Note: Descriptions are shown in the official language in which they were submitted.
t 3372~4
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to lubricating oil compositions
which exhibit marked improvements in fuel economy. More
particularly, this invention relates to lubricating oil
compositions which contain minor proportions of mixtures of
calcium and magnesium sulfonates with primary and secondary
zinc antiwear agents, in addition to dispersant and
antioxidant additives.
DESCRIPTION OF THE PRIOR ART
It is an objective of the industry to provide lubricating
oil compositions which exhibit improvements in fuel savings in
gasoline and diesel engine vehicles. To meet that current
goal, a new category of additives commonly referred to as fuel
economy additives are being developed which function primarily
to increase miles or kilometers obtained per unit volume of
fuel. Since modern day lubricating oil compositions are
complex formulations, such additives must be compatible with
the other components of such compositions and should not
adversely affect the numerous other functions of conventional
lubricants additives such as dispersancy, viscosity stability,
corrosion and oxidation inhibition, and the like.
U.S. Patent 2,911,367 relates to mineral oil compositions
adapted to preventing rusting and corrosion of metal surfaces
which are exposed to moisture and comprise a major proportion
of a mineral lubricating oil and a minor proportion of each of
an alkali metal salt, an oil soluble sulfonic acid, a metal
alkylthiophosphate, a partial ester of a fatty acid containing
at least 8 carbon atoms and a polyol containing from 3 to 6
carbon atoms and from 3 to 6 hydroxyl radicals per molecule
and an ethylene glycol C6 branched-chain alkyl ether.
1 3372q4
- 2 -
The metal alkylthiophosphates are said to include magnesium,
calcium, zinc, strontium, cadmium and barium thiophosphates,
of which zinc dioctyl and zinc octyl hexyl dithiophosphates
are exemplary. The sulfonate is employed in an amount of from
about 1 to about 5 weight percent based on the total
composition and the metal alkylthiophosphate, including the
above-mentioned zinc octyl hexyl and zinc dioctyl
dithiophosphate, are said to be used preferably in an amount
of between about 0.1 and about 1.5 weight percent of the total
composltlon.
U.S. Patent 3,562,159 relates to synthetic lubricants
containing a carboxylic acid ester of lubricating viscosity as
the basic liquid and, as additives, an akylated alkylene
polyamine (about 5 to 30 parts by weight), a basic alkaline
earth metal sulfonate (about 5 to 15 parts by weight), a metal
phosphorodithioate (about 5 to 70 parts by weight), a basic
alkaline earth metal salt of a phophosulfurized hydrocarbon,
esters of a hydrocarbon-substituted succinic acid, and a basic
alkaline earth metal salt of an alkylphenol sulfide.
U.S. Patent 3,714,042 relates to treated overbased
complexes, which are disclosed as being useful as additives in
lubricating oils, gasolines and other organic materials,
wherein basic metal complexes selected from the class
consisting of sulfonate, sulfonate-carboxylate and carboxylic
complexes with up to an amount equivalent to the total
basicity thereof with high molecular weight aliphatic
carboxylic acid or anhydrides containing at least about 25
aliphatic carbon atoms per carboxy group under recited
temperature conditions. The metal of the basic metal salt
complex may be magnesium or calcium (among other recited
metals). Additional additives may be used in combination with
the recited compositions, including Group II metal
phosphorodithioates such as zinc dicyclohexyl
phosphorodithioate, and zinc dioctyl phosphorodithioate.
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_ - 3 -
U.S. Patent 3,933,659 relates to lubricating oil
compositions which comprise a major amount of an oil of
lubricating viscosity and an effective amount of an alkenyl
succinimide, a Group II metal salt of a dihydrocarbyl
dithiophosohoric acid, a basic sulfurized alkaline earth metal
alkylphenate, and a compound selected from the group
consisting of certain fatty acid esters and fatty acid amides
and amines. The Group II metal salt of the dihydroycarbyl
dithiophosphoric acids are indicated to be present in an
amount of from 0.5 to 1.5 weight percent of the functional
fluid and the basic sulfurized alkaline earth metal
alkylphenates are indicated to be present in the functional
fluid in an amount of from about 0.4 to about 4 weight
percent.
U.S. Patent 4,308,154 relates to mixed metal salts
(especially zinc salts) of dialkylphosphorodithioic acids and
carboxylic acids, which are said to be useful in lubricants
and functional fluids (such as hydraulic fluids) as
antioxidants and extreme pressure agents having improved
thermal stability. The mixed metal salts of this invention
are said to also include those of the Group I and Group II
metals.
U.S. Patent 4,417,990 relates to mixed metal
salts/sulfurized phenate compositions, useful in lubricants
and functional fluids as antioxidants and extreme pressure
agents having improved thermal stability and contains a
disclosure related that of U.S. Patent 4,308,154, discussed
above.
Various suggestions have been made in the prior art
regarding the nature, type, and carbon content of the alkyl or
aryl groups present in dialkylphosphorodithioic acids used to
prepare desired metal salts. For example, U.S. Patent No.
2,344,393 taught that it was previously recognized that metal
dithiophosphates should have one or more long chain alkyl
X
_ - 4 - I 33 72 94
groups to render them sufficiently soluble in lubricating oils
to be of practical value. The patentees found, however that
the zinc salt of diamylphosphorodithioic acid was oil-soluble.
U.S. Patent No. 3,318,808 discloses that the higher carbon
containing alkyl groups (above 4 carbon atoms) enhance oil
solubility. Thus, the patent teaches combinations of C4 and
lower primary and/or secondary alcohols with C5 and above
alcohols, and the ratio of the alcohols is selected to suit
the balance between economics and solubility.
U.S. Patent No. 3,190,833 describes oil-soluble metal
phosphorodithioates which are the salts of metals in Group II
of the periodic table and comprise preferably the salts of
calcium, barium, strontium, zinc and cadmium with
phosphorodithioic acids which contain a total of at least
about 7.6 aliphatic carbon atoms per atom of phosphorus. To
improve the oil solubility of the metal salts, they are
reacted with up to about 0.75 mole of an epoxide.
Another patent which relates to the preparation of
phosphorodithioic acid salts as useful additives in lubricants
is U.S. Patent No. 3,000,822. This patent describes zinc
salts of a mixture of dialkyl phosphorodithioic acids wherein
the alkyl groups comprise a mixture of lower molecular weight
primarily aliphatic hydrocarbon radicals having less than 5
carbon atoms and higher molecular weight primary aliphatic
hydrocarbon radicals having at least 5 carbon atoms. The mole
ratios of lower molecular weight radicals to higher molecular
weight radicals in the zinc salt is within the range of 1:1 to
3:1.
Various suggestions have been made in the prior art for
improving the utility of lower alkyl phosphorodithioic acid
salts which have a tendency to be oil insoluble. U.S. Patent
No. 4,306,984 describes a procedure for rendering oil
insoluble metal C2-C3 dialkyldithiophosphates oil-soluble by
forming a complex between the dithiophosphate and an alkenyl
~i,,~
. ~
~ - 5 - 1337294
or alkyl mono- or bis-succinimide. This combination of
additives is used in lubricating oils which can be employed
for crankcase lubrication of internal combustion engines.
Another method which has been suggested for preparing non-
crystalline mixtures of basic or mixed basic and neutral zinc
salts of dialkyldithiophosphates containing from 1 to 13
carbon atoms in the alkyl groups has been suggested in U.S.
Patent No. 3,843,530. The mixtures of basic or mixed basic
and neutral zinc salts described in this patent contain from 4
to 13 different alkyl groups, have an average carbon content
of 3.5 to 4.5, and contain at least 12~ by weight of zinc.
U.S. Patent 4,466,895 relates to lubricating oil
compositions containing metal salt of one or more
dialkylphosphorodithioic acids wherein the alkyl groups each
contain from 2 to 4 carbon atoms and at least one alkyl group
is a butyl group, the total number of carbon atoms per
phosphorus atoms is less than 8, from about 30 to 90 mole
percent of the alkyl groups are primary alkyl groups, from
about 10 to 70 mole percent of the alkyl groups are secondary
alkyl groups, and wherein the metal salt as zinc, copper or
iron salt, mixtures thereof, or a mixture of calcium salt and
one or more of said metal salts, provided that when only 2
alkyl groups are present, from about 30 to 80 mole percent of
the alkyl groups are n-butyl groups, and from about 20 to 70
mole percent of said alkyl groups are isopropyl groups. The
patentees disclose that these metal salts are useful in
lubricating oil compositions as anti-wear agents and
antioxidants. The patentees metal salts of lower
dialkylphosphorodithioic acids are illustrated in combination
with a conventional higher alkyl ZDDP in sufficient
formulations also containing mixtures of basic calcium
petroleum sulphonate and basic magnesium petroleum sulfonate.
Zinc dialkyl dithiophosphates, prepared from mixed
dialkyldithiophosphoric acids, have been heretofore prepared.
U.S. Patent 3,293,181 relates to mixed salts prepared from a
~' ~
- 6 - l 3372q4
mixture of at least two different branched chain primary
alcohols, one of said alcohols being isobutyl alcohol and the
other said alcohols containing at least 6 carbon atoms.
U.S. Patent 3,397,145 discloses that the alkyl groups of
the alkylthiophosphoric acids can be straight or branched
chain and that the alkyl groups may be primary, secondary
and/or tertiary substituents (e.g., same or different alkyl
groups).
U.S. Patent 3,442,804 relates to zinc
phosphorodithioates, useful in lubricating compositions, in
which the hydrocarbon radicals are primary alkyl radicals and
consist of a mixture of lower molecular weight radicals and
higher molecular weight radicals.
U.S. Patent 4,328,111 relates to modified overbased
sulfonates and phenates wherein the basic compound is reacted
with acidic compound comprising an organic carboxylic acid,
organic carboxylic acid anhydride, phosphoric acid, phosphoric
acid ester, thiophosphoric acid ester, or mixtures thereof.
U.S. Patent 4,614,602 relates to lubricant compositions
containing an overbased detergent-dispersant lubricant
additive comprising a reaction product of an alkaline earth
metal phenate and an ammonium alkylbenzene sulfonate, which
the patentees indicate can be used in combination with other
conventional lubricant additives, including anti-wear agents
such as ZDDP. The alkyl benzene sulfonate can comprise
sulfonic acid salts derived from alkaline earth metals, such
as Ca, Mg, Ba oxides or hydroxides, alone or in admixture.
Exemplified as a modifying agent for reaction with overbased
magnesium sulfonate is 2-ethylhexyl dithiophosphoric acid.
U.S. Patent 4,326,972 discloses improvement in fuel
economy of internal combustion engines by use of specific
lubricant compositions in which the essential
,.. ~ _..
,~.~
,~
- 1 3372~4
ingredients are a specific sulphurized composition and a
basic metal sulphonate.
U.S. Patent 4,362,633 relates to lubricating oil
additives containing molybdenum-containing aminated
sulphurized additives. The Patentee illustrates the use of
such additives in combination with mixtures containing
overbased calcium phenate, overbased magnesium sulphonate
and zinc dialkyldiphiophosphates.
