Note: Descriptions are shown in the official language in which they were submitted.
; 21738~5
BACKGROUND OF THE rNVENTION
FIELD OF THE INVENTION
The present invention relates to a novel lubricant oil composition.
More specifically, the present invention relates to a lubricant oil composition
with a small friction coefficient under a wide variety of applicable conditions,particularly under operating conditions at a medium to low oil temperature and alow-speed rotation, which is preferable as a lubricant oil composition for intPrn~l
combustion eng-nes such as automobile engines for sustaining a fuel-efficiency.
DESCRIPTION OF THE RELATED ART
So as to smoothly operate internal combustion engines, driving
systems such as automatic tr~n~mi~ions, buffers, and power steerings, and
gears, use has been made therein of lubricant oils. Lubricant oils for internal
combustion engines, in particular, have roles in lubricating principally a variety
of sliding parts such as piston rings/cylinder liners, bearings of a crank shaft and
connecting rods, valve meçhAnism inclusive of cams and valve lifters, and the
like, as well as in cooling the inside of an engine and cleaning to disperse
combustion products and furthermore preventing rust and corrosion.
As has been described above, a wide variety of efficiencies are
demanded of lubricant oils for internal combustion engines. In recent years,
furthermore, higher efficiency has been required therefor, as intern~l combustion
engines have acquired higher performance and higher output and the operating
conditions have become more severe. In order to satisfy such demanded
propellies, thus, a variety of additives including for example wear preventing
agents, metal cleaning agents, non-ash dispersants, antioxidants and the like have
been added to lubricant oils for internal combustion engines.
For the filn~ment~l functions of lubricant oils for int~rn~l
combustion engines, smooth operation of internal combustion engines under any
of the conditions, in particular, is significant, so as to prevent wear and seizure.
Lubricated engine parts are mostly in the state of fluid lubrication, but valve
systems and top and bottom dead centers of pistons are likely to be put in the
~17;38~S
- 2 -
state of boundary lubrication. The wear preventing property in such a state of
boundary lubrication is generally given by the addition of zinc dithiophosphate
and zinc dithioc~l,~,late. The energy loss due to friction of moving parts
involving lubricant oils is so large in internal combustion engines that use is
made of a lubricant oil in combination with a variety of additives primarily
including a friction conditioner, as a measure for decreasing a frictional loss or
for increasing the fuel efficiency (for example, see Japanese Patent PublicationNo. 23595/1991).
Automobile internal combustion engines are operated at a wide
range of oil temperature, and rates of rotation and load, and so as to promote the
fuel-efficiency, lubricant oils for intçrn~l combustion engines should have
greater friction properties under a wide variety of applicable conditions. How-
ever, the friction properties may be sometimes deteriorated by generated coking
deposit and the like. Thus, so as to m~int~in the fuel-efficiency for a long term,
less coking deposit should be demanded. Hence, the standard ILSAC GF-2
specifying such demand is now going to be established.
On the other hand, so as to lower the friction coefficient, use has
been made of molybdenum-cont~inin~ friction conditioners such as sulfoxy-
molybdenum dithiocarbamate. When the improvement of the fuel-efficiency is
intended by decreasing the friction coefficient by means of the molybdenum-
co~ friction conditioner, the coking deposit is increased in proportion to
the molybd~Pnllm content thereof, disadvantageously, involving sometimes the
occurrence of such a drawback that the fuel-efficiency property which has been
laboriously re~li7ed cannot be m~int~ined.
Practically, some lubricant oil compositions blended with such
molybdPnllm-co~ & friction conditioners have a drawback such that in a
deposit test according to the hot tube coking test of the GF-2 standard, they
absolutely cannot satisfy the standard [the deposit content at the hot tube coking
(at 310C for 16 hours) should be 100 mg or less] because occlusion develops in
them through the coking deposit.
The objective of the present invention is to improve the property of
sll~ ~e fuel-coefficiency of a lubricant oil composition with a smaller
2~7389~
- 3 -
friction coefficient, the composition being blended with a molybdenum-
co~ g friction conditioner, more specifically, to provide a lubricant oil
composition blended with a molybdenllm-cont~ining friction conditioner, the
composition satisfying the coke deposit criterion of the GF-2 standard on hot
tube coking test.
