FIELD OF THE INVENTION
[0001] The present invention relates to natural oils or synthetic triglycerides that contain
a styrene-diene viscosity modifier. The styrene-diene viscosity modifier is soluble
in the natural oil and the synthetic triglyceride. Natural oils and synthetic triglycerides
that contain the styrene-diene viscosity modifiers have utility in environmentally
friendly farm tractor lubricants and chain bar lubricants and hydraulic fluids.
BACKGROUND OF THE INVENTION
[0002] Successful use of vegetable oils and other biodegradable oils as environmentally
friendly base fluids in industrial applications is contingent on improving their viscometries
and low temperature flow properties. For example, a sunflower oil containing an oleic
acid content of 80 percent has a pour point of -12°C and turns solid in the Brookfield
viscosity measurement. Many of the industrial applications require a pour point of
less than -25°C and a Brookfield viscosity of 7500 to 150,00 centipoises (cP) at -25°C.
[0003] A key to utilizing a polymer for the thickening of a base oil is that the polymer
be soluble in the base oil. This solubility problem is not present for polymers in
mineral oil. Natural oils and synthetic triglycerides is another matter. In fact,
it is very difficult in finding hydrocarbon polymers that are soluble in natural oils
and synthetic triglycerides. Hydrocarbon polymers insoluble in natural oils and synthetic
triglycerides are olefin copolymers (OCP), ethylene-propylene diene monomer (EPDM),
high molecular weight polybutylene (PBU) and butyl rubbers. The present invention
relates to hydrogenated random block styrene/diene polymers that are soluble in natural
oils and synthetic triglycerides.
[0004] U.S. Patent No. 2,336,195 (Sparks et al, December 7, 1943) relates to improving viscosity
characteristics of hydrocarbon oils by the addition of normal mono-olefin polymers.
A normal mono-olefin polymer is converted to a high molecular weight polymer by compressing
an olefin, such as ethylene or propylene, to a high superatomspheric pressure in excess
of 500 atmospheres.
[0005] U.S. Patent No. 3,554,911 (Schiff et al, January 12, 1971) relates to improved lubricating
oils, particularly mineral lubricating oils, and processes of preparing the same.
In another aspect, this reference relates to the addition of a small amount of a hydrogenated
random butadiene-styrene copolymer to lubrication oils to produce formulations that
are shear stable and have a high viscosity index (V.I.). Accordingly, this reference
relates to hydrogenated random butadiene-styrene copolymers having defined amounts
of butadiene and styrene which are blended with suitable mineral oils to increase
the viscosity and improve the viscosity index.
[0006] U.S. Patent No. 3,772,169 (Small et al, November 13, 1973) provides an oil composition
which comprises:
1. a lubricating oil,
2. a random copolymer of butadiene and styrene containing 30-44 percent weight of
units derived from butadiene and 56 - 70 percent weight of units derived from styrene,
which copolymer has been hydrogenated until at least 95 percent of the olefinic double
bonds and at most 5 percent of the aromatic unsaturation has been saturated, and
3. an oil - soluble polyester which comprises molecular unit derived from an alkyl
ester of an α - olefinically unsaturated carboxylic acid in which the alkyl chain
or chains contain(s) at least 7 carbon atoms.
[0007] U.S. Patent No. 3,772,196 (St. Clair et al, November 13, 1973) provides for lubricating
oil compositions for internal combustion engines that have unexpectedly wide temperature
operating characteristics. This composition contains a combination of a 2-block copolymer
comprising a first polymer block of an alkenyl arene, e.g., styrene and a second essentially
completely hydrogenated polymer block of isoprene and certain pour point depressants
in a lubricant base stock having a viscosity index of at least 85
SUMMARY OF THE INVENTION
[0008] A composition is disclosed which comprises
(A) a major amount of at least one natural oil or synthetic triglyceride of the formula

wherein R1, R2 and R3 are aliphatic groups that contain from about 7 to about 23 carbon atoms, and
(B) a minor amount of a composition comprising a hydrogenated aliphatic conjugated
diene/mono-vinyl aromatic random block copolymer.
[0009] Various preferred features and embodiments of the present invention will now be described
by way of non-limiting example.
(A) The Natural Oil Or Synthetic Triglyceride
[0010] In practicing this invention, a synthetic triglyceride or a natural oil is employed
of the formula

wherein R
1, R
2 and R
3 are aliphatic hydrocarbyl groups that contain from about 7 to about 23 carbon atoms
and preferably from about 11 to about 21 carbon atoms. The term "hydrocarbyl group"
as used herein denotes a radical having a carbon atom directly attached to the remainder
of the molecule. The aliphatic hydrocarbyl groups include the following:
(1) Aliphatic hydrocarbon groups; that is, alkyl groups such as heptyl, nonyl, undecyl,
tridecyl, heptadecyl; alkenyl groups containing a single double bond such as heptenyl,
nonenyl, undecenyl, tridecenyl, heptadecenyl, heneicosenyl; alkenyl groups containing
2 or 3 double bonds such as 8,11-heptadecadienyl and 8,11,14-heptadecatrienyl. All
isomers of these are included, but straight chain groups are preferred.
(2) Substituted aliphatic hydrocarbon groups: that is groups containing non-hydrocarbon
substituents which, in the context of this invention, do not alter the predominantly
hydrocarbon character of the group. Those skilled in the art will be aware of suitable
substituents: examples are hydroxy, carbalkoxy, (especially lower carbalkoxy) and
alkoxy (especially lower alkoxy), the term, "lower" denoting groups containing not
more than 7 carbon atoms.
(3) Hetero atom groups; that is. groups which, while having predominantly aliphatic
hydrocarbon character within the context of this invention, contain atoms other than
carbon present in a chain or ring otherwise composed of aliphatic carbon atoms. Suitable
hetero atoms will be apparent to those skilled in the art and include, for example,
oxygen, nitrogen and sulfur.
[0011] Naturally occurring oils are vegetable oil triglycerides. The synthetic triglycerides
are those formed by the reaction of one mole of glycerol with three moles of a fatty
acid or mixture of fatty acids. Preferred are vegetable oil triglycerides. The preferred
vegetable oils are soybean oil, corn oil, lesquerella oil, rapeseed oil, sunflower
oil, canola oil, coconut oil, peanut oil, safflower oil, castor oil and palm olein.
[0012] In a preferred embodiment, the aliphatic hydrocarbyl groups are such that the triglyceride
has a monounsaturated character of at least 60 percent, preferably at least 70 percent
and most preferably at least 80 percent. Naturally occurring triglycerides having
utility in this invention are exemplified by vegetable oils that are genetically modified
such that they contain a higher than normal oleic acid content. Normal sunflower oil
has an oleic acid content of 25-30 percent. By genetically modifying the seeds of
sunflowers, a sunflower oil can be obtained wherein the oleic content is from about
60 percent up to about 90 percent. That is, the R
1, R
2 and R
3 groups are heptadecenyl groups and the R
1COO-, R
2COO-and R
3COO-to the 1,2,3-propanetriyl group -CH
2CHCH
2- are the residue of an oleic acid molecule. U.S. Patent No. 4,627,192 and 4,743,402
are herein incorporated by reference for their disclosure to the preparation of high
oleic sunflower oil.
[0013] For example, a triglyceride comprised exclusively of an oleic acid moiety has an
oleic acid content of 100% and consequently a monounsaturated content of 100%. Where
the triglyceride is made up of acid moieties that are 70% oleic acid, 10% stearic
acid, 13% palmitic acid, and 7% linoleic acid, the monounsaturated content is 70%.
The preferred triglyceride oils are high oleic (at least 60 percent) acid triglyceride
oils. Typical high oleic vegetable oils employed within the instant invention are
high oleic safflower oil, high oleic canola oil, high oleic peanut oil, high oleic
corn oil, high oleic rapeseed oil, high oleic sunflower oil, high oleic soybean oil,
high oleic cottonseed oil, and high oleic palm olein. Canola oil is a variety of rapeseed
oil containing less than 1 percent eruic acid. A preferred high oleic vegetable oil
is high oleic sunflower oil obtained from
Helianthus sp. This product is available from SVO Enterprises Eastlake, Ohio as Sunyl® high oleic
sunflower oil. Sunyl 80 oil is a high oleic triglyceride wherein the acid moieties
comprise 80 percent oleic acid. Another preferred high oleic vegetable oil is high
oleic rapeseed oil obtained from
Brassica campestris or
Brassica napus, also available from SVO Enterprises as RS high oleic rapeseed oil. RS80 oil signifies
a rapeseed oil wherein the acid moieties comprise 80 percent oleic acid.
[0014] It is further to be noted that genetically modified vegetable oils have high oleic
acid contents at the expense of the di-and tri- unsaturated acids. A normal sunflower
oil has from 20-40 percent oleic acid moieties and from 50-70 percent linoleic acid
moieties. This gives a 90 percent content of mono- and di- unsaturated acid moieties
(20+70) or (40+50). Genetically modifying vegetable oils generate a low di- or tri-
unsaturated moiety vegetable oil. The genetically modified oils of this invention
have an oleic acid moiety:linoleic acid moiety ratio of from about 2 up to about 90.
A 60 percent oleic acid moiety content and 30 percent linoleic acid moiety content
of a triglyceride oil gives a ratio of 2. A triglyceride oil made up of an 80 percent
oleic acid moiety and 10 percent linoleic acid moiety gives a ratio of 8. A triglyceride
oil made up of a 90 percent oleic acid moiety and 1 percent linoleic acid moiety gives
a ratio of 90. The ratio for normal sunflower oil is 0.5 (30 percent oleic acid moiety
and 60 percent linoleic acid moiety).
(B) The Random Block Copolymer
[0015] The random block copolymers of this invention comprise the product copolymerization
of two monomers. The first monomer is a conjugated diene and the second monomer is
a mono-vinyl aromatic. The random block copolymer formed is then hydrogenated to remove
substantially all of the unsaturation.
[0016] Examples of vinyl substituted aromatics include styrene, alphamethylstyrene, ortho-methylstyrene,
meta-methylstyrene, para-methylstyrene, para-tertiary-butylstyrene, with styrene being
preferred. Examples of conjugated dienes include piperylene, 2,3-dimethyl-1,3-butadiene,
chloroprene, isoprene and 1,3-butadiene with isoprene and 1,3-butadiene being particularly
preferred. Mixtures of such conjugated dienes are useful.
[0017] The vinyl substituted aromatic monomer content of these random block copolymers is
in the range of from about 20 percent to about 70 percent by weight and preferably
from about 40 percent to about 60 percent by weight. Thus, the aliphatic conjugated
diene monomer content of these copolymers is in the range of from about 30 percent
to about 80 percent by weight and preferably from about 40 percent to about 60 percent
by weight.
[0018] What follows is a discussion on the different types of random block copolymers.
[0019] In general, it is preferred that these block copolymers, for reasons of oxidative
stability, contain no more than about 5 percent and preferably no more than about
0.5 percent residual olefinic unsaturation on the basis of the total number of carbon-to-carbon
covalent linkages within the average molecule. Such unsaturation can be measured by
a number of means well known to those of skill in the art, such as infrared, NMR,
etc. Most preferably, these copolymers contain no discernible unsaturation as determined
by the aforementioned analytical techniques.
[0020] The random block copolymers of this invention typically have a number average molecular
weight in the range of about 5,000 to about 1,000,000; preferably about 30,000 to
about 300,000. The weight average molecular weight for these copolymers is generally
in the range of about 50,000 to about 500,000; preferably about 30,000 to about 300,000.
I. Random Copolymers: Those in which the comonomers are randomly, or nearly randomly,
arranged in the polymer chain, with no significant degree of blocking homopolymer
segments of either monomer. The general polymer structure of a random copolymer can
be represented by:

wherein S denotes a vinyl aromatic monomer such as styrene, and D denotes a conjugated
diene monomer such as 1,3-butadiene or isoprene. Such random copolymers, may easily
be made by free radical copolymerization.
While the diene monomer introduces an olefinic unsaturation of some sort, either in
the main backbone of the polymer, or pendant on it, it is to be understood that the
olefinic sites may be substantially removed by hydrogenation.
II. Regular Linear Block Copolymers: Those in which a small number of relatively long
chains of homopolymer of one type of monomer are alternately jointed to a small number
of relatively long chains of homopolymer of another type of monomer. Normal, or regular,
block copolymers usually have from 1 to about 3, preferably only from 1 to 2 relatively
large homopolymer blocks of each monomer. Thus, a linear regular diblock copolymer
of styrene or other vinyl aromatic monomer S and conjugated diene D would have a general
structure represented by a large block of homopolymer S attached to a large block
of homopolymer D:

The blocks of monomer S and monomer D are not necessarily of the same size or molecular
weight. As before, it is understood that the initial olefinic unsaturation introduced
into the copolymer by diene monomer D has been substantially removed by hydrogenation.
Linear diblock copolymers comprising hydrogenated poly-(styrene-b-isoprene) are sold
under the trade names "Shellvis 40, 50 and 90" by Shell Chemical Company.
In like manner, regular triblock copolymers are understood as having three relatively
large major blocks, or segments of homopolymer composed of either two monomers; i.e.,
as in:

and,

A third monomer A may also be incorporated in these linear, regular block copolymers.
In this instance, several configurations are possible, depending on how the homopolymer
segments are incorporated with respect to each other. For example, a linear triblock
copolymer of monomers S, D and A could be represented by several different configurations:

or,

III. Linear Random Block Copolymers: Those in which a relatively large number of relatively
short segments of homopolymer of one type of monomer alternate with a relatively large
number of short segments of homopolymer of another monomer type.
Random block polymers of this invention may be linear, or they may be partially, or
highly branched. The relative arrangement of homopolymer segments in a linear random
block polymer, which is the most preferred block polymer of this invention, may be
represented by:

wherein D represents a conjugated diene monomer, and A represents a vinyl aromatic
monomer. The arrangement of the individual homopolymer segments of each type of monomer
in a linear random block polymer is alternating.
IV. Linear Tapered Random Block Copolymers:
A special type of configuration in linear random block copolymers is the linear tapered
random block structure. In this arrangement, a major portion of the polymer backbone
is of the random block type, with larger blocks of one type of homopolymer situated
at one end of the molecule. The synthesis of this type of polymer is usually carried
out by preparing a linear random block copolymer, then adding more of one of the monomer
types near the end of the polymerization, so that the additional polymer forms a series
of ever larger homopolymer blocks at the end of the growing linear polymer chain.
The vinyl substituted aromatic monomer is generally chosen to provide the larger,
tapered homopolymer blocks, although other types of monomers may be used for this
purpose.

[0021] Linear tapered random block copolymers may have significantly different solubilities
in diluents normally used in lubricant formulations, as well as superior thickening
power at high temperature, better high temperature viscosity under conditions of high
shear, and improved low temperature viscometrics, compared to simple random block
copolymers of similar molecular weight, made from the same monomers.
[0022] The styrene/diene block polymers considered in this invention are usually made by
anionic polymerization, using a variety of techniques, and altering reaction conditions
to produce the most desirable microstructural features in the resulting polymer.
[0023] In an anionic polymerization, the initiator may be either an organometallic such
as an alkyl lithium, or the anion formed by electron transfer from a Group IA metal
to an aromatic such as naphthalene. The most efficacious organometallic is usually
an alkyl lithium such as
sec-butyl lithium, and the polymerization is initiated by butyl anion addition to either
the diene monomer, or to styrene. With sec-butyl lithium initiator, propagation occurs
in only one direction, and the growing polymer is anionically charged on one end,
the negative charge being associated with a positively-charged lithium gegenion.
[0024] Using an alkyl lithium initiator, a homopolymer of one monomer, e.g., styrene, may
be grown selectively, with each polymer molecule having an anionic terminus, and lithium
gegenion:

Since all the anionic sites are presumed to have equal reactivity toward monomer molecules,
polymer growth at each site is essentially the same, and the resulting polymers will,
when monomer is completely depleted, all be of similar molecular weight and composition.
Thus, polymers made by anionic polymerization are said to be nearly "monodisperse";
i.e., the ratio of weight average molecular weight to number average molecular weight
is very nearly 1.0. In practice, the polydispersity factor for properly synthesized
styrene-diene anionic block polymers is usually about 1.05- 1.10.
[0025] As long as nothing is introduced into the polymerization mixture that would act to
terminate the activity of the growing anionic end of a styrene homopolymer segment,
the composition constitutes a "living" polymer that maintains its activity, and can
grow further by interaction with monomers that are also capable of anionic polymerization.
These monomers may be additional styrene or similar vinyl aromatic monomers, or they
may comprise a different chemical type, such as 1,3-dienes (e.g., 1,3-butadiene or
isoprene). Addition of 1,3-butadiene or isoprene to the homopolystyrene-lithium living
polymer produces a second segment which grows from the anion site to produce a living
di-block polymer having an anionic terminus, with lithium gegenion.

[0026] Again, the size of this "D" block, i.e., the degree of polymerization ("DP"), will
be determined principally by the amount of diene monomer added, and the number of
active anionic sites available. As in the case of the first (polystyrene) segment,
the molecular weight of the new (polydiene ) segments will all be about the same,
and the polydispersity factor of the new poly S-block-poly-D living polymer will remain
about 1.0. Similarly, the terminus of the new S-D diblock polymer will be anionic
with a lithium gegenion, and the diblock will be "living" in the sense that the anionic
site will remain active toward further polymerization when exposed to additional anionically-polymerizable
monomers. Introduction of additional styrene could produce a new poly S-block-poly
D-block-poly S, or S-D-S triblock polymer; higher orders of block polymers could theoretically
be made by consecutive stepwise additions of different monomers in different sequences.
[0027] A common practice in manufacture of S-D-S type triblock polymers is to couple a living
diblock polymer by exposure to an agent such as dialkyldichlorosilane. When the carbanionic
"heads" of two S-D diblock living polymers are coupled using such an agent, precipitation
of LiCl occurs to give an S-D-S tri

lock po

ymer of somewhat different
-structure than that o

tained by the sequential monomer addition method described above, wherein the size
of the central D block is double that of the D block in the starting living (anionic)
diblock intermediate:

[0028] The polymerization to form block polymers may also be approached in a slightly different
manner. In cases where metal naphthalide is used to initiate polymerization, single
electron-transfer to monomer (S) generates a radical-anion which may dimerize to yield
a di-anionic nuceophile which is capable of initiating polymerization in two directions
simultaneously. Thus,



The polyS segment is a living dianionic species that can continue to initiate polymerization
in two directions. Exposure to a second monomer (D) results in formation of a polyD-block-PolyS-block-PolyD,
or a D-S-D triblock polymeric dianion.:

Again, the dianion is living, in the sense that it may continue to interact with additional
anionically-polymerizable monomers of the same, or different chemical type, in the
formation of higher order block polymers.
[0029] The effect of solvents in anionic polymerization is considerable, and can determine
in large measure the nature of the copolymer that is ultimately formed. Polymerization
is frequently carried out in what is considered to be a non-polar solvent such as
hexane, heptane or an aromatic such as benzene or toluene. Non-polar paraffinic solvents
tend to inhibit charge separation at the growing anion, and diminish the basicity
of the active organolithium head. These paraffinic solvents also tend to slow down
the rates of initiation and emphasize the differences in relative rate of polymerization
between various anionically-polymerizable monomers. Thus, when two different monomer
types are available, the one which initiates faster takes precedence.
[0030] Usually, the same monomer will also polymerize faster, building a segment that is
richer in that monomer, and contaminated by occasional incorporation of the other
monomer. In some cases, this can be used beneficially to build a type of polymer referred
to as a "random block polymer", or "tapered block polymer". When a mixture of two
different monomers is anionically polymerized in a non-polar paraffinic solvent, one
will initiate selectively, and usually polymerize to produce a relatively short segment
of homopolymer. Incorporation of the second monomer is inevitable, and this produces
a short segment of different structure. Incorporation of the first monomer type then
produces another short segment of that homopolymer, and the process continues. to
give a more or less "random" alternating distribution of relatively short segments
of homopolymers, of different lengths. At some point, one monomer will be considerably
depleted over the other, favoring incorporation of the first, more or less on the
basis of the principle of mass action. The result of enrichment of one monomer over
the other in the latter stages of polymerization produces even longer blocks of homopolymer
derived from the monomer in higher concentration. The result is a "tapered block copolymer",
having a multitude of shorter homopolymer segments, usually diads (2 monomers) to
pentads (5-monomers), and a "tail" enriched in longer segments of the less reactive
monomer.
[0031] An alternative way of preparing random or tapered block copolymers involves initiation
of styrene, and interrupting with periodic, or step, additions of diene monomer. The
additions are programmed according to the relative reactivity ratios and rate constants
of the styrene and particular diene monomer.
[0032] "Promoters" are electron-rich molecules that tend to enhance the basic nature of
the organolithium active site by coordinating with the positively-charged lithium
cation, polarizing the charged species to effect greater charge separation at the
active site where interaction with virgin monomer occurs. Promoters include tetrahydrofuran,
tetrahydropyran, linear and crown ethers, N,N-dimethylformamide, tetramethyl ethylenediamine,
and other non-protic agents that have non-bonding electron pairs available for coordination.
Promoters tend to facilitate anionic initiation and polymerization rates in general.
while lessening the relative differences in rates between various monomers. Promoters
may be added in small amounts to polymerization mixtures containing mixed monomers
in non-polar paraffinic or aromatic solvents in order to speed the reaction, and to
effect the nature of the size and distribution of blocks in the final copolymer.
[0033] Promoters also influence the way in which diene monomers are incorporated into the
block polymer. A diene monomer can polymerize by 1,2- or 1,4-addition (see following
reaction scheme), and the 1,4-addition can (theoretically) be either in a trans- or
cis- configuration. Studies using 1,3-butadiene/styrene monomers with sec-butyl lithium
initiator, have shown that in non-polar paraffinic solvents, the diene monomer incorporates
predominantly (86-95%) by cis-1,4-addition. Addition of small amounts of tetrahydrofuran
promoter cause 1,3-butadiene to increasingly favor 1,2-polymerization over the normal
1,4-cis-polymerization.
[0034] Hydrogenation of the unsaturated block polymers obtained initially as polymerization
products produces polymers that are more oxidatively and thermally stable. Reduction
is typically carried out at part of the polymerization process, using finely divided,
or supported, nickel catalyst. Other transition metals may also be used to effect
transformation. Hydrogenation is normally carried out to the extent of reducing approximately
94-96% of the olefinic unsaturation in the initial polymer. This means that the manner
in which the diene monomer incorporates becomes an important parameter affecting the
final physical and solution properties of the hydrogenated polymers at ambient and
low temperatures. The figure below shows diene incorporated both in a 1,4-cis and
1,2-manner. Hydrogenation of a 1,4-cis configuration produces linear polyethylene
segments in the polymer, reducing solubility in general, and introducing highly crystalline
sites that tend to associate at low temperatures, and introduce potentially undesirable
melt-associated thermal transitions.

In contrast, hydrogenation of diene introduced by 1,2-polymerization results in a
pendant alkyl group that enhances solubility, decreases crystallinity in the diene
segments, and substantially reduces the tendency toward association. The ability to
control the balance of 1,4- and 1,2-modes of diene monomer incorporation, in order
to optimize overall properties of the hydrogenated block polymer, for use as a viscosity
modifier in lubricating oil compositions.
[0035] Isoprene incorporates into block polymers in a similar manner to that of 1,3-butadiene,
i.e., either by 1,4-cis or 3,4-polymerization. As with 1,3-butadiene, predominantly
cis-1,4-incorporation is usual in non-polar paraffinic solvents, but promoters, such
as tetrahydrofuran, favor 3,4-polymerization. Again, a balance of properties may be
achieved by using small amounts of electron-rich promoters to speed initiation and
polymerization, and to influence the nature and properties of the final, hydrogenated
polymer. With isoprene, there will be no possibility of formation of crystalline polyethylene
segments on the hydrogenation, because there will always be aliphatic substituents
in the polyisoprene blocks.

[0036] It can be seen, then that the physical and solution properties of block copolymers
are dependent on both the monomers used, and the method of preparation. The morphological
characteristics of polymer solutions are similarly dependent on polymer microstructure.
Morphology refers to the actual conformation of polymers under a defined set of conditions,
and is dependent on structure, polymer concentration, temperature, and additional
influences of solvents and other agents. Many types of block polymers show a good
deal of intermolecular associative behavior, wherein blocks, or segments, of like
homopolymer may agglomerate. In this sense, the block polymers demonstrate a kind
of surface-active nature,wherein they form micelles, similar to those formed by classical
surfactants. Supporting this property are studies which have shown that block polymers
have the ability to stabilize colloidal dispersions. An example of surfactant properties
can be shown by the ability of polystyrene-block copolymers to stabilize dimethylformamide-hexane
emulsions.
[0037] Associative polymers can agglomerate in several ways, to produce discreetly different
structures, depending on the nature and arrangement of their blocks. Morphological
structures range from spherical and core-shell, to cylindrical and lamellar. In a
spherical or core-shell association, the center of the sphere is usually formed by
the more highly associative or crystalline segments, surrounded by a (usually more
diffuse) mantle or shell which is enriched in the second type of segment, which is
frequently swollen by solvent or diluent. The cylindrical form is similar to a spherical
form, except that the core extends from one end to the other, in an elongated shape,
rather than a sphere. The lamellar form comprises an arrangement of parallel planes
of associated blocks, alternating by type of segment. The morphology of copolymers
having highly crystalline segments are usually controlled by the temperature at which
such crystallization occurs, since this effectively "freezes" the entire structure.
Thus, segments having significant crystallinity can effectively impose their morphology
on the remainder of the copolymer.
[0038] Intermolecular association of oil-soluble block copolymers used as viscosity modifiers
for lubricants can pose significant problems, in terms of handleability of concentrates.
The polymer content of a polymeric viscosity improver concentrate ranges typically
from about 540% by weight, in a mineral oil, synthetic hydrocarbon, or ester diluent.
With non-associative polymers, such as OCP, EPDM, butyl polymer or polymethacrylates,
concentrates can be prepared at relatively high polymer concentrations, without experiencing
unduly highly bulk viscosities. The styrene-diene block copolymers, however, are highly
associative through the mutual affinity of their polystyrene segments, so that the
amount of polymer that can be dissolved before the concentrate viscosity become too
great to pour, is relatively low. The association problem is exacerbated by the use
of non-polar mineral oils or synthetic hydrocarbon diluents that are relatively poor
solvents for the polystyrene segments in the block copolymers. In these diluents,
the degree of association is relatively high, and the combined effective molecular
weight of the aggregates, astronomical. The effective thickening power of the copolymer
aggregates renders the concentrate a gel, and the concentrate becomes unpourable at
temperatures as high as 100°C.
[0039] In general, polystyrene-block-polyisoprene hydrogenated diblock copolymers have two
relatively large segments associated to a much greater degree than do random block
polymers of similar composition and molecular weight that have a much larger number
of relatively short polystyrene segments. Typically, the diblock copolymer concentrate
can contain no more than about 6% by weight, and the random block copolymer no more
than about 8% to be pourable at 100°C.
[0040] In general, it is preferred that these block copolymers, for reasons of oxidative
stability, contain no more than about 5 percent and preferably no more than about
0.5 percent residual olefinic unsaturation on the basis of the total number of carbon-to-carbon
covalent linkages within the average molecule. Such unsaturation can be measured by
a number of means well known to those of skill in the art, such as infrared NMR, etc.
Most preferably, these copolymers contain no discernible unsaturation as determined
by the aforementioned analytical techniques.
[0041] Examples of commercially available random block copolymers include the varioius Glissoviscal
block copolymers manufactured by BASF. Two especially preferred copolymers are Glissoviscal®
SGH and Glissoviscal® CE-5260.
[0042] In addition to components (A) and (B), the compositions of this invention may also
contain (C) at least one oxidation inhibitor, (D) at least one extreme pressure/anti-wear
additive or mixtures thereof.
(C) The Oxidation Inhibitor
[0043] The oxidation inhibitor comprises
(1) an alkyl phenol,
(2) an aromatic amine, or
(3) a heterocyclic amine.
(C1) The Alkyl Phenol
[0044] Component (C)(1) is an alkyl phenol of the formula

wherein R
4 is an alkyl group containing from 1 up to about 24 carbon atoms, a is an integer
of from 1 up to 3 and z is 1 or 2. Preferably R
4 contains from 1 to 12 carbon atoms and most preferably from 4 to 12 carbon atoms.
R
4 may be either straight chained or branched chained and branched chain is preferred.
The preferred value for a is 2 and the preferred value for z is 1.
[0045] Mixtures of alkyl phenols may be employed. Preferably the phenol is a butyl substituted
phenol containing two t-butyl groups. When a is 2, the t-butyl groups occupy the 2,6-position,
that is the phenol is sterically hindered:

When a is 3, the t-butyl groups occupy the 2,4,6- positions.
(C2) The Aromatic Amine
[0046] Component (C)(2) is an aromatic amine of the formula

wherein b is 1 or 2 and when b is 1, R
5 is

and R
6 and R
7 are independently a hydrogen or an alkyl group containing from 1 up to about 24 carbon
atoms, and when b is 2, R
5 and R
6 are independently hydrogen, an aryl group or an alkyl group containing from 1 up
to about 18 carbon atoms. Preferably b is 1, R
5 is

and R
6 and R
7 are both nonyl groups. When b is 2, R
5 preferably is

and R
6 and R
7 are both hydrogen.
(C3) The Heterocyclic Amine
[0047] Component (C3) is a heterocyclic amine of formulae (a) or (b)

wherein R
8 is independently a hydrogen or an alkyl group containing from 1 up to about 4 carbon
atoms, Z is hydrogen or → O· and X is hydrogen, -NR
14R
15 or -OR
15 wherein R
14 and R
15 are independently hydrogen or alkyl groups containing from 1 up to about 18 carbon
atoms.
[0048] Within formula (C3a) and (C3b) R
8 is preferably methyl. Compounds having utility in this invention within formula (C3a)
are 2,2,6,6-tetramethylpiperidine where X and Z are both hydrogen; 2,2,6,6-tetramethyl-1-piperidinol
where X is -OR
15 and R
15 and Z are both hydrogen; and 2,2,6,6-tetramethyl-1-piperidinyloxy free radical where
Z is → O· and X is hydrogen. A compound having utility in this invention within formula
(C3b) is 2,2,6,6-tetramethyl-4-piperidone where Z is hydrogen.
(D) The Extreme Pressure/Antiwear Additive
[0049] The extreme pressure/antiwear additive comprises
(1) a metal sulfur/phosphorus salt,
(2) a metal sulfur/nitrogen salt,
(3) a benzotriazole,
(4) a sulfurized composition, and
(5) a derivative of a dimercaptothiadiazole.
(D1) The Metal Sulfur/Phosphorus Salt
[0050] Component (D1) is a metal sulfur/phosphorus salt of the formula

wherein R
9 and R
10 are independently hydrocarbyl groups containing from 3 up to about 20 carbon atoms,
M
1 is a metal selected from the group consisting of lithium, sodium, calcium, barium,
copper, zinc, antimony, tin, cerium and other members of the lanthanide series, and
x is the valence of M
1.
[0051] Component (D1) is readily obtainable by the reaction of phosphorus pentasulfide (P
2S
5) and an alcohol or phenol. The reaction involves mixing at a temperature of about
20°C to about 200°C. four moles of an alcohol or phenol with one mole of phosphorus
pentasulfide. Hydrogen sulfide is liberated in this reaction.
[0052] The R
9 and R
10 groups are independently hydrocarbyl groups that are preferably free from acetylenic
and usually also from ethylenic unsaturation and have from 3 to about 20 carbon atoms,
preferably 3 to about 16 carbon atoms and most preferably 3 to about 12 carbon atoms.
[0053] Preferred metals acting as M
1 are copper, zinc, tin and cerium.
[0054] The following examples outline how component (D1) is prepared.
Example (D1)-1
[0055] A reaction vessel is charged with 804 parts of a mixture of 6.5 moles of isobutyl
alcohol and 3.5 moles of mixed primary amyl alcohols (65% w n-amyl and 35% w 2-methyl-1-butanol).
Phosphorus pentasulfide (555 parts, 2.5 moles) is added to the vessel while maintaining
the reaction temperature between about 104°-107°C. After all of the phosphorus pentasulfide
is added, the mixture is heated for an additional period to insure completion of the
reaction and filtered. The filtrate is the desired phosphorodithioic acid which contains
about 11.2% phosphorus and 22.0% sulfur.
[0056] A reaction vessel is charged with 448 parts of zinc oxide (11 equivalents) and 467
parts of the above alcohol mixture. The above phosphorodithioic acid (3030 parts,
10.5 equivalents) is added at a rate to maintain the reaction temperature at about
45°-50°C. The addition is completed in 3.5 hours whereupon the temperature of the
mixture is raised to 75°C for 45 minutes. After cooling to about 50°C, an additional
61 parts of zinc oxide (1.5 equivalents) are added, and this mixture is heated to
75°C for 2.5 hours. After cooling to ambient temperature, the mixture is stripped
to 124°C at mm. pressure. The residue is filtered twice through diatomaceous earth,
and the filtrate is the desired zinc salt containing 22.2% sulfur (theory, 22.0),
10.4% phosphorus (theory, 10.6) and 10.6% zinc (theory, 11.1).
Example (D1)-2
[0057] The procedure of Example (D1)-1 is essentially followed except that 2-methylpentyl
alcohol is used in place of the isobutyl alcohol and amyl alcohols. The product obtained
has 8.5% phosphorus, 17.6% sulfur and 9.25% zinc.
(D2) The Metal Sulfur/Nitrogen Salt
[0058] Component (D2) is a metal sulfur/nitrogen salt of the formula

wherein R
11 and R
12 are independently hydrocarbyl groups containing from 1 up to about 24 carbon atoms,
M
2 is a metal moiety selected from the group consisting of copper, zinc, antimony, tin,
cerium and other members of the lanthanide series and a molybdenum cation selected
from the group consisting of -Mo=O and

and y is the valence of M
2.
[0059] Preferably R
11 and R
12 are aliphatic groups containing from 3 up to about 12 carbon atoms and M
2 is preferably copper, antimony or zinc.
[0060] An example of a metal sulfur/nitrogen salt is an antimony dialkyldithiocarbamate
obtained from the R.T. Vanderbilt Company and known as Vanlube 73. From laboratory
analysis Vanlube 73 is believed to consist of antimony dipentyldithiocarbamate.
(D3) The Benzotriazole
[0061] Component (D3) is a benzotriazole of the formula

wherein R
13 is hydrogen or an alkyl group containing from 1 up to about 12 carbon atoms, R
16 is hydrogen or -CH
2SR
17 where R
17 is an alkyl group containing from 1 up to about 18 carbon atoms.
[0062] Preferably R
13 is a methyl group and R
16 is hydrogen which results in (D3) being tolyltriazole of the formula