European Patent 24,146 relates to lubricating oil
compositions containing copper antioxidants, and
exemplifies copper antioxidants in lubricating oil
compositions also containing 1.0 wt. % of a 400 TBN
magnesium sulphonate (containing 9.2 wt. % magnesium), 0.3
wt. % of a 250 TBN calcium phenate (containing 9.3 wt. ~ of
calcium) and a zinc dialkyldithiophosphate in which the
alkyl groups or a mixture of such groups having between 4
and 5 carbon atoms and made by reacting phosphorous
P2S5 with a mixture of about 65% isobutyl alcohol and
35% of amyl alcohol, to give a phosphorous level of 1.0 wt.
% in lubricating oil composition.
European Patent No. 0092946, granted March 16, 1988, relates to
lubricating oil compositions having improved fuel economy
which contain glycerol partial esters, oil-soluble organic
copper compounds and oil-soluble organic copper compounds.
The Patent illustrates compositions containing such
combinations in admixture with basic metal detergents and
anti-wear additives. The Patent discloses that the
preferred detergent materials are the normal or overbased
calcium or magnesium phenates, sulphurized phenates, and/or
sulphontes, and further discloses that the anti-wear
additives generally are the oil soluble zinc dihydrocarbyl
dithiophosphates having a total of at least 5 carbon atoms.
U.S. Patent 4,394,276 relates to lubricating oils
containing sulphur-containing alkene diols to reduce fuel
consumption in an internal combustion engine. The Patentee
illustrates this fuel economy additive in a fully
_ 8 1 337294
formulated oil containing 30 millimoles per kilogram
overbased magnesium hydrocarbyl sulphate, 20 millimoles per
kilogram overbased sulphurized cal :ium polypropylene
phenate and 18 millimoles per kilogram zinc
O,O-di(2-ethylhexyl)dithiophosphate.
U.S. Patents 4,362,636 4,406,803, 4,495,088,
4,563,293 and 4,629,576 also relate to lubricating oil fuel
economy additives and exemplify each additive in a similar
fully formulated lubricating oil.
U.S. Patent 4,104,180 relates to a process for
producing overbased carbonates. Example 11 of this Patent
illustrates lubricating oils containing 1.2 wt. % neutral
calcium phenate, 1.2 wt. % zinc dialkyl dithiophosphate and
1.2 wt. % magnesium sulphonate.
N. E. Gallopoulos et al., ASLE Transactions, Vol.
14, pp. 1-7, (1971) investigated the interactions between a
zinc dialkyl phosphoro dithioate and lubricating oil
dispersants including the effect of alkaline calcium
petroleum sulphonate on aging of mixtures of the sulphonate
with zinc dialkyl phosphoro dithioate, and concluded that
chemical reactions are likely to occur. No investigation
was reported for mixtures of alkaline earth metal
sulphonates.
J. A. McGeehan et al., SAE Paper 852133, 1983,
pps. 879-892 investigated the effects of zinc
dithiophosphates and detergents on controlling engine
wear. Zinc diaryl dithiophosphates were concluded to be
less effective in controlling valve wear in gasoline
engines than zinc dialkyl dithiophosphates. The authors
concluded that the control of engine wear requires a
critical balance of zinc dithiophosphate and detergent
types in order to control gasoline engine valve train wear,
diesel cylinder poor polishing wear and diesel roller
follower bronze pin wear, based on the authors' studies
conducted with various zinc dialkyl dithiophosphates and
either calcium or magnesium detergents. However, the alkyl
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type of these zinc dithiophosphates was not identified and
mixtures of calcium and magnesium detergents were not
assessed.
However, none of the above references discloses
advantages to be achieved in controlling the relative amounts
of mixed calcium/magnesium detergents and mixed
primary/secondary zinc dithiophosphate antiwear agents.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagrammatic illustration of the data
obtained in Examples 1 - 27, exhibiting the surprisingly
improved fuel economy achieved by use of the compositions of
the present invention.
SUMMARY OF THE INVENTION
In accordance with the present invention, there are
provided fuel economy promoting lubricating oil compositions
which comprise an oil of lubricating viscosity as the major
component and as the minor component a fuel economy improving
amount of a mixture of
(A) a mixture of (1) at least one calcium overbased
detergent inhibitor, and (2) at least one magnesium overbased
detergent inhibitor;
(B) a mixture of (1) at least one zinc di-(primary
hydrocarbyl) dithiophosphate, and (2) at least one zinc di-
(secondary hydrocarbyl) dithiophosphate;
(C) at least one ashless dispersant; and
(D) an antioxidant effective amount of at least one
copper carboxylate compound;
wherein component (A)(1), expressed as Ca, comprises from
about 0.03 to 0.5 weight percent of the lubricating oil
composition, component A(2), expressed as Mg, comprises from
about 0.01 to 0.25 weight percent of the lubricating oil
composition, and component (B) is employed in an amount
sufficient to provide from about 0.05 to 0.15 weight percent
phosphorous in the lubricating oil
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composition, and wherein the mixed ca~cium and magnesium
detergent in~ibitors are present in a weight:weight ratio
of components A(l):A(2) of from about 0.3:1 to about 6:1,
and the mixed zinc di(primary hydrocarbyl~ dithiophosphate
and the zinc di(secondary hydrocarbyl) dithiophosphate
antiwear agents are present in a weight:weight ratio of
B(l):B(2) of from about 0.4:1 to about 9:1.
The present invention is based on the discovery
that there i~ a surpris~ngly pronounced relationship
between improved fuel economy and the proportions of mixed
calciu~/magnesium detergent inhibitor~3 and mixed
primary/secondary zinc antiwear agent in crank case
lubricating oil compo~itions, and that such mixtures impart
a degree of fuel economy per unit weight of additive not
heretofore recognized by the art. Of equal significance is
the fact that other de~;irable affecta and properties of
lubricating oils, e.g., compatibility,- detergency and
dispersancy, are not diminished.
DESCRIPTION OF PREFERRED EMBODIMENTS
comPonent ~
Component A is a mixture of basic (viz, o~rerbased)
Ca and Mg salt of one or more organic sulfonic acid
(generally a petroleum sulfonic acid or a synthetically
prepared alkaryl sulfonic acid), petroleum naphthenic
acids, alkyl benzene sulfonic acids, alkyl phenols,
alkylene-bis-phenols, oil soluble fatty acids, salicylic
acid and the like, such as are described in U.S. Patent
Nos. 2, 501, 731; 2, 616,904; 2,616,905; 2,616,906;
2,6~6,911; 2,616,924; 2,616,g25; 2,617,049; 2,777,874;
3,027,325; 3,256,186; 3,282,835; 3,384,585; 3,373,10B:
3,365,396; 3,342,733; 3,320,162; 3,312,618; 3,318,809; and
3,562,159. AmQng the petrole~n sulfonates,
B-
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the most useful products are those prepared by the sulfonation
of suitable petroleum fractions with subsequent removal of
acid sludge and purification. Synthetic alkaryl sulfonic
acids are usually prepared from alkylated benzenes such as the
Friedel-Crafts reaction product of benzene and a polymer such
as tetrapropylene. Suitable acids may also be obtained by
sulfonation of alkylated derivatives of such compounds as
diphenylene oxide thianthrene, phenolthioxine, diphenylene
sulfide, phenothiazine, diphenyl oxide, diphenyl sulfide,
diphenylamine, cyclohexane, decahydro naphthalene and the
like.
Highly basic Ca and Mg sulfonates are frequently used as
detergents. They are usually produced by heating a mixture
comprising an oil-soluble sulfonate or alkaryl sulfonic acid,
with an excess of alkaline earth metal compound above that
required for complete neutralization of any sulfonic acid
present and thereafter forming a dispersed carbonate complex
by reacting the excess metal with carbon dioxide to provide
the desired overbasing. The sulfonic acids are typically
obtained by the sulfonation of alkyl substituted aromatic
hydrocarbons such as those obtained from the fractionation of
petroleum by distillation and/or extraction or by the
alkylation of aromatic hydrocarbons as for example those
obtained by alkylating benzene, toluene, xylene, naphthalene,
diphenyl and the halogen derivatives such as chlorobenzene,
chlorotoluene and chloronaphthalene. The alkylation may be
carried out in the presence of a catalyst with alkylating
agents having from about 3 to more than 30 carbon atoms. For
example haloparaffins, olefins obtained by dehydrogenation of
paraffins, polyolefins produced from ethylene, propylene, etc.
are all suitable. The alkaryl sulfonates usually contain from
about 9 to about 70 or more carbon atoms, preferably from
about 16 to about 50 carbon atoms per alkyl substituted
aromatic moiety.
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The alkaline earth metal compounds which may be used in
neutralizing these alkaryl sulfonic acids to provide the
sulfonates includes the oxides and hydroxides, alkoxides,
carbonates, carboxylate, sulfide, hydrosulfides, nitrate,
borates and ethers of magnesium, calcium, and barium.
Examples are calcium oxide, calcium hydroxide, magnesium
acetate and magnesium borate. As noted, the alkaline earth
metal compound is used in excess of that required to complete
neutralization of the alkaryl sulfonic acids. Generally, the
amount ranges from about 100 to 220~, although it is preferred
to use at least 125~, of the stoichiometric amount of metal
required for complete neutralization.
Various other preparations of basic alkaline earth metal
alkaryl sulfonates are known, such as U.S. Patents 3,150,088
and 3,150,089 wherein overbasing is accomplished by hydrolysis
of an alkoxide-carbonate complex with the alkaryl sulfonate in
a hydrocarbon solvent-diluent oil.
A preferred Mg sulfonate additive is magnesium alkyl
aromatic sulfonate having a total base number ranging from
about 300 to about 400 with the magnesium sulfonate content
ranging from about 25 to about 32 wt.~, based upon the total
weight of this additive system dispersed in mineral
lubricating oil. A preferred Ca sulfonate additive is calcium
alkyl aromatic sulfonate having a total base number ranging
from about 300 to about 400 with the calcium sulfonate content
ranging from about 25 to about 32 wt.~, based upon the total
weight of this additive system dispersed in mineral
lubricating oil.
As an example of a particularly convenient process for
the preparation of the complexes used, an oil-soluble sulfonic
acid, such as a synthetically prepared didodecylbenzene
sulfonic acid, is mixed with an excess of lime (e.g., 10
equivalents per equivalent of the acid) and a promoter such as
methanol, heptylphenol, or mixture thereof, and a solvent such
as mineral oil, at 50C-150C and the process mass is then
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carbonated until a homogeneous mass is obtained. Complexes of
sulfonic acids, carboxylic acids, and mixtures thereof are
obtainable by processes such as are described in U.S. Patent
No. 3,312,618. Another example is the preparation of a
magnesium sulfonate normal magnesium salt thereof, an excess
of magnesium oxide, water, and preferably also an alcohol such
as methanol.
The carboxylic acids useful for preparing sulfonate
carboxylate complexes, and carboxylate complexes, i.e., those
obtainable from processes such as the above wherein a mixture
of sulfonic acid and carboxylic acid or a carboxylic acid
alone is used in lieu of the sulfonic acid, are oil-soluble
acids and include primarily fatty acids which have at least
about 12 aliphatic carbon atoms and not more than about 24
aliphatic carbon atoms. Examples of these acids include:
palmitic, stearic, myristic, oleic, linoleic, dodecanoic,
behenic, etc. Cyclic carboxylic acids may also be employed.
