Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CONCENTRATES WITH HIGH MOLECULAR WEIGHT DISPERSANTS
AND THEIR PREPARATION
FIELD OF THE INVENTION
This invention relates to oleaginous compositions useful in fuel and
lubricating oil compositions. More particularly, this invention relates to
oleaginous concentrates containing high molecular weight dispersants and
their preparation thereof.
BACKGROUND OF THE INVENTION
This invention relates to lubricating oil compositions, e.g. automatic
transmission fluids, heavy duty oils suitable for gasoline and diesel engines
and cranckcase oils. 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, detergents, dispersants, pour point depressants, antiwear
agents, etc.
In the preparation of lubricating oil compositions, it is common
practice to introduce the additives in the form of 10 to 80 mass %, e.g. 20
to 80 mass % active ingredient concentrates in hydrocarbon oil, e.g.
mineral lubricating oil, or other suitable solvent. Usually these
concentrates are subsequently diluted with 3 to 100, e.g. 5 to 40 parts by
weight of lubricating oil, per part by weight of the concentrate to form
finished lubricating oil compositions.
It is convenient to provide a so-called "additive package" comprising
two or more of the above mentioned additives in a single concentrate in a
hydrocarbon oil or other suitable solvent. However, a problem with
preparing additive packages is that some additives tend to interact with
3o each other. For example, dispersants having a high molecular weight or a
high functionality ratio, for example, of 1.3 or higher, have been found to
interact with other additives in additive packages, particularly overbased
metal detergents. This interaction causes a viscosity increase upon
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blending, which may be followed by subsequent growth or increase of
viscosity with time. In some instances, the interaction results in gelation.
The viscosity increase can hamper pumping, blending and handling of the
additive package. Although the additive package can be further diluted
s with more diluent oil to reduce viscosity in order to offset the effect of
interaction, dilution reduces the economy of using an additive package by
increasing shipping, storage and other handling costs.
U.S. Patent No. 4,398,880 describes a process for improving the
stability of oleaginous concentrates in the form of additive packages
io comprising ashless dispersants, particularly polyisobutylene containing
dispersants, in combination with overbased metal detergents in which the
additives are contacted in a lubricating oil basestock at a temperature of
from 100 C to 160 C for 1 to 10 hours. The resultant heat-treated blend is
then cooled to a temperature of 85 C or below and further mixed with
15 copper antioxidant additives, zinc dihydrocarbyldithiophosphate antiwear
additives and, optionally, other additives useful in lubricating oil
compositions. The process enables the stability of the additive package to
be improved to the extent that the tendency for phase separation is
substantially reduced.
20 However, the molecular weight of the dispersant used in U.S. Patent
No. 4,398,880 is relatively low. The number average molecular weight of
the polyisobutylene polymer used in the examples to make the dispersant
is only 1725. The resulting dispersant number average molecular weight
can be calculated to be approximately 3900 (e.g., 2 moles isobutylene
25 polymer (MW=1725)+ 2 moles maleic anhydride (MW=98) + 1 mole
polyethyleneamine (MW=250) = 2(1725)+2(98)+1(250) -3900). The
significant increase in viscosity due to the dispersant/detergent interaction,
which will be described in more detail below, does not occur until the
molecular weight of the polyisobutylene derivatized dispersant is much
3o higher (i.e., approximately 7000).
Another problem with concentrates containing high molecular weight
dispersants is their stability. As dispersant size increase, concentrates
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containing these high molecular weight dispersants are unstable and have
a tendency to phase separate resulting in sediments. The phase
separation reduces the performance of the concentrate, and the sediments
increase the cost of shipping and handling.
There is a trend in the industry to go to higher molecular weight
dispersants because they have improved dispersant properties to satisfy
more rigorous performance requirements in the automobile industry. -
However, when higher molecular weight dispersants are used in
concentrates, they interact with the colloidal overbased detergents to form
io a complex. This complex substantially increases the viscosity of the
concentrate, which could result is blending difficulties unless the blending
procedure is carefully designed.
Below is a simplified description of a concentrate containing an
overbased detergent and an ashless dispersant. When an overbased
detergent is added to an oil-based solvent, a colloidal structure forms
containing hydrophilic groups and lipophilic groups, where the lipophilic
groups extend out in the oil-based solvent. The ashiess dispersant also
contains hydrophilic groups and lipophilic groups. At sufficiently high
concentrations, the dispersant could interact with the overbased detergent
colloidal structure to form a dispersant/detergent complex where the
hydrophilic groups of the overbased metal detergent colloidal structure
interacts with the hydrophilic groups of the ashiess dispersant.
Not wishing to be bound by any theory, it is believed that a
dispersant/detergent complex could cause an increase in viscosity
because lipophilic groups of the ashiess dispersant of one complex can
interact with lipophilic groups of another complex. This results in an
effective high molecular weight aggregate complex that increases the
viscosity of the concentrate. The viscosity may rise uncontrollably to the
extent that gels may form that are impossible to blend into a finished
lubricating oil composition. The latter effect can evidence itself as the
Weissenberg Effect. The Weissenberg Effect occurs when the viscosity of
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the concentrate significantly increases such that composition is seen to rise
up the shaft of the mixing blades during blending.
It should be noted that the increase in viscosity would not occur if
the concentration of the complex, or the molecular weight of the ashiess
dispersant in the concentrate is low. If the concentration of the complex is
low (i.e., if the concentrate is dilute), there is sufficient space between
the
complexes such that the lipophilic groups of the dispersants will not
interact. Likewise, if the molecular weight of the ashiess dispersants is
low, the lipophilic groups are too small to interact with each other. Thus,
io for example, a high molecular weight dispersant in a concentrate that is
sufficiently dilute may not have a blending problem because there is
sufficient space between the complexes such that an aggregate complex
will not form. In contrast, a low molecular weight dispersant could have a
blending problem in a highly concentrated composition because the space
between the complexes is small. At typical additive package
concentrations, the blending problems will not typically occur until the
number average molecular weight of the dispersant is over about 7000 for
polyisobutylene derivatized dispersants and over about 3000 for
poly(alpha-olefin) derivatized dispersants.
Therefore, it is an objective of the present invention to provide a
concentrated additive package composition that contains a higher
molecular weight ashiess dispersant and an overbased metal detergent
than previously has been available due to viscosity considerations. It is
another object of the present invention to provide a concentrate containing
a high molecular weight ashiess detergent and an overbased metal
detergent that has good stability and does not phase separate. It is also an
object of the present invention to provide a process for preparing the
concentrate composition.
