Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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LUBRICATING OIL COMPOSITIONS
This invention relates to lubricating oil compositions, especially lubricants
used in
internal combustion engines, comprising base oils high in saturates which are
resistant to
oxidation.
Lubricating oil compositions are used for the smooth operation of internal
combustion engines, power transmission components including automatic
transmissions,
shock absorbers and power steering devices and gears. The engine oils for
internal
combustion engines in particular serve to (i) lubricate various sliding
interfaces eg between
the piston ring and cylinder liner, in bearings of the crank shaft and the
connecting rod, and
in the valve driving mechanism including cams and valve lifters, (ii) cool the
engine, (iii)
clean and disperse the combustion products and (iv) prevent corrosion and
consequent rust
formation. The stringent requirements for high performance engines in recent
years has
meant greater demand from lubricants used in such engines. Lubricating oils
used in such
engines usually deteriorate due to oxidation by oxygen and nitrogen oxides
(NOx) formed
during combustion of fuels and lubricants and that contained in blow-by gas in
turn formed
by leakage of combustion gases into the crankcase via the piston and cylinder
interface. The
concentration of NOx increases in the blow-by gas with increasing demand in
performance
of the engine. The deleterious effects of oxidation can be and have been
mitigated by the use
of various additives including antioxidants, anti-wear agents, ash-free
detergent dispersants,
friction modifiers and the like.
Hitherto these have been mitigated to some extent by the use of lubricating
compositions which comprise a Group I base oil which is relatively low in
saturated
hydrocarbons (hereafter "saturates") in spite of its relatively high
propensity to oxidation.
Whilst this has meant that the base oil itself is relatively inexpensive, it
has had to be
supplemented with relatively large amounts of additives/antioxidants to
achieve the desired
performance. However, by using a relatively more refined feedstock such as the
Group II &
Group III basestocks high in saturates, it is possible to achieve the desired
performance
without unduly supplementing the additives/antioxidants used.
It has now been found that by using a specific combination of antioxidants, it
is
possible to use Group II and Group III base stocks high in saturates with
enhanced
performance in respect of oxidation stability and fuel efficiency.
Accordingly, the present invention is a lubricating oil composition comprising
a base
stock and an antioxidant comprising an oil soluble trinuclear organomolybdenum
compound
of the generic formula:
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Mo3Sz (Q) (I)
wherein z is from 4 to 10, preferably 7, and Q is a core group, which may be a
ligand, and at
least one other compound selected from a phenolic and an aminic compound
characterised in
that the base stock has a kinematic viscosity at 100 C (KV1.) from about 2 cSt
to 20 cSt (2 x
10-6 to 20 x 10-6 m 2/sec) and a saturates content of at least 85%.
The lubricating oil compositions of the present invention are those that
comprise a
major amount of a Group II or Group III base stock which may be a natural or
synthetic
lubricating oil having a KV1 . of 2-20 cSt, preferably from 2-12 cSt and a
saturates content of at
least 85 %, preferably at least 88 %. Specific examples of Group II basestock
high in saturates
include inter alia RLOP 500R and Mobil Jurong 500N (with >97 % saturates), and
MXT 5
(with 92 % saturates); and examples of Group III basestock include inter alia
Yubase 4 (with
saturate contents of 99.5 %) and YubaseT"" 6 (with saturate contents of 97.5
%).
According to a further embodiment, the present invention is a method of
stabilizing a
lubricant composition against oxidative degradation, said composition
comprising a base stock
which has a kinematic viscosity at 100 C (KV1.) from about 2 cSt to 20 cSt (2
x 10-6to 20 x
10-6 mZ/sec) and a saturates content of at least 85 % said method comprising
adding to the
basestock an effective amount of an antioxidant comprising an oil soluble
trinuclear
organomolybdenum compound of the generic formula:
Mo3Sz (Q) (I)
wherein z is from 4 to 10, preferably 7, and Q is a core group, which may be a
ligand, and at
least one other compound selected from a phenolic and an aminic compound.