These include aromatic and cyclo-aliphatic acids. The
aromatic acids are those containing a benzenoid structure
(i.e., benzene, naphthalene, etc.) and an oil-solubilizing
radical or radicals having a total of at least about 15 to 18
carbon atoms, preferably from about 15 to about 200 carbon
atoms. Examples of the aromatic acids include: stearyl-
benzoic acid, phenyl stearic acid, mono- or polywax-
substituted benzoic or naphthoic acids wherein the wax group
consists of at least about 18 carbon atoms, cetyl
hydroxybenzoic acids, etc. The cycloaliphatic acids
contemplated have at least about 12, usually up to about 30
carbon atoms. Examples of such acids are petroleum naphthenic
acids, cetyl cyclohexane carboxylic acids, di-lauryl
decahydronaphthalene carboxylic acids, di-octyl cyclopentane
carboxylic acids, etc. The thiocarboxylic acid analogs of the
above acids, wherein one or both of the oxygen atoms of the
carboxyl group are replaced by
~ - 14 - l 337 294
sulfur, are also contemplated.
The ratio of the sulfonic acid to the carboxylic acid in
mixtures is at least 1:1 (on a chemical equivalent basis) and
is usually less than 5:1, preferably from 1:1 to 2:1.
The terms "basic salt" and "overbased salt" are used to
designate metal salts wherein the metal is present in
stoichiometrically larger amounts than the sulfonic acid
radical.
As used in the present specification and claims, the term
"complex" refers to basic metal salts which contain metal in
an amount in excess of that present in a neutral or normal
metal salt. The "base number" of a complex is the number of
milligrams of KOH to which one gram of the complex is
equivalent as measure by titration. The commonly employed
methods for preparing the basic salts involve heating a
mineral oil solution of the normal metal salt of the acid with
a metal neutralizing agent such as the oxide, hydroxide,
carbonate, bicarbonate or sulfide at a temperature above 5C
and filtering the resulting mass. The use of a "promoter" in
the neutralization step to aid the incorporation of a large
excess of metal is known and is preferred for the preparation
of such compositions. Examples of compounds useful as the
promoter include phenolic substances such as phenol, naphthol,
alkyl phenols, thiophenol, sulfurized alkyl phenols, and
condensation products of formaldehyde with a phenolic
substance; alcohols such as methanol, 2-propanol, octanol,
cellosolve, carbitol, ethylene glycol, stearyl alcohol and
cyclohexanol; and amines such as aniline, phenylene diamine,
phenothiazine, phenol beta-naphthylamine and dodecylamine.
Usually, the basic composition obtained according to the
above-described method is treated with carbon dioxide until
its base number is less than about 50, as determined by ASTM
1 337294
_ - 15 -
procedure D2896 (TBN). In many instances, it is advantageous
to form the basic product by adding the Ca or Mg base
portionwise and carbonating after the addition of each
portion. Products with very high metal ratios (10 or above)
can be obtained by this method. As used herein, the term
"metal ratio" refers to the ratio of total equivalents of
alkaline earth metal in the sulfonate complex to equivalents
of sulfonic acid anion therein. For example, a normal
sulfonate has a metal ratio of 1.0 and a calcium sulfonate
complex containing twice as much calcium as the normal salt
has a metal ratio of 2Ø The compositions suitable for use
as Component A have metal ratios of at least about 1.1, for
example, from about 1.1 to about 30, with metal ratios of from
about 2 to 20 being preferred.
It is frequently advantageous to react the basic
sulfonate with anthranilic acid, by heating the two at about
140-200C. The amount of anthranilic acid used is generally
less than about 1 part (by weight) per 10 parts of sulfonate,
preferably 1 part per 40-200 parts of sulfonate. The presence
of anthranilic acid improves the oxidation- and corrosion-
inhibiting effectiveness of the sulfonate.
Basic alkaline earth metal sulfonates are known in the
art and methods for their preparation are described in a
number of patents, such as U.S. Patent Nos. 3,027,325;
3,312,618; and 3,350,308. Any of the sulfonates described in
these and numerous other patents are suitable for use in the
present invention.
The basic Ca and Mg salts are preferably separately
prepared and then admixed in the controlled amounts as
provided herein. It will be generally convenient to admix
such separately prepared detergent inhibitors in the presence
of the diluent or solvent used in their preparation.
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- 16 - l 337 2q4
The Ca detergent inhibitor composition should be employed
in an amount of from about 0.03 to 0.5 wt.~, preferably from
about 0.04 to 0.4 wt.%, and more preferably from about 0.05 to
0.2 wt.~ of the lubricating oil composition, expressed as Ca.
The Mg detergent inhibitor should be employed in an amount of
from about 0.01 to 0.25 wt.~, preferably from about 0.01 to
0.2 wt.~, and more preferably from about 0.02 to 0.11 wt.~ of
the lubricating oil composition, expressed as Mg. Preferably,
the overbased Ca detergent inhibitor and overbased Mg
detergent inhibitor are employed in an amount of from about
0.3 to 6 parts, and more preferably from about 0.4 to 3 parts,
and most preferably from about 0.8 to 1.2 parts of the Ca
detergent inhibitor per part of the Mg detergent inhibitor,
expressed as the respective metals.
The Component A can also contain other alkaline earth
and/or alkali metal detergent inhibitors, (e.g. basic or
neutral Na, K and Li sulfonates, and salicylates, and basic or
neutral Ba sulfonates, phenates and salicylates). Examples of
such mixtures as Component A are mixtures of overbased Ca
sulfonate, overbased Mg sulfonate and overbased Na sulfonate
detergent inhibitors.
Component B
This component is a mixture of (1) a metal salt of a
di(primary hydrocarbyl) dithiophosphoric acid and (2) a metal
salt of a di(secondary hydrocarbyl) dithiophosphoric acid.
The acids from which B-1 metal salts can be derived can be
illustrated by acids of the formula (I)
R'--CH2-O--P-S-H (I)
R2--CH2-0
wherein R' and R2 are the same or different and are alkyl,
cycloalkyl, aralkyl, alkaryl or substantially hydrocarbon
radical of a similar structure. The acids from which B-2
~`
1 337294
- 17 -
metal salts can be derived can be illustrated by acids of the
formula (II):
R3 S
11
R4-CH-o-P-S-H (II)
I
R6-CH-O
I
Rs
wherein R3, R4, Rs and R6 are the same or different and are
alkyl, cycloalkyl, alkaryl, aralkyl, or a substantially
hydrocarbon radical of a similar structure.
By "substantially hydrocarbon" is meant radicals
containing substituent groups such as ether, ester, nitro or
halogen which do not materially affect the hydrocarbon
character of the radical.
Therefore, the acids of formula I can be seen to comprise
di-primary-hydrocarbyl substituents wherein each oxygen-bonded
carbon is primary, that is, -CH2-O. Correspondingly, the acids
of formula II can be seen to comprise di-secondary hydrocarbyl
substituents wherein each oxygen-bonded carbon is secondary,
that is, _CH-O.
Specific examples of suitable R1 through R6 radicals
include isopropyl, isobutyl, n-butyl, sec-butyl, n-hexyl,
heptyl, 2-ethylhexyl, diisobutyl, isoocytl, decyl, dodecyl,
tetradecyl, hexadecyl, octadecyl, butylphenyl, o,p-
depentylphenyl, octylphenyl, polyisobutene-(molecular weight
350)-substituted phenyl, tetrapropylene-substituted phenyl,
beta-octylbutylnaphthyl, cyclopentyl, cyclohexyl, phenyl,
chlorophenyl, o-dichlorophenyl, bromophenyl, naphthenyl, 2-
methylcyclohexyl, benzyl, chlorobenzyl, chloropentyl,
dichlorophenyl, nitrophenyl, dichlorodecyl and xenyl radicals.
Alkyl radicals having about 3-30 carbon atoms, and aryl
radicals having about 6-30 carbon atoms, are preferred.
Particularly preferred R1 through R6 radicals are alkyl of 3 to
18 carbons.
X
_ - 18 - 1337294
The phosphorodithioic acids are readily obtainable by the
reaction of phosphorus pentasulfide and an alcohol or phenol.
The reaction involves mixing, at a temperature of about 20-
200C, 4 moles of the alcohol or phenol with one mole of
phosphorus pentasulfide. Hydrogen sulfide is liberated as the
reaction takes place.
The metal salts which are useful in this invention
include those salts containing Group I metals, Group II
metals, aluminum, lead, tin, molybdenum, manganese, cobalt and
nickel. Zinc is the preferred metal. Examples of metal
compounds which may be reacted with the acid include lithium
oxide, lithium hydroxide, lithium carbonate, lithium
pentylate, sodium oxide, sodium hydroxide, sodium carbonate,
sodium methylate, sodium propylate, sodium phenoxide,
potassium oxide, potassium hydroxide, potassium carbonate,
potassium methylate, silver oxide, silver carbonate, magnesium
oxide, magnesium hydroxide, magnesium carbonate, magnesium
ethylate, magnesium propylate, magnesium phenoxide, calcium
oxide, calcium hydroxide, calcium carbonate, calcium
methylate, calcium propylate, calcium pentylate, zinc oxide,
zinc hydroxide, zinc carbonate, zinc propylate, strontium
oxide, strontium hydroxide, cadmium oxide, cadmium hydroxide,
cadmium carbonate, cadmium ethylate, barium oxide, barium
hydroxide, barium hydrate, barium carbonate, barium ethylate,
barium pentylate, aluminum oxide, aluminum propylate, lead
oxide, lead hydroxide, lead carbonate, tin oxide, tin
butylate, cobalt oxide, cobalt hydroxide, cobalt carbonate,
cobalt pentylate, nickel oxide, nickel hydroxide and nickel
carbonate.
In some instances, the incorporation of certain
ingredients such as small amounts of the metal acetate or
acetic acid used in conjunction with the metal reactant will
facilitate the reaction and result in an improved product.
For example, the use of up to about 5~ of zinc acetate in
combination with the required amount of zinc
~ir
; ~"
1 3372~4
-19-
oxide facilitates the formation of a zinc phosphoro-
dithioate.
The preparation of metal phosphorodithioates is
well known in the art and is described in a large number of
issued patents, including U.S. Patents 3,293,181;
3,397,145; 3,396,109; and 3,442,804 l
_ ..
The B-l and B-2 metal salts are preferably made
separately and then admixed to form the mixed antiwear
component B. Alternatively, a mixture of primary and
secondary acids I and II can be charged in the formation of
mixed B-1 and B-2 metal salts in situ, to form the
Component B having the desired ratio of metal salt B-1
equivalents to metal salt B-2 equivalents.