SUMMARY OF THE INVENTION
This invention relates to a phase stable, oleaginous additive
concentrate comprising a diluent oil, at least one borated or unborated
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ashiess dispersant where the ashless dispersant has a hydrodynamic
radius of about 8 to 40 nm, at least one overbased metal detergent, and at
least one other concentrate additive. The weight ratio of the ashless
dispersant to the overbased metal detergent is about 1:1 to 8:1, and the
sum of the ashless dispersant and the overbased metal detergent on an
active ingredient basis is about 25 to 50 wt.% based upon the total weight
of said concentrate. In the present invention, unless otherwise specified,
the amount of ashless detergent, overbased detergent and other
concentrate additives are on an active ingredient basis.
This invention also relates to a process for preparing the additive
concentrate described above. The inventors of the present invention have
surprisingly discovered that when the high molecular weight ashiess
dispersant or overbased detergent are first mixed with at least one of the
concentrate additives, the concentrate is readily blendable and no
Weissenberg effect is observed. In addition, when the ashiess dispersant
is first mixed with the other additives and the detergent is blended last, the
tendency for phase separation is significantly reduced. It is believed that
the present invention provides a concentrated additive package
composition that contains a higher molecular weight ashiess dispersant
than previously has been available due to viscosity and phase separation
concerns.
DETAILED DESCRIPTION
The present invention solves the problem of increased viscosity and
phase separation concems when a high molecular weight dispersants and
overbased metal detergents are blended to form a concentrate. The
concentrate comprises a diluent oil, at least borated or unborated one
ashiess dispersant where the ashiess dispersant has a hydrodynamic
radius of about 8 to 40 nm, at least one overbased metal detergent and at
least one other concentrate additive. The weight ratio of the ashless
dispersant to the metal detergent is about 1:1 to 8:1, and the sum of the
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ashless dispersant and the metal detergent is about 25 to 50 wt.% based
upon the total weight of said concentrate.
The inventors have discovered that when the ashless dispersant or
the overbased detergent is first mixed with at least one other additive, they
s are readily blendable and do not show a Weissenberg effect. In addition,
when the dispersant is first blended with at least one other additive, and
the detergent is blended last, the concentrate is stable with minimal or no -
phase separation.
Although not wishing to be bound by any theory, it is believed that
io when other additives are first mixed with either the dispersant or the
detergent, they compete with the binding sites on the detergent or
dispersant, and block the complex between the detergent and the
dispersant from forming. It is also believed that the additives aid in
breaking up the aggregate complexes that do form. Therefore, it is not
15 dilution that prevents the formation of the aggregate complex, but the
specific properties of the concentrate additives of this invention that
prevents the complexes from forming.
The hydrodynamic radius of the present invention is a convenient
way to measure the size of the dispersant. The hydrodynamic radius is a
20 measure of the volume of space occupied by the dispersant. The longer
the hydrodynamic radius of the dispersant, the more likely it will interact
with other dispersants that are complexed with the overbased metal
detergent.
The concept of hydrodynamic radius is a more useful measure of
25 the volume occupied by the dispersant than just molecular weight. This is
because the volume occupied by the dispersant, depends, in part, on the
amount and length of branches in the polymer dispersant. A dispersant
that has many branches may have a high molecular weight, but its
hydrodynamic radius may not be large because a significant part of the
30 molecular weight is concentrated in the branches. In contrast, a low
molecular weight polymer dispersant may have a large hydrodynamic
radius because it contains few branches, and has a long polymer
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backbone. Therefore, a better indication of the tendency of polymer
dispersants to interact is hydrodynamic radius rather than molecular
weight. It is believed that the hydrodynamic radius of the dispersants used
in the present invention is larger than those that have been previously used
in concentrate additive packages.
The hydrodynamic radius of the dispersants may be measured by
the technique of dynamic light scattering (hereinafter "DLS") which is
described in B.J. Berne and R. Pecora, Dynamic Light Scattering (Krieger,
Malabar, FL, 1990) and in D.E. Dahneke, Measurement of Suspended
io Particles by Quasielastic Light Scattering (Wiley, New York, 1983). The
dispersants of the present invention should be measured in heptane or
other comparable solvents in concentrations of 0.1 to 1 Wt.%. For most
dispersants, the measurement temperature has little impact on the
measurement results, and the temperature can range from room
is temperature to 60 C. However, with ethylene based dispersants, the
hydrodynamic radius measurement should be performed at 60 C to
eliminate association of ethylene segments.
The additives, as components of the concentrate, may be mixed in
any order, provided that the additives are first mixed with either the
2o dispersant or the detergent. For example, the dispersant and other
concentrate additives are first mixed together and the detergent is added
last, or the detergent and other concentrate additives are first mixed
together and then the dispersant is added. Preferably, the detergent is
added last because this improves the stability of the concentrate.
25 In order for the concentrate to be oleaginous, the additives may be
in solution in an oleaginous carrier or such a carrier may be provided
separately or both. Examples of suitable carriers are oils of lubricating
viscosity, such as described in detail hereinafter, and aliphatic, naphthenic
and aromatic hydrocarbons.
30 The dispersant, detergent and other additives of the present
invention must be "oil-soluble" or "oil-dispersible" in the oleaginous carrier
or oil of lubricating viscosity, but these descriptions do not mean that they
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are soluble, dissolvable, miscible or capable of being suspended in the oil
in all proportions. They do mean, however, that they are stable and
soluble in the oil to an extent sufficient to exert their intended effect in
the
environment in which the lubricating oil composition is employed.
s Moreover, the additional incorporation of other additives such as those
described hereinafter may affect their oil-solubility or dispersability.
The concentrate of the present invention is prepared at elevated
temperatures, i.e. above ambient temperature. The blending temperature
should be about 500 to 150 C, preferably about 50 to 120 C, more
io preferably about 60 to 120 C and even more preferably about 60 to
100 C. Although energy is saved at low temperatures, practical
considerations dictate the most convenient temperature that can be used.
Thus, where any additive is used that is solid at ambient temperature, it is
usually more convenient to raise its temperature to a temperature at which
15 it flows, rather than dissolving it in oil prior to addition to the other
additives.
Temperatures of 100 C or more can be employed if any additive is more
conveniently handled at such temperatures.
The components are advantageously held at the mixing temperature
for a time sufficient to achieve a homogenous mixture thereof. This can
20 usually be effected within 2 hours with the present invention.