The trinuclear molybdenum compounds are of formula (I)
Mo3Sz (Q) (I)
wherein z is from 4 to 10, preferably 7, and Q is a core group. These
compounds are relatively
new and are claimed and described in our prior published US-A-5,906,968. The
matter
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2a
disclosed in this prior US patent on the structure, preparation and properties
of the trinuclear
molybdenum compounds is hereby noted. In these compounds the core group (Q)
may be a
ligand capable of rendering the organomolybdenum compound of formula (I) oil
soluble and
ensuring that said molybdenum compound is substantially charge neutral. The
core group (Q)
is generally associated with suitable ligands such as Ly wherein L is the
ligand and y is of a
sufficient number, type and charge to render the compound of formula (I) oil
soluble and to
neutralize the charge on the compound of formula (I) as a whole. Thus, more
specifically, the
trinuclear molybdenum compound used in the compositions of the present
invention may be
represented by the formula (II):
Mo3SZLY (II)
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The ligands "L" are suitably dihydrocarbyl dithiocarbamates of the structure
(-S2CNR2) wherein the dihydrocarbyl groups, R2 impart oil solubility to the
molybdenum
compound. In this instance, the term "hydrocarbyl" denotes a substituent
having carbon
atoms directly attached to the remainder of the ligand and is predominantly
hydrocarbyl in
character within the context of this invention. Such substituents include the
following:
(1) hydrocarbon substituents, ie, aliphatic (for example alkyl or alkenyl),
alicyclic (for
example cycloalkyl or cycloalkenyl), aromatic-, aliphatic- and alicyclic-
substituted
aromatic nuclei and the like, as well as cyclic substituents wherein the ring
is
completed through another portion of the ligand (that is, any two indicated
substituents may together form an alicyclic group);
(2) substituted hydrocarbon substituents, ie, those containing nonhydrocarbon
groups
which, in the context of this invention, do not alter the predominantly
hydrocarbyl
character of the substituent. Those skilled in the art will be aware of
suitable groups
(eg halo (especially chloro), amino, alkoxyl, mercapto, alkylmercapto, nitro,
nitroso,
sulphoxy etc.); and
(3) hetero substituents, ie, substituents which, while predominantly
hydrocarbon in
character within the context of this invention, contain atoms other than
carbon
present in a chain or ring otherwise composed of carbon atoms.
The hydrocarbyl groups are preferably alkyl (e.g, in which the carbon atom
attached
to the remainder of the ligand "L" is primary, secondary or tertiary), aryl,
substituted aryl
and/or ether groups.
Importantly, the hydrocarbyl groups of the ligands should be such that they
have a
sufficient number of carbon atoms to render the compound (I) soluble or
dispersible in the
oil to which the trinuclear organomolybdenum compound containing the ligand is
added.
The total number of carbon atoms present among all of the hydrocarbyl groups
of the
organomolybdenum compounds' ligands is suitably at least 21, preferably at
least 25, more
preferably at least 30 and even more preferably at least 35, typically e.g.,
21 to 800. For
instance, the number of carbon atoms in each hydrocarbyl group will generally
range from 1
to 100, preferably from 1 to 40 and more preferably from 3 to 20.
The antioxidant in the compositions of the present invention suitably also
include at
least one other compound selected from a phenolic compound and an aminic
compound.
Among the phenolic compounds, hindered phenols are preferred.
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Examples of such phenolic compounds include inter alia:
4,4'-methylene bis(2,6-di-tert-butylphenol)
4,4'-bis(2,6-di-tert-butylphenol)
4,4'-bis(2-methyl-6-tert-butylphenol)
2,2'-methylene bis(4-ethyl-6-tert-butylphenol)
2,2'-methylene bis(4-methyl-6-tert-butylphenol)
4,4'-butylidene bis(3-methyl-6-tert-butylphenol)
4,4'-isopropylidene bis(2,6-di-tert-butylphenol)
2,2'-methylene bis(4-methyl-6-nonylphenol)
2,2'-isobutylidene bis(4,6-dimethyl phenol)
2,2'-methylene bis(4-methyl-6-cyclohexylphenol)
2, 6-di-tert-butyl-4-methylphenol
2,6-di-tert-butyl-4-ethylphenol and
2,4-dimethyl-6-tert-butylphenol
Specific hindered phenols which are preferred as the antioxidants may be
represented by the
generic formulae (III) - (IV) below in which Rl, R2, and R3 are the same or
different alkyl
groups from 3-9 carbon atoms and x and y are integers from 1 to 4.
RI
O
(III) HO (CH2)x-C-O-R3
2
R1
O
(IV) HO (CH2)x-S-((-, H2)y-C-O-R3
R2
R1
O
(V) [Ho(cH2)xo(cH2)yc
4
R2
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R1
O
5 (VI) [HO(CH2)x--O-(CH2)}S
R2
Suitable aminic compounds for use in the compositions of the present invention
are
diaryl amines, aryl naphthyl amines and alkyl derivatives of diaryl amines and
the aryl
naphthyl amines. Preferred aminic antioxidants are represented by the formulae
(VII) and
(VIII) wherein each of R4 and R5 is a hydrogen atom or represents the same or
different alkyl
groups from 1-8 carbon atoms.
