Note: Descriptions are shown in the official language in which they were submitted.
74~L
This invention relates to grease and gear
lubricant compositions and particularly to additives for
improving extreme pressure properties of grease and gear
lubricant compositions. More specifically, the invention
relates to these lubricant compositions comprising at
least one metal-containing composition and at least one
sulfurized organic compound. It is the combination of
the two components making up the additive mixture that
imparts the improved load bearing characteristics of the
grease or gear lubricant composition.
Additives of the type of the present invention
have found use in lubricants formulated for a very
specific utility, specifically in metal working
processes. Such utility is disclosed in U.S. Patents
Nos. 4,505,830 and 4,659,488.
A similar type of additive comprising a mixture
of zirconium salt of a carboxylic acid or mixture of
carboxylic acids and a~ least one oil-soluble sulfur-
containing extreme pressure agent which additive mixture
-- 2
ic useful for lubricants is disclosed in U.S. Paten~ I.o.
4,171,268.
Halogenated disulfide compounds which are useful as
extreme pressure additives for lubricating oils ar-
disclosed in U.S. Patent No. 4,228,021.
In U.S. Patent No. 4,283,294, an additive mixture of
Group II A, metal overbased salts and Group I ~, metal
overbased salts, which may also further comprise an organo
sulfur antioxidant compound, is disclosed. It is
disclosed in this patent that the lubricating oil
compositions containirg such additive mixtures are useful
in marine diesel engines.
It is disclosed in U.S. Patent Nos. 4,394,276 and
4,394,277 that various sulfur-containing alkane diols may
be formulated with lubricating oils to effectively reduce
fuel consumption in an internal combustion engine.
- U.S. Patent No. 3,384,586 discloses various non-
Newtonian colloidal disperse svstems and materials which
are useful in lubricating oils for imparting improved
rheological properties of the oil.
It is pointed out that none of the foregoing
disclosures teach the additive mixture of the present
invention to be useful in grease or gear lubricant
formulations and more particularly, that they impart
unexpectedly high weld points when evaluated for ext.eme
pressure properties.
SUMMARY OF THE INVENTIQN
In accordance with the present invention, grease
compositions exhibiting improved extreme pressure
properties have been developed.
Further, in accordance with the present lnvention, it
has been discovered that an additive mixture of a
metal-containing composition, preferably a basic alkaline
earth or alkali metal salt material, and at least one
sulfurized organic compound have been found to
~3~374~
unexpectedly improve the extreme pressure properties of
grease compositions.
Still further, in a~cordance with the present
invention, it has been discovered that the additive mixture
of the present invention may also be useful in gear
lubricant compositions.
Still further in accordance with the present
invention, a method for improving the load bearing
characteristics of grease and gear lubricant compositions is
provided.
These and other aspects of the invention will
become clear to those skilled in the art upon the reading
and understanding o~ the specification.
DETAILED DESCRIPTION OF THE INVENTION
It has been discovered that the load bearing
characteristics of a grease composition and a gear lubricant
may be unexpectedly improved by formulating these
compositions with a specific additive mixture.
Specifically, the additive mixture comprises:
(A) a metal-containing composition; and
(B) at least one sulfurized organic compound.
The (A) component of the additive mixture may
be a Newtonian material or a non-Newtonian colloidal
disperse system which comprises solid metal-containing
colloidal particles predispersed in a disperse medium
of at least one inert, organic liquid and a third
component selected from the class consisting of organic
compounds which are substantially soluble in the
disperse medium. The molecules of the organic
compound, i.e., the third component, are
characterized by containing polar substituents and
hydrophobic portions in the mol~cule. Such systems ar2
disclosed and dascribed in U.S. patent No. 3,384,586,
discussed above. The metal-containing composition of
the present invention are preferably salts of alkaline
~3
~X~3(~7~
earth metals or alkali metals and at least one acidic
organic compound. These salt materials are among those
art recognized metal-containing compositions that may be
also described by such terms of the art as "overbased",
"superbased" and "hyperbased" salts, which terms are
recognized as being generic to the materials of the
present invention as well as other classes of metal
containing materials that have been employed as
detergents and/or dispersants in lubricating oil
compositions. The method for their preparation is
commonly referred to as "overbasing". The term "metal
ratio" is also used to define the ~uantity of metal in
these salts or complexes relative to the quantity or
or~anic anion, and is defined as a ratio of the number
of equivalents of metal to the number of equivalents
thereof which would be present in a normal salt based
upon the usual stoichiometry of the compounds involved.
For the purposes of the present invention, a metal ratio
of 5 or higher is preferred. Such metal-containing
compositions are also disclosed in U.S. Patent Nos.
4,505,830, discussed above, and 4,230,586.
The particular metal cation which makes up the
metal-containing composition is not particularly critical
to the present invention. It is, however, intended to
exclude such zinc salts as zinc dialkyldithiophosphate
and zinc dialkyldithiocarbamates and similar zinc salts
from the scope of this invention. Otherwise, practically
any other metal salt is useful for the preparation of
component (A) of the additive mixture. ~ore specific-
ally, useful metal compounds in preparing the overbasedmaterials of the additive mixture of the present
invention are normally the basic salts of metals in Group
I-A and Group II-A of the Periodic Table as well as the
transition metals with the exception of zinc within the
~roup-B elements of the Periodic Table. Such metals
i ?
~X9~74~
-- 5
include Ma, K, Mg, C2, Ba, Ti, Cr, Fe, Mo, Cu and the
like. Also, Group IV-A and Group V-A ~,etals such as Pb,
Sn and Sb may be useful within the scope of the present
invention.