One or more further lubricating oil additives, desirable for conferring
a full range of properties may be added to the concentrate. These
additives preferably include corrosion inhibitors, metal dihydrocarbyl
dithiophosphates, antioxidants, antiwear agents. friction modifiers, viscosity
25 modifiers, a low base number metal detergent having a TBN less than 50,
and mixtures thereof. The temperature at which these further additives are
added will depend on the stability of the particular additives. Preferably,
the temperature for blending further additives is about 50 to 85 C. For
example, when one of the additives is zinc dihydrocarbyl dithiophosphate,
30 the blending temperature should be about 60 to 85 C.
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Boron may usefully be provided in the concentrate, for example in
the form of a borated ashless dispersant, or in the form of an additional
boron-containing compound or both.
The concentrate of the present invention can be incorporated into a
lubricating oil composition in any convenient way. Thus, they can be
added directly to an oil of lubricating viscosity by dispersing or dissolving
them in the oil at the desired concentrations of the dispersant and
detergent, respectively. Such blending can occur at ambient temperature
or elevated temperatures. Alternatively, the composite can be blended
io with a suitable oil-soluble solvent and base oil to form a further
concentrate
which is then blended with an oil of lubricating viscosity to obtain the final
lubricating oil composition.
The concentrate of the present invention will typically contain (on an
active ingredient (A.I.) basis) from 3 to 50 mass %, and preferably from 10
1s to 40 mass % dispersant additive, from 3 to 45 mass %, and preferably
from 5 to 30 mass %, overbased metal detergent based on the concentrate
weight. The concentrate will typically contain an ashiess dispersant to
overbased metal detergent weight ratio on an active ingredient basis of
about 0.1:1 to 12:1, preferably about 0.5:1 to 10:1, more preferably about
20 1:1 to 8:1, and even still more preferably about 1:1 to 4:1.
The sum of the detergent and dispersant on an active ingredient
basis is typically from 20 to 70 wt.%, preferably about 25 to 60 wt.%, more
preferably about 25 to 55 wt.%, even more preferably about 30 to 55 wt.%,
still more preferably about 30 to 50 wt.% and even still more preferably
25 about 35 to 50 wt.% based on the total weight of the concentrate.
The practical concentration (sum of the detergent and dispersant)
will depend, in part, on the size of the dispersant. If the dispersant size is
large, e.g., a hydrodynamic radius of 15 to 40 nm, the practical
concentration in the present invention will typically range from about 25 to
3o 40 wt.%. If the size of the dispersant is smaller, e.g., a hydrodynamic
radius of about 8 to 40 nm, the practical concentration will typically be
about 30 to 50 wt.%.
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In a preferred embodiment, the overbased detergent is pre-treated,
prior to introduction to the blending process, with about 1 to 50 wt.%,
relative to the overbased detergent, of a pretreatment additive selected
from the group consisting of an polyamine-derivatized poly(isobutylene)
ashless dispersant having a number average molecular weight of about
500 to 6000 and a poly(isobutylene) succinic anhydride with a molecular
weight of about 300 to 2500. Preferably, the pretreatment additive is a -
poly(isobutylene) succinic anhydride with a molecular weight of about 300
to 2500.
to The components of the invention will now be discussed in further
detail as follows:
ASHLESS DISPERSANTS
The high molecular weight ashiess dispersants in the concentrate of
ts the present invention include the range of ashless dispersants known as
effective for adding to lubricant oils for the purpose of reducing the
formation of deposits in gasoline or diesel engines. Preferably, "high
molecular weight" dispersant means having a number average molecular
weight of greater than 3000, such as between 3000 and 20,000. The exact
20 molecular weight ranges will depend on the type of polymer used in the
dispersants. For example, for a polyisobutylene derivatized dispersant, a
high molecular weight dispersant means having a number average
molecular weight of about 7000 to 20,000. A high molecular weight
poly(alpha -olefin) derivatized dispersant means having a molecular weight
25 from about 3000 to 20,000. It is believed that the high molecular
dispersants of the present invention have not previously been used with
overbased metal detergents in the concentrations needed to prepare a
concentrate due to stability problems and the uncontrollable rise in
viscosity during blending.
30 As previously discussed, a useful measure of the size of the
dispersant is hydrodynamic radius (RH). In the present invention, the
hydrodynamic radius may range from about 8 to 40 nm, such as 10, 12 or
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15 to 40 nm. It is believed that the above ranges for the dispersants are
higher than those that have been previously used in concentrates.
Typical commercially available polyisobutylene based dispersants
contain polyisobutylene polymers having a number average molecular
weight ranging from 900 to 2300, functionalized by maleic anhydride, (MW
= 98), and derivatized with polyamines having a molecular weight of about
100 to 350. Each dispersant contains 1.5 to 2.5 polyisobutylene polymers
per dispersant. Thus, the molecular weight of the polyisobutylene
derivatized dispersant can be calculated and ranges from about 1600 to
io 6300. For example, with a dispersant averaging about 2.5 polymers per
dispersant, the molecular weight of the dispersant can be calculated to be:
2.5 moles polyisobutylene (MW=2300) + 2.5 moles maleic anhydride
(MW=98)+ I mole polyamine (350) which gives a molecular weight of
about 6300. For comparison, a polyisobutylene based dispersant having a
number average molecular weight of about 5000 has a hydrodynamic
radius of about 5.5 nm. In cases where the molecular weight of the
dispersant can not be readily estimated from the molecular weight of the
starting materials, e.g., in more complex chain extended systems, an
empirical measurement of molecular weight and hydrodynamic radius must
2o be made.
The ashiess dispersant of the present invention includes an oil
soluble polymeric long chain hydrocarbon backbone having functional
groups that are capable of associating with particles to be dispersed.
Typically, the dispersants comprise amine, alcohol, amide, or ester polar
moieties attached to the polymer backbone often via a bridging group. The
ashless dispersant may be, for example, selected from oil soluble salts,
esters, amino-esters, amides, imides, and oxazolines of long chain
hydrocarbon substituted mono and dicarboxylic acids or their anhydrides;
thiocarboxylate derivatives of long chain hydrocarbons; long chain aliphatic
3o hydrocarbons having a polyamine attached directly thereto; and Mannich
condensation products formed by condensing a tong chain substituted
phenol with formaldehyde and polyalkylene polyamine.
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The long chain hydrocarbyl substituted mono- or dicarboxylic acid
material, i.e. acid, anhydride, or ester, used in the invention includes long
chain hydrocarbon, generally a polyolefin, substituted with an average of at
least about 0.8, (e.g., about 0.8 to 2.0) generally from about 1.0 to 2.0,
preferably 1.05 to 1.25, 1.1 to 1.2, moles per mole of polyolefin, of an
alpha or beta unsaturated C.4 to Cio dicarboxylic acid, or anhydride or ester
thereof, such as 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 are polymers comprising a major molar amount of C2 to
CIo, e.g. C2 to C5 monoolefin. Such olefins include ethylene, propylene,
butylene, isobutylene, pentene, octene-1, styrene, etc. The polymers can
be homopolymers such as polyisobutylene, as well as copolymers of two or
more of such olefins such as copolymers of: ethylene and propylene;
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
2o ethylene, propylene and 1,4-hexadiene; etc.