Component B should be employed in the lubricating
oil composition in an amount effective to provide from
about 0.05 to 0.15 wt.%, preferably from about 0.07 to 0.12
wt.%, and more preferbly from about 0.08 to 0.11 wt.%
phosphorous. The relative amounts of metal salts B-1 and
B-2 which are employed are critical to the present
invention. Metal salt B-l (that is, the metal salts of the
di-(primary hydrocarbyl) dithiophosphoric acids of formula
I) should be used in an amount of from about 0.4 to 9,
preferably from about 0.5 to 3, and most preferably from
about 0.7 to 1.8 parts by weight per part by weight of the
metal salt B-2 (that is, the metal salts of the
di- (secondary hydrocarbyl) dithiophosphoric acids of
formula II).
o 1 337294
Component C
Ashless, nitrogen or ester containing dispersants
useful in this invention comprise members selected from the
group consisting of (i) oil soluble salts, amides, imides,
oxazolines and esters, or mixtures thereof, of long chain
hydrocarbon substituted mono and dicarboxylic acids or
their anhydrides; (ii) long chain aliphatic hydrocarbons
having a polyamine attached directly thereto; and (iii)
Mannich condensation products formed by condensing about a
molar proportion of long chain hydrocarbon substituted
phenol with about 1 to 2.5 moles of formaldehyde and about
0.5 to 2 moles of polyalkylene polyamine; wherein said long
chain hydrocarbon group in (i), (ii) and (iii) is a polymer
of a C2 to C10, e.g., C2 to C5 monoolefin, said
polymer having a number average molecular weight of about
300 to about 5000.
C(i) The long chain hydrocarbyl substituted mono
or dicarboxylic acid material, i.e. acid, anhydride, or
ester, used in the dispersant includes long chain
hydrocarbon, generally a polyolefin, substituted with an
average of at least about 0.8, preferably from about 1.0 to
1.8, e.g., 1.1 to 1.6 moles, per mole of polyolefin, of an
alpha or beta- unsaturated C4 to C10 dicarboxylic acid,
or anhydride or ester thereof. Exemplary of such mono-
and dicarboxylic acids, anhydrides and esters thereof are
fumaric acid, itaconic acid, maleic acid, maleic anhydride,
chloromaleic acid, dimethyl fumarate, chloromaleic
anhydride, acrylic acid, methacrylic acid, crotonic acid,
cinnamic acid, etc.
Preferred olefin polymers for reaction with the
unsaturated dicarboxylic acids to form the dispersants are
polymers comprising a major molar amount of C2 to C10,
e.g., C2 to C5 monoolefin. Such olefins include
ethylene, propylene, butylene, isobutylene, pentene,
octene-l, styrene, etc. The polymers can be homopolymers
such as polyisobutylene, as well as copolymers of two or
~ -21- 1 337294
more o~ ~uch olefin~ such ~ copolymer~ of: ethylene and
propyl~ne; butylene and isobutylene; propylene and
isobutylene; etc. Other copolymers include those in which
a minor molar amount of the copolymer monomers, e.g., 1 to
10 mole ~, is a C4 to C18 non-conjugated diolefin,
e.g., a copolymer of isobutylene and butadiene: or a
copolymer of ethylene, propylene and 1,4-hexadiene; etc.
In some case~, the olefin polymer may be
completely saturated, for example an ethylene-propylene
copolymer made by a Ziegler-Natta synthesis using hydrogen
as a moderator to control molecular weight.
The olefin polymers u~ed in the dispersants will
usually have number average molecular weights within the
range of about 700 and about 5,000, more usually between
about 900 and about 3000. Particularly useful olefin
polymer~ have number average molecular wQights within the
range of about 9oO and about 2500 with approximately one
terminal double bond per polymer chain. An especially
useful starting material for highly potent dispersant
additives i8 polyisobutylene. The number average molecular
weight for such polymers can be determined by several known
ter-hn;ques. A convenient method for such determination is
by gel permeation chromatography (GPC) which additionally
provides molecular weight distribution information, see W.
W. Yau, J.J. Kirkland and D.D. Bly, "Modern Size
Exclusion Liquid Chromatography", John Wiley and Sons, New
York, 1979.
~ o~ e- for reacting the olefin polymer with the
C4_10 unsaturated dicarboxylic acid, anhydride or ester
are known in the art. For example, the olefin polymer and
the dicarboxylic acid material may be simply heated
together as disclosed in U.S. Patents 3,361,673 and
3,401,118 to cause a thermal "ene" reaction to take place.
Or, the olefin polymer can be first halogenated, for
example, chlorinated or brominated to about 1 to 8 wt. %,
preferably 3 to 7 wt. % chlorine, or bromine, based on the
~- - 22 - 1337294
weight of polymer, by passing the chlorine or bromine through
the polyolefin at a temperature of 60 to 2500C, e.g. 120 to
160C, for about 0.5 to 10, preferably 1 to 7 hours. The
halogenated polymer may then be reacted with sufficient
unsaturated acid or anhydride at 100 to 250C, usually about
180 to 235C, for about 0.5 to 10, e.g. 3 to 8 hours, so the
product obtained will contain the desired number of moles of
the unsaturated acid per mole of the halogenated polymer.
Processes of this general type are taught in U.S. Patents
3,087,436; 3,172,892; 3,272,746 and others.
Alternatively, the olefin polymer, and the unsaturated
acid material are mixed and heated while adding chlorine to
the hot material. Processes of this type are disclosed in
U.S. Patents 3,215,707; 3,231,587; 3,912,764; 4,110,349;
4,234,435; and in U.K. 1,440,219.
By the use of halogen, about 65 to 95 wt.~ of the
polyolefin, e.g. polyisobutylene will normally react with the
dicarboxylic acid material. Upon carrying out a thermal
reaction without the use of halogen or a catalyst, then
usually only about 50 to 75 wt.~ of the polyisobutylene will
react. Chlorination helps increase the reactivity. For
convenience, the aforesaid functionality ratios of
dicarboxylic acid producing units to polyolefin, e.g., 0.8 to
2.0, etc. are based upon the total amount of polyolefin, that
is, the total of both the reacted and unreacted polyolefin,
used to make the product.
The dicarboxylic acid producing materials can also be
further reacted with amines, alcohols, including polyols,
amino-alcohols, etc., to form other useful dispersant
additives. Thus, if the acid producing material is to be
further reacted, e.g., neutralized, then generally a major
proportion of at least 50 percent of the acid units up to all
the acid units will be reacted.
Amine compounds useful as nucleophilic reactants for
neutralization of the hydrocarbyl substituted dicarboxylic
`~7P
- 23 _ l 337294
acid materials include mono- and (preferably) polyamines, most
preferably polyalkylene polyamines, of about 2 to 60,
preferably 2 to 40 (e.g. 3 to 20), total carbon atoms and
about 1 to 12, preferably 3 to 12, and most preferably 3 to 9
nitrogen atoms in the molecule. These amines may be
hydrocarbyl amines or may be hydrocarbyl amines including
other groups, e.g., hydroxy groups, alkoxy groups, amide
groups, nitriles, imidazoline groups, and the like. Hydroxy
amines with 1 to 6 hydroxy groups, preferably 1 to 3 hydroxy
groups are particularly useful. Preferred amines are
aliphatic saturated amines, including those of the general
formulas:
R-N-R', and R-N-(CH2)8 - ~~(CH2)8 ~-R
R~ R' R''' R'
--t
(III) (IV)
wherein R, R', R'' and R''' are independently selected from
the group consisting of hydrogen; C1 to C25 straight or
branched chain alkyl radicals; C1 to C12 alkoxy C2 to C6
alkylene radicals; C2 to C12 hydroxy amino alkylene radicals;
and Cl to Cl2 alkylamino C2 to C6 alkylene radicals; and wherein
R"' can additionally comprise a moiety of the formula:
( 2)8~ N~ II (V)
I t~
R'
wherein R' is as defined above, and wherein s and s' can be
the same or a different number of from 2 to 6, preferably 2 to
4; and t and t' can be the same or different and are numbers
of from 0 to 10, preferably 2 to 7, and most preferably about
3 to 7, with the proviso that the sum of t and t' is not
greater than 15. To assure a facile reaction, it is preferred
that R, R', R'', R''', s, s', t and t' be selected in a manner
sufficient to provide the compounds of Formulas III and IV
with typically at least one primary or secondary amine group,
X
~ - 24 - 1 337294
preferably at least two primary or secondary amine groups.
This can be achieved by selecting at least one of said R, R',
R'' or R''' groups to be hydrogen or by letting t in Formula
IV be at least one when R''' is H or when the V moiety
possesses a secondary amino group. The most preferred amine
of the above formulas are represented by Formula IV and
contain at least two primary amine groups and at least one,
and preferably at least three, secondary amine groups.
Non-limiting examples of suitable amine compounds
include: 1, 2-diaminoethane; 1, 3-diaminopropane; 1,
4-diaminobutane; 1, 6-diaminohexane; polyethylene amines such
as diethylene triamine; triethylene tetramine; tetraethylene
pentamine; polypropylene amines such as 1, 2-propylene
diamine; di-(1,2-propylene) triamine; di-(1,3-propylene)
triamine; N, N-dimethyl-1, 3-diaminopropane; N, N-di-(2-
aminoethyl) ethylene diamine; N, N-di(2-hydroxyethyl) -1, 3-
propylene diamine; 3-dodecyloxypropylamine; N-dodecyl-1, 3-
propane diamine; tris hydroxymethylaminiomethane (THAM);
diisopropanol amine: diethanol amine; trethanol amine; mono-,
di-, and tri-tallow amines; amino morpholines such as N-(3-
aminopropyl) morpholine; and mixtures thereof.
Other useful amine compounds include: alicyclic diamines
such as 1, 4-di(aminomethyl) cyclohexane, and heterocyclic
nitrogen compounds such as imidazolines, and N-aminoalkyl
piperazines of the general formula (Va):
CH2-cH2 -
H--NH--(CH2)p-- ,, N (CH2)--NH H
_ , n~ CH2-CH2 ~ n2~ P2 ~n3
wherein P1 and P2 are the same or different and are each
integers of from 1 to 4, and n1, n2 and n3 are the same or
different and are each integers of from 1 to 3. Non-limiting
examples of such amines include 2-pentadecyl imidazoline: n-
(2-aminoethyl) piperazine; etc.
~,
1 3372q4
-~5-
Commercial mixture~ cf amin~ compGunds may
advantageously be used. For example, one process for
preparing alkylene amines involves the reaction of an
al~ylene dihalide (such as ethylene dichloride or propylene
dichloride) with ammonia, which result~ in a complex
mixture of alkylene amines wherein pairs of nitrogens are
joinQd by alkylene group~, forming such compounds as
diethylene triamine, triethylenetetramine, tetraethylene
pentamine and iComeric piperazines. Low cost
poly(ethyleneamines) compounds averaging about 5 to 7
nitrogen atoms per molecule are available commercially
under trade m~r~s such as "Polyamine Hn, "Polyamine 400",
"Dow Polyamine E-100~, etc.