The alkaline earth metals are preferred for the
purposes of the present invention as basic al~.aline earth
metal salts and include principally calcium, magnesium,
barium and strontium, with calcium salts being the most
preferred ~ecause of their availability and relatively 10;J
cost. The most useful acidic organic compounds are
carboxylic acids, sulfonic acids, organic phosphorus acids
and phenols.
The sulfonic acids are preferred for use in the
preparation of component A. They include those
represented by the formulas R (SO3H)r and (R )XT(SO3H)y.
In these formulas, R is an aliphatic or aliphatic-
substituted cycloaliphatic hydrocarbon or essentially
hydrocarbon radical free from acetylenic unsaturation and
containing up to about 60 carbon atoms. When Rl is
aliphatic, it usually contains at least about 15 carbon
atoms; when it is an aliphatic-substituted cycloaliphatic
radical, the aliphatic substituents usually contain a
total of at least about 12 carbon atoms. Examples of R
are alkyl, alkenyl and alkoxyalkyl radicals, and aliphatic
substituents are alkyl, alkenyl, alkoxy, alkoxyalkyl,
carboxyalkyl and the like. General~y, the cycloaliphatic
nucleus is derived from a cycloalkane or a cycloalkene
such as cyclopentane, cyclohexane, cyclohexene or cyclo-
pentene. Specific examples of R are cetylcyclohexyl,
laurylcyclohexyl, cetyloxyethyl, octadecenyl, and radicals
derived from petroleum, saturated and unsaturated paraffin
wax, and olefin polymers including polymerized monoolefins
and diolefins containing about 2-8 carbon atoms per
olefinic monomer unit. R can also contain other
substituents such as phenyl, cycloalkyl, hvdroxy,
mercapto, halo, nitro, amino, nitroso, lower alkoxy, lower
alkylmercapto, carboxy, carbalkoxy, oxo or thio, or
374~
-- 6
interrupting groups such as -NH-, -O- or -S-, as long as
the essentially hydrocarbon character thereof is not
destroyed.
R2 is generally a hydrocarbon or essentially hydro-
carbon radical free from acetylenic unsaturation andcontaining from about 4 to about 60 aliphatic carbon
atoms, preferably an aliphatic hydrocarbon radical such as
alkyl or alkenyl. It may also, however, contain
substituents or interrupting groups such as those
enumerated above provided the essentially hydrocarbon
character thereof is retained. In general, any non-carbon
atoms present in R or R do not account for more than 10
of the total weight thereof.
The radical T is a cyclic nucleus which may be
derived from an aromatic hydrocarbon such as benzene,
naphthalene, anthracene or biphenyl, or from a hetero-
cyclic compound such as pyridine, indole or isoindole.
Ordinarily, T is an aromatic hydrocarbon nucleus,
especially a benzene or naphthalene nucleus.
The subscript x is at least 1 and is generally 1-3.
The subscripts r and y have an average value of about 1-~
per molecule and are generally also 1.
Illustrative sulfonic acids useful in the preparation
of component A are mahogany sulfonic acids, pertolatum,
sulfonic acids, mono- and polywax-substituted naphthalene
sulfonic acids, cetylchlorobenzene sulfonic acids, cetyl-
phenol sulfonic acids, cetylphenol disulfide sulfonic
acids, cetoxycapryl benzene sulfonic acids, dicetyl
thianthrene sulfonic acids, dilauryl beta-naphthol
sulfonic acids, dicapryl nitronaphthalene sulfonic acids,
saturated paraffin wax sulfonic acids, unsaturated
paraffin wax sulfonic acids, hydroxy-substitued paraffin
wax sulfonic acids, tetraisobutylene sulfonic acids,
tetra-amylene sulfonic acids, chloro-substituted paraffin
wax sulfonic acids, nitroso-substituted paraffin wax
sulfonic acids, petroleum naphthene sulfonic acids,
cetylcyclopentyl sulfonic acids, lauryl cyclohexyl
-- 7
sulfonic acids, mono- and polywax-substituted cyclohexyl
sulfonic acids, postdodecylbenzene sulfonic acids, "dimer
alkylate" sulfonic acids, and the like. These sulfonic
acids are well-known in the art and require no further
discussion herein.
Suitable carboxylic acids include aliphatic, cyclo-
aliphatic and aromatic mono- and polybaslc carboxylic
acids free from acetylenic unsaturation, includin~
naphthenic acids, alkyl- or alkenyl-substituted cyclo-
pentanoic acids, alkyl~ or alkenyl-substituted
cyclohexanoic acids, and alkyl- or alkenyl-substituted
aromatic carboxylic acids. The aliphatic acids generally
contaln from about 8 to about 50, and preferably from
about 12 to about 25, carbon atoms, The cycloaliphatic
and aliphatic carboxylic acids are preferred, and they can
be saturated or unsaturated. Specific examples include
2-ethylhexanoic acid, linolenic acid, propylene tetramer-
substituted maleic acid, behenic acid, isostearic acid,
pelargonic acid, capric acid, palmitoleic acid, linoleic
acid, lauric acid, oleic acid, ricinoleic acid, undecvclic
acid, dioctylcyclopentanecarboxylic acid, mvristic acid,
dilauryldechydronaphthalenecarboxylic acid, stearyl-octa-
hydroindenecarboxylic acid, palmitic acid, alkyl- and
alkenylsuccinic acids, acids formed by oxidation of
petrolatum or of hydrocarbon waxes, and commercially
available mixtures of two or more carboxylic acids, such
as tall oil acids, rosin acids, and the like.
The pentavalent phosphorus acids useful in the
preparation of component ~ may be represented by the
formula
X4
R3 (X~
P-X H
R ~X ~b
,"
~07~
-- 8
wherein each of R3 and R4 is hydrogen or a hydrocarbcr or
essentially hydrocarbon radical preferably having from
about 4 to about 25 carbon atoms, at least one of R3 and
R being hydrocarbon or essentially hydrocarbon; each o
Xl, X2, X3 and X4 is oxygen or sulfur; and each of a and b
is 0 or 1. Thus, it will be appreciated that the
phosphorus acid may be an organophosphoric, phosphonic or
phosphinic acid, or a thio analog of any of these.