Processes for reacting polymeric hydrocarbons with unsaturated
carboxylic acids, anhydrides or esters and the preparation of derivatives
from those compounds are disclosed in US-A-3087936, US-A-3172892,
US-A-3215707, US-A-3231587, US-A-3231587, US-A-3272746, US-A-
3275554, US-A-3381022, US-A-3442808, US-A-356804, US-A-3912764,
US-A-4110349, US-A-4234435 and GB-A-1440219.
A preferred class of ashless dispersants are ethylene alpha-olefin
copolymers and alpha-olefin homo-, co- and terpolymers prepared using
new metallocene catalyst chemistry, which may have a high degree (e.g.
>30%) of terminal vinylidene unsaturation is described in US-A-5128056,
5151204, 5200103, 5225092, 5266223, 5334775; WO-A-94/19436,
94/13709; and EP-A-440506, 513157, 513211. These dispersants are
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described as having superior viscometric properties as expressed in a ratio
of CCS viscosity to kV 100 C.
The term "aipha-olefin" is used herein to denote an olefin of the
formula
R'
I
H - C =CH 2 -
wherein R' is preferably a CI-C18 alkyl group. The requirement for terminal
vinylidene unsaturation refers to the presence in the polymer of the
io following structure:
R
I
Poly - C CH 2
wherein Poly is the polymer chain and R is typically a CI-C18 alkyl group,
ts typically methyl or ethyl. Preferably the polymers will have at least 50%,
and most preferably at least 60%, of the polymer chains with terminal
vinylidene unsaturation. As indicated in WO-A-94/19426, ethylene/1-
butene copolymers typically have vinyl groups terminating no more than
about 10 percent of the chains, and internal mono-unsaturation in the
2o balance of the chains. The nature of the unsaturation may be determined
by FTIR spectroscopic analysis, titration or C-13 NMR.
The oil-soluble polymeric hydrocarbon backbone may be a
homopolymer (e.g., polypropylene) or a copolymer of two or more of such
olefins (e.g., copolymers of ethylene and an alpha-olefin such as propylene
25 or butylene, or copolymers of two different alpha-olefins). Other
copolymers include those in which a minor molar amount of the copolymer
monomers, e.g., 1 to 10 mole %, is an a,w-diene, such as a C3 to C22 non-
conjugated diolefin (e.g., a copolymer of isobutylene and butadiene, or a
copolymer of ethylene, propylene and 1,4-hexadiene or 5-ethylidene-2-
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norbomene). Atactic propylene oligomers of the present invention have a
number average molecular weight of from about 3000 to 10000 may also
be used as well as heteropolymers such as polyepoxides.
One preferred class of olefin polymers is polybutenes and
specifically poly-n-butenes, such as may be prepared by polymerization of
a C4 refinery stream. Other preferred classes of olefin polymers are
ethylene alpha-olefins (EAO) copolymers that preferably contain 1 to 50
mole % ethylene, and more preferably 5 to 48 mole % ethylene. Such
polymers may contain more than one alpha-olefin and may contain one or
io more C3 to C22 diolefins. Also useable are mixtures of EAO's of varying
ethylene content. Different polymer types, e.g., EAO, may also be mixed
or blended, as well as polymers differing in number average molecular
weight components derived from these also may be mixed or blended.
Particularly preferred copolymers are ethylene butene copolymers.
Preferably, the olefin polymers and copoiymers may be prepared by
various catalytic polymerization processes using metallocene catalysts
which are, for example, bulky ligand transition metal compounds of the
formula:
[L]mM[A]n
where L is a bulky ligand; A is a leaving group, M is a transition metal, and
m and n are such that the total ligand valency corresponds to the transition
metal valency. Preferably the catalyst is four co-ordinate such that the
compound is ionizable to a 1+ valency state.
Such polymerizations, catalysts, and cocatalysts or activators are
described, for example, in US-A-4530914, 4665208, 4808561, 4871705,
4897455, 4937299, 4952716, 5017714, 5055438, 5057475, 5064802,
5096867, 5120867, 5124418, 5153157, 5198401, 5227440,.5241025; EP-
3o A-129368, 277003, 277004, 420436, 520732; and WO-A-91/04257,
92/00333, 93/08199, 93/08221, 94/07928 and 94/13715.
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The oil-soluble polymeric hydrocarbon backbone may be
functionalized to incorporate a functional group into the backbone of the
polymer, or as one or more groups pendant from the polymer backbone.
The functional group typically will be polar and contain one or more hetero
atoms such as P, 0, S, N, halogen, or boron. It can be attached to a
saturated hydrocarbon part of the oil-soluble polymeric hydrocarbon
backbone via substitution reactions or to an olefinic portion via addition or -
cycloaddition reactions. Alternatively, the functional group can be
incorporated into the polymer in conjunction with oxidation or cleavage of
to the polymer chain end (e.g., as in ozonolysis).
Useful functionalization reactions include: halogenation of the
polymer at an olefinic bond and subsequent reaction of the halogenated
polymer with an ethylenically unsaturated functional compound (e.g.,
maleation where the polymer is reacted with maleic acid or anhydride);
reaction of the polymer with an unsaturated functional compound by the
"ene" reaction absent halogenation; reaction of the polymer with at least
one phenol group (this permits derivatization in a Mannich base-type
condensation); reaction of the polymer at a point of unsaturation with
carbon monoxide using a Koch-type reaction to introduce a carbonyl group
in an iso or neo position; reaction of the polymer with the functionalizing
compound by free radical addition using a free radical catalyst;
copolymerization of the polymer with the functionalizing compound, (e.g.,
maleic anhydride), with or without low molecular weight olefins via free
radical initiation; reaction with a thiocarboxylic acid derivative; and
reaction
of the polymer by air oxidation methods, epoxidation, chloroamination, or
ozonolysis.