Tolyltriazole is available under the trade name Cobratec TT-100 from Sherwin-Williams
Chemical.
(D4) The Sulfurized Composition
[0063] Within the purview of this invention, three different sulfurized compositions (D4a),
(D4b) and (D4c) are envisaged and have utility. The first sulfurized composition (D4a),
is a sulfurized olefinic hydrocarbon prepared in essentially a two-step process that
involves: 1) reacting an olefin with a sulfur halide to form a sulfochlorinated adduct,
and 2) contacting the sulfochlorinated adduct with sodium sulfide or sodium polysulfide
in a protic solvent. The protic solvent may be water and an alcohol of 4 carbon atoms
or less. Preferably, the alcohol is isopropyl alcohol. The sodium polysulfide solution
is best prepared by dissolving sulfur into an aqueouss Na
2S or NaSH/Na
2S solution. Water and aqueous NaOH are added as necessary to adjust the basic sulfide
concentration to a range of 18-21 percent Na
2S and 2-5 percent NaOH.
[0064] Additions of sulfur dichloride (SCl
2) or sulfur monochloride (S
2Cl
2) to an olefin produces sulfochloride intermediates having sulfide and disulfide groups
in the adducts. Contact of the sulfochloride intermediates withi the sodium sulfide
or sodium polysulfide solutions described results in nucleophilic displacement of
active chlorine as sodium chloride, and produces additional sulfide or polysulfide
groups within the product molecule. The product is a substantially chlorine-free sulfurized
compound that can be used as a lubricant additive.
[0065] A wide variety of olefins may be charged to the initial sulfochlorination reaction
including hydrocarbon olefins having a single double bond with terminal or internal
double bonds and containing from about 2 to 50 or more, preferably 2 to 8 carbon atoms
per molecule in either straight, branched chain or cyclic compounds, and these may
be exemplified by ethylene, propylene, butene-1, cis-and trans- butene-2, isobutylene,
diisobutylene, triisobutylene, pentenes, cyclopentene, cyclohexene, the octenes, decene-1,
etc. In general C
3-6 olefins or mixtures thereof are desirable for preparing sulfurized products for use
as extreme pressure additives. The combined sulfur content of the product decreases
with increasing olefin carbon number, while miscibility with oil increases.
[0066] The molar ratio of olefin to sulfur halide will vary depending on the amount of sulfurization
desired in the end product and the amount of olefinic unsaturation. The molar ratio
of sulfur halide to olefin could vary from 1:(1-20). When the olefin to be sulfurized
contains a single double bond, one mole of the olefin can be reacted with 0.5 moles
or less of S
2Cl
2 (sulfur monochloride). The olefin is generally added in excess with respect to the
amount of the sulfur being added so that all of the sulfur halide will be reacted
and any unreacted olefin can remain as unreacted diluent oil or can be removed and
recycled.
[0067] After the sulfurization-dechlorination reaction, the reaction mixture is allowed
to stand and separate into an aqueous layer and another liquid layer containing the
desired organic sulfide product. The product is usually dried by heating at moderately
elevated temperatures under subatmospheric pressure, and its clarity may often be
improved by filtering the dried product through a bed of bauxite, clay or diatomaceous
earth particles.
[0068] The following example is provided so as to provide those of ordinary skill in the
art with a complete disclosure and description of how to make the first sulfurized
composition.
Example (D4a)-1
[0069] Added to a three-liter, four-necked flask are 1100 grams (8.15 moles) of sulfur monochloride.
While stirring at room temperature 952 grams (17 moles) of isobutylene are added below
the surface. The reaction is exothermic and the addition rate of isobutylene controls
the reaction temperature. The temperature is allowed to reach a maximum of 50°C and
obtained is a sulfochlorination reaction product.
[0070] A blend of 1800 grams of 18% Na
2S solution is obtained from process streams. To this blend is added 238 grams 50%
aqueous NaOH, 525 grams water and 415 grams isopropyl alcohol to prepare a reagent
for use in the sulfurization-dechlorination reaction. To this reagent is added 1000
grams of the sulfochlorination reaction product in about 1.5 hours. One hour after
the addition is completed, the contents are permitted to settle and the liquid layer
is drawn off and discarded. The organic layer is stripped to 120°C and 100 mm Hg to
remove any volatiles. Analyses: % sulfur 43.5, % chlorine 0.2.
[0071] Table I outlines other olefins and sulfur chlorides that can be utilized in preparing
the first sulfurized composition. The procedure is essentially the same as in Example
(D4a)-1. In all the examples, the metal ion reagent is prepared according to Example
(D4a)-1.
[0072]
Table I
Example |
Olefin |
Sulfur Chloride |
Mole Ratio of Olefin:SC1 |
(D4a)-2 |
n-butene |
SCl2 |
2.3:1 |
(D4a)-3 |
propene |
S2Cl2 |
2.5:1 |
(D4a)-4 |
n-pentene |
S2Cl2 |
2.2:1 |
(D4a)-5 |
n-butene/isobutylene 1:1 weight |
S2Cl2 |
2.5:1 |
(D4a)-6 |
isobutylene/2-pentene 1:1 weight |
S2Cl2 |
2.2:1 |
(D4a)-7 |
isobutylene/2-pentene 3:2 weight |
S2Cl2 |
2.2:1 |
(D4a)-8 |
isobutylene/propene 6:1 weight |
S2Cl2 |
2.3:1 |
(D4a)-9 |
n-pentene/2-pentene 1:1 weight |
S2Cl2 |
2.2:1 |
(D4a)-10 |
2-pentene/propene 3:2 weight |
S2Cl2 |
2.2:1 |
[0073] The second sulfurized composition (D4b), is also a sulfurized olefinic hydrocarbon
that comprises the reaction product of sulfur and a Diels-Alder adduct. The Diels-Alder
adducts are a well known, art-recognized class of compounds prepared by the diene
synthesis or Diels-Alder reaction. A summary of the prior art relating to this class
of compounds is found in the Russian monograph,
Dienovyi Sintes, Izdatelstwo Akademii Nauk SSSR, 1963 by A.S. Onischenko. (Translated into the English
language by L. Mandel as A.S. Onischenko,
Diene Synthesis, N.Y., Daniel Davey and Co., Inc., 1964). This monograph and references cited therein
are incorporated by reference into the present specification.
[0074] Basically, the diene synthesis (Diels-Alder reaction) involves the reaction of at
least one conjugated diene, >C=C-C=C<, with at least one ethylenically or acetylenically
unsaturated compound, >C=C<, these latter compounds being known as dienophiles. The
reaction can be represented as follows:
[0075]

[0076]

[0077] The products, A and B are commonly referred to as Diels-Alder adducts. It is these
adducts which are used as starting materials for the preparation of the second sulfurized
composition.
[0078] Representative examples of such 1,3-dienes include aliphatic conjugated diolefins
or dienes of the formula

wherein R
18 through R
23 are each independently selected from the group consisting of halogen, alkyl, halo,
alkoxy, alkenyl. alkenyloxy, carboxy, cyano, amino, alkylamino, dialkylarnino, phenyl,
and phenyl-substituted with 1 to 3 substituents corresponding to R
18 through R
23 with the proviso that a pair of R's on adjacent carbons do not form an additional
double bond in the diene. Preferably not more than three of the R variables are other
than hydrogen and at least one is hydrogen. Normally the total carbon content of the
diene will not exceed 20. In one preferred aspect of the invention, adducts are used
where R
20 and R
21 are both hydrogen and at least one of the remaining R variables is also hydrogen.
Preferably, the carbon content of these R variables when other than hydrogen is 7
or less. In this most preferred class, those dienes where R
18, R
19, R
22 and R
23 are hydrogen, chloro, or lower alkyl are especially useful. Specific examples of
the R variables include the following groups: methyl, ethyl, phenyl, HOOC-, N≡C-,
CH
3COO-, CH
3CH
2O-, CH
3C(O)-, HC(O), -C1, -Br, tert-butyl, CF
3, tolyl, etc. Piperylene, isoprene, methylisoprene, chloroprene, and 1,3-butadiene
are among the preferred dienes for use in preparing the Diels-Alder adducts.
[0079] The dienophiles suitable for reacting with the above dienes to form the adducts used
as reactants can be represented by the formula