Usually, the phosphorus acids are those of the
formula:
R O O
P OH
R O
wherein R3 is a phenyl radical or (preferably) an alkyl
radical having up to 18 carbon atoms, and R is hydrogen
or a similar phenyl or alkyl radical. Mixtures of such
phosphorus acids are often preferred because of their ease
of preparation.
Component A may also be prepared from phenols; that
is, compounds containing a hydroxy radical bound directly
to an aromatic ring. The term "phenol" as used herein
includes compounds having more than one hydroxy group
bound to an aromatic ring, such as catechol, resorcinol
and hydroquinone. It also includes alkylphenols such as
the cresols and ethylphenols, and alkenylphenols.
Preferred are phenols containing at least one alkyl
substituent containing about 3-100 and especially about
6-50 carbon atoms, such as heptylphenol, octylphenol,
dodecylphenol, tetrapropenealkylated phenol, octadecyl-
phenol and polybutenylphenolsO Phenols containing morethan one alkyl substituent may also be used, but the
monoalkylphenols are preferred because of their
availability and ease of production.
Also useful are condensation products of the above-
described phenols with at least one lower aldehyde, the
~;~9~74~
term "lower" denotina aldehydes containina not more than 7carbon atoms. Suitable aldehydes include formaldehyde,
acetaldehyde, propionaldehyde, the butyraldehydes, the
valeraldehydes and benzaldehyde. Also suitable are
aldehyde-yielding reagents such as paraformaldehyde,
trioxane, methylol, Methyl Formcel and paraldehyde.
Formaldehyde and the formaldehyde-yielding reagents are
especially preferred.
The equivalent weight of the acidic organic compound
is its molecular weight divided by the number of acidic
yroups (i.e., sulfonic acid, carboxy or acidic hydroxy
groups) present per molecule.
Especially preferred for use as component A are basic
alkaline earth metal salts having metal ratios from about
4 to about 40, preferably from about 6 to about 30 and
especially from about 8 to about 25, and prepared by
intimately contacting for a period of time sufficient to
form a stable dispersion, at a temperature between the
solidification temperature of the reaction mixture and its
decomposition temperature:
(A-l) at least one acidic gaseous material
selected from the group consisting of carbon dioxide,
hydrogen sulfide and sulfur dioxide, with
(A-2) a reaction mixture comprising
(A-2-a) at least one oil-soluble sulfonic
acid, or derivative thereof susceptible to over-
basing,
(A-2-b~ at least one alkaline earth metal or
basic alkeline earth metal compound;
(A-2-c) at least one lower aliphatic alcohol;
and
(A-2-d) at least one oil-soluble carboxylic
acid or functional derivative thereof.
Reagent A-l is at least one acidic gaseous material
which may be carbon dioxide, hydrogen sulfide or sulfur
dio~ide; miY~tUreS of these gases are also useful. Carbon
4~
-- 10 --
dioxide is preferred because of its relatively 10W COSt,
availability, ease of use and performance.
Reagert A-2 is a mixture containlng at least our
components of which component A-2-a is at least one
oil-soluble sulfonic acid as previously defined, or a
derivative thereof susceptible to overbasing. Mixtures of
sulfonic acids and/or their derivatives may also be used.
Sulfonic acid derivatives susceptible to overbasing
include their metal salts, especially the alkaline earth,
copper, managanese, iron and lead salts; ammonium salts
and amine salts (e.g., the ethylamine, butylamine and
ethylene polyamine salts~; and esters such as butylamine
and ethylene polyamine salts); and esters such as the
ethyl, butyl and glycerol esters.
Component A-2-b is at least one alkaline earth metal
or a basic compound thereof. Illustrative of basic
alkaline earth metal compounds are the hydroxides,
alkoxides Itypically those in which the alkoxy group
contains up to 10 and preferably up to 7 carbon atoms),
~0 hydrides and amides. Thus, useful basic alkaline earth
metal compounds include calcium hydroxide, magnesium
hydroxide, barium hydroxide, stratium hydroxide, calcium
oxide, magnesium oxide, barium oxide, strontium oxide,
calcium hydride, magnesium hydride, barium hydride,
stratium hydride, calcium ethoxide, calcium buto ide and
calcium amide. Especially preferred are calcium oxide and
calcium hydroxide and the calcium lower alkoxides (i.e.,
those containing up to 7 carbon atoms). The equivalent
weight of component A-2-b for the purpose of this
invention is equal to twice its molecular weight, since
the alkaline earth metals are divalent.
Component A-2-c is at least one lower aliphatic
alcohol, preferably a monohydric or dihydric alcohol.
Illustrative alcohols are methanol, ethanol, l-propanol,
l-hexanol, isopropanol, isobutanol, 2-pentanol, ?,2-
dimethyl-l-propanol, ethylene glycol, 1-3-propanediol and
1,5-pentanediol. Of these, the preferred alcohols are
7~
methanol, ethanol and propanol, ~ith methanol being
especially preferred. The equivalent weight of component
B 2-c is its molecular weight divided by t~e number of
hydroxy groups per molecule.
Component A-2-d is at least one oil-soluble carbo-
xylic acid as previously described, or functional
derivative thereof. Especially suitable carboxylic acids
are those of the formula R5(COOH)n, wherein n is an
integer from 1 to 6 and is preferably 1 or 2 and R5 is a
saturated or substantially saturated aliphatic radical
(preferably a hydrocarbon radical) having at least 8
aliphatic carbon atoms. Depending upon the value of n, P5
will be a monovalent to hexavalent radical.