The functionalized oil-soluble polymeric hydrocarbon backbone is
then further derivatized with a nucleophilic reactant such as an amine,
amino-alcohol, alcohol, metal compound or mixture thereof to form a
corresponding derivative. Useful amine compounds for derivatizing
functionalized polymers comprise at least one amine and can comprise
one or more additional amine or other reactive or polar groups. These
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amines may be hydrocarbyl amines or may be predominantly hydrocarbyl
amines in which the hydrocarbyl group includes other groups, e.g., hydroxy
groups, alkoxy groups, amide groups, nitriles, imidazoline groups, and the
like. Particularly useful amine compounds include mono- and polyamines,
e.g. polyalkylene and polyoxyalkylene polyamines of about 2 to 60,
conveniently 2 to 40 (e.g., 3 to 20), total carbon atoms and about 1 to 12,
conveniently 3 to 12, and preferably 3 to 9 nitrogen atoms in the molecule.
Mixtures of amine compounds may advantageously be used such as those
prepared by reaction of alkylene dihalide with ammonia. Preferred amines
io are aliphatic saturated amines, including, e.g., 1,2-diaminoethane; 1,3-
diaminopropane; 1,4-diaminobutane; 1,6-diaminohexane; polyethylene
amines such as diethylene triamine; triethylene tetramine; tetraethylene
pentamine; and polypropyleneamines such as 1,2-propylene diamine; and
di-(1,2-propylene)triamine.
ts Other useful amine compounds include: alicyclic diamines such as
1,4-di(aminomethyl) cyclohexane, and heterocyclic nitrogen compounds
such as imidazolines. A particularly useful class of amines are the
polyamido and related amido-amines as disclosed in US 4,857,217;
4,956,107; 4,963,275; and 5,229,022. Also usable is
20 tris(hydroxymethyl)amino methane (THAM) as described in US 4,102,798;
4,113,639; 4,116,876; and UK 989,409. Dendrimers, star-like amines, and
comb-structure amines may also be used. Similarly, one may use the
condensed amines disclosed in US 5,053,152. The functionalized polymer
is reacted with the amine compound according to conventional techniques
25 as described in EP-A 208,560; US 4,234,435 and US 5,229,022 .
The functionalized oil-soluble polymeric hydrocarbon backbones
also may be derivatized with hydroxy compounds such as monohydric and
polyhydric alcohols or with aromatic compounds such as phenols and
naphthols. Polyhydric alcohols are preferred, e.g., alkylene glycols in
30 which the alkylene radical contains from 2 to 8 carbon atoms. Other useful
polyhydric alcohols include glycerol, mono-oleate of glycerol, monostearate
of glycerol, monomethyl ether of glycerol, pentaerythritol, dipentaerythritol,
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and mixtures thereof. An ester dispersant may also be derived from
unsaturated alcohois such as allyl alcohol, cinnamyl alcohol, propargyl
alcohol, 1-cyclohexane-3-ol, and oleyl alcohol. Still other classes of the
alcohols capable of yielding ashless dispersants comprise the ether-
alcohols and including, for example, the oxy-alkylene, oxy-arylene. They
are exemplified by ether-alcohols having up to 150 oxy-alkylene radicals in
which the alkylene radical contains from 1 to 8 carbon atoms. The ester
dispersants may be di-esters of succinic acids or acidic esters, i.e.,
partially
esterified succinic acids, as well as partially esterified polyhydric alcohols
io or phenols, i.e., esters having free alcohols or phenolic hydroxyl
radicals.
An ester dispersant may be prepared by one of several known methods as
illustrated, for example, in US 3,381,022.
One preferred group of dispersant is poly(alpha olefin) dispersants.
They are preferably employed in the invention as polyamine-derivatized
poly(alpha-olefin) dispersants having a number average molecular weight
of about 3000 to 20,000, preferably about 4000 to 15,000 and more
preferably about 5000 to 10,000, or a weight average molecular weight of
about 6,000 to 50,000, preferably about 8,000 to 40,000 and more
preferably 10,000 to 30,000. One convenient method to measure
molecular weight is 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). Another useful
method, particularly for lower molecular weight polymers, is vapor pressure
osmometry (see, e.g., ASTM D3592).
In a preferred embodiment the poly(alpha olefin) dispersant is
derived from an ethylene/butene alpha-olefin polymer having a number
average molecular weight of about 4,000 to 15000 or a weight average
molecular weight of about 8,000 to 40,000.
Another preferred group of ashless dispersants are those derived
from polyisobutylene substituted with succinic anhydride groups and
reacted with polyethylene amines, e.g. tetraethylene pentamine,
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pentaethylene e.g. polyoxypropylene diamine, trismethylolaminomethane
and pentaerythritol, and combinations thereof. One particularly preferred
dispersant combination involves a combination of (A) polyisobutylene
substituted with succinic anhydride groups and reacted with (B) a hydroxy
compound, e.g. pentaerythritol, (C) a polyoxyalkylene polyamine, e.g.
polyoxypropylene diamine, or (D) a polyalkylene polyamine, e.g.
polyethylene diamine and tetraethylene pentamine using about 0.3 to -
about 2 moles either (B), (C) or (D) per mole of A. Another preferred
dispersant combination involves the combination of (A) poiyisobutenyl
io succinic anhydride with (B) a polyalkylene polyamine, e.g. tetraethylene
pentamine, and (C) a polyhydric alcohol or polyhydroxy-substituted
aliphatic primary amine, e.g. pentaerythritol or trismethylolaminomethane
as described in U.S. Pat. No. 3,632,511.
Preferably, the polyamine-derivatized polyisobutylene dispersant
1s has a number average molecular weight of about 7000 to 20000,
preferably about 9000 to 20,000 and more preferably about 12,000 to
20,000, or a weight average molecular weight of about 17,000 to 50,000,
preferably about 20,000 to 40,000 and more preferably about 25,000 to
40,000.
20 The above polyisobutylene-derivatized dispersant may also be used
as a pretreatment additive for the overbased detergent when the number
average molecular weight is about 500 to 6000. In addition, the
polyisobutylene substituted anhydride may also be used as a pretreatment
additive when the number average molecular weight is about 300 to 2500.
25 Another class of ashless dispersants comprises Mannich base
condensation products. Generally, these are prepared by condensing
about one mole of an alkyl-substituted mono- or polyhydroxy benzene with
about I to 2.5 moles of carbonyl compounds (e.g., formaldehyde and
paraformaldehyde) and about 0.5 to 2 moles polyalkylene polyamine as
3o disclosed, for example, in US 3,442,808. Such Mannich condensation
products may include a polymer product of a metallocene catalyzed
polymerization as a substituent on the benzene group or may be reacted
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with a compound containing such a polymer substituted on a succinic
anhydride, in a manner similar to that shown in US 3,442,808.
Examples of functionalized and/or derivatized olefin polymers based
on polymers synthesized using metallocene catalyst systems are described
in publications identified above.