R4 j~ Rs
(VII) O-N 20
(VIII) 0 25 0
Specific examples of the aminic compounds that may be used in the compositions
of
the present invention include inter alia:
Monoalkyldiphenyl amines such as eg monooctyldiphenyl amine and monononyl
diphenyl amine; dialkyldiphenyl amines such as eg 4,4'-dibutyldiphenyl amine,
4,4'-
dipentyldiphenyl amine, 4,4'-dihexyldiphenyl amine, 4,4'-diheptyldiphenyl
amine, 4,4'-
dioctyldiphenyl amine and 4,4'-dinonyldiphenyl amine; polyalkyldiphenyl amines
such as eg
tetra-butyldiphenyl amine, tetra-hexyldiphenyl amine, tetra-octyldiphenyl
amine and tetra-
nonyldiphenyl amine; the naphthylamines such as eg a-naphthylamine and phenyl-
a-
naphthylamine; butylpheny-a-naphthylamine, pentylphenyl-a-naphthylamine,
hexylphenyl-
a-naphthylamine, heptylphenyl-a-naphthylamine, octylphenyl-a-naphthylamine and
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nonylphenyl-a-naphthylamine. Of these, dialkyldiphenyl amine and
naphthylamines are
preferable.
In general, the antioxidant which comprises the organomolybdenum compound in
combination with a phenolic and/or an aminic compound will form a minor
component of
the total lubricant composition. For example, the organomolybdenum compound
typically
will comprise about 0.05 to about 5.00 wt % of the total composition,
preferably from 0.05
to 2.0 wt%, and more preferably from 0.1 to 0.7 wt%, i.e., the molybdenum
metal is suitably
present in an amount of from about 25 to 2500 ppm, preferably from about 50 to
1000 ppm,
and more preferably from 100 to 700 ppm, and the phenolic and/or aminic
compounds about
0.10 to about 3.0 wt % of the total composition.
It has also been found that if the weight ratio of organomolybdenum compound
to the
phenolic and/or aminic compound in the antioxidant is in the range of about
80:20 to about
20:80, optimum dispersancy retention can be achieved by these combined
antioxidants of the
present invention.
It is particularly preferred that the antioxidant comprises in addition to the
organo
molybdenum compound, a mixture of the phenols (III)-(VI) above and the diaryl
amines
(VII)-(VIII) in a weight ratio ranging from about 80:10:10 to about 10:30:60
respectively,
preferably typically 50:15:35 respectively.
Optionally, the antioxidants may be combined with a carrier liquid in the form
of a
concentrate. The concentration of the combined antioxidants in the concentrate
may vary
from 1 to 80% by weight, and will preferably be in the range of 5 to 50% by
weight.
The antioxidant combination of the present invention can be used with any of
the
conventional dispersants used hitherto in the lubricating compositions.
Examples of such
dispersants include inter alia the polyalkylene succinimides, Mannich
condensation products
of polylalkylphenol-formaldehyde polyamine and boronated derivatives thereof.
However,
it is preferable to use ashless dispersants such as the ashless succinimides,
especially the
polyisobutenyl succinimides of a polyamine such as eg tetraethylenepentamine
or its
homologues, benzylamine ashless dispersants, and ester ashless dispersants.
The dispersants
are generally used in the compositions of the present invention in an amount
ranging from
about 2-10% by weight based on the total weight of the lubricant composition,
preferably
from about 4-8% by weight.
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A feature of the present invention is that the compositions of the present
invention
the presence of a trinuclear organo molybdenum compound facilitates the
control of deposit
formation from engine oils. More specifically, formulations containing eg a
contribution of
200- 750 ppm, preferably from 450-550 ppm of Mo metal from the trimer and an
additional
contribution of from 80-100 ppm from a detergent inhibitor package enables the
amount of
deposit formed to be significantly reduced. Adverse effects, if any, due the
presence of such
molybdenum compounds in the formulation, eg copper strip corrosion, are
readily mitigated
by including in the formulation a corrosion inhibitor or a metal passivator.