DESCRIPTION OF THE FIGURES
Figure 1 is a graph representing the relation between the
molybdenum content and the amount of deposit generated.
Figure 2 is a graph representing the relation between the boron
content and the amount of deposit generated.
DESCRIPTION OF THE INVENTION
It has been discovered that coke deposit can be decreased
prol"illently by adding a specific amount of a specific compound having a higherboron content into a lubricant oil composition with friction properties improvedby use of a molybdenum series additive.
More specifically, the present invention is to provide:
(1) a lubricant oil composition produced by blending (A) a molybdenum-
CO.~t~ g friction conditioner and (B) a boron-containing compound with
a lubricant base oil, wherein the content of the molybdenum derived from
the molybdenum-cont~ining friction conditioner is 100 to 2,000 ppm (as
the ratio by weight) and the content of the boron derived from the boron-
col.l;.il-il~g compound is 0.015% by weight or more, to the total weight of
the composition; and
(2) a lubricant oil composition produced by blending (A) a molybenum-
COI~ g friction conditioner, (B) a boron-cont~ining compound and (C)
a minor amount of an antioxidant with a lubricant base oil, wherein the
conlent of the molybdenu-m derived from the molybdenum-col~
friction conditioner is 100 to 2,000 ppm (as the ratio by weight) and the
- 4 -
content of the boron derived from the boron-co~ compound is
0.015% by weight or more, to the total weight of the composition.
Furthermore, prefelable embodiments of the present invention
include:
(3) a lubricant oil composition according to 1 or 2 above, wherein the
molybdenum-co~ friction conditioner is sulfoxymolybdenum
dithioc~l,~nate;
(4) a lubricant oil composition according to 1, 2 and 3 above, wherein the
boron-co~ g compound is boron-cont~inin~ succinimide or boron-
CO~ g succinate ester;
(5) a lubricant oil composition according to 2 to 4 above, wherein the content
of the antioxidant is 0.05 to 5.0% by weight, to the total weight of the
composition; and
(6) a lubricant oil composition according to 2 to 5 above, wherein the anti-
oxidant is phenol sulfide.
In the lubricant oil compositions in accordance with the present
invention, any lubricant base oil may be used with no specific limitation; use
may be made of those base oils conventionally used as the base oils of lubricantoils, for example, mineral oils and synthetic oils. Mineral oils include, for
example, r~ffin~te produced through the solvent refining of lubricant oil raw
materials in aromatic extraction solvents such as phenol,N-methylpyrolidone and
furfural; hydrogenated oils produced by hydrogenation using a hydrogenation
catalyst such as cobalt and molybdenum on a carrier silica-alumina; or mineral
oils such as lubricant fractions produced by isomerization of wax, for example,
60 Neutral Oil, 100 Neutral Oil, 150 Neutral Oil, 300 Neutral Oil, 500 Neutral
Oil, bright stock and the like. Alternatively, synthetic oils include poly(a-olefin
oligomer), polybutene, aLkylbenzene, polyol ester, polyglycol ester, dibasic acid
ester, ~hosphate ester, silicone oil and the like may be used. These base oils may
be used singly or in combination with two or more thereof. Likewise, mixlu~es
of such mineral oil and such synthetic oil may be used. Preferably the base oil
217389~
S
has a lrinem~tic viscosity generally in a range of 3 to 20 mm2/s at a temperature
of 100C.
As the molybdenum-cont~ining friction conditioner to be used for
the friction conditioner of the present invention, any molybdenum-cont~inin~;
compound may be used with no specific limitation, provided that the compound
has an action of decreasing the friction property when added to a lubricant oil.For example, use may be made of sulfoxymolybdenum dithiocarbamate, sulfoxy-
molybdenum dithiophosphate, molybdenum oxide ester and molybdenum amine
salt and the like, and the derivatives thereof, having an alkyl sub~ elll with 1 to
18 carbon atoms.
As the molybdenum-cont~inin~ friction conditioner in accordance
with the present invention, use may be made of one or two or more of these
molybdenum compounds preferably.