The dispersant can be further post-treated by a variety of
conventional post treatments such as boration, as generally taught in US -
3,087,936 and 3,254,025. This is readily accomplished by treating an acyl
nitrogen-containing dispersant with a boron compound selected from the
io group consisting of boron oxide, boron halides, boron acids and esters of
boron acids, in an amount to provide from about 0.1 atomic proportion of
boron for each mole of the acylated nitrogen composition to about 20
atomic proportions of boron for each atomic proportion of nitrogen of the
acylated nitrogen composition. Usefully the dispersants contain from about
0.05 to 2.0 wt. %, e.g. 0.05 to 0.7 wt. % boron based on the total weight of
the borated acyl nitrogen compound. The boron, which appears be in the
product as dehydrated boric acid polymers (primarily (HBO03), is believed
to attach to the dispersant imides and diimides as amine salts e.g., the
metaborate salt of the diimide. Boration is readily carried out by adding
from about 0.05 to 4, e.g., I to 3 wt. % (based on the weight of acyl
nitrogen compound) of a boron compound, preferably boric acid, usually as
a slurry, to the acyl nitrogen compound and heating with stirring at from
135 to 190 C, e.g., 140 -170 C, for from 1 to 5 hours followed by
nitrogen stripping. Alternatively, the boron treatment can be carried out by
adding boric acid to a hot reaction mixture of the dicarboxylic acid material
and amine while removing water.
Also, boron may be provided separately, for example as a boron
ester or as a boron succinimide, made for example from a polyisobutylene
succinic anhydride, where the polymer has a molecular weight of from 450
to 700.
OIL-SOLUBLE METAL DETERGENT
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Metal-containing or ash-forming detergents function both as
detergents to reduce or remove deposits and as acid neutralizers or rust
inhibitors, thereby reducing wear and corrosion and extending engine life.
Detergents generally comprise a polar head with a long hydrophobic tail,
with the polar head comprising a metal salt of an acidic organic compound.
The salts may contain a substantially stoichiometric amount of the metal in
which case they are usually described as normal or neutral salts, and "
would typically have a total base number or TBN (as may be measured by
ASTM D2896) of from 0 to 80. It is possible to include large amounts of a
io metal base by reacting an excess of a metal compound such as an oxide
or hydroxide with an acidic gas such as carbon dioxide. The resulting
overbased detergent comprises neutralized detergent as the outer layer of
a metal base (e.g. carbonate) micelle. The detergents of the present
invention are overbased detergents that have a TBN of 150 or greater, and
1s typically about 250 to 450 or more.
Detergents that may be used in the present invention include oil-
soluble overbased sulfonates, phenates, sulfurized phenates,
thiophosphonates, salicylates, and naphthenates and other oil-soluble
carboxylates of a metal, particularly the alkali or alkaline earth metals,
e.g.,
20 sodium, potassium, lithium, calcium, and magnesium. The most commonly
used metals are calcium and magnesium, which may both be present in
detergents used in a lubricant, and mixtures of calcium and/or magnesium
with sodium. Particularly convenient metal detergents are overbased
calcium sulfonates, calcium phenates and sulfurized phenates and
25 salicylates having a TBN of about 150 to 450. In the practice of the
present invention, combinations of surfactants, e.g., sulfonates and
phenates, and combination of overbased and neutral detergents may also
be used.
Sulfonates may be prepared from sulfonic acids which are typically
30 obtained by the sulfonation of alkyl substituted aromatic hydrocarbons
such as those obtained from the fractionation of petroleum or by the
alkylation of aromatic hydrocarbons. Examples included those obtained by
CA 02327829 2006-01-23
alkylating benzene, toluene, xylene, naphthalene, diphenyi or their halogen
derivatives such as chtorobenzene, chlorototuene and chloronaphthalene.
The alkylation may be carried out in the presence of a catalyst with
alkylating agents having from about 3 to more than 70 carbon atoms. The
alkaryl sulfonates usually contain from about 9 to about 80 or more carbon
atoms, preferably from about 16 to about 60 carbon atoms per alkyl
substituted aromatic moiety.
The oil soluble sulfonates or alkaryl sutfonic acids may be
neutralized with oxides, hydroxides, alkoxides, carbonates, carboxylate,
i o sulfides, hydrosulfides, nitrates, borates and ethers of the metal. The
amount of metal compound is chosen having regard to the desired TBN of
the final product but typically ranges from about 100 to 220 wt %
(preferably at least 125 wt %) of that stoichiometrically required.
Metal salts of phenois and sulfurized phenols are prepared by
ts reaction with an appropriate metal compound such as an oxide or
hydroxide and neutral or overbased products may be obtained by methods
well known in the art. Sulfurized phenols may be prepared by reacting a
phenol with sulfur or a sulfur containing compound such as hydrogen
sulfide, sulfur monohalide or sulfur dihalide, to form products which are
20 generally mixtures of compounds in which 2 or more phenols are bridged
by sulfur containing bridges.
The detergent may have a particle diameter size in the range of
about 4 to 40 nm, preferably about 4 to 30 nm and more preferably about 6
to 20 nm. The overbased metal detergent. diameter size can be measured
25 using the small angle neutron scattering technique as described in I.
Markovic, R.H. Ottewill, D.J Cebula, I. Field and J.F. Marsh, "Small angle
neutron scattering studies on non-aqueous dispersions of calcium
carbonate", Colloid & Polymer Science, 262:648-656 (1984).
30 OIL OF LUBRICATING VISCOSITY
The oil of lubricating viscosity, useful for making concentrates of the
invention or for making lubricating oil compositions therefrom, may be
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selected from natural (vegetable, animal or mineral) and synthetic
lubricating oils and mixtures thereof. It may range in viscosity from light
distillate mineral oils to heavy lubricating oils such as gas engine oil,
mineral lubricating oil, motor vehicle oil, and heavy duty diesel oil.
Generally, the viscosity of the oil ranges from 2 centistokes to 30
centistokes, especially 5 centistokes to 20 centistokes, at 100 C.
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, napthenic and mixed paraffinic-
io napthenic types. Oils of lubricating viscosity derived from coal or shale
are
also useful base oils.
Synthetic lubricating oils include hydrocarbon oils and halo-
substituted hydrocarbon oils such as polymerized and interpolymerized
olefins (e.g., polybutylenes, polypropylenes, propylene-isobutylene
copolymers, chlorinated polybutylenes, poly(1-hexenes), poly(1-octenes),
poly(1-decenes)); alkylbenzenes (e.g., dodecylbenzenes,
tetradecylbenzenes, dinonylbenzenes, di(2-ethylhexyl)benzenes);
polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenols); and
alkylated diphenyl ethers and alkylated diphenyl sulfides and the
2o derivatives; analogs and homologs thereof.