This reduction in
deposit formation has been monitored by the so-called TEOST-MHT-2 test which
test is
similar to the conventionally used TEOST-33 test method except that it is run
at a relatively
lower temperature and for a longer time. These tests are especially designed
to test the
formulations for a GF-3 specification. The TEOST-33 test is carried out at
temperature
cycles which fluctuate from 200-500 C and last for about 2 hours and results
in bulk
oxidation of the oil (about 100 g). In contrast, the TEOST-MHT-2 test relates
to high
temperature engine deposits as measured in tests such as TU3HT and is carried
out at about
285 C over 24 hours and is a thin-film test on about 8 g of oil. The TEOST-MHT-
2 test
measures deposits produced on a heated rod or in the oil itself (filtered
residue) and the GF-3
specification is envisioned to specify a limit of 40 mg deposit. From the
results in the
Examples below it will be seen that the presence of a trinuclear organo
molybdenum
compound in such oils results in about 66% reduction in the total weight of
the deposits
formed which satisfies the GF-3 specification.
In general, these lubricating compositions may include additives commonly used
in
lubricating oils especially crankcase lubricants, such as antiwear agents,
detergents,
dispersants, rust inhibitors, viscosity index improvers, extreme-pressure
agents, friction
modifiers, corrosion inhibitors, emulsifying aids, pour point depressants,
anti-foams and the
like.
A feature of the present invention is that lubricant compositions comprising
high
saturates base oils and trinuclear organomolybdenum compounds in combination
with a
phenolic and/or an aminic compound as antioxidant provide unexpected
improvement in
oxidation control and significant benefits in fuel economy. In the case of
lubricants
compositions comprising high saturates base oils for diesel engine oils, the
present invention
confers the added benefits of viscosity increase control and dispersancy
retention over
compositions which contain only one of these antioxidants used alone.
The present invention is further illustrated with reference to the following
Examples:
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EXAMPLES
General Procedure:
A series of Test oils were prepared. These oils were then tested in a bench
oxidation
test which was conducted at 165 C under a mixed nitrogen/air flow, with 40 ppm
iron from
added ferric acetylacetonate as catalyst. The flow rates of air and nitrogen
were controlled at
500 ml/min and 350m1/min respectively.
In these tests the following commercial materials have been used:
Irganox L57 is an octylated/butylated diphenylamine (ex Ciba Geigy)
Irganox L101 is a high molecular weight phenolic antioxidant (ex Ciba Geigy)
Irganox L115 and Irganox L 1035 are high molecular weight phenolic
antioxidants with a thioether group (ex Ciba Geigy)
Irganox L06 is an alkylated phenyl-a-naphthylamine (ex Ciba Geigy)
Irganox L135 is a high molecular weight phenolic antioxidant (ex Ciba Geigy)
Irganox L150 is a mixture of alkylated diphenylamine, a phenolic antioxidant
and a phenolic antioxidant with a thioether group (ex Ciba Geigy)
Paranox 106 is a polyisobutenylsuccinimide dispersant (ex Infenium, Linden,
NJ)
Molyvan 822 is a dinuclear molybdenum dithiocarbamate containing 5 % wt
molybdenum (ex R T Vanderbilt Co)
PDN5203 is an experimental sample of trinucler molybdenum
dithiocarbamate containing 5% wt molybdenum
Paratone 8451 is a viscosity index improver (ex Oronite)
Paraflow 390 is a pour point depressant (ex Oronite)
DI is a conventional detergent inhibitor package which is free of a
friction modifier package
120X is a Group II base oil with > 92% in saturates (ex.Imperial Oil,
Canada)
The same conventional DI package was used in all the Examples and tests, where
indicated.
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Examples A-I
Comparison between low and high saturates base oils:
The compositions of the test oils in these used in these Examples and their
changes in
respective viscosities after a 48 hour oxidation test are given in Table 1
below:
TABLE 1
Example A B C D E F G H I
MCT 30 % wt 93.0 93.0 93.0 - - - - - -
RLOP 500R (% wt) - - - 93.0 93.0 93.0 - - -
Mobil Jurong 500N (%wt) - - - - - - 93.0 93.0 93.0
Paranox 106 (% wt) 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0
Mo3-dithiocarbamate* 1.0 - 0.5 1.0 - 0.5 1.0 - 0.5
Ir anox L57 - 1.0 0.5 - 1.0 0.5 - 1.0 0.5
Fresh Oil KVloo, cSt 12.99 13.18 13.06 12.87 12.64 12.78 12.6 12.31 12.38
Used Oil KVioo, cSt 14.3 21.66 15.54 25.03 28.76 12.87 46.25 34.6 12.59
% Increase** 10.08 64.34 3.68 94.48 127.53 0.70 267.06 181.1 1.70
* containing 11.5% wt of molybdenum
**changes in viscosity after 48 hr oxidation tests.
From the above it can be seen that the trinuclear molybdenum dithiocarbamate
and
the diarylamine individually perform better in low saturates base oil, but,
unexpectedly, a
combination of the two gives a better performance in high saturates base oils
than the
individual components.