R5 may contain non-hydrocarbon substituents provided
they do not alter substantially its hydrocarbon character.
Such substituents are preferably present in amounts of not
more than about 10~ by weight. Exemplary substituents
i~clude the non-hydrocarbon substituents enumerated
hereinabove with reference to component A-2-a. R5 ma~r
also contaln olefinic unsaturation up to a maximum cf
about 5~ and preferably not more than 2% olefinic linkages
based upon the total number of carbon-to-carbon covalent
linkages present. The number of carbon atoms in R is
usually about 8-700 depending upon the source of R5. As
~5 discussed below, a preferred series of carboxylic acids
and derivatives is prepared by reacting an olefin polymer
or halogenated olefin polymer with an alpha, beta-
unsaturated acid or its anhydride such as acrylic,
methacrylic, maleic or fumaric acid or maleic anhydride to
form the corresponding substituted acid or derivative
thereof. The R5 groups in these products have a number
average molecular weight from about 150 to about 10,000
and usually from about 700 to about 5000, as determined,
for example, by gel permeation chromatography.
The monocarboxylic acids useful as component A-2-d
have the formula R5COO~I. Examples of such acids are
caprylic, capric, palmitic, stearic, isostearic, linoleic
~9(J 741
- 12 -
and behenic acids. A particularly preferred group or
mono-carboxylic acids is prepared by the reaction of a
halogenate~ olefin polymer, such as a chlorinated
polybutene, with acrylic acid or methacrylic acid.
Suitable dicarboxylic acids include the substitutea
succinic acids having the formula
R CHCOOH
CH2COOH
wherein R is the same as R as defined above. R may be
an olefin polymer-derived group foxmed by polymerization
of such monomers as ethylene, propylene, l-butene,
isobutene, l-pentene, 2-pentene, l-hexene and 3-hexene.
R6 may also be derived from a high molecular weight
substantially saturated petroleum fraction. The hydro-
carbon-substituted succinic acids and their derivatives
constitute the most preferred class of carboxylic acids
for use as component A-2-d.
The above-described classes of carboxylic acids
clerived from olefin polymers, and their derivatives, are
well known in the art, and me~hods for their preparation
as well as representative examples of the types useful in
the present invention are described in detail in a rumber
of U.S. patents, e.g., U. S. Patent No., 4,119,549.
Functional derivatives of the above-discussed acids
useful as component A-2-d includes the anhydrides, esters,
amides, imides, amidines and metal salts. The reaction
products of olefin polymer-substituted succinic acids and
mono- or polyamines, particularly polyalkylene polyamines,
having up to about ten amino nitrogens are especially
suitable. These reaction products generally comprise
mixtures of one or more of amides, imides and amidines.
The reaction products of polyethylene amines containing up
to about 10 nitrogen atoms and polybutene-substituted
succinic anhydride wherein the polybutene ràdical
comprises principally isobutene units are particularly
~Z~3~74~L
- 13 -
useful. Included in this group of functional deriv~ti-Jes
are the compositions prepared by post-treating the amine-
anhydride reaction product with carbon disulfide, bGron
compounds, nitriles, urea, thiourea, guanidine, alkylene
oxides or the like. The half-amide, half-metal sal L and
half-ester, half-metal salt derivatives of such
substituted succinic acids are also useful.
Also useful are the esters prepared by the reaction
of the substituted acids or anhydrides with a mono- or
polyhydro~y compound, such as an aliphatic alcohol or a
phenol. Preferred are the ersters of ole~in polymer-
substituted succinic acids or anhydrides ard polyhydric
aliphatic alcohols containing 2-10 hydroxy groups and up
to about 40 aliphatic carbon atoms. This class of
alcohols includes ethylene glycol, glycerol, sorbitol,
pentaerythritol, polyethylene glycol, diethanolamine,
triethanolamine, N,~-di(hydroxyethyl)-ethylene diamine and
the like. When the alcohol contains reactive amino
groups, the reaction product may comprise products
resulting from the reaction of the acid group with both
the hydroxy and amino functions. Thus, this reaction
mixture can include half-esters, half-amides, esters,
amides, and imides.
In summary, the non-metal portion or anion is
selected from the group consisting of acetates, formates,
carbonates, hydrogen carbonates, sulfides, hydrogen
sulfides, sulfites, hydrogen sulfites, chlorides or
mixtures thereof.
The ratios of equivalents of the constituents of
~0 reagent A-2 may vary widely. In general, the ratio of
component A-2-b to A-2-a is at least about ~:1 and usually
not more than about 40:1, preferably between 61 and 30:1
and most preferably between 8:1 and 25:1. While this
ratio may sometimes e~ceed 40:1, such an excess normally
will serve no useful purpose.
The ratio of equivalents of component A-2-c to
component A-2-a is between about 1:1 and 80:1, and
- 14 -
preferably between about 2:1 and 5G.l; and the ratio of
equivalents of component A-2-d to component A-2-a is ~rom
abou-t 1:1 to about 1:20 and preferably from about 1:2 ~o
about 1:10.
Reagents A-l and A-2 are generally contacted until
there is no further reaction between the two or until the
reaction substantially ceases. While it is usually
preferred that the reaction be continued until no further
overbased product is formed, useful dispersions can be
prepared when contact between reagents A-l and A-2 is
maintained for a period of time sufficient for about 70~
Of reagent A-l, relative to the amount required if the
reaction were permitted to proceed to its completion or
"end point", to react.
The point at which the reaction is completed or
substantially ceases may be ascertained by any of a number
of conventional methods. One such method is measurement
of the amount of gas (reagent A-l~ entering and leaving
the mixture; the reaction may be considered suhstantiall~
~0 complete when the amount leavins is about q0--100% of the
amount entering. These amounts are readily determined bv
the use of metered inlet and outlet valves.