Useful amines also include polyoxyalkylene
polyamines such as those of the formulae:
NH2 alkylene O-alkylene NH2 (VI)
_ m
where m has a value of about 3 to 70 and preferably 10 to
35; and
R t alkylenc O-alkylenc NH2)
~ _ n a (VII)
where "n" haR a value of about 1 to 40 with the provision
that the sum of all the n's is from about 3 to about 70 and
preferably from about 6 to about 35, and R is a polyvalent
saturated hydrocarbon radical of up to ten carbon atoms
wherein the number of substituents on the R group is
represented by the value of "a", which is a number of from
3 to 6. The alkylene groups in either formula (VI) or
(VII) may be straight or branched chains containing about 2
to 7, and preferably about 2 to 4 carbon atoms.
The polyoxyalkylene polyamines of formulas (VI) or
1 337294
--26--
(VII~ above, preferably polyoxyalkylene diamines and
polyoxy~lkylene triam.nes, may have average moie::ular
weigh~ ranging from about 200 to about 40~0 and preferably
from about 400 to about 2000. The preferred polyoxyalky-
lene polyoxyalkylene polyamines include the polyoxyethylene
and polyoxypropylene diamines and the polyoxypropylene
triamines having average molecular weights ranging from
about 200 to 2000. The polyoxyalkylene polyamines are
commercially available and may be obtained, for example,
from the Jefferson Chemical Company, Inc. under the trade
marks "Jeffamines D-230, D-400, D-1000, D-2000, T-403", etc.
The amine i~ readily reacted with the selected
dicarboxyl ic acid material, e.g. alkenyl succinic
anhydride, by heating an oil solution containing 5 to 95
wt. % of dicarboxylic acid material to about 100 to
250-C., preferably 125 to 175-C., generally for 1 to 10,
e.g. 2 to 6 hours until the desired amount of water is
removed. The heating is preferably carried out to favor
formation of imides or mixtures of imides and amides,
rather than amides and salts. Reaction ratios of
dicarboxylic material to equivalents of amine as well as
the other nucleophilic reactants described herein can vary
considerably, depending on the reactants and type of bonds
formed. Generally from 0.1 to 1.0, preferably from about
0.2 to 0.6, e.g., 0.4 to 0.6, moles of dicarboxylic acid
moiety content (e.g., grafted maleic anhydride content) is
used pQr equivalent of nucleophilic reactant, e.g., amine.
For example, about 0.8 mole of a pentaamine (having two
primary amino groups and five equivalents of nitrogen per
molecule) i8 preferably used to convert into a mixture of
amides and imides, the product formed by reacting one mole
of olefin with sufficient maleic anhydride to add 1.6 moles
of succinic anhydride groups per mole of olefin, i.e.,
preferably the pentaamine is used in an amount sufficient
to provide about 0.4 mole (that is, 1.6 divided by (0.8 x
-27- 1 337294
~) molQ) of succinic anhydride moiety per nitrogen
equiv~lent of the amine.
Th~ nitrogen containing dispersants can be further
treated by boration as generally taught in U.S. Patent
Nos. 3,087,936 and 3,254,025. This is readily
accomplished by~ t
treating the selected acyl nitrogen dispersant with a boron
compound selected from the class consisting of boron oxide,
boron halides, boron acids and esters o~ boron acid~ in an
amount to provide from about 0.1 atomic proportion of boron
for each molQ of said acylated nitrogen compo~ition to
about 20 atomic proportions o~ boron for each atomic
proportion of nitrogen o~ said acylated nitrogen
composition. Usefully the dispersants of the inventive
co~bination contain from about 0.05 to 2.0 wt. %, e.g. 0.05
to 0.7 wt. % boron based on the total weight of said
borated acyl nitrogen compound. The boron, which appears
to be in the product as dehydrated boric acid polymers
(primarily (HB02)3), is believed to attach to the
dispQrsant imides and diimides as amine salts e.g. the
metaborate salt of said diimide.
Treating is readily carried out by adding from
about 0.05 to 4, Q . g. 1 to 3 wt. % (based on the weight of
said acyl nitrogen compound) of said boron compound,
preferably boric acid which is most usually added as a
slurry to said acyl nitrogen compound and heating with
stirring ~t from about 135-C. to 190, e.g. 140-170-C., for
~ro~ 1 to 5 hours followed by nitrogen stripping at said
to~p~rature ranges. Or, the boron treatment can be carried
out by adding boric acid to the hot reaction mixture of the
dicarboxylic acid material and amine while removing water.
The tris(hydroxymethyl) amino methane (THAM) can
be reacted with the aforesaid acid material to form amides,
imides or ester type additives as taught by U.K. 984,409,
or to form oxazoline compounds and borated oxazoline
-2~ 3372q4
compounds a~ described, for example, in U.S. 4,102,798;
4,116,~76 and 4,113,639.
The ashless dispersants may also be esters derived
from the aforesaid long chain hydrocarbon substituted
dicarboxylic acid material and from hydroxy compounds such
as monohydric and polyhydric alcohols or aromatic compounds
such as phenol~ and naphthols, etc. The polyhydric
alcohols are the most preferred hydroxy compound and
preferably contain from 2 to about 10 hydroxy radical~, for
example, ethylene glycol, diethylene glycol, triethylene
glycol, tetraethylQne glycol, dipropylene glycol, and other
alkylene glycols in which the alkylene radical contains
from 2 to about 8 carbon atom~. Other u~eful polyhydric
alcohols include glycerol, mono-oleatQ of glycerol,
monostearate of glycerol, monomethyl ether of glycerol,
pentaerythritol, dipentaerythritol, and mixture~ thereof.
The ester dispersant may also be derived from
unsaturated alcohols such as allyl alcohol, cinnamyl
alcohol, propargyl alcohol, 1-cyclohexane-3-ol, and oleyl
alcohol. Still other classes of the alcohols capable of
yielding the esters of this invention comprise the
ether-alcohols and amino-alcohols including, for example,
the oxy-alkylene, oxy-arylene-, amino-alkylene-, and
amino-arylene-substituted alcohols having one or more
oxy-alkylene, amino-alkylene or amino-arylene oxy-arylene
radicals. They are exemplified by Cellosolve, Carbitol,
N,N,N',N'-tetrahydroxy-trimethylene di-amine, and
ether-~lcohols having up to about 150 oxy-alkylene radicals
in which the alkylene radical contains from 1 to about 8
carbon atoms.
The ester dispersant may be di-esters of succinic
acids or acidic esters, i.e., partially esterified succinic
acids; as well as partially e~terified polyhydric alcohols
or phenols, i.e., esters having free alcohols or phenolic
hydroxyl radicals. Mixtures of the above illustrated
* Trade Mark
- - 29 - l 3372q4
esters likewise are contemplated within the scope of this
invention.
The ester dispersant may be prepared by one of several
known methods as illustrated for example in U.S. Patent
3,381,022. The ester dispersants may also be borated, similar
to the nitrogen containing dispersants, as described above.
Hydroxyamines which can be reacted with the aforesaid
long chain hydrocarbon substituted dicarboxylic acid materials
to form dispersants include 2-amino-1-butanol, 2-amino-2-
methyl-1-propanol, p-(beta-hydroxyl-ethyl)-aniline, 2-amino-1-
propanol, 3-amino-1-propanol, 2-amino-2-methyl-1, 3-propane-
diol, 2-amino-2-ethyl-1, 3-propanediol, N-(beta-hydroxy-
propyl)-N'-(beta-amino-ethyl)-piperazine, tris(hydroxymethyl)
amino-methane (also known as trismethylolaminomethane), 2-
amino-1-butanol, ethanolamine, beta-(beta-hydroxyethoxy)
ethylamine, and the like. Mixtures of these or similar amines
can also be employed. The above description of neucleophilic
reactants suitable for reaction with the hydrocarbyl
substituted dicarboxylic acid or anhydride includes amines,
alcohols, and compounds of mixed amine and hydroxy containing
reactive functional groups, i.e., amino-alcohols.
A preferred group of ashless dispersants are those
derived from polyisobutylene substituted with succinic
anhydride groups and reacted with polyethylene amines, e.g.
tetraethylene pentamine, pentaethylene hexamine,
polyoxyethylene and polyoxypropylene amines, e.g.
polyoxypropylene diamine, trismethyloloaminomethane and
pentaerythritol, and combinations thereof. One particularly
preferred dispersant combination involves a combination of (i)
polyisobutene substituted with succinic anhydride groups and
reacted with (ii) and hydroxy compound, e.g., pentaerythritol,
(iii) a polyoxyalkylene polyamine, e.g., polyoxypropylene
diamine, and (iv) a polyalkylene
'`' 'X~'
t
1 337294
-30-
polya~ine, e.g., polyethylene diamine and tetraethylene
p~nt~ine using about 0.3 to abcut 2 mole~ each of ~ii) and
(i~ and about 0.3 to about 2 molQ~ of ~iii) per mole of
~i) a~ describQd in U.S. Patent 3,804,763. Another
proferred dispersant combination involves the combination
of (i) polyisobutenyl succinic anhydride with (ii) a
polyalkylene polyamine, e.g. tetraethylene pentamine, and
(iii) a polyhydric alcohol or polyhydroxy-~ub~tituted
aliphatic primary aminQ, o.g. pentaQrythritol or
trismethylolaminomethane as described in U.S. Patent
3,632,511.
C(~ Also useful as ashlQ~s nitrogen-containing
dispersant in this invention are dispersants wherein a
nitrogen con~Ainin~ polyamine is attached directly to the
long chain aliphatic hydrocarbon as shown in U.S. Patents
3r275~554 and 3,565,804 where the halogen group on the
halogenated hydrocarbon is displaced with various alkylene
polyamine~.
C~iii) Another class of nitrogen containing
dispersants which may be used are those containing Mannich
base or Mannich condensation products as they are known in
the art. Such Mannich condensation products generally are
prepared by condensing about 1 mole of a high molecular
weight hydrocarbyl substituted mono- or polyhydroxy benzene
(e.g., having a number average molecular weight of 1,000 or
greater) with about 1 to 2.5 moles of formaldehyde or
parafor~aldehyde and about O.S to 2 moles polyalkylene
polya~ine as disclosed, e.g., in U.S. Patents 3,442,808;
3,649,229 and 3,798,165. Such~
Mannich condensation products may include a long chain,
high molecular weight hydrocarbon on the phenol group or
may be reacted with a compound containing such a
hydrocarbon, e.g., polyalkenyl succinic anhydride as shown
in said aforementioned U.S. Patent 3,442,808.