In accordance with the present invention, the molybdenum-
Co~ friction conditioner may be blended within a range of having the
effect of decreasing a friction coefficient, that is, at such an amount that thecontent of the molybdenum derived from the molybdenum-cont~ining friction
conditioner should be 100 to 2,000 ppm (as the ratio by weight), preferably 200
to 2,000 ppm (as the ratio by weight), more preferably 400 to 1,500 ppm (as the
ratio by weight) and most preferably 600 to 1,300 ppm (as the ratio by weight) to
the total weight of the lubricant oil composition. When the molybdenum-
Co~ g friction conditioner is blended at such an amount that the content of
the molybdenum derived from the molybdenum-co~ il-il-g friction conditioner is
below 100 ppm (as the ratio by weight) to the total weight of the composition,
the effect of improving the friction property cannot be s~ti~f~ctorily exerted.
When the molybdenum-co~ -il-g friction conditioner is blended at such an
amount that the content of the molyb-lenllm derived from the molybdenum-
co.~ friction conditioner is above 2,000 ppm (as the ratio by weight) to thetotal weight of the composition, the improvement in the friction decreasing effect
cannot be brought about in proportion to the amount; additionally, such an
amount is likely to cause the generation of coking deposit.
21.7~8g5
- 6 -
When only the molybdenum-cont~ining friction conditioner is
added into a lubricant oil, the lubricant oil rapidly falls into an occlusive state
supposing the molybdenum content is àbove 100 ppm at the hot coking test as
shown in Figure 1.
As the sulfoxymolybdenum dithiocarbamate to be used preferably
in the lubricant oil composition of the present invention with respect to the effect
of decreasing friction, prefelably, use may be made of a compound represented
by the general formula [1]:
/N C S Mo2SmOn [ 1 ]
R2
--2
wherein Rl and R2 are hydrocarbon groups with 8 to 18 carbon atoms,
respectively, and they may be the same or different from each other; "m" and
"n" are individually positive integers in which the sum thereof is 4.
The hydrocarbon groups with 8 to 18 carbon atoms, represented by
Rl and R2 in the general formula [1], include for example hydrocarbon groups
such as alkyl groups with 8 to 18 carbon atoms; alkenyl groups, with 8 to 18
carbon atoms; cycloaLkyl groups with 8 to 18 carbon atoms; allyl groups, alkyl-
allyl groups and allylaLkyl groups with 8 to 18 carbon atoms. The alkyl groups
and the alkenyl groups may be in the form of a straight chain or otherwise in the
form of a branched chain. The hydrocarbon groups represented by R1 and R2
have particularly ~,efelably eight carbon atoms in the lubricant oil compositionof the present invention.
Specific examples of the hydrocarbon groups represented by Rl
and R2 include octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, octenyl, nonenyl,
decenyl, lmdecenyl, dodecenyl, tridecenyl, tetradecenyl, hexadecenyl,
oct~dec~nyl, dimethylcyclohexyl, ethylcyclohexyl, methylcyclohexylmethyl,
217389~
.
- 7 -
cyclohexylethyl, propylcyclohexyl, butylcyclohexyl, hepthylcyclohexyl, di-
methylphenyl, methylbenzyl, phenetyl, naphthyl, dimethylnaphthyl and the like.
For the lubricant oil composition of the present invention, one type
of sulfoxymolybdenum dithiocarbamates may be used; otherwise, two types or
more thereof may be used mixed with each other. Additionally, sulfoxymolyb-
denum dithiocarbamate may be blended at such an amount that the content of the
molybdenllm derived from sulfoxymolybdenum dithiocarbmate should be 100 to
2,000 ppm (as the ratio by weight), preferably 200 to 2,000 ppm (as the ratio byweight), more ~rerelably 400 to 1,500 ppm (as the ratio by weight) and most
~-~relably 600 to 1,300 ppm (as the ratio by weight), to the total weight of thecomposition. When sulfoxymolybdenum dithiocarbamate is blended at such an
amount that the content of the molybdenum derived from sulfoxymolybdenum
dithioc~l,~ate is below 100 ppm (as the ratio by weight) to the total weight of
the composition, the effect of improving the friction property cannot
s~ticfactorily be exerted; otherwise, when sulfoxymolybdenum dithiocarbamate
is blended at such an amount that the content of the molybdenum derived from
sulfoxymolybdenum dithiocarbamate is above 2,000 ppm (as the ratio by weight)
to the total weight of the composition, the effect of decreasing the friction
prope, l~ cannot be improved in proportion to the content; furthermore, the
generation of coking deposit might be likely to be caused.