The reaction temperature is not critical. Generally,
it will be between the solidification temperature of the
reaction mixture and its decomposition temperature (i.e.,
the lowest decomposition temperature of an~r component
thereof3. Usually, the temperature will be from about 25
to about 200C. and preferably from about 150C. Reagents
A-l and A-2 are conveniently contacted at the reflux
temperature of the mixture. This temperature will
obviously depend upon the boiling points of the various
components; thus, when methanol is used as component
A~2~c~ the contact temperature will be about the reflux
temperature of methanol.
The reaction ls ordinarily conducted at atmospheric
pressure, although superatmospheric pressu-e often
expedites the reactlon and promotes op'imum utilization of
~9~
reagent A-1. The process can also be carried out at
reduced pressure but, for obvious practical reasons, ~his
is rarely done.
The reaction is usually conducted in the presence of
a substantially inert, normally liquid organic diluent,
which functions as both the dispersing and reaction
medium. This diluent will comprise at least about 10% of
the total weight of the reaction mixture. Ordinarily it
wlll not exceed about 80% by weight, and it is preferably
about 30-70~ thereof.
Although a wide variety of diluents are useful, it is
preferred to use a diluent which is soluble in lubricating
oil. The diluent usually itself comprises a low viscosity
lubricating oil.
Other organic diluents can be employed either alone
or in combination with lubricating oil. Preferred
diluents for this purpose include the aromatic hydro-
carbons such as bezene, toluene and xylene; halogenated
derivatives thereof such as chlorobenzene; lower boiling
petroleum distillates such as petro]eum ether and the
various naphthas; normally liquid aliphatic and cyclo-
aliphatic hydrocarbons such as hexane, heptane, hexene,
cyclohexene, cyclopentane, cyclohexane and ethylcyclo-
hexane, and their halogenated derivatives. Dialkyl
ketones such as dipropyl ketone and ethyl butyl ketone,
and the alkyl aryl ketones such as acetophenone, are
likewise useful, as are ethers such as n-propyl ether,
n-butyl ether, n-butyl methyl ether and isoamyl ether.
When a combination of oil and other diluent is used,
the weight ratio of oil to the other diluent is generally
from about 1:20 to about 20:1. It is usually desirable
for a mineral lubricating oil to comprise at least about
50% by weight of the diluent, especially if the product is
to be used as a lubricant additive. The total amount of
diluent present is not particularly critical since it is
inactive. However, the diluent will ordinarily comprise
~()7~
- 16 -
about 10-80~ and preferabl~ about 30-70~ by ~,7eisht of the
reaction mixture.
The reaction is preferably conducted in the absence
of water, although small amounts may be present (e.g.,
because of the use of technical grade reagents). Water
may be present in amounts up to about 10~ by weight of the
reaction mixture without having harmful effects.
Upon completion of the reaction, any solids in the
mixture are preferably removed by filtration or other
conventional means. Optionally, readily removable
diluents, the alcoholic promoters, and water formed during
the reaction can be removed by conventional techniques
such as distillation. It is usually desirable to remove
substantially all water from the reaction mixture since
the presence of water may lead to difficulties in
filtration and to the formation of undesirable emulsions
in fuels and lubricants. Any such water present is
readily removed by heating at atmospheric or reduced
pressure or by azeotropic distillation.
The chemical structure of component A is not known
with certainty. The basic salts or complexes may be
solutions or, more likely, stable dispersions.
Alternatively, they may be regarded as "polymeric salts"
formed by the reaction of the acidic material, the oil-
soluble acid being overbased, and the metal compound. In
view of the above, these compositions are most
conveniently defined by reference to the method by which
they are formed. Representative of such useful com-
positions are illustrated by the following examples.
Example 1
A calcium mahogany sulfonate is prepared by double
decomposition of a 60~ oil solution of 750 parts of sodium
mahogany sulfonate with the solution of 75Q parts of
sodium mahogany sulfonate with the solution of 67 parts of
calcium chloride and 63 parts of water. The reaction mass
is heated for 4 hours at 90-100C. to effect the
conversion of the sodium mahogany sulfonate to calcium
- 17 -
mahogany sulfonate. Then, 54 parts of 91~ calcium
hydroxide solution is added and the material ls heated to
150C. over a period of five hours. When ~he material h2s
cooled to ~0C., 98 parts of methanol is added and 152
parts of carbo~ dioxide is introduced over a period of 2
hours at 42-43C. Water and alcohol are then removed by
heating the mass to 150C. The residue in the reaction
vessel is diluted with 100 parts of mineral oil. The
filtered oil solution and the desired carbon~ted calcium
sulfonate overbased material shows the follo~ing
analysis: sulfate ash content, 16.4%; a neutralization
number, as measured against phenopthalein of 0.6(acidic);
and a metal ratio of 2.5.
Example 2
A mixture comprising 2890 parts of the overbased
material of Example 1 (2.79 equivalents based on sulfonic
acid anion), 217 parts of the calcium phenate prepared as
indicated below (0.25 equivalents), 939 parts of mineral
oil, 494 parts methanol, 201 parts isobutyl alcohol, 1 8
~0 parts of mixed isomeric primary amyl alcohols (containing
about 65% normal amyl, 3% isoamyl and 32% 2-methyl-1-butyl
alcohols), 4.7 parts calcium chloride dissolved in 5.8
parts water, and 428 parts of 91~ calcium hydroxide (10.6
equivalents) is stirred vigorously at 40C and 146 parts
of carbon dioxide is introduced over a period of 1. 2 hours
at 40~55C. Thereafter, five additional portions of
calcium hydroxide amounting to 173 parts each are added
and each such addition is followed by the introduction of
carbon dioxide as previously illustrated. After the sixth
calcium hydroxide addition and the carbonation step is
completed, the reaction mass is carbonated for an
additional one hour at 40-55C to reduce the neutrali-
zation number of the mass to 55 ~basic). The carbonated
reaction mixture is then heated to 150C under a nitrogen
atmosphere to remove alcohol and any by-product water.