wherein the K variables are the same as the R variables in the diene formula above.
[0080] A preferred class of dienophiles are those wherein at least one of the K variables
is selected from the class of electron-accepting groups such as formyl, cyano, nitro,
carboxy, carbohydrocarbyloxy, hydrocarbylcarbonyl, hydrocarbylsulfonyl, carbamyl,
acylacarbanyl, N-acyl-N-hydrocarbylcarbamyl, N-hydrocarbylcarbamyl, and N,N-dihydrocarbylcarbamyl.
Those K variables which are not electron-accepting groups are hydrogen, hydrocarbyl,
or substituted-hydrocarbyl groups. Usually the hydrocarbyl and substituted hydrocarbyl
groups will not contain more than 10 atoms each.
[0081] The hydrocarbyl groups present as N-hydrocarbyl substituents are preferably alkyl
of 1 to 30 carbon atoms and especially 1 to 10 carbon atoms. Representative of this
class of dienophiles are the following: maleic anhydride, nitroalkenes, e.g., 1-nitrobutene-1,
1-nitropentene-1, 3-methyl-1-nitro-butene-1, 1-nitroheptene-1, 1-nitrooctene-1, 4-ethoxy-1-nitrobutene-1;
alpha, beta-ethylenically unsaturated aliphatic carboxylic acid esters, e.g., alkylacrylates
and alpha-methyl alkylacrylates (i.e., alkyl methacrylates) such as butylacrylate
and butylmethacrylate, decyl acrylate and decylmethacrylate, di-(n-butyl)-maleate,
di-(t-butyl-maleate); acrylonitrile, methacrylonitrile, beta-nitrostyrene, methylvinyl-sulfone,
acrolein, acrylic acid; alpha, beta-ethylenically unsaturated aliphatic carboxylic
acid amides, e.g., acrylamide, N,N-dibutylacrylamide, methacrylamide, N-dodecylmethacrylamide,
N-penyl-crotonamide; crotonaldehyde, crotonic acid, beta, beta-dimethyldivinylketone,
methyl-vinyl-ketone, N-vinyl pyrrolidone, alkenyl halides, and the like.
[0082] One preferred class of dienophiles are those wherein at least one, but not more than
two of K variables is -C(O)O-R° where R° is the residue of a saturated aliphatic alcohol
of up to about 40 carbon atoms; e.g., for example at least one K is carbohydrocarbyloxy
such as carboethoxy, carbobutoxy, etc., the aliphatic alcohol from which -R° is derived
can be a mono- or polyhydric alcohol such as alkyleneglycols, alkanols, aminoalkanols,
alkoxy-substituted alkanols, ethanol, ethoxy ethanol, propanol, beta-diethylaminoethanol,
dodecyl alcohol, diethylene glycol, tripropylene glycol, tetrabutylene glycol, hexanol,
octanol, isooctyl alcohol, and the like. In this especially preferred class of dienophiles,
not more than two K variables will be -C(O)-O-R° groups and the remaining K variables
will be hydrogen or lower alkyl, e.g.. methyl. ethyl, propyl, isopropyl, and the like.
[0083] Specific examples of dienophiles of the type discussed above are those wherein at
least one of the K variables is one of the following groups: hydrogen, methyl, ethyl,
phenyl, HOOC-, HC(O)-. CH
2=CH-, HC≡C-, CH
3C(O)-, C1CH
2-, HOCH
2-, alpha-pyridyl, -NO
2, -C1, -Br, propyl, iso-butyl, etc.
[0084] In addition to the ethylenically unsaturated dienophiles, there are many useful acetylenically
unsaturated dienophiles such as propiolaldehyde, methylethynylketone, propylethynylketone,
propenylethynylketone, propiolic acid, propiolic acid nitrile, ethylpropiolate, tetrolic
acid, propargylaldehyde, acetylenedicarboxylic acid, the dimethyl ester of acetylenedicarboxylic
acid, dibenzoylacetylene, and the like.
[0085] The second sulfurized compositions are readily prepared by heating a mixture of sulfur
and at least one of the Diels-Alder adducts of the types discussed hereinabove at
a temperature within the range of from about 100°C to about 200°C will normally be
used. This reaction results in a mixture of products, some of which have been identified.
In the compounds of know structure, the sulfur reacts with the substituted unsaturated
cycloaliphatic reactants at a double bond in the nucleus of the unsaturated reactant.
[0086] The molar ratio of sulfur to Diels-Alder adduct used in the preparation of this sulfur-containing
composition is from about 1:2 up to about 4:1. Generally, the molar ratio of sulfur
to Diels-Alder adduct will be from about 1:1 to about 4:1 and preferably about 2:1
to about 4:1.
[0087] The reaction can be conducted in the presence of suitable inert organic solvents
such as mineral oils, alkanes of 7 to 18 carbons, etc., although no solvent is generally
necessary. After completion of the reaction, the reaction mass can be filtered and/or
subjected to other conventional purification techniques. There is no need to separate
the various sulfur-containing products as they can be employed in the form of a reaction
mixture comprising the compounds of known and unknown structure.
[0088] As hydrogen sulfide is an undesirable contaminant, it is advantageous to employ standard
procedures for assisting in the removal of the H
2S from the products. Blowing with steam, alcohols, air, or nitrogen gas assists in
the removal of H
2S as does heating at reduced pressures with or without the blowing.
[0089] It is sometimes advantageous to incorporate materials useful as sulfurization catalysts
in the reaction mixture. These materials may be acidic, basic or neutral. Useful neutral
and acidic materials include acidified clays such as "Super Filtrol", p-toluenesulfonic
acid, dialkylphosphoro-dithioic acids, phosphorus sulfides such as phosphorus pentasulfide
and phosphites such as triaryl phosphites (e.g., triphenyl phosphite).
[0090] The basic materials may be inorganic oxides and salts such as sodium hydroxide, calcium
oxide and sodium sulfide. The most desirable basic catalysts, however, are nitrogen
bases including ammonia and amines. The amines include primary, secondary and tertiary
hydrocarbyl amines wherein the hydrocarbyl radicals are alkyl, aryl, aralkyl, alkaryl
or the like and contain about 1-20 carbon atoms. Suitable amines include aniline,
benzylamine, dibenzylamine, dodecylamine, naphthylamine, tallow amines, N-ethyl-dipropylamine,
N-phenylbenzylamine, N,N-diethylbutylamine, m-toluidine and 2,3-xylidine. Also useful
are heterocyclic amines such as prrolidine, N-methylpyrrolidine, piperidine, pyridine
and quinoline.
[0091] The preferred basic catalysts include ammonia and primary, secondary or tertiary
alkylamines having about 1-8 carbon atoms in the alkyl radicals. Representing amines
of this type are methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine,
triethylamine, di-n-butylanine, tri-n-butylamine, tri-sec-hexylamine and tri-n-octylamine.
Mixtures of these amines can be used, as well as mixtures of ammonia and amines.
[0092] When a catalyst is used, the amount is generally about 0.05-2.0% of the weight of
the adduct.
[0093] The following example illustrates the preparation of the second sulfurized composition.
Unless otherwise indicated in these examples and in other parts of this specification,
as well as in the appended claims, all parts and percentages are by weight.
Example (D4b)-1
[0094] A mixture comprising 400 parts of toluene and 66.7 parts of aluminum chloride is
charged to a two-liter flask fitted with a stirrer, nitrogen inlet tube, and a solid
carbon dioxide-cooled reflux condenser. A second mixture comprising 640 parts (5 moles)
of butyl acrylate and 240.8 parts of toluene is added to the AlCl
3 slurry while maintaining the temperature within the range of 37-58°C over a 0.25-hour
period. Thereafter, 270 parts (5 moles) of butadiene is added to the slurry over a
2.75-hour period while maintaining the temperature of the reaction mass at 50-61°C
by means of external cooling. The reaction mass is blown with nitrogen for about 0.33
hour and then transferred to a four-liter separatory funnel and washed with a solution
of 150 parts of concentrated hydrochloric acid in 1100 parts of water. Thereafter,
the product is subjected to two additional water washings using 1000 parts of water
for each wash. The washed reaction product is subsequently distilled to remove unreacted
butyl acrylate and toluene. The residue of this first distillation step is subjected
to further distillation at a pressure of 9-10 millimeters of mercury whereupon 785
parts of the desired product is collected over the temperature of 105-115°C.
[0095] A mixture of 728 parts (4.0 moles) of the above material, 218 parts (6.8 moles) of
sulfur, and 7 parts of triphenyl phosphite is prepared and heated with stirring to
a temperature of about 181°C over a period of 1.3 hours. The mixture is maintained
under a nitrogen purge at a temperature of 181-187°C for 3 hours. After allowing the
material to cool to about 85°C over a period of 1.4 hours, the mixture is filtered
using a filter aid, and the filtrate is the desired second sulfurized composition
containing 23.1% sulfur.
[0096] The third sulfurized composition (D4c) is prepared by sulfurizing a mixture comprising
three essential reagents. This first reagent is a fatty oil; that is, at least one
naturally occurring ester of glycerol and a fatty acid, or a synthetic ester of similar
structure. Such fatty oils are animal or vegetable oil tryiglycerides of the formula

wherein R
1, R
2 and R
3 are aliphatic groups containing from about 7 to about 23 carbon atoms. A non-exhaustive
list of triglycerides include peanut oil, cottonseed oil, soybean oil, sunflower oil
and corn oil. These triglycerides are the same as component (A) disclosed above.
[0097] The second reagent is at least one alkenyl carboxylic acid of the formula R
25COOH wherein R
25 contains about 7 to about 29 carbon atoms. The carboxylic acids are ordinarily free
from acetylenic unsaturation. Suitable acids include (preferably) oleic acid, linoleic
acid, linolenic acid, 14-hydroxy-11-eicosenoic acid and ricinoleic acid. In particular,
the carboxylic acid may be an unsaturated fatty acid such as oleic or linoleic acid,
and may be a mixture of acids such as is obtained from tall oil or by the hydrolysis
of peanut oil, soybean oil or the like. The amount of carboxylic acid used is about
2-50 parts by weight per 100 parts of triglyceride; about 2-8 parts by weight is preferred.
[0098] The third reagent is at least one substantially aliphatic monoolefin containing from
about 4 to about 36 carbon atoms, and is present in the amount of about 25-400 parts
by weight per 1000 parts of triglyceride. Suitable olefins include the octenes, decenes,
dodecenes, eicosenes and triacontenes, as well as analogous compounds containing aromatic
or non-hydrocarbon substituents which are substantially inert in the context of this
invention. (As used in the specification and appended claims, the term "substantially
inert" when used to refer to solvents, diluents, substituents and the like is intended
to mean that the solvent, diluent, substituent, etc. is inert to chemical or physical
change under the conditions which it is used so as not to interfere materially in
an adverse manner with the preparation, storage, blending and/or functioning of the
composition, additive, compound, etc. in the context of its intended use). For example,
small amounts of a solvent, diluent, substituent, etc. can undergo minimal reaction
or degradation without preventing the making and using of this component as described
herein. In other words, such reaction or degradation, while technically discernible,
would not be sufficient to deter a worker of ordinary skill in the art from making
and using this component for its intended purposes. "Substantially inert" as used
herein is, thus, readily understood and appreciated by those of ordinary skill in
the art. Terminal olefins, or α - olefins, are preferred, especially those containing
from about 12 to about 20 carbon atoms. Especially preferred are straight chain α
olefins. Mixtures of these olefins are commercially available and such mixtures are
contemplated for use in this invention.
[0099] This sulfurized composition is prepared by reacting a mixture comprising a triglyceride,
a fatty acid and an aliphatic monoolefin with a sulfurizing agent at a temperature
between about 100°C and about 250°C, usually between about 150° and about 210°C. The
sulfurizing reagent may be, for example, sulfur, a sulfur halide such as sulfur monochloride
or sulfur dichloride, a mixture of hydrogen sulfide and sulfur dioxide, or the like.
Elemental sulfur is often preferred and the invention especially contemplates the
use of sulfurized composition prepared by reacting sulfur with the aforesaid mixture.
The weight ratio of the combination of triglyceride, fatty acid and aliphatic monoolefin
to sulfur is between about 5:1 and about 15:1, generally between about 5:1 and about
10:1.
[0100] In addition to the above described reagents, the reaction mixture may contain other
materials. These may include, for example, sulfurization promoters, typically phosphorus-containing
reagents such as phosphorous acid esters such as lecithin.
[0101] The sulfurization reaction is effected by merely heating the reagents at the temperature
indicated above, usually with efficient agitation and in an inert atmosphere (e.g.,
nitrogen). If any of the reagents, especially the aliphatic monoolefin, are appreciably
volatile at the reaction temperature, the reaction vessel may be maintained under
pressure. It is frequently advantageous to add sulfur portionwise to the mixture of
the other reagents. While it is usually preferred of the reagent previously described,
the reaction may also be effected in the presence of a substantially inert organic
diluent (e.g., an alcohol, ether, ester, aliphatic hydrocarbon, halogenated aromatic
hydrocarbon or the like) which is liquid within the temperature range employed. When
the reaction temperature is relatively high, e.g., about 200°C, there may be some
evolution of sulfur from the product which is avoided if a lower reaction temperature
(e.g., from about 150° to about 170°C) is used. However, the reaction sometimes requires
a longer time at lower temperatures and an adequate sulfur content is usually obtained
when the temperature is at the high end of the recited range.
[0102] Following the reaction, volatile materials may be removed by blowing with air or
nitrogen and insoluble by products by filtration, usually at an elevated temperature
(from about 80° to about 120°C). The filtrate is the desired sulfur product.
[0103] U.S. Patent Nos. 3,926,822 and 3,953,347 are incorporated by reference herein for
their disclosures of a suitable sulfurized mixture of triglyceride, carboxylic acid
and aliphatic monoolefin. Several specific sulfurized compositions are described in
examples 10-18 of 3,926,822 and 10-19 of 3,953,347. The following example illustrates
the preparation of one such composition. (In the specification and claims, all parts
and percentages are by weight unless otherwise indicated.)
Example (D4c)-1
[0104] A mixture of 100 parts of soybean oil, 5.25 parts of tall oil acid and 44.8 parts
of commercial C
15-18 straight chain ∝ - olefins is heated to 167°C under nitrogen, and 17.4 parts of sulfur
is added. The temperature of the mixture rises to 208°C. Nitrogen is blown over the
surface at 165°-200°C for 6 hours and the mixture is then cooled to 90°C and filtered.
The filtrate is the desired product and contains 10.6% sulfur.
(D5) The Derivative Of A Dimercaptothiadiazole
[0105] The dimercaptothiadiazole derivatives which can be utilized as component (D5) in
the composition of the present invention contain the dimercaptothiadiazole nucleus
have the following structural formulae and names:
2,5-dimercapto-1,3,4-thiadiazole