-31- 1 3372q4
Com~nent D
~ hQ antioxidant~ useful in thi~ invention include
copper carboxylate compound~ which are sources of oil
soluble copper in the lubricating oil. The copper may be
blended into the oil as any suitable oil soluble copper
carboxylate compound. By oil soluble we mean the
carboxylate compound is at least partially oil soluble
under normal blen~nq conditions in the oil or additive
package. The copper compound may be in the cuprous or
cupric form. The copper may be in the form of the copper
dihydrocarbyl thio- or dithio-phosphates wherein copper may
be ~ubstituted for zinc in the compounds and reactions
described above although one mole of cuprous or cupric
oxide may be reacted with one or two moles of the
dithiophosphoric acid, respectively. Alternatively the
copper may be added as the copper salt of a synthetic or
natural carboxylic acid. Examples include C10 to C18
fatty acids such as stearic or palmitic, but unsaturated
acid~ such as oleic or branched carboxylic acids such as
napthenic acids of molecular weight from 200 to 500 or
synthetic carboxylic acids are preferred because of the
improved handling and solubility properties of the
resulting copper carboxylates. Also useful are oil soluble
copper dithiocarbamates of the general formula
(RR'NCSS)nCu, where n is 1 or 2 and R and R' are the same
or different hydrocarbyl radicals containing from 1 to 18
and preferably 2 to 12 carbon atoms and including radicals
such a~ alkyl, alkenyl, aryl, aralkyl, alkaryl and
cycloaliphatic radicals. Particularly preferred as R and R'
y~OU~_ are alkyl yLO~_ of 2 to 8 carbon atoms. Thus, the
radicals may, for example, be ethyl, n-propyl, i-propyl,
n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl,
n-heptyl, n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl,
phenyl, butylphenyl, cyclohexyl, methylcyclopentyl,
propenyl, butenyl, etc. In order to obtain oil solubility,
_ - 32 - l 3372q4
the total number of carbon atoms (i.e., R and R') will
generally be about 5 or greater. Copper sulphonates,
phenates, and acetylacetonates may also be used.
The copper antioxidants (e.g., Cu-naphthenate, Cu-oleate,
or mixtures thereof) will be generally employed in an amount
of from about 40-500 ppm by weight of the metal, in the final
lubricating or fuel composition.
The copper antioxidants used in this invention are
inexpensive and are effective at low concentrations and
therefore do not add substantially to the cost of the product.
The results obtained are frequently better than those obtained
with previously used antioxidants, which are expensive and
used in higher concentrations. In the amounts employed, the
copper compounds do not interfere with the performance of
other components of the lubricating composition, in many
instances, completely satisfactory results are obtained when
the copper compound is the sole antioxidant in addition to
Component B. The copper compounds can be utilized to replace
part or all of the need for supplementary antioxidants. Thus,
for particularly severe conditions it may be desirable to
include a supplementary, conventional antioxidant. However,
the amounts of supplementary antioxidant required are small,
far less than the amount required in the absence of the copper
compound.
While any effective amount of the copper antioxidant can
be incorporated into the lubricating oil composition, it is
contemplated that such effective amounts be sufficient to
provide said lube oil composition with an amount of the copper
antioxidant of from about 40 to 500 (more preferably 50 to
200, still more preferably 80 to 150) parts per million of
added copper based on the weight of the lubricating oil
composition. Of course, the preferred amount may depend
amongst other factors on the quality of the basestock
lubricating oil.
- - 33 - 1337294
LUBRICATING COMPOSITIONS
Lubricating oil compositions, e.g., automatic
transmission fluids, heavy duty oils suitable for gasoline and
diesel engines, etc., can be prepared with the additives of
the invention. Universal type crankcase oils wherein the same
lubricating oil compositions can be used for both gasoline and
diesel engine can also be prepared. These lubricating oil
formulations conventionally contain several different types of
additives that will supply the characteristics that are
required in the formulations. Among these types of additives
are included viscosity index improvers, antioxidants,
corrosion inhibitors, other detergents, ashless dispersants,
pour point depressants, other antiwear agents, etc.
In the preparation of lubricating oil formulations it is
common practice to introduce the additives in the form of 10
to 80 wt.~, e.g. 20 to 80 wt.~ active ingredient concentrates
in hydrocarbon oil, e.g. mineral lubricating oil, or other
suitable solvent. Usually these concentrates may be diluted
with 3 to 100, e.g. 5 to 40 parts by weight of lubricating
oil, per part by weight of the additive package, in forming
finished lubricants, e.g. crankcase motor oils. The purpose
of concentrates, of course, is to make the handling of the
various materials less difficult and awkward as well as to
facilitate solution or dispersion in the final blend. Thus, a
Component A Ca/Mg hydrocarbyl sulfonate mixture or a Ca/Mg
alkyl phenate would be usually employed in the form of a 40 to
50 wt.~ concentrate, for example, in a lubricating oil
fraction.
Components A, B, C and D of the present invention will be
generally used in admixture with a lube oil basestock,
comprising an oil of lubricating viscosity, including natural
and synthetic lubricating oils and mixtures thereof.
.
_ _ 34 _ l 337 294
Components A, B, C and D can be incorporated into a
lubricating oil in any convenient way. Thus, these mixtures
can be added directly to the oil by dispersing or dissolving
the same in the oil at the desired level of concentrations of
the detergent inhibitor and antiwear agent, respectively.
Such blending into the additional lube oil can occur at room
temperature or elevated temperatures. Alternatively, the
Components can be blended with a suitable oil-soluble solvent
and base oil to form a concentrate, and then blending the
concentrate with a lubricating oil basestock to obtain the
final formulation.
The lubricating oil basestock for Components A and B
typically is adapted to perform a selected function by the
incorporation of additional additives therein to form
lubricating oil compositions (i.e., formulations).
Natural oils include animal oils and vegetable oils
(e.g., castor, lard oil) liquid petroleum oils and
hydrorefined, solvent-treated or acid-treated mineral
lubricating oils of the paraffinic, naphthenic and mixed
paraffinic-naphthenic types. Oils of lubricating viscosity
derived from coal or shale are also useful base oils.
Alkylene oxide polymers and interpolymers and derivatives
thereof where the terminal hydroxyl groups have been modified
by esterification, etherification, etc., constitute another
class of known synthetic lubricating oils. These are
exemplified by polyoxyalkylene polymers prepared by
polymerization of ethylene oxide or propylene oxide, the alkyl
and aryl ethers of these polyoxyalkylene polymers (e.g.,
methyl-poly isopropylene glycol ether having an average
molecular weight of 1000, diphenyl ether of poly-ethylene
glycol having a molecular weight of 500-1000, diethyl ether of
polypropylene glycol having a molecular weight of 1000-1500);
and mono- and polycarboxylic esters thereof, for example, the
acetic acid esters, mixed C3-C8 fatty acids esters and C13 Oxo
acid diester of tetraethylene glycol.
X
~ - 35 - 13372~4
Another suitable class of synthetic lubricating oils
comprises the esters of dicarboxylic acids (e.g., phthalic
acid, succinic acid, alkyl succinic acids and alkenyl succinic
acids, maleic acid, azelaic acid, suberic acid, sebasic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid,
alkylmalonic acids, alkenyl malonic acids) with a variety of
alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, ethylene glycol, diethylene glycol
monoether, propylene glycol). Specific examples of these
esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-
n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate,
dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid
dimer, and the complex ester formed by reacting one mole of
sebacic acid with two moles of tetraethylene glycol and two
moles of 2-ethylhexanoic acid.
Esters useful as synthetic oils also include those made
from Cs to C12 monocarboxylic acids and polyols and polyol
ethers such as neopentyl glycol, trimethylolpropane,
pentaerythritol, dipentaerythritol and tripentaerythritol.
Silicon-based oils such as the polyalkyl-, polyaryl-,
polyalkoxy-, or polyaryloxysiloxane oils and silicate oils
comprise another useful class of synthetic lubricants; they
include tetraethyl silicate, tetraisopropyl silicate, tetra-
(2-ethylhexyl) silicate, tetra-(4-methyl-2-ethylhexyl)
silicate, tetra-(p-tert-butylphenyl) silicate, hexa-(4-methyl-
2-pentoxy)disiloxane, poly (methyl) siloxanes and poly
(methylphenyl) siloxanes. Other synthetic lubricating oils
include liquid esters of phosphorus-containing acids (e.g.,
tricresyl phosphate, trioctyl phosphate, diethyl ester of
decylphosphonic acid) and polymeric tetrahydrofurans.
Unrefined, refined and rerefined oils can be used in the
lubricants of the present invention. Unrefined oils
~w
S~;7 '
.~``
- 36 - 1 337294
are those obtained directly from a natural or synthetic source
without further purification treatment. For example, a shale
oil obtained directly from retorting operations, a petroleum
oil obtained directly from distillation or ester oil obtained
directly from an esterification process and used without
further treatment would be an unrefined oil. Refined oils are
similar to the unrefined oils except they have been further
treated in one or more purification steps to improve one or
more properties. Many such purification techniques, such as
distillation, solvent extraction, acid or base extraction,
filtration and percolation are known to those skilled in the
art. Rerefined oils are obtained by processes similar to
those used to obtain refined oils applied to refined oils
which have been already used in service. Such rerefined oils
are also known as reclaimed or reprocessed oils and often are
additionally processed by techniques for removal of spent
additives and oil breakdown products.
The novel detergent inhibitor/antiwear agent mixtures of
the present invention can be used with V.I. improvers to form
multi-grade automobile engine lubricating oils. Viscosity
modifiers impart high and low temperature operability to the
lubricating oil and permit it to remain relatively viscous at
elevated temperatures and also exhibit acceptable viscosity or
fluidity at low temperatures. Viscosity modifiers are
generally high molecular weight hydrocarbon polymers including
polyesters. The viscosity modifiers may also be derivatized
to include other properties or functions, such as the addition
of dispersancy properties. These oil soluble viscosity
modifying polymers will generally have number average
molecular weights of from 103 to 106, preferably 104 to 106,
e.g., 20,000 to 250,000, as determined by gel permeation
chromatography or osmometry.
Examples of suitable hydrocarbon polymers include
homopolymers and copolymers of two or more monomers of C2
.~
_ 37 _ l 337294
to C30, e.g. C2 to C8 olefins, including both alpha olefins and
internal olefins, which may be straight or branched,
aliphatic, aromatic, alkyl-aromatic, cycloaliphatic, etc.
Frequently they will be of ethylene with C3 to C30 olefins,
particularly preferred being the copolymers of ethylene and
propylene. Other polymers can be used such as
polyisobutylenes, homopolymers and copolymers of C6 and higher
alpha olefins, atactic polypropylene, hydrogenated polymers
and copolymers and terpolymers of styrene, e.g. with isoprene
and/or butadiene and hydrogenated derivatives thereof. The
polymer may be degraded in molecular weight, for example by
mastication, extrusion, oxidation or thermal degradation, and
it may be oxidized and contain oxygen. Also included are
derivatized polymers such as post-grafted interpolymers of
ethylene-propylene with an active monomer such as maleic
anhydride which may be further reacted with an alcohol, or
amine, e.g. an alkylene polyamine or hydroxy amine, e.g. see
U.S. Patent Nos. 4,089,794; 4,160,739; 4,137,185; or
copolymers of ethylene and propylene reacted or grafted with
nitrogen compounds such as shown in U.S. Patent Nos.
4,068,056; 4,068,058; 4,146,489 and 4,149,984.
The preferred hydrocarbon polymers are ethylene
copolymers containing from 15 to 90 wt. ~ ethylene, preferably
30 to 80 wt.~ of ethylene and 10 to 85 wt.~, preferably 20 to
70 wt.~ of one or more C3 to C28, preferably C3 to C18, more
preferably C3 to C8, alpha-olefins. While not essential, such
copolymers preferably have a degree of crystallinity of less
than 25 wt.~, as determined by ~-ray and differential scanning
calorimetry. Copolymers of ethylene and propylene are most
preferred. Other alpha-olefins suitable in place of propylene
to form the copolymer, or to be used in combination with
ethylene and propylene, to form a terpolymer, tetrapolymer,
etc., include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-
octene, 1-nonene, 1-decene, etc.; also branched chain alpha-
~S
13372q4
_ - 38 -
olefins, such as 4-methyl-1-pentene, 4-methyl-1-hexene, 5-
methylpentene-1, 4,4-di-methyl-1-pentene, and 6-methylheptene-
1, etc., and mixtures thereof.