EXAMPLES J-Q
Comparison between a trinuclear molybdenum compound and a dinuclear molybdenum
compound
The compositions of the test oils in Examples J-Q and their respective changes
in
viscosity data after a 48-hour oxidation test on each are shown in Table 2
below:
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TABLE 2
Example J K L M N 0 P Q
MCT 30 (% wt) 93.0 93.0 93.0 93.0 - - - -
RLOP 500R (% wt) - - - - 93.0 93.0 93.0 93.0
Paranox 106 (% wt) 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0
PDN 5203 (wt%)* 1.0 - 0.5 - 1.0 - 0.5 -
Mol an 822 (wt%) - 1.0 - 0.5 - 1.0 - 0.5
Ir anox L57 (wt%) - - 0.5 0.5 - - 0.5 0.5
Fresh Oil KV100, cSt 12.98 13.00 12.91 12.97 12.65 12.71 12.64 12.63
Used Oil KV,00, cSt 16.19 24.94 13.59 13.93 78.99 79.50 12.77 12.87
% Increase* 24.7 91.8 5.3 7.4 524 526 1.0 1.9
*changes in viscosity after 48 hr oxidation tests.
5 Examples J-Q show that the trinuclear molybdnum dithiocarbamate gives better
performance than conventional dinuclear molybdenum dithiocarbamate in
oxidation control.
The performance of the trinuclear molybdenum compound is further enhanced in
base oils
high in saturates.
10 Synergy of Trinuclear Molybdenum Dithiocarbamate with a Base Oil High in
Saturates in
the presence of Antioxidant Mixtures:
Examples R-U
The changes in viscosity after a 32 hour oxidation test in Examples R-U is
shown in Table 3
below:
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TABLE 3
Example R S T U
MCT 30 (% wt) 93.0 93.0 - -
RLOP 500R (% wt) - - 93.0 93.0
Paranox 106 (% wt) 6.0 6.0 6.0 6.0
Mo3-dithiocarbamate* (% wt) 0.5 0.5 0.5 0.5
Ir anox L57 0.5 - 0.5 -
Ir anox L150 (%wt) - 0.5 - 0.5
Fresh Oil KVIoo, cSt 13.39 13.41 12.73 12.78
Used Oil KVIoo, cSt 13.64 13.62 12.78 12.82
% Increase** 1.87 1.57 0.39 0.31
*containing 11.5% by wt molybdenum
**changes in viscosity after 48 hr oxidation tests.
Examples R-U demonstrate that mixtures of aminic and phenolic antioxidants
give
equivalent performance to an aminic antioxidant. Base oils high in saturates
provide
additional benefit in viscosity control.
Fuel Economy Improvement:
Fuel economy is measured in different types of engine tests including the
Sequence
VIA, Sequence VIB and the M111 tests. Sequence VIA and the M111 tests evaluate
initial
fuel economy while Sequence VIB test determines initial and retained fuel
economy after 96
hours.
In all engine tests, fuel economy is estimated as a function of the
hydrodynamic and
boundary contribution of the lubricant to fuel consumption. The lubricant
contribution under
hydrodynamic conditions is mostly governed by the lubricant viscometrics under
both low
and high shear conditions while the lubricant contributions under boundary
conditions are
most governed by the friction modifier technology.
For the purpose of illustrating this invention, we concentrate on the
lubricant
contribution to the boundary operating range of the engine, which in the
Sequence VIB test
is measured in Stage 5 of that test whereas the Sequence VIA is measured in
Stage 1 of that
test. The following Examples, therefore, refer to test performances in Stage
1, Stage 5 and
the M11 l tests as appropriate.