908 parts of oil are added and the contents of the
reaction vessel is then filtered. The filtrate, an oil
3'74~
- 18 -
solution of the desired carbonated calcium sulfonate
overbased material of high metal ratio shows the following
analysis: sulfate ash content 52.7; neutralization number
50.9 (basic~; total base numb~r 420 (basi~); and a metal
ratio of 20.25.
The calcium phenate used above is prepared by
adding 2550 parts of mineral oil, 960 parts (5 moles) of
heptyl phenol, and 50 parts of water into a reaction vessel
and stirring at 25C. The mixture is heated to 40C and 7
parts o~ calcium hydroxide and 231 parts (7 moles) of 91%
commercial paraformaldehyde is added over a period of one
hour. The contents are heated to 80C and 200 additional
parts of calcium hydroxide (making a total of 207 parts or
5 moles~ is added over a period of one hour at 80-90C. The
contents are heated to 150C and maintained at that
temperature for 12 hours while nitrogen is blown through the
mixture to assist in the removal of water. If foaming is
encountered, a few drops of polymerized dimethyl-silicone
foam inhibitor may be added to control the foaming. The
reaction mass is then filtered. The filtrate, a 33.6% oil
solution of the desired calcium phenate of heptyl phenol-
formaldehyde condensation product is found to contain 7.56%
sulfate ash. Borated complexes ~f this type may be prepared
by heating the basic alkaline earth metal salt with boric
25 acid at about 50-100C., the number of equivalents of boric
acid being roughly equal to half the number of eguivalents
of alkaline earth metal in the salt. U.S. Patent 3,929,650
may be referred to for its disclosure of borated complexes.
~xample 3
(a) To a mixture of 1,145 grams of a mineral oil
solution of a 40% solution of barium mahogany
sulfonates (1.0 equivalent) and 200 grams o~ methyl alcohol
at 55C, there is added 220 grams of barium oxide while the
mixture is being blown with carbon dioxide at a rate of 2 to
3 cubic feet per hour. To this mixture there is added an
additional 78 grams of methyl alcohol and then 460 qrams
'~
74~
-- 19 --
of barium oxide while the mixture is blown with carbsn
dioxide. The carbonated product is heated to 150C for 1
hour and filtered. The filtrate is found to ha~Je a barium
sulfate ash content of 53.8% and a metal ratio of 8.9.
(b) A carbonated basic metal salt is prepared in
accordance with the procedure of (a) except that a total
of 16 equivalents of barium oxide is used per equivalent
of the barium mahogany sulfonate. The product possess a
metal ratio of 13.4.
~_~
A mixture of 520 parts (by weight~ of a mineral oil,
480 parts of a sodium petroleum sulfonate (molecular
weight of 480) and 84 parts of water is heated at 100C
for 4 hours. The mixture is then heated with 86 partsof a
76% aqueous solution of calcium chloride and 72 parts of
lime (90% purity) at 100C for 2 hours, dehydrated by
hearing to a water content of less than 0.5%, cooled to
50C, mixed with 130 parts of methyl alcohol, and then
blown with carbon dioxide at 50C until substantially
neutral. The mixture is then heated to 150C to remove
the methyl alcohol and water and the resulting oil
solution of the basic calcium sulfonate fi~tered. The
filtrate is found to have a calcium sulfate ash content of
16~ and a metal ratio of 2.5.
A mixture of 1,305 grams of the above carbonated
calcium sulfonate, 930 grams of mineral oil, 220 grams of
methyl alcohol, 72 grams of isobutyl alcohol, and 38 grams
of pirmary amyl alcohol is prepared, heated to 35C, and
subjected to the following operating cycle 4 times; mixing
30 with 143 grams of 90% calcium hydroxice and treating the
mixture with carbon dioxid~ until it has a base number of
32-39. The resulting product is then heated to 155C
during a period of 9 hours to remove the alcohols and
flltered through a siliceous filter aid at this tempera-
ture. The filtrate has a calcium sulfate ash content of
39.5% and a metal ratio of 12.2.
~9~74~
- 20 -
Example 5
A mixture of 880 grams (0.968 moles) of a 57.5~ oil
solution of the calcium sulfonate of tridecylbenzene
bottoms (the bottoms constitute a mixture of mono-, di-,
5and tri-decylbenzene), 15=49 grams of methanol, and 59
grams (1.58 equivalents) of calcium hydroxice are
introduced into a reaction vessel and stirred vigorously.
The whole is heated to 40-45C and carbon dioxide is
introduced for 0.5 hour at the rate of 2 cubic feet per
hour. The carbonated reaction mixture is then heated to
150C to remove alcohol and any water present, and the
residue is filtered for purposes of purification. The
product, a 61% oil solution of the desired overbased
carbonated calcium sulfonate material shows the following
15anaylsis: ash content, 16.8~, neutralization number, 7.0
(acidic); and metal ratio, 2.42. By further carbonation
in the presence of an alkali or alkaline earth metal
oxice, hydroxice, or alkoxide, the metal ratio can readily
be increased to 3.5 or greater.
~0Like component (A) of the additive mixture, the
particular species of component (B), i.e., the sulfurized
organic compound, is not particularly critical to the
present invention. However, it is preferred that the
sulfur be incorporated in the organic compound as the
sulfide moiety, i.e., in its divalent oxidation state and
that it is oil-soluble. Component (B~ may be the product
- of an aliphatic, arylaliphatic or alicyclic hydrocarbon.