Terpolymers, tetrapolymers, etc., of ethylene, said C3-C28
alpha-olefin, and a non-conjugated diolefin or mixtures of
such diolefins may also be used. The amount of the non-
conjugated diolefin generally ranges from about 0.5 to 20 mole
percent, preferably from about 1 to about 7 mole percent,
based on the total amount of ethylene and alpha-olefin
present.
The polyester V.I. improvers are generally polymers of
esters of ethylenically unsaturated C3 to C3 mono- and
dicarboxylic acids such as methacrylic and acrylic acids,
maleic acid, maleic anhydride, fumaric acid, etc.
Examples of unsaturated esters that may be used include
those of aliphatic saturated mono alcohols of at least 1
carbon atom and preferably of from 12 to 20 carbon atoms, such
as decyl acrylate, lauryl acrylate, stearyl acrylate,
eicosanyl acrylate, docosanyl acrylate, decyl methacrylate,
diamyl fumarate, lauryl methacrylate, cetyl methacrylate,
stearyl methacrylate, and the like and mixtures thereof.
Other esters include the vinyl alcohol esters of C2 to C22
fatty or mono carboxylic acids, preferably saturated such as
vinyl acetate, vinyl laurate, vinyl palmitate, vinyl stearate,
vinyl oleate, and the like and mixtures thereof. Copolymers
of vinyl alcohol esters with unsaturated acid esters such as
the copolymer of vinyl acetate with dialkyl fumarates, can
also be used.
The esters may be copolymerized with still other
unsaturated monomers such as olefins, e.g. 0.2 to 5 moles of C2
- C20 aliphatic or aromatic olefin per mole of unsaturated
ester, or per mole of unsaturated acid or anhydride followed
by esterification. For example, copolymers of styrene with
'r
~_ _ 39 _ 1337294
maleic anhydride esterified with alcohols and amines are
known, e.g., see U.S. Patent 3,702,300.
Such ester polymers may be grafted with, or the ester
copolymerized with, polymerizable unsaturated nitrogen-
containing monomers to impart dispersancy to the V.I.
improvers. Examples of suitable unsaturated nitrogen-
containing monomers include those containing 4 to 20 carbon
atoms such as amino substituted olefins as p-(beta-
diethylaminoethyl) styrene; basic nitrogen-containing
heterocycles carrying a polymerizable ethylenically
unsaturated substituent, e.g. the vinyl pyridines and the
vinyl alkyl pyridines such as 2-vinyl-5-ethyl pyridine, 2-
methyl-5-vinyl pyridine, 2-vinyl-pyridine, 4-vinyl-pyridine,
3-vinyl-pyridine, 3-methyl-5-vinyl-pyridine, 4-methyl-2-vinyl-
pyridine, 4-ethyl-2-vinyl-pyridine and 2-butyl-1-5-vinyl-
pyridine, 4-ethyl-2-vinyl-pyridine and 2-butyl-1-5-vinyl-
pyridine and the like.
N-vinyl lactams are also suitable, e.g. N-vinyl
pyrrolidones or N-vinyl piperidones.
The vinyl pyrrolidones are preferred and are exemplified
by N-vinyl pyrrolidone, N-(1-methylvinyl) pyrrolidone, N-
vinyl-5-methyl pyrrolidone, N-vinyl-3, 3-dimethylpyrrolidone,
N-vinyl-5-ethyl pyrrolidone, etc.
Corrosion inhibitors, also known as anti-corrosive
agents, reduce the degradation of the metallic parts contacted
by the lubricating oil composition. Illustrative of corrosion
inhibitors are phosphosulfurized hydrocarbons and the products
obtained by reaction of a phosphosulfurized hydrocarbon with
an alkaline earth metal oxide or hydroxide, preferably in the
presence of an alkylated phenol or of an alkylphenol
thioester, and also preferably in the presence of carbon
dioxide. Phosphosulfurized hydrocarbons are prepared by
reacting a suitable hydrocarbon such as a terpene, a heavy
petroleum fraction of a C2 to C6 olefin polymer such as
polyisobutylene, with from 5 to 30 weight percent of a sulfide
of phosphorus
~,-
_40_ 1 337294
for 1~2 to 15 hours, at a temperature in the range of 66-
to 320 C. Neutralization of the~phosphosulfurized
hyd~ocarbon may be effected in the manner taught in U.S.
Patent No. 1,969,324.
Oxidation inhibitors reduce the tendency of
mineral oils to deteriorate in service which deterioration
can be evidenced by the products of oxidation such as
sludgQ and varnish-like deposits on the metal surfaces and
~y viscosity growth. Such oxidation inhibitors include
alkaline earth metal salts of alkylphenolthioesters having
preferably C5 to C12 alkyl side chains, calcium
nonylphenol sulfide, barium t-octylphenyl ~ulfide,
dioctylphenylamine, phenylalphanaphthylamine,
phosphosulfurized or sulfurized hydrocarbons, etc.
Friction modifiers serve to impart the proper
friction characteristics to lubricating oil compositions
such a~ automatic transmission fluids.
Representative examples of suitable friction
modifiers are found in U.S. Patent No. 3,933,659 which
discloses fatty acid esters and amides; U.S. Patent No.
4,176,074 which describes molybdenum complexes of polyiso-
butenyl succinic anhydride-amino alkanols; U.S. Patent No.
4,105,571 which discloses glycerol esters of dimerized
fatty acids; U.S. Patent No. 3,779,928 which discloses
alkane phosphonic acid salts; U.S. Patent No. 3,778,375
which discloses reaction products of a phosphonate with an
olea~ide; U.S. Patent No. 3,852,205 which discloses
S-carboxy-alkylene hydrocarbyl succinimide, S-carboxy-
alkyleno hydrocarbyl succinamic acid and mixtures thereof;
U.S. Patent No. 3,879,306 which discloses N-(hydroxy-
alkyl) alkenyl-~uccinamic acids or succinimides; U.S.
Patent No. 3,932,290 which discloses reaction products of
di-tlower alkyl) phosphites and epoxides; and U.S. Patent
No. 4,028,258 which discloses the alkylene oxide adduct of
phosphosulfurized N-(hydroxyalkyl) alkenyl succinimides.
-41- 1 337294
The most preferred friction ~
modifiers are glycerol mono and dioleates, and succinate
esters, or metal salts thereof, of hydrocarbyl substituted
succinic acids or anhydrides and thiobis alkanols such as
described in U.S. Patent No. 4,344,853.
Pour point depressants lower the temperature at
which the fluid will flow or can be poured. Such depres-
sant~ are well known. Typical of those additives which
usefully optimize the low temperature fluidity of the fluid
are C8-C18 dialkylfumarate vinyl acetate copolymers,
polymethacrylates, and wax naphthalene.
Foam control can be provided by an antifoamant of
the polysiloxane type, e.g. silicone oil and polydimethyl
siloxane.
Organic, oil-soluble compounds useful as ru~t
inhibitors in this invention comprise nonionic surfactants
such as polyoxyalkylene polyols and esters thereof, and
anionic surfactants such as alkyl sulfonic acids. Such
anti-rust compounds are known and can be made by
conventional means. Nonionic surfactants, useful as
anti-rust additives in the oleaginous compositions of this
invention, usually owe their surfactant properties to a
number of weak stabilizing groups such as ether linkages.
Nonionic anti-rust agents containing ether linkages can be
made by alkoxylating organic substrates containing active
hydrogens with an excess of the lower alkylene oxides (such
as ethylene and propylene oxides) until the desired number
of alkoxy groups have been placed in the molecule.
The preferred rust inhibitors are polyoxyalkylene
polyols and derivatives thereof. This class of materials
are commercially available from various sources: Pluronic
Polyols from Wyandotte Chemicals Corporation; Polyglycol
112-2, a liquid triol derived from ethylene oxide and
propylene oxide available from Dow Chemical Co.; and
Tergitol, dodecylphenyl or monophenyl polyethylene glycol
ethers, and Ucon* polyalkylene glycols and derivatives,
* Trade Mark I
-~ -42- 1 337294
both available from Union Carbide Corp. These are but a few
of the commercial products suitable as rust inhibitors in
the improved composition of the present invention.
In addition to the polyols ~er se, the esters
thereof obtained by reacting the polyols with various
carboylic acids are also suitable. Acids useful in
preparing these esters are lauric acid, stearic acid,
succinic acid, and alkyl- or alkenyl-substituted succinic
acids wherein the alkyl-or alkenyl group contains up to
about twenty carbon atoms.
The preferred polyols are prepared as block
polymers. Thus, a hydroxy-substituted compound, R-(OH)n
(wherein n i8 1 to 6, and R is the residue of a mono- or
polyhydric alcohol, phenol, naphthol, etc.) is reacted with
propylene oxide to form a hydrophobic base. This base is
then reacted with ethylene oxide to provide a hydrophylic
portion resulting in a molecule having both hydrophobic and
hydrophylic portions. The relative sizes of these portions
can be adjusted by regulating the ratio of reactants, time
of reaction, etc., as is obvious to those skilled in the
art. Thus it is within the skill of the art to prepare
polyols whose molecules are characterized by hydrophobic
and hydrophylic moieties which are present in a ratio
rendering rust inhibitors suitable for use in any lubricant
composition regardless of differences in the base oils and
the presqnce of other additives.
If more oil-solubility is needed in a given
lubricating composition, the hydrophobic portion can be
increased and/or the hydrophylic portion decreased. If
greater oil-in-water emulsion breaking ability is required,
the hydrophylic and/or hydrophobic portions can be adjusted
to accomplish this.
Compounds illustrative of R-(OH)n include alkylene
polyols such as the alkylene glycols, alkylene triols,
alkylene tetrols, etc., such as ethylene glycol, propylene
glycol, glycerol, pentaerythritol, sorbitol, mannitol, and
4 1 337294
-- 3--
the like. Aromatic hydroxy compounds such as alkylated
mono- and polyhydric phenols and naphthols can also be
used, e.g., heptylphenol, dodecylphenol, etc.
Other suitable demulsifiers include the esters
disclosed in U.S. Patents 3,098,827 and 2,674,619.
The liquid polyols available from Wyandotte
Chemical Co. under the name Pluronic Polyols and other
similar polyols are particularly well suited as rust
inhibitors. These Pluronic Polyols correspond to the
formula:
HO (CH2CH2O)x(clHcH2O)y(cH2cH2o)zH (VIII)
CH3
wherein x,y, and z are integers greater than 1 such that
the -CH2CH2O- groups comprise from about 10% to
about 40% by weight of the total molecular weight of the
glycol, the average molecule weight of said glycol being
from about 1000 to about 5000. These products are prepared
by first condensing propylene oxide with propylene glycol
to produce the hydrophobic base
HO(~ICH~CH2~0)y~H (IX)
CH3
This condensation product is then treated with ethylene
oxide to add hydrophylic portions to both ends of the
molecule. For best results, the ethylene oxide units
should comprise from about 10 to about 40% by weight of the
molecule. Those products wherein the molecular weight of
the polyol is from about 2500 to 4500 and the ethylene
oxide units comprise from about 10% to about 15% by weight
of the molecule are particularly suitable. The polyols
having a molecular weight of about 4000 with about 10%
attributable to (CH2CH2O) units are particularly good.