The boron-cont~ining compound cont~inin~ a high percentage of
boron, capable of suppressing coking deposit, by which the present invention is
characterized, has conventionally been added as a dispersant, for example, at a
trace amount below 0.015% by weight as the boron content, to a lubricant oil.
However, so as to acquire the effect of preventing coking deposit in accordance
with the present invention, the compound should necessarily be added above
0.015% by weight, calculated in terms of boron.
Embodying examples of the boron-containing compounds contain-
ing a high percentage of boron, capable of ~upl)ressing coking deposit, by whichthe present invention is characterized, include boron-co~"~ succinimide,
boron-col~ g succinate ester and the like. The boron-col.l;~ succinimide
includes for example those represented by the following general formulas [2] and
[3].
~ ~ ~ 73895
- 8 -
R3 Cll C~ _ _
~N R4--NH nH [2]
C112 C -- -
1l
R3 CH C~ Cl-l R3
~N R4--N'l nR4 N~ [ 3 ]
CH2- C -- -- C CH2
Z O
where R3 represents a hydrocarbon group with 1 to 50 carbon atoms, R4
represents an aLkylene group with 2 to 5 carbon atoms, and "n" is an integer of 1
to 10; in the compound of the general formula [3], the two R3's may be the same
or di~, clll from each other; the R4's of the number "n" in the general formula
[2] and the R4's of the number "n+ 1 " in the general formula [3] may be the same
or different from each other, respectively; Z represents a boron-containing
substituent, including for example
~OH
~OH ~ B\
B O--B~ B~ O [4]
OH ~ O--B<
bH
More specifically, ECA 5025 (m~nllf~ctured by Exxon Chemical
Co., Ltd.), LUBRIZOL 935 (~ .r~ctured by Lubrizol Co., Ltd.) and the like
may be viewed as illustrative.
Furthermore, boron-cont~ining succiniate esters include for
example those represented by the general formula [5].
21738~
g
f H3 f H3 C H3 11
CH3 C~CH2 C~CH2--CH CH2 CH--C O
,R5 [5 ]
CH3 CH3 CH2 C O
wherein "n" represents an integer of 1 to 20; R5 represents a straight or
branched hydrocarbon group with 2 to 18 carbon atoms, which may contain any
aromatic groups or double bonds; Y and Z are boron-cont~ining substit lçnts,
respectively, at least one of which is bound through a coordinate bond to the
succinate ester).
Specifically, for example, LUBRIZOL 936 (manufactured by
Lubrizol Co., Ltd.) may be viewed as illustrative.
In accordance with the present invention, the effect of adding
boron-cont~ining succinimide and/or boron-cont~inin~ succinate ester is
necessary, and furthermore the amount thereof to be added is extremely critical.
For example, when the boron content is above 0.015% by weight
to a lubricant oil composition having a molybdneum content of 1,000 ppm (as
the ratio by weight), the coking deposit decreases along the steep curve as shown
in Figure 2. The deposit amount rapidly decreases below 100 mg from the
occlusive state.
Therefore, as shown in the figure, no specific adverse effect will be
brought about by the addition thereof above the critical value, but the effect of
decreasing the coking deposit will never be increased in proportion to the
amount thereof to be added.
In the lubricant oil composition of the present invention, the boron-
co~ compound should be blended at such an amount that the content of
the boron derived from the boron-cont~ining compound is above 0.015% by
weight~ l,r~ferably above 0.030% by weight, to the total weight of the composi-
tion.
2i73895
- 10-
When the boron-co~Ail-il-g compound is blended at such an
amount that the content of the boron derived from the boron-cont~inin,e
compound is below 0.015% by weight, the effect of preventing coking deposit is
not s~tisf~ctorily exerted.
In the lubricant oil composition of the present invention, one type
or a combination of two types or more of the boron-col~ compounds may
be used.
The amount of deposit has some relation with the molybdenum
content and the boron content. As shown in the examples described below, the
~uppressive effect of deposit gets higher at a lower molybdenum content,
provided that the boron content is fixed at a given value. Furthermore, the
~upplessive effect of deposit gets higher at a higher boron content, provided that
the molybdenum content is fixed at a given value.