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., methylpolyisopropylene
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 acid esters and C13 Oxo acid diester of
tetraethylene glycol.
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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, subericacid,
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, dilsooctyl azelate, disodecyl azelate, dioctyl
io 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 C5 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-, polyakoxy-, or
potyaryloxysiloxne 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-
butyl-phenyl)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 decyiphosphonic
acid) and polymeric tetrahydrofurans.
Unrefined, refined and rerefined oils can be used in the lubricants of
the present invention. Unrefined oils are those obtained directly from a
natural or synthetic source without further purification treatment. For
3o 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
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WO 99/52999 PCT/US99/07794
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.
OTHER ADDITIVE COMPONENTS
As indicated above, additional additives may be incorporated in the
composites of the invention to enable them to meet particular
requirements. Examples of additives which may be included in the
ts lubricating oil compositions are metal rust inhibitors, viscosity index
improvers, corrosion inhibitors, other oxidation inhibitors, friction
modifiers,
other dispersants, anti-foaming agents, anti-wear agents, pour point
depressants, and rust inhibitors. Some are discussed in further detail
below.
Dihydrocarbyl dithiophosphate metal salts are frequently used as
antiwear and antioxidant agents. The metal may be an alkali or alkaline
earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel or
copper. The zinc salts are most commonly used in lubricating oil in
amounts of 0.1 to 10, preferably 0.2 to 2 wt %, based upon the total weight
of the lubricating oil composition. They may be prepared in accordance
with known techniques by first forming a dihydrocarbyl dithiophosphoric
acid (DDPA), usually by reaction of one or more alcohol or a phenol with
P2S5 and then neutralizing the formed DDPA with a zinc compound. For
example, a dithiophosphoric acid may be made by reacting mixtures of
primary and secondary alcohols. Alternatively, multiple dithiophosphoric
acids can be prepared where the hydrocarbyl groups on one are entirely
secondary in character and the hydrocarbyl groups on the others are
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WO 99/52999 PCT/US99/07794
entirely primary in character. To make the zinc salt, any basic or neutral
zinc compound could be used but the oxides, hydroxides and carbonates
are most generally employed. Commercial additives frequently contain an
excess of zinc due to use of an excess of the basic zinc compound in the
neutralization reaction.
The preferred zinc dihydrocarbyl dithiophosphates are oil soluble
salts of dihydrocarbyl dithiophosphoric acids and may be represented by
the following formula:
S
RO
{1
S Zn
/
~
2
wherein R and R' may be the same or different hydrocarbyl radicals
containing from 1 to 18, preferably 2 to 12, carbon atoms and including
radicals such as alkyl, alkenyl, aryl, arylalkyl, alkaryl and cycloaliphatic
is radicals. Particularly preferred as R and R' groups are alkyl groups 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, 1-hexyl, n-octyl, decyl,
dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl,
methylcyclopentyl, propenyl, butenyl. In order to obtain oil solubility, the
total number of carbon atoms (i.e. R and R') in the dithiophosphoric acid
will generally be about 5 or greater. The zinc dihydrocarbyl
dithiophosphate can therefore comprise zinc dialkyl dithiophosphates.
Oxidation inhibitors or antioxidants reduce the tendency of mineral
oils to deteriorate in service. Oxidative deterioration can be evidenced by
sludge in the lubricant, varnish-like deposits on the metal surfaces, and by
viscosity growth. Such oxidation inhibitors include hindered phenols,
alkaline earth metal salts of alkylphenolthioesters having preferably C5 to
CA 02327829 2000-10-06
WO 99/52999 PCT/US99/07794
C12 alkyl side chains, calcium nonylphenol sulphide, oil soluble phenates
and sulfurized phenates, phosphosulfurized or sulfurized hydrocarbons,
phosphorous esters, metal thiocarbamates, oil soluble copper compounds
as described in US 4,867,890, and molybdenum-containing compounds.
Aromatic amines having at least two aromatic groups attached
directly to the nitrogen constitute another class of compounds that is
frequently used for antioxidancy. While these materials may be used in -
small amounts, preferred embodiments of the present invention are free of
these compounds. They are preferably used in only small amounts, i.e.,
io up to 0.4 wt %, or more preferably avoided altogether other than such
amount as may result as an impurity from another component of the
composition.
Typical oil soluble aromatic amines having at least two aromatic
groups attached directly to one amine nitrogen contain from 6 to 16 carbon
atoms. The amines may contain more than two aromatic groups.
Compounds having a total of at least three aromatic groups in which two
aromatic groups are linked by a covalent bond or by an atom or group
(e.g., an oxygen or sulphur atom, or a -CO-, -SO2- or alkylene group) and
two are directly attached to one amine nitrogen also considered aromatic
2o amines having at least two aromatic groups attached directly to the
nitrogen. The aromatic rings are typically substituted by one or more
substituents selected from alkyl, cycioalkyl, alkoxy, aryioxy, acyl,
acylamino, hydroxy, and nitro groups. The amount of any such oil soluble
aromatic amines having at least two aromatic groups attached directly to
one amine nitrogen should preferably not exceed 0.4 wt % active
ingredient.
Representative examples of suitable viscosity modifiers are
polyisobutylene, copolymers of ethylene and propylene, polymethacrylates,
methacrylate copolymers, copolymers of an unsaturated dicarboxylic acid
3o and a vinyl compound, interpolymers of styrene and acrylic esters, and
partially hydrogenated copolymers of styrene/ isoprene, styrene/butadiene,
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WO 99/52999 PCT/US99/07794
and isoprene/butadiene, as well as the partially hydrogenated
homopolymers of butadiene and isoprene.
Friction modifiers and fuel economy agents which are compatible
with the other ingredients of the final oil may also be included. Examples
of such materials are glyceryl monoesters of higher fatty acids, for
example, glyceryl mono-oleate; esters of long chain polycarboxylic acids
with diols, for example, the butane diol ester of a dimerized unsaturated
fatty acid; oxazoline compounds; and alkoxylated alkyl-substituted mono-
amines, diamines and alkyl ether amines, for example, ethoxylated tallow
io amine and ethoxylated tallow ether amine.