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Example V:
A 5W-20 formulation comprising a Group II base oil is shown in Table 4 below:
TABLE 4
Component Weight % Component type
MXT 5 79.034 Group II basestock
Paratone 8452* 6.10 OCP VI Improver
Parabar 9230** 10.50 Borated PIBSA-PAM
dispersant
SAP 001** 2.25 Ca salicylate - 165 TBN
SAP007** 0.56 Mg salicylate - 345 TBN
Ir anox L135 0.30 High M W phenolic AOX
Parabar 9417** 0.36 Secondary ZnDDP
Paranox 15** 0.69 Primary ZnDDP
Parabar 10100** 0.20 Corrosion Inhibitor
Parabar 9499** 0.006 Demulsifier
* Paratone 8452 is sold by Oronite, Richmond, California, USA
** Parabar , Paranox and SAP additives are sold by Infenium, Linden, New
Jersey, USA.
The fuel economy and fuel economy retention data were collected using a
gasoline
passenger car M111 fuel economy test (CES-L54-X-94) and a M111 fuel economy
retention
test. In the M 111 fuel economy retention test, the duration of the test is
extended by
repeating the standard test cycles 21 times. Each test cycle is followed by a
period of steady
state aging. The aging is equivalent to 500 miles. The total test is thus
equivalent to about
10,000 miles, and takes about 185 hours. Fuel consumptions are measured at
every cycle,
hence every 500 miles. The fuel consumption reference RL191 is measured both
at the
beginning and end of the test, thereby allowing uninterrupted aging of the
test oil. The
effects of a trinuclear molybdenum dithiocarbamate on fuel economy and fuel
economy
retention are shown in Table 5 below. The initial fuel economy improvement
data are thus
based on comparison with the industry reference oil RL191 (which is a 15W-40
engine oil).
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TABLE 5
Formulation Initial Fuel Economy /% Integrated fuel economy
improvement (vs base case) over
10,000 mile drain interval / %
Base case 5W-20 (Table 4) 2.20 -
Base case + 1.1% 2.38 10.6
Sakaralube 155 *
Base case + 0.2% PDN5203 2.54 34.6
Base case + 1.0% PDN 5203 2.73 36.2
*Sakaralube 155 is a dinuclear Mo dithiocarbamate (5% wt Mo, ex Asahi Denko
Kogyo KK)
Example V shows that addition of molybdenum compounds leads to better fuel
economy retention in a European gasoline passenger car engine. The use of
trinuclear
molybdenum dithiocarbamate provides significant improvement in initial fuel
economy and
fuel economy retention over the conventional dinuclear molybdenum
dithiocarbamate.
Example W:
A 5W-20 engine oil formulation comprising a Group III base oil is shown in
Table 6
below:
TABLE 6
Component Weight % Component type
Yubase 6 45.4 Group III basestock
Yuabse 4 40.3 Group III basestock
DI 8.3 DI package free of friction
modifier
Paratone 8464* 6.10 OCP VI Improver
* Paratone 8464 is sold by Oronite, Richmond, California, USA
The sequence VIA screener data in stages 1, 4 and 7 (stages sensitive to
friction
modifier) using a trinuclear molybdenum dithiocarbamate on fuel economy are
shown in
Table 7. The % fuel economy improvement was measured versus an industry
baseline
calibration oil (BC-3) for Sequence VIA (BC-3 is a non-friction modified
synthetic 5W-30).
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TABLE 7
% Fuel Economy Improvement
Formulation Stage 1 Stage 4 Stage 7
Base case (Table 6) 0.612 1.804 -0.622
Base case + 1.0% PDN 5203 2.214 1.998 0.854
Thus, Example W further demonstrates the benefit of trinuclear molybdenum
dithiocarbamate in fuel economy improvement in a North American gasoline
engine.
EXAMPLE X:
The TEOST-MHT-2 test was performed in a manner very similar to the
conventional
TEOST-33 test for a GF-2 specification by running at a lower temperature (285
C) but for a
longer period of time ie 24 hours on an 8 g sample of oil. The test is set to
measure deposits
produced on a heated rod or in the oil itself (filtered residue) and it was
expected to match
the currently given GF-3 specification limit of 40 mg of deposit. The results
are tabulated in
Table 8 below:
TABLE 8
Components Type Blend
5W-30 5W-30
120X (wt %) Baseoil 81.51 80.51
DI (wt %) Free of friction 8.29 8.29
modifier
PDN5203 Mo-trimer - 1.00
Paratone 8451 VI improver 10.00 10.00
Paraflow 390 Pour point depressant 0.20 0.20
MHT-2 TEOST Test
Filter wt (mg) 5.2 0.9
Rod wt (mg) 70 26.4
Total wt (mg) 75.2 27.3