Within the limits not detrimental to the objective of the present
invention, a wide variety of additives conventionally used in lubricant oils, may
be added ap~3rop,iately to the lubricant oil composition of the present invention,
including for example antioxidants, metal cleaning agents, other friction condi-tioners, viscosity index improvers, pour point depressants, defoaming agents,
other wear preventing agents, rust preventives, corrosion inhibitors and the like.
Preferably, these additives have a structure not subject to dehydrogenation
reaction, from the viewpoint of decreasing coking deposit.
Among these additives, the antioxidants in particular are preferable
because the generation of coking deposit can be decreased by suppressing the
progress of radical polymerization. The antioxidants which can be used in the
present invention include for example amine-series antioxidants such as
alkylated diphenyl~mine, phenyl-a-naphthylamine, alkylated a-naphthyl~mine,
and phenol-series antioxidants such as 2,6-di-t-butyl-4-methylphenol, 4,4'-
methylenebis(2,6-di-t-butylphenol), phenol sulfide, etc. These are used general-ly at a ratio of 0.05 to 5% by weight. Among these antioxidants, a phenol-seriesantioxidant with greater radical-ca~lu.h~g function is preferable in particular.
217~89~
1 1
The metal-series cleaning agents include for example calcium
sulfonate, magnesium sulfonate, barium sulfonate, calcium phenate, barium
phPn~te, calcium salicylate, magnesium salicylate and the like, and these may beused generally at a ratio of 0.1 to 5 % by weight.
The friction conditioners include for example polyhydric alcohol
partial ester, amine, amide, sulfide ester and the like.
The viscosity index improvers include for example polymeth-
acrylate-series, polyisobutylene-series, ethylene-propylene copolymer-series,
styrene-butadiene hydrogenated copolymer series and the like, and these may be
used generally at a ratio of 0.5 to 35 % by weight.
The pour point depressants include for example polyalkyl-
methacrylate, chlorinated pa~ -naphthalene cond-Pns~te and the like.
The defoaming agents include for example dimethylpolysiloxane,
polyacrylic acid and the like.
The wear preventing agents include for example thiophosphate
metal salt, thiocarbamate metal salt, sulfur compound, phosphate ester, phosphite
ester and the like, and these may be used generally at a ratio of 0.05 to 5.0 % by
weight.
The rust preventives include for example fatty acid, alkenyl-
succiniate semi-ester, fatty acid soap, alkylsulfonate, fatty acid polyhydric
alcohol ester, fatty acid amine, oxidized paraffin, alkylpolyoxyethylene ether and
the like.
The corrosion inhibitors include for example benzotriazole,
benzoimidazole and the like, th~ 7oles and the like.
The present invention will now be a~parellt from the following
more particular description of the examples, but it will be understood that the
examples do not purport to be wholly definitive with respect to the scope of themventlon.
21738~5
- 12-
In the examples and con-palali~/e examples, herein, the hot tube
cooling test was carried out and ~sessed by means of Hot Tube Coking Test
(HTCT) m~mlf~Ghlred by Komatsu Kabushiki Kaisha. HTCT was carried out as
follows: after passing individual sample oils through a glass tube having a 2 mminner diameter and a 300 mm length at air flow of 10 + 0.5 cc/min., oil flow of
0.31 + 0.01 cc/hour, a temperature of 310C for 16 hours, the glass tube was
washed in n-hexane and dried sufficiently to measure the weight of the coking
deposit attached to the inside of the glass tube.
EXAMPLES 1 TO 7
A lubricant oil composition was prepared such that as a
molybdenum-cont~ining friction conditioner, 1,000 or 1,500 ppm of sulfoxy-
molybdneum-N,N-dioctyl dithocarbamate, calculated in terms of molybdenum,
and as a boron-cont~ining compound, 0.015 to 0.140% by weight of borated
succinimide (LUBRIZOL 935, manufactured by Lubrizol Co., Ltd.), calculated
in terms of boron were contained, respectively, in a base oil (100 Neutral Oil
with a viscosity of 4.4 mm2/s at 100C). The deposit was measured by the hot
tube coking test. The results are shown in Table 1.