A viscosity index improver dispersant functions both as a viscosity
index improver and as a dispersant. Examples of viscosity index improver
dispersants include reaction products of amines, for example polyamines,
with a hydrocarbyl-substituted mono -or dicarboxylic acid in which the
hydrocarbyl substituent comprises a chain of sufficient length to impart
viscosity index improving properties to the compounds. In general, the
viscosity index improver dispersant may be, for example, a polymer of a C4
to C24 unsaturated ester of vinyl alcohol or a C3 to CIo unsaturated mono-
carboxylic acid or a C4 to Clo di-carboxylic acid with an unsaturated
2o nitrogen-containing monomer having 4 to 20 carbon atoms; a polymer of a
C2 to C20 olefin with an unsaturated C3 to Clo mono- or di-carboxyiic acid
neutralized with an amine, hydroxyamine or an alcohol; or a polymer of
ethylene with a C3 to C20 olefin further reacted either by grafting a C4 to
C20
unsaturated nitrogen - containing monomer thereon or by grafting an
unsaturated acid onto the polymer backbone and then reacting carboxylic
acid groups of the grafted acid with an amine, hydroxy amine or alcohol.
Examples of dispersants and viscosity index improver dispersants
may be found in European Patent Specification No. 24146 B.
Pour point depressants, otherwise known as lube oil flow improvers,
lower the minimum temperature at which the fluid will flow or can be
poured. Such additives are well known. Typical of those additives which
improve the low temperature fluidity of the fluid are C8 to C18 dialkyl
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WO 99/52999 PCT/US99/07794
fumarate/vinyl acetate copolymers, and polymethacrylates. Foam control
can be provided by an antifoamant of the polysiloxane type, for example,
silicone oil or polydimethyl siloxane.
Some of the above-mentioned additives can provide a multiplicity of
effects; thus for example, a single additive may act as a dispersant-
oxidation inhibitor. This approach is well known and need not be further
elaborated herein.
When lubricating concentrate contain one or more of the above-
mentioned additives, each additive is typically blended into the base oil in
lo an amount, which enables the additive to provide its desired function.
The amount of the above mentioned additives, other than the
overbased metal detergent, ashiess dispersant and diluent oil, can range
from about 0.1 to 50 wt.%, preferably about 0.2 to 40 wt.%, more
preferably about 0.5 to 30 wt. % and even more preferably about I to 20
V11t.%.
The concentrate may be further added to a lubricating oil in
concentration resulting in a final lubricating oil composition which may
employ from 5 to 25 mass %, preferably 5 to 18 mass %, typically 10 to 15
mass % of the concentrate, the remainder being oil of lubricating viscosity.
2o Representative effected amounts of such additives, when used in
crankcase lubricants, are listed below. All the values listed are stated as
mass percent active ingredient.
ADDITIVE MASS % MASS %
(Broad) Preferred
Ashless Dispersant 0.1 - 20 1-8
Metal Detergents 0.1 - 15 0.2 - 9
Corrosion Inhibitor 0-5 0- 1.5
Metal Dihydrocarbyl Dithiophosphate 0.1 - 6 0.1 - 4
Antioxidant 0-5 0.01 - 2
Pour Point Depressant 0.01 - 5 0.01 - 1.5
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Antifoaming Agent 0-5 0.001 - 0.15
Supplemental Antiwear Agents 0- 1.0 0- 0.5
Friction Modifier 0-5 0- 1.5
Viscosity Modifier 0.01 - 10 0.25 - 3
Basestock Balance Balance
All 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 is explained below in further detail with references to
examples, which are not by way of limitation, but by way of illustration.
Example I
Blend components
In the following example, oleaginous additive concentrates were
made by blending the following dispersant, detergent and additives. A
dispersant was made by functionalizing an ethylene-butene copolymer (46
wt. % ethylene) with a carbonyl group introduced by Koch reaction,
derivatized with polyamine and borated according to the procedure
described in WO-A-94/13709. The number average molecular weight of
the dispersant was approximately 6000 and the hydrodynamic radius, as
measured by the dynamic light scattering technique at 60 C, was
approximately 30 to 40 nm. A overbased detergent containing
magnesium sulfonate with a TBN of 400 and a diameter of 10 2 nm as
measured the small angle neutron scattering technique. The weight
ratio of the dispersant to the detergent was 3:1 on an active ingredient
basis and the sum of the overbased detergent and ashless dispersant on
an active ingredient basis is about 27 wt. % based on the total weight of
the concentrate.
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The concentrate additives used in this example included an
antifoam agent, anti-oxidants, a demulsifier, zinc dihydrocarbyl
dithiophosphates and friction modifiers.
Example 2
Blending Procedure
The oleaginous concentrate blending procedures were
performed at 60 C. In the dispersant last procedure, the overbased
detergent was mixed with the concentrate additives listed in Example 1 and
io allowed to mix for about 1 hour. The dispersant was then added and
blended for a further hour. The blend was observed for the Weissenberg
effect. The blend was stored at 60 C for 8 weeks and then tested for
sediment content, which is an indication of phase separation.
The same methods were used in the detergent last procedure
is except that the dispersant was first mixed with the concentrate additives
for
about one hour, followed by the detergent.
In addition to the above procedures, the detergent was optionally
mixed with a pretreatment additives for 8 hours at 95 C before being mixed
with the blend. The pretreatment additive was a poly(isobutylene) succinic
2o anhydride having a number average molecular weight of approximately
2300. The pretreatment additive was blended at 10 wt.% based on the
total weight of the detergent.
The blending results for the concentrates are shown in Table 1
below.
Table 1
Blending procedure Pretreatment Blendability Wt. % sediments (8
additive (Weissenberg) weeks at 60 C)
Dispersant last No Blendable, (No 1.7%
Weissenberg)
Dispersant last Yes Blendable, (No 0.2%
Weissenberg)
CA 02327829 2000-10-06
WO 99/52999 PCT/US99/07794
Detergent last No Blendable (No 0.01%
Weissenberg)
Detergent last Yes Blendable, (No Trace
Weissenberg)
Control (conventional No Unblendable N/A (unblendable)
according to US Patent (Large
No. 4,938,880) Weissenberg)
The results in Table 1 show that when the conventional method is
used (i.e., the dispersant and detergent are mixed together before adding
the additives), the concentrate is unblendable. However, when the
s additives are first mixed with either the detergent or the dispersant, the
concentrate is blendable. In addition, the results surprisingly and
unexpectedly show that when the detergent is blended last, the amount of
the sediments are greatly reduced. Furthermore, the results also show that
the amount of sediments is reduced by pretreating the detergent with
io polyisobutylene succinic anhydride. Therefore, due to the procedure of the
present method, it is now possible to used high molecular weight
dispersants and overbased detergents at concentrations used in additive
packages.
The foregoing is illustrative of the present invention and is not
15 construed as limiting thereof. The invention is defined by the following
ciaims with equivalents of the claims to be included therein.
31