Olefinic hydrocarbons containing from about 3 to about 30
carbon atoms are preferred for the purposes of the present
invention.
The olefinic hydrocarbons which ma~ be
sulfurized to form component B are diverse in nature.
They contain at least one olefinic double bond, which is
defined as a non-aromatic double bond; that is, one
connecting two aliphatic carbon atoms. In its broadest
sense, the olefinic hydrocarbon may be defined by the
formula R R C=CR R , wherein each of R7, R8, R9 and R10
4~
- 21 -
is hydrogen or a hydrocarbon (especially alkyl or alkenyl)
radical. Any two of R , R , R and R may also together
form an alkylene or substituted alkylene group; i.e., the
olefinic compound may be alicyclic.
Monoolefinic and diolefinic compounds, particularly
the former, are preferred in the preparation of component
B, and especially terminal monoolefinic hydrocarbons; that
is, those compounds in which ~ and R are hydrogen and
R and R8 are alkyl (that is, the olefin is aliphatic).
Olefinic compounds having about 3-30 and especially about
3-20 carbon atoms are particularly desirable.
Propylene, isobutene and their dimers, trimers and
tetramers, and mixtures thereof are especially preferred
olefinic compounds. Of these compounds, isobutene and
diisobutene are particularly desirable because of their
availability and the particularly high sulfur-containing
compositions which can be prepared therefrom.
The sulfurizing reagent used from the preparation of
component B may be, ~or example, sulfur, a sulfur halide
such as sulfur monochloride or sulfur dichloride, a
mixture of hydrogen sulfidç and sulfur or sulfur dio~ide,
or the like. Sulfur-hydrogen sulfide mixtures are often
preferred and are frequently referred to hereinafter;
~owever, it will be understood that other sulfurization
agents may, when appropriate, by substituted therefor.
The amounts of sulfur and hydrogen sulfide per mole
of olefinic compound aret respectively, usually about
0.3-3.0 gram-atoms and about 0.1-1.5 moles. The preferred
ranges are about 0.5-2.0 gram-atoms and about 0.4-1.25
moles respectively, and the most desirable ranges are
about 1.2 1.8 gram-atoms and about 0.4-0.8 mole
respectively.
The temperature range in which the sulfurization
reaction is carried out is generally about 50-350C. The
35 preferred range is about 100-200C., with about 125-180C.
being especially suitable. The reaction is often
preferably conducted under superatmospheric pressure; this
7~
- 22 -
may be and usually is autogenous pressure (i.e., the
pressure which naturally develops during the course o~
the reaction) but may also be externally applied
pressure. The exact pressure developed during the
reaction is dependent upon such factor~ as the design and
operation of the system, the reaction temperature, and
the vapor pressure of the reactants and products and it
may vary during the course of the reaction.
It is frequently advantageous to incorporate
materials useful as sulfurization catalysts in the
reac~ion mixture. These materials may be acidic, basic
or neutral, but are pre-ferably basic materials,
especially nitrogen bases including ammonia and amines,
most often alkylamines. The amount of catalyst used is
15 generally about 0.05-2.0% of the weight of the olefinic
compound. In the case of the preferred ammonia and amir.e
catalysts, about 0.0005-0.5 mole per mole o~ olefin is
preferred, and about 0.001-~.1 mole is especially
desirable.
Follo~ing the preparation of the sulfurized mixture,
it is preferred to remove substantially all low boiling
materials, typically by venting the reaction vessel or by
distillation at atmospheric pressure, vacuum distillation
or stripping, or passage of an inert gas such as nitrogen
through the mixture at a suitable temperature and
pressure.
A further optional step in the preparation of
component B is the treatment of the sulfurized product,
obtained as described hereinabove, to reduce active
sulfur. An illustrative method is treatment with an
alkali metal sulfide. Other optional treatments may be
employed to remove insoluble byproducts and improve such
qualities as the odor, color and staining characteristics
of the sulfurized compositions.
U.S. Patent 4,119,549 discloses suitable sulfur-
ization products useful as component B. Several specific
sul~urized compositions are described in the working
- 23 -
examples thereof. The following examples illustrate ~he
preparation of two such compositions.
EXAMPLE A
Sulfur (629 parts, 19.6 moles) is charged to a
jacketed high-pressure reactor which is fitted with an
agitator and internal cooling coils. Refrigerated brine
is circulated through the coils to cool the reactor prior
to the introduction of the gaseous reactants. After
sealing the reactor, evacuating to about 6 torr and
cooling, 1100 parts (19.6 moles) of isobutene, 334 parts
(9.8 moles) of hydrogen sulfide and 7 parts of n-butyl-
amine are charged to the reactor. The reactor is heated,
using steam in the external jacket, to a temperature of
about 171C. over about 105 hours. A maximum pressure of
720 psig. is reached at about 138C. during this heat-up.
Prior to reaching the peak reaction temperature, the
pressure starts to decrease and continues to decrease
steadily as the gaseous reactants are consumed. After
about 4.75 hours at about 171C., the unreacted hydrogen
sulfide and isobutene are vented to a recovery system.
After the pressure in the reactor has decreased to
atmospheric, the sulfurized product is recovered as a
liquid.
EXAMPLE B
Following substantially the procedure of Example 3,
773 parts of diisobutene is reacted with 428.6 parts of
sulfur and 143.6 parts of hydrogen sulfide in the presence
of 2.6 parts of n-butylamine, under autogenous pressure at
a temperature of about 150-155C~ Volatile materials are
removed and the sulfurized product is recovered as a
liquid.