The lubricant oil compositions cont~ining 1,000 ppm molybdenum
of Examples 1 to 5 in accordance with the present invention generated less
HTCT coke deposit, which decreased as the increase in the boron content.
Additionally, the lubricant oil compositions having an increased molybdenum
content of 1,500 ppm of Examples 6 and 7 generated less HTCT coke deposit.
However, when the compositions of Examples 3 and 6, both of which have the
same boron content, are con~a~ed with each other and the compositions of
Examples 5 and 7, both of which have the same boron content, are compared
with each other, those of Examples 3 and 5, with a lower molybdenum content,
generated less HTCT coke deposit, which indicates that those with a lower
molyb~lçmlm content in such a range generate less HTCT coke deposit.
2173895
- 13 -
COMPARATIVE EXAMPLE 1
The same procedure was carried out as in Examples 1 to 5, except
that the boron-cont~ining succinimide to be blended was decreased to a content
of 0.013% by weight, calcnl~ted in terms of boron. Then, the HTCT coke
deposit was 211.8 mg in weight, which exceeded the GF-2 standard.
COMPARATIVE EXAMPLE 2
The same procedure was carried out as in Examples 1 to 5, except
that succin~ ide was blended at 3.0% by weight, instead of the boron-co~
succinimide. The resulting composition did not contain boron. Occlusion
occurred at the hot tube coking test.
EXAMPLES 8 TO 13
The same procedure was carried out as in Examples 1 to 7, except
that sulfoxymolybdenum-N,N-ditridecyl dithiocarbamate was used as the
molybdenum-col.t~ il-g friction conditioner, which was blended at a content of
100 and 400 ppm, calc~ ted in terms of molybdenum. The results are shown in
Table 2.
The lubricant oil compositions of Examples 8 to 13 generated less
HTCT coke deposit. The same results are yielded as those in Examples 1 to 7 to
the effect that the increase in the boron content decreased HTCT deposit and a
lower molybdenum content generated less HTCT deposit in such a range,
provided that the boron content was fixed at a given value.
COMPARATIVE EXAMPLE 3
The same procedure was carried out as in Examples 8 and 9,
except that boron-col.~i~il-il-g succi~ nide to be blended was decreased to a
content of 0.013% by weight, calc~ ted in terms of boron. The HTCT coke
deposit was 132.9 mg in weight, which exceeded the GF-2 standard.
2173~
- 14-
EXAMPLES 14 AND 15
The same procedure was carried out as in Examples 1 to 5, except
that boron-co.~ succinate ester (LUBRIZOL 936, manufactured by
Lubrizol Co., Ltd.) was used as the boron-cont~inin~ compound, which was
blended at a content of 0.015 or 0.030% by weight, calculated in terms of boron.The results are shown in Table 3.
EXAMPLES 16 AND 17
The same procedure was calTied out as in Examples 8 and 9,
except that boron-co~ succinate ester (LUBRIZOL 936, manufactured by
Lubrizol Co., Ltd.) was used as the boron-cont~inin~ compound, which was
blended at a content of 0.015 or 0.030% by weight, calculated in terms of boron.The results are shown in Table 4.
All the lubricant oil compositions of Examples 14 to 17 satisfy the
GF-2 standard. However, boron-con~ ing succinimide to be used as the boron-
cont~inin~ compound obtained slightly better results than boron-cont~ining
succiniate ester, provided that the boron content was at a given value.
EXAMPLES 18 TO 26
With respect to the lubricant oil compositions of Examples 1 to 5,
to which was further added an antioxidant, an e~min~tion was made of their
properties.
A lubricant oil composition was pl epared such that as a
molybdenum-co~ friction conditioner, 1,000 ppm of sulfoxymolybdenum-
N,N-dioctyl dithioc&~ te, calculated in terms of molybdenum, and as a
boron-co~ compound, 0.015 to 0.140% by weight of succinimide
(LUBRIZOL 935, m~mlf~ctured by Lubrizol Co., Ltd.) calculated in terms of
boron, and as an antioxidant, 0.7 or 1.4% by weight of phenol sulfide were
cont~ine-l respectively, in a base oil (100 Neutral Oil with a viscosity of
4.4 mm2/s at 100C). The deposit was measured by the hot tube coking test.
The results are shown in Table 5.