Also useful are alkoxylated fatty amines, amides, alcohols
and the like, including such alkoxylated fatty acid
derivatives treated with Cg to C16 alkyl-substituted
phenols (such as the mono- and di-heptyl, octyl, nonyl,
decyl, undecyl, dodecyl and tridecyl phenols), as described
_ -44~ l 337294
in U.S. Patent 3,849,501.
These composition~ of our invention may also
contain other additives such as those previously described,
and other metal containing additives, for example, those
containing barium and sodium.
The lubricating composition of the present
invention may also include copper lead bearing corrosion
inhibitors. Typically such compound~ are the thiadiazole
polysulphides containing from 5 to 50 carbon atoms, their
derivatives and polymers thereof. Preferred materials are
the derivatives of 1,3,4 thiadiazoles such as those
described in U.S. Patents 2,719,125; 2,719,126; and
3,087,932; especially preferred is the compound 2,5-bis
(t-octadithio)-1,3,4 thiadiazole commercially available as
Amoco 150. Other similar materials also suitable are
described in U.S. Patents 3,821,236; 3,904,537; 4,097,387;
4,107,059; 4,136,043; 4,188,299; and 4,193,882.
Other suitable additives are the thio and polythio
sulphenamides of thiadiazoles such as those described in
U.K. Patent Specification 1,560,830. When these compounds
are included in the lubricating composition, we prefer that
they be present in an amount from 0.01 to 10, preferably
0.1 to 5.0 weight percent based on the weight of the
composition.
Some of these numerous additives can provide a
multiplicity of effects, e.g., a dispersant-oxidation
inhibitor. This approach is well known and need not be
further elaborated herein.
Compositions when containing these conventional
additives are typically blended into the base oil in
amounts effective to provide their normal attendant
function. Representative effective amounts of such
additives (as the respective active ingredients) in the
fully formulated oil are illustrated as follows:
-45- l 3372q4
Wt.% A.~. Wt.% A.I.
Compositions (Preferred~ (Broad)
Component A(1) Ca 0.04-0.4 0.03-0.5
Oetergent*
Component A(2) Mg 0.01-0.2 0.01-0.25
Component B Antiwear 0.07-0.12(1) 0.05-0.15(1)
Agents
Component C Dispersant 0.5-4 0.1-8
Component D Antioxidant Cu(~P 40-500 ppmcu(2)
Viscosity Modifier .01-4 0.01-12
Corrosion Inhibitor 0.01-1.5 .01-5
Oxidation Inhibitors 0.01-1.5 .01-5
Pour Point Depressant 0.01-1.5 .01-5
Anti-Foaming Agents 0.001-0.15 .001-3
Friction Modifiers 0.01-1.5 .01-5
Mineral Oil Base Balance Balance
(1) Expressed as wt.% phosphorous.
(2) ppm by weight added Cu.
* Expressed as Ca (or Mg) metal.
Most preferably, the lubricating oil compositions
of this invention comprise from about 0.05 to 0.2 wt.% of
Component (A)(l), expressed as Ca; from about 0.02 to 0.11
wt.% of Component (A)(2), expressed as Mg; an amount of
Component B sufficient to provide from about 0.08 to 0.11
wt.% phosphorous; from about 1.5 to 3 wt.% A.I. Component C
ashless dispersant, and from about 80 to 150 ppm of
Component D antioxidant (expressed as ppm of Cu).
When other additives are employed, it may be
desirable, although not necessary, to prepare additive
concentrates comprising concentrated solutions or disper-
sions of the novel detergent inhibitor/antiwear agent
mixtures of this invention (in concentrate amounts
hereinabove described), together with one or more of said
other additives (said concentrate when constituting an
additive mixture being referred to herein as an
additive-package) whereby several additives can be added
simultaneously to the base oil to form the lubricating oil
composition. Dissolution of the additive concentrate into
the lubricating oil may be facilitated by solvents and by
- 1 3372q4
-46-
mixing accompanied with mild heatiny, but this is no~
e~sential. The concentrate or additive-packaye will
typically be formulated to contain the additives in proper
amounts to provide the desired concentration in the final
formulation when the additive-package is combined with a
predetermined amount of base lubricant. Thus, the detergent
inhibitor/antiwear agent mixtures of the present invention
can be added to small amounts of base oil or other
compatible solvents along with other desirable additives to
form additive-packages containing active ingredients in
collective amounts of typically from about 2.5 to about
90%, and preferably from about 15 to about 75%, and most
preferably from about 25 to about 60% by weight additives
in the appropriate proportions with the remainder being
base oil.
The final formulations may employ typically about
10 wt. % of the additive-package with the remainder being
base oil.
All of said weight percents expressed herein
(unless otherwise indicated) are based on active ingredient
(A.I.) content of the additive, and/or upon the total
weight of any additive-package, or formulation which will
be the sum of the A.I. weight of each additive plus the
weight of total oil or diluent.
This invention will be further understood by
reference to the following examples, wherein all parts are
parts by weight, unless otherwise noted and which include
preferred embodiments of the invention.
_47_ 1 337294
~MPL~S
A series of fully formulated lubricating oils were
prepared containing the selected detergent inhibitors, zinc
dialkyl dithiophosphate anti-wear agents, ashless
dispersants, anti-oxidants and fuel economy additives. The
data thereby obtained are summarized in Table I below.
1 337294
-- -48-
'~ Fa
m s s S s S S S ~ v v v v w ~ * * * * * *
o a~ o ~ o o o r1 ~ O ~ ~ g ~
~ g~l g~1
~ q o o ~ S ~ o o ~ S ~ S ~ S S:
, ~
; ~ ~ o S o S S S S S S S S S oo S S o o o o o o o o
~ . ' ~ o u~ o~ ~ O O u~ o o ~r
H ~ 2 ~ ~1 ~r ~ s ~r ~ ~r ~ ~r ~ ~ ~r ~ ~
H: :::: H::::: H H S: H H H H ::: H:: _
1 1 1 1 1 1 1 1 1 1 1 o oo8 1 Oa ~oooo
~_
o o o ,~ o o o o
a. o::::::::: . .::: . .
. o o I o ~
~.~
O O O I I O ,~ ~ ~ ~1 o
--1 .: : s : s s:: s s s: o s s . . . . . . . . .
O I N t' ~ 1~ ~0 r~ CO a~ O ~1 ~ ~ ~r In U~ t~ 00 C~ O
_ -49~ 1 337294
NOTES:
(1) (Wt.% Ca). Overbased calcium sulphonate, 400
TBN, 55 wt. % A.I.
(2) (Wt.% Mg). Overbased magnesium sulphonate,
400 TBN, 52 wt. % A.I.
(3) (Wt.% Phosphorous). Zinc di(primary alkyl)
dithiophosphate concentrate (75 wt. % A.I. in
dilute mineral oil) in which the alkyl groups
or a mixture of such groups have between 4 and
5 carbon atoms and made by reacting P2S5
with a mixture of about 65 wt. % isobutyl
alcohol and 35 wt. % amyl alcohol.
(4) (Wt.% Phosphorous). Zinc di(secondary
alkyl)dithiophosphate concentrate (71 wt. %
A.I. in dilute mineral oil) in which the alkyl
groups or a mixture of such groups having
between about 3 and 6 carbon atoms and made by
reacting P2S5 with a mixture of isopropyl
alcohol (30%) and methyl tertiary-butyl
carbinol (70%).
(5) Vol%. Ashless dispersant I= 50 wt. % A.I.
dilute mineral oil solution containing borated
polyisobutenyl succinimide having a nitrogen
content of about 1.47 wt. %, a boron content
of about 0.35 wt. % and derived from a
polyisobutenyl succinic anhydride having a
ratio of about 1.1 succinic anhydride moieties
per polyisobutylene molecule (derived from
polyisobutylene having a number average
molecular weight of about 1300) which was
_50_ 1 337294
aminated with a commercial grade of mixed
polyethylene amines having about 5 to 7
nitrogens per molecule. Ashless dispersant
II= 50 wt. % A.I. dilute mineral oil solution
containing borated polyisobutenyl succinimide
containing about 0.97 wt. % nitrogen, about
0.25 wt. % boron and derived from
polyisobutenyl succinic anhydride having about
1.1 succinic anhydride moieties per
polyisobutenyl molecule (derived from
polyisobutylene having a number average
molecular weight of about 2200) which was
aminated with a commercial mixture
polyethylene amines averaging from about 5 to
7 nitrogens per molecule.
(6) Vol% Dilute mineral oil of cupric oleate (38
wt.% A.I.).
(7) Vol% Dilute mineral oil solution of glycerol
monooleate; 50 wt.% A.I. total monoglycerides.
(8) Five car equivalent.
*Data points as identified in Figure 1.
Figure 1 illustrates fuel economy data as
summarized in the Examples. In Figure 1, the relative
ratios of the Ca and Mg metal detergents and the primary
and secondary ZDDP's of Examples 1-27, versus the observed
fuel economy test data, are schematically illustrated. The
x-axis indicates the relative percentage of Ca to Mg
detergent inhibitor, and the y-axis the relative percentage
of the primary to secondary ZDDP's. In the circled numbers
(e.g., 1.98/1), the numerators indicate the average
deserved fuel economy and the denominator the number of
_ -51- 1 3372q4
examples so averaged, for the indicated example or region
(indicated at A, B, C, D and E).
From the above tests, it is seen that the fuel
economy data in Region A (Examples 1 and 2, 100% Mg, 100~
primary 2DDP) is statistically poorer than the fuel economy
obtained in Region C (Examples 14-17, 50/50 Ca/Mg, 50/50
primary/secondary ZDDP), at the 99% confidence level. The
fuel economy of Region B (Examples 3-13, 100% Mg, 100~
secondary ZDDP) is statistically poorer than Region C of
this invention, at the 99% confidence level.
Region C is also statistically better than the
fuel economy of Region E (Examples 18-20, characterized by
high Ca/Mg and high secondary/primary ZDDP ratios), at the
95% confidence level.
Added fuel economy single data points are
illustrated in Figure 1 for Examples 22-27.
An additional series of lubricating oil
compositions were prepared and fuel economy tests
conducted, as in Examples 1-27. These additional runs,
Examples 28-37, are reported in Table II below. In these
runs, no glycerol monooleate friction modifier was included
in the formulations.
-52- 1 3372q4
~q I I I I I I I I I I
C"~3 00:S:SSS SS
r ~s s s s
H ~ ~ H H H H H H s s s S
.~ ~ 1 1 - s s s - s s
s S S S S S S
o o o o o o
o ~ a~ o ,~
'Z N