The amount of the (A~ component combined with the (B)
component to make up the additive mixture of the present
invention may vary over a wide range. For example, the
weight ratio of ~A):(B) may range from about 50:1 to about
1:1. However, as a preferred range, the weight ratio of
(A):(B) is from about 20:1 to about 10:1.
)7~1
- 24 -
The (A) component and (~) component of the additi-Je
mixture may be added separatel~ or as a mixture to a base
grease stock to obtain the grease composition of the
present invention or to a base stock for a gear lubricant.
Grease compositions or base grease stocks are deri~ted
from both mineral and synthetic oils. The synthetic oils
include polyolefin oils (e.g., polybutene oil, decene
oligimer, and the like), synthetic esters (e.g., dinonyl
sebacate, trioctanoic acid ester of trimethylolpropane,
and the like), polyglycol oils, and the like. The grease
composition is then made from these oils by adding a
thickening agent such as a sodium, calcium, lithium, or
aluminum salts of fatty acids such as stearic acid. To
this base grease stock, then may be blended the components
of the additive mixture of the present invention âS well
as other known or conventional additives. The grease
composition of the present invention may contain from
about l weight percent to about 50 weight percent of
component A and from 0.1 percent to about 5 weight percent
of component B of the additive of the present invention.
As a preferred embodiment, the effective amcunt of
component A in the grease composition will range from
about 5 weight percent to about 25 weigh-t percent and the
effective amount of component B will range from about 0.5
weight percent to about 2 weight percent.
Other additives which may optionally be present in
the grease compositions and gear lubricants for use in
this invention include:
Antioxidants, typically hindered phenols.
Surfactants, usually non-ionic surfactants such as
o~yalkylated phenols and the like.
Corrosion, wear and rust inhibiting agents.
Friction modifying agents~ of which the following are
illustrative: alkyl or alkenyl phosphates or phosphites
in which the alkyl or alkenyl group contains from about 10
to about ~0 carbon atoms, and metal salts thereof,
especially zinc salts; C10-20 fatty acid amides; C10-20
~l290741
- 25 -
alkyl amines, especially tallow amines and etho~.ylated
derivatives thereof; salts of such amines with acids such
as boric acid or phosphoric acid which have been partially
esterified as noted above; C10-20 alkyl-substituted
imidazolines and similar nitrogen heterocycles.
Various grease formulations for comparative purposes
were tested according to the 4-Ball extreme pressure test,
i.e~, ASTM D-2783, and according to the roller bearing
rust test, i.e., ASTM D-1748. The results for these
various grease compositions which were evaluated in side
by side tests are set out in Tables I and II.
,
~l29~)74~
-- 26 --
4~ o\o
o m
O~,a ~) ~ ~)
~ S~
3 m ~ o
~ ~ ~1 ~ o
3 0 o co O E
o ~ ~ ~o
N l¢
C~ ~
H O
O ~ d,
o~o ~ ~ o'~
~1
a~ ~D ~ '
. ~: ~ O
~ O u~~r ~ Z
3 ~ ~~r O 3
o Eo~ r~
N ~ +
m
o\O O d~ ~
o~o O L~ ~ C
.IJ . O ~ U
~ + ~ ~ u~
3 3 3 ~ ~i
o ~ o E
~ o Z
H ¦O m H ¦
m0~O ~
~: ~ o
O 00
E Ifl N
~ O ~
;1~
O ~ ~ h
o~ ~ t~ ~
~ ~ o
O O 1~) N O
~1 C)
a~
~ ~ U~ ~0
O ~ I~ ~ L
z .~ N N ~ t~
~ a~ .
_. ~ ~ 1--
+ _ 5~ ~ m
~ ~ m
a)-- ~ ~
h H
~1 ~ tD ;~
a) ~ ~` ~ ~ a) ~ s ~ ~ E~ ~
rl u, ~ mu~ N ~J r~ r~ z ~ r I U~ U~ Z
h ~ ~ I O O ~ I O a) ~ I
,1 m ~ ~ ~ ~ ~ 3 ~I H ~ P~
~9~
- 27 -
~ s has been demonstrated by the results set out in
the above Tables, particularly Tahle I, the additive
mixture, i.e., the combination of the metal-containing
composition with a sulfurized oryanic compound gives
unexpecte~ly and syneryistically high results for the ,~eld
points and the load wear index in the 4-Ball EP test. It
should be noted that the weld point obtained for grease
compositions containing only component A or only component
B are each 250(Kg). However, the weld point obtained for
a grease composition containing both of these components
(i.e., A and B) is 500(Kg). It is further pointed out
that the addition of the sulfurized organic compound does
not affect the rust or oxidative properties in the grease
formulation.
As previously pointed out, the additive mixture of
the present invention may be also used in gear lubricant
compositions which are prepared and formulated for use in
differentials, axles, some manual transmissions and the
like. These oils, likewise, may be prepared from mineral
or synthetic oils as described above, however, are
generally of higher viscosity than typical crankcase or
motor oil. Furthermore, these types of lubricants must
hold up under extreme pressure conditions, and thus,
require the inclusion of extreme pressure agents in their
formulation. It has been discovered that the additive
mixture of the present invention is the same concentration
range and is particularly useful in formulating such gear
lubricants.
While the invention has been described and
illustrated with reference to certain preferred
embodiments thereof, those s~illed in the art will
appreciate the various changes, modifications and
substitutions that can be made therein without departing
from the spirit of the inventionO For example, different
ratios or amounts of the A and B components of the
additive mixture, other than preferred ranges set ~ut
hereinabove, may be applicable as a consequence of the
~X~ 7~
~ 28 -
variations in the particular grease base stock or gear
lubricant base stock or in the type o' engine o~-
particular end use or the like. It is intended,
therefore, that the invention be limited only by the scope
of the claims which follow:
