separation qualities, even at high temperatures.
14. Nontoxic.
15. Safe.
2 0 16. Environmentally acceptable.
17. Economical.
18. Effective.
Although ~mb~diments of this invention have been described, it is to be
2 S understood that various modifications and substitutions, as well as
rearrangements of process steps, can b~ made by those skill~d in the art
without departing from the novel spirit and scope of this invention.
-69-