21738~1~
- 15 -
Colllp~il~g the results of Examples 18 to 22 with the results of
Examples 1 to 5, it will be noted that the mixtures of the same amounts of the
molybdenum-co~ g friction conditioner and the boron-cont~inin,e compound
generated less HTCT coke deposit through the addition of the antioxidant.
Furthermore, COlll~ g the results of Examples 18 to 22 with the results of the
Examples 23 to 26, it will be noted that less HTCT coke was deposited in the
case of the same amounts of the molybdenum-cont~inin~ friction conditioner and
the boron-col~ -g compound, as the amount of the antioxidant to be added in
such a range was increased. Based on these results, the effect of the antioxidant
were able to be verified in the lubricant oil compositions in accordance with the
present invention.
EXAMPLE 27
Further adding an antioxidant, that is, phenol sulfide at 0.7% by
weight to the compound of Example 14, a lubricant oil composition was
prepa~ed. Then, the hot tube coking test was carried out. The HTCT coke
deposit was 81.6 mg in weight.
EXAMPLE 28
Further adding an antioxidant, that is, phenol sulfide at 0.7% by
weight to the compound of Example 16, a lubricant oil composition was
plel)aled. Then, ~e hot tube coking test was prepared. The HTCT coke deposit
was 5.0 mg in weight.
The lubricant oil compositions of Examples 27 and 28 generated
less HTCT coke deposit than the deposit generated from those with no blend of
~e corresponding antioxidant. In Example 28, in particular, the effect of the
antioxidant was plo~ ent.
As is seen, the lubricant oil compositions of the present invention
are the lubricant oil compositions blended with a molybdenum-cont~ining
friction conditioner and a boron-co.~ -g compound, and are capable of
decreasing coking deposit in internal combustion engines such as automobile
217389~
- 16-
engines, which is advantageous for s~lst~inin~ a fuel-efficiency property for a
long te-m. Hence, the compositions can be used p-efelably for automobile
lubricant oils.
TABLE 1
HTCT
Molybdenum (ppm) Boron (wt%) Deposit (mg)
Example 1 1,000 0.015 82.5
Example 2 1,000 0.030 17.8
Example 3 1,000 0.050 1.8
Example 4 1,000 0.080 1.6
Example 5 1,000 0.140 1.4
Example 6 1,500 0.050 13.7
Example 7 1,500 0.140 1.7
Comparative 1,000 0.013 211 .8
Example 1
Compa~ali~re 1,000 0.000 occluded
Example 2
21~389~
. ..~
- 17-
TABLE 2
HTCT
Molybdenum (ppm) Boron (wt%) Deposit (mg)
Example 8 100 0.015 52.4
Example 9 100 0.030 0.8
Example 10 400 0.015 68.3
Example 11 400 0.030 1.9
Example 12 400 0.050 1.0
Example 13 400 0.140 0.3
Comp~ali~/e 100 0.013 132.9
Example 3
TABLE 3
HTCT
Molybdenum (ppm) Boron (wt%) Deposit (mg)
Example 14 1,000 0.015 93.9
Example 15 1,000 0.030 38.5
TABLE 4
HTCT
Molybdenum (ppm) Boron (wt%) Deposit (mg)
Example 16 100 0.015 66.9
Example 17 100 0.030 8.1
2~7~9~
- 18-
TABLE 5
Molyb~lenl-m BoronAntioxidant HTCT
(ppm) (wt%) (wt%) Deposit (mg)
Example 18 1,000 0.015 0.7 73.2
Example 19 1,000 0.030 0.7 15.6
Example 20 1,000 0.050 0.7 1.6
Example 21 1,000 0.080 0.7 1.3
Example 22 1,000 0.140 0.7 1.2
Example 23 1,000 0.015 1.4 69.8
Example 24 1,000 0.030 1.4 13.7
Example 25 1,000 0.050 1.4 1.3
Example 26 1,000 0.140 1.4 1.1
TABLE 6
Molybdenum BoronAntioxidant HTCT
(ppm) (wt%) (wt%) Deposit(mg)
Example 27 1,000 0.015 0.7 81.6
TABLE 7
Molybdenum BoronAntioxidant HTCT
(ppm) (wt%) (wt%) Deposit (mg)
Example 27 1,000 0.015 0.7 5.0