3,5-dimercapto-1,2,4-thiadiazole

3,4-dimercapto-1,2,5-thiadiazole

4,5-dimercapto-1,2,3-thiadiazole

Of these the most readily available, and the one preferred for the purpose of this
invention, is 2,5-dimercapto-1,3,4-thiadiazole. This compound will sometimes be referred
to hereinafter as DMTD. However, it is to be understood that any of the other dimercaptothiadiazoles
may be substituted for all or a portion of the DMTD.
[0106] DMTD is conveniently prepared by the reaction of one mole of hydrazine, or a hydrazine
salt, with two moles of carbon disulfide in an alkaline medium, followed by acidification.
[0107] Derivatives of DMTD have been described in the art, and any such compounds can be
included in the compositions of the present invention. The preparation of some derivatives
of DMTD is described in E.K. Fields "Industrial and Engineering Chemistry",
49, p. 1361-4 (September 1957). For the preparation of the oil-soluble derivatives of
DMTD, it is possible to utilize already prepared DMTD or to prepare the DMTD in situ
and subsequently adding the material to be reacted with DMTD.
[0108] U.S. Patents 2,719,125; 2,719,126; and 3,087,937 describe the preparation of various
2,5-bis-(hydrocarbon dithio)-1,3,4-thiadiazoles. The hydrocarbon group may be aliphatic
or aromatic, including cyclic, alicyclic, aralkyl, aryl and alkaryl. Such compositions
are effective corrosion-inhibitors for silver, silver alloys and similar metals. Such
polysulfides which can be represented by the following general formula

wherein R and R' may be the same or different hydrocarbon groups, and x* and y* be
integers from 0 to about 8, and the sum of x* and y* being at least 1. A process for
preparing such derivatives is described in U.S. Patent 2,191,125 as comprising the
reaction of DMTD with a suitable sulfenyl chloride or by reacting the dimercapto diathiazole
with chlorine and reacting the resulting disulfenyl chloride with a primary or tertiary
mercaptan. Suitable sulfenyl chlorides useful in the first procedure can be obtained
by chlorinating a mercaptan (RSH or R'SH) with chlorine in carbon tetrachloride. In
a second procedure, DMTD is chlorinated to form the desired bissulfenyl chloride which
is then reacted with at least one mercaptan (RSH and/or R'SH). The disclosures of
U.S. Patents 2,719,125; 2,719,126; and 3,087,937 are hereby incorporated by reference
for their description of derivatives of DMTD useful in the compositions of the invention.
[0109] U.S. Patent 3,087,932 describes a one-step process for preparing 2,5-bis (hydrocarbyldithio)-1,3,4-thiadiazole.
The procedure involves the reaction of either DMTD or its alkali metal or ammonium
salt and a mercaptan in the presence of hydrogen peroxide and a solvent. Oil-soluble
or oil-dispersible reaction products of DMTD can be prepared also by the reaction
of the DMTD with a mercaptan and formic acid. Compositions prepared in this manner
are described in U.S. Patent 2,749,311. Any mercaptan can be employed in the reaction
although aliphatic and aromatic mono- or poly-mercaptan containing from 1 to 30 carbon
atoms are preferred. The disclosures of U.S. Patents 3.087,932 and 2,749,311 are hereby
incorporated by reference for their description of DMTD derivatives which can be utilized
as a metal passivator.
[0110] Carboxylic esters of DMTD having the general formula

wherein R and R' are hydrocarbon groups such as aliphatic, aryl and alkaryl groups
containing from about 2 to about 30 or more carbon atoms are described in U.S. Patent
2,760,933. These esters are prepared by reacting DMTD with an organic acid halide
(chloride) and a molar ratio of 1:2 at a temperature of from about 25 to about 130°C.
Suitable solvents such as benzene or dioxane can be utilized to facilitate the reaction.
The reaction product is washed with dilute aqueous alkali to remove hydrogen chloride
and any unreacted carboxylic acid. The disclosure of U.S. Patent 2,760,933 is hereby
incorporated by reference for its description of various DMTD derivatives which can
be utilized in the compositions of the present invention.
[0111] Condensation products of alpha-halogenated aliphatic monocarboxylic acids having
at least 10 carbon atoms with DMTD are described in U.S. Patent 2,836,564. These condensation
products generally are characterized by the following formula

wherein R is an alkyl group of at least 10 carbon atoms. Examples of alpha-halogenated
aliphatic fatty acids which can be used include alpha-bromo-lauric acid, alphachloro-lauric
acid, alpha-chloro-stearic acid, etc. The disclosure of U.S. Patent 2,836,564 is hereby
incorporated by reference for its disclosure of derivatives of DMTD which can be utilized
in the compositions of the present invention.
[0112] Oil-soluble reaction products of unsaturated cyclic hydrocarbons and unsaturated
ketones are described in U.S. Patents 2,764,547 and 2,799,652, respectively, and a
disclosure of these references also are hereby incorporated by reference for their
description of materials which are useful as a DMTD derivative in the present invention.
Examples of unsaturated cyclic hydrocarbons described in the '547 patent include styrene,
alpha-methyl styrene, pinene, dipentene, cyclopentadiene, etc. The unsaturated ketones
described in U.S. Patent 2,799,652 include aliphatic, aromatic or heterocyclic unsaturated
ketones containing from about 4 to 40 carbon atoms and from 1 to 6 double bonds. Examples
include mesityl oxide, phorone, isophorone, benzal acetophenone, furfural acetone,
difurfuryl acetone, etc.
[0113] U.S. Patent 2,765,289 describes products obtained by reacting DMTD with an aldehyde
and a diaryl amine in molar proportions of from about 1:1:1 to about 1:4:4. The resulting
products are suggested as having the general formula

wherein R and R' are the same or different aromatic groups, and R" is hydrogen, and
alkyl group, or an aromatic group. The aldehydes useful in the preparation of such
products as represented by Formula X include aliphatic or aromatic aldehydes containing
from 1 to 24 carbon atoms, and specific examples of such aldehydes include formaldehyde,
acetaldehyde, benzaldehyde, 2-ethylehexyl aldehyde, etc. The disclosure of this patent
also is hereby incorporated by reference for its identification of various materials
which can be utilized in the compositions of this invention.
[0114] Amine salts of DMTD such as those having the following formula

in which Y is hydrogen or the amino group

in which R is an aliphatic, aromatic or heterocyclic group, containing from about
6 to about 60 carbon atoms also have utility as component (D5). The amine used in
the preparation of the amine salts can be aliphatic or aromatic mono- or polyamines,
and the amines may be primary, secondary or tertiary amines. Specific examples of
suitable amines include hexylamine, dibutylamine, dodecylamine, ethylenediamine, propylenediamine,
tetraethylenepentamine, and mixtures thereof. The disclosure of U.S. Patent 2,910,439
is hereby incorporated by reference for its listing of suitable amine salts.
[0115] Dithiocarbamate derivatives of DMTD are described in U.S. Patents 2,690,999 and 2,719,827.
Such compositions can be represented by the following formulae

and

wherein the R groups are straight-chain or branch-chain saturated or unsaturated
hydrocarbon groups selected from the group consisting of alkyl, aralkyl and alkaryl
groups. The disclosures of these two patents also are hereby incorporated by reference
for the identification of various thiadiazyl dithiocarbamates which are useful in
the compositions of the present invention.
[0116] U.S. Patent 2,850,453 describes products which are obtained by reacting DMTD, an
aldehyde and an alcohol or an aromatic hydroxy compound in a molar ratio of from 1:2:1
to 1:6:5. The aldehyde employed can be an aliphatic aldehyde containing from 1 to
20 carbon atoms or an aromatic or heterocyclic aldehyde containing from about 5 to
about 30 carbon atoms. Examples of suitable aldehydes include formaldehyde, acetaldehyde,
benzaldehyde. The reaction can be conducted in the presence or absence of suitable
solvents by (a) mixing all of the reactants together and heating, (b) by first reacting
an aldehyde with the alcohol or the aromatic 2-hydroxy compound, and then reacting
the resultant intermediate with the thiadiazole, or (c) by reacting the aldehyde with
thiadiazole first and the resulting intermediate with the hydroxy compound. The disclosure
of U.S. Patent 2,850,453 is hereby incorporated by reference for its identification
of various materials which can be utilized in the compositions of the present invention.
[0117] U.S. Patent 2,703,784 describes products obtained by reacting DMTD with an aldehyde
and a mercaptan. The aldehydes are similar to those disclosed in U.S. Patent 2,850,453,
and the mercaptans may be aliphatic or aromatic mono- or poly-mercaptans containing
from about 1 to 30 carbon atoms. Examples of suitable mercaptans include ethyl mercaptan,
butyl mercaptan, octyl mercaptan, thiophenol. etc. The disclosure of this patent also
is incorporated by reference.
[0118] The preparation of:
2-hydrocarbyldithio-5-mercapto-1,3,4-thiadiazoles having the formula

wherein R' is a hydrocarbyl substituent is described in U.S. Patent 3,663,561. The
compositions are prepared by the oxidative coupling of equimolecular portions of a
hydrocarbyl mercaptan and DMTD or its alkali metal mercaptide. The compositions are
reported to be excellent sulfur scavengers and are useful in preventing copper corrosion
by active sulfur. The mono-mercaptans used in the preparation of the compounds are
represented by the formula
R'SH
wherein R' is a hydrocarbyl group containing from 1 to about 280 carbon atoms. A peroxy
compound, hypohalide or air, or mixtures thereof can be utilized to promote the oxidative
coupling. Specific examples of the monomercaptan include methyl mercaptan, isopropyl
mercaptan, hexyl mercaptan, decyl mercaptan, and long chain alkyl mercaptans, for
example mercaptans derived from propene polymers and isobutylene polymers especially
polyisobutylenes. having 3 to about 70 propene or isobutylene units per molecule.
The disclosure of U.S. Patent 3,663,561 is hereby incorporated by reference for its
identification of DMTD derivative which are useful as in the compositions of this
invention.
[0119] Another material useful as component (D5) in the compositions of the present invention
is obtained by reacting a thiadiazole, preferably DMTD with an oil-soluble dispersant,
preferably a substantially neutral or acidic carboxylic dispersant in a diluent by
heating the mixture above about 100°C. This procedure, and the derivatives produced
thereby are described in U.S. Patent 4,136,043, the disclosure of which is hereby
incorporated by reference. The oil-soluble dispersants which are utilized in the reaction
with the thiadiazoles are often identified as "ashless dispersants". Various types
of suitable ashless dispersants useful in the reaction are described in '043 patent.
[0120] Another material useful as component (D5) in the compositions of the invention is
obtained by reacting a thiadiazole, preferably DMTD, with a peroxide, preferably hydrogen
peroxide. The resulting nitrogen- and sulfur-containing composition is then reacted
with a polysulfide, mercaptan or amino compound (especially oil-soluble, nitrogen-containing
dispersants). This procedure and the derivatives produced thereby are described in
U.S. Patent 4,246,126, the disclosure of which is incorporated herein by reference.
[0121] U.S. Patent 4,140,643 describes nitrogen and sulfur-containing compositions which
are oil-soluble and which are prepared by reacting a carboxylic acid or anhydride
containing up to about 10 carbon atoms and having at least one olefinic bond with
compositions of the type described in U.S. Patent 4,136,043. The preferred carboxylic
acid or anhydride is maleic anhydride. The disclosures of U.S. Patents 4,136,043 and
4,140,643 are hereby incorporated by reference for their disclosures of materials
useful as component (D5) in the compositions of the present invention.
[0122] U.S. Patent 4,097,387 describes DMTD derivatives prepared by reacting a sulfur halide
with an olefin to form an intermediate which is then reacted with an alkali metal
salt of DMTD. More recently, U.S. Patent 4,487,706 describes a DMTD derivative prepared
by reacting an olefin, sulfur dichloride and DMTD in a one-step reaction. The olefins
generally contain from about 6 to 30 carbon atoms. The disclosures of U.S. Patents
4,097,387 and 4,487,706 are hereby incorporated by reference for their descriptions
of oil-soluble DMTD derivatives which are useful as component (D5) in the compositions
of this invention.
[0123] The compositions of the present invention comprising components (A) and (B) or (A)
and (B) with (C) or (D) or with (C) and (D) are useful as viscosity modified environmentally
friendly farm tractor lubricants and chain bar lubricants and hydraulic fluids.
[0124] When the composition comprises components (A) and (B), the following states the ranges
of these components in parts by weight:
Component |
Generally |
Preferred |
Most Preferred |
(A) |
80 - 99.5 |
90 - 99.5 |
96 - 99 |
(B) |
0.5 - 20 |
0.5 - 10 |
1 - 4 |
[0125] When the composition comprises components (A), (B) and (C); or (A), (B) and (D),
the following states the range of these components in parts by weight:
Component |
Generally |
Preferred |
Most Preferred |
(A) |
80 - 99.5 |
90 - 99.5 |
93 - 98.5 |
(B) |
0.5 - 12 |
0.5 - 6 |
1 - 4 |
(C) or (D) |
0.5 - 8 |
0.5 - 4 |
0.5 - 3 |
[0126] When the composition comprises components (A), (B), (C) and (D), the following states
the range of these components in parts by weight:
Component |
Generally |
Preferred |
Most Preferred |
(A) |
80 - 99 |
90 - 99 |
91 - 98 |
(B) |
0.5 - 10 |
0.5 - 6 |
1 - 5 |
(C) |
0.25 - 5 |
0.25 - 2 |
0.5 - 2 |
(D) |
0.25 - 5 |
0.25 - 2 |
0.5 - 2 |
[0127] It is understood that other components besides (A), (B), (C) and (D) may be present
within the composition of this invention.
[0128] The components of this invention are blended together according to the above ranges
to effect solution. Ther following Table II outlines examples so as to provide those
of ordinary skill in the art with a complete disclosure and description on how to
make the compositions of this invention and is not intended to limit the scope of
what the inventor regards as the invention. All parts are by weight.
[0129] While the invention has been explained in relation to its preferred embodiments,
it is to be understood that various modifications thereof will become apparent to
those skilled in the art upon reading the specification. Therefore, it is to be understood
that the invention disclosed herein is intended to cover such modifications as fallwithin
the scope of the appended claims.
Table II
Example |
(A) |
(B) |
Visc 40° cSt |
Vis 100°C cSt |
1 |
100 parts Sunyl 80 oil |
|
39.52 |
8.65 |
2 |
99 parts Sunyl 80 oil |
1 part Glissoviscal SGH |
63.57 |
13.16 |
3 |
98 parts Sunyl 80 oil |
2 parts Glissoviscal SGH |
117.97 |
20.11 |
4 |
97 parts Sunyl 80 oil |
3 parts Glissoviscal SGH |
268.85 |
30.70 |
5 |
96 parts Sunyl 80 oil |
4 parts Glissoviscal SGH |
705.67 |
46.21 |
6 |
95 parts Sunyl 80 oil |
5 parts Glissoviscal SGH |
1915.2 |
70.43 |
7 |
94 parts Sunyl 80 oil |
6 parts Glissoviscal SGH |
5007.4 |
113.37 |
8 |
92 parts Sunyl 80 oil |
8 parts Glissoviscal SGH |
10,000 |
344.4 |
9 |
90 parts Sunyl 80 oil |
10 parts Glissoviscal SGH |
88,600 |
1181.0 |
10 |
99 parts Sunyl 80 oil |
1 part Glissoviscal CE-5260 |
61.56 |
12.50 |
11 |
98 parts Sunyl 80 oil |
2 parts Glissoviscal CE-5260 |
98.70 |
18.74 |
12 |
97 parts Sunyl 80 oil |
3 parts Glissoviscal CE-5260 |
152.56 |
25.72 |
13 |
96 parts Sunyl 80 oil |
4 parts Glissoviscal CE-5260 |
242.05 |
36.65 |
14 |
95 parts Sunyl 80 oil |
5 parts Glissoviscal CE-5260 |
392.20 |
49.23 |
15 |
94 parts Sunyl 80 oil |
6 parts Glissoviscal CE-5260 |
694.21 |
72.17 |
16 |
92 parts Sunyl 80 oil |
8 parts Glissoviscal CE-5260 |
2487.9 |
140.09 |
17 |
90 parts Sunyl 80 oil |
10 parts Glissoviscal CE-5260 |
9919.0 |
265.88 |