U.S. patent application number 17/286644 was filed with the patent office on 2021-12-02 for lubricating oil composition, mechanical device equipped with lubricating oil composition, and method for producing lubricating oil composition.
This patent application is currently assigned to Idemitsu Kosan Co., Ltd.. The applicant listed for this patent is Idemitsu Kosan Co., Ltd.. Invention is credited to Keiichi NARITA.
Application Number | 20210371766 17/286644 |
Document ID | / |
Family ID | 1000005829303 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210371766 |
Kind Code |
A1 |
NARITA; Keiichi |
December 2, 2021 |
LUBRICATING OIL COMPOSITION, MECHANICAL DEVICE EQUIPPED WITH
LUBRICATING OIL COMPOSITION, AND METHOD FOR PRODUCING LUBRICATING
OIL COMPOSITION
Abstract
A lubricating oil composition containing a lubricating base oil
(A), a neutral phosphorus-based compound (B), an acidic
phosphorus-based compound (C), a sulfur-based compound (D) and an
organic molybdenum compound (E).
Inventors: |
NARITA; Keiichi;
(Ichihara-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Idemitsu Kosan Co., Ltd. |
Tokyo |
|
JP |
|
|
Assignee: |
Idemitsu Kosan Co., Ltd.
Chiyoda-ku
JP
|
Family ID: |
1000005829303 |
Appl. No.: |
17/286644 |
Filed: |
October 16, 2019 |
PCT Filed: |
October 16, 2019 |
PCT NO: |
PCT/JP2019/040538 |
371 Date: |
April 19, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 2219/106 20130101;
C10N 2020/02 20130101; C10M 141/12 20130101; C10N 2040/04 20130101;
C10M 169/04 20130101; C10M 139/00 20130101; C10N 2040/08 20130101;
C10M 2223/041 20130101; C10M 2223/04 20130101; C10M 135/36
20130101; C10M 137/04 20130101; C10M 2227/09 20130101 |
International
Class: |
C10M 141/12 20060101
C10M141/12; C10M 169/04 20060101 C10M169/04; C10M 137/04 20060101
C10M137/04; C10M 135/36 20060101 C10M135/36; C10M 139/00 20060101
C10M139/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 23, 2018 |
JP |
2018-199242 |
Claims
1. A lubricating oil composition, comprising a lubricating base oil
(A), a neutral phosphorus-based compound (B), an acidic
phosphorus-based compound (C), a sulfur-based compound (D) and an
organic molybdenum compound (E).
2. The lubricating oil composition according to claim 1, wherein
the organic molybdenum compound (E) is a compound represented by
the following formula (1) ##STR00005## wherein R.sup.1 to R.sup.4
are each independently a hydrocarbon group having 4 to 18 carbon
atoms, and X.sup.1 to X.sup.4 are each independently an oxygen atom
or a sulfur atom.
3. The lubricating oil composition according to claim 2, wherein
R.sup.1 to R.sup.4 are each independently an alkyl group having 4
to 18 carbon atoms, an alkenyl group having 4 to 18 carbon atoms, a
cycloalkyl group having 4 to 18 carbon atoms, an aryl group having
6 to 18 carbon atoms, an alkylaryl group having 7 to 18 carbon
atoms or an arylalkyl group having 7 to 18 carbon atoms.
4. The lubricating oil composition according to claim 1, wherein a
content of the organic molybdenum compound (E) is 0.01 mass % or
more and 1.0 mass % or less based on a total amount of the
lubricating oil composition.
5. The lubricating oil composition according to claim 1, wherein a
flash point of the lubricating base oil (A) is 172.degree. C. or
higher.
6-7. (canceled)
8. A mechanical device, comprising the lubricating oil composition
according to claim 1.
9. The mechanical device according to claim 8, wherein the
mechanical device is a hydraulic device, a stationary transmission
device, an automobile transmission device or a cooling device of a
motor/battery.
10. A method for producing a lubricating oil composition,
comprising mixing a lubricating base oil (A), a neutral
phosphorus-based compound (B), an acidic phosphorus-based compound
(C), a sulfur-based compound (D) and an organic molybdenum compound
(E).
11. A method of lubricating a mechanical device, comprising
contacting the mechanical device with the lubricating oil
composition according to claim 1.
12. The method of lubricating a mechanical device according to
claim 11, wherein the mechanical device is a hydraulic device, a
stationary transmission device, an automobile transmission device
or a cooling device of a motor/battery.
Description
TECHNICAL FIELD
[0001] The present invention relates to a lubricating oil
composition, a mechanical device including the lubricating oil
composition, and a method for producing the lubricating oil
composition.
BACKGROUND ART
[0002] In recent years, reduction of carbon dioxide has been
strongly required from the viewpoint of protection of the global
environment, and thus efforts have been put into development of a
fuel saving technology in the field of automobile. Examples of a
fuel saving automobile include a hybrid automobile and an electric
automobile, and it is expected that these automobiles will rapidly
become widespread in the future. A hybrid automobile and an
electric automobile are provided with an electric motor, a
generator, an inverter, a storage battery etc., and travel by
utilizing power generated by an electric motor.
[0003] For cooling of an electric motor and a generator in such a
hybrid automobile and an electric automobile, existing automatic
transmission fluid (hereinafter, referred to as ATF) and
continuously variable transmission fluid (hereinafter, referred to
as CVTF) are primarily used. Since some hybrid automobiles and
electric automobiles are in the form of those having gear reducers,
a lubricating oil composition is required to have both cooling
ability and lubricating ability.
[0004] Therefore, a lubricating oil composition has been proposed
which is obtained by blending a base oil, a neutral
phosphorus-based compound, at least one acidic phosphorus-based
compound selected from a group consisting of an amine salt of an
acidic phosphoric acid ester having a specified structure and an
acidic phosphorous acid ester having a specified structure, and a
sulfur-based compound (Patent Literature 1: International
publication No. WO11/080970).
CITATION LIST
Patent Literature
[0005] Patent Literature 1 [0006] International Publication No.
WO11/080970
SUMMARY OF INVENTION
Technical Problem
[0007] However, although volume resistivity, abrasion resistance
between metals and solubility were improved in the lubricating oil
composition described in Patent Literature 1, a lubricating oil
composition satisfying all of abrasion resistance, seizure
resistance and low friction at a higher level is required.
Furthermore, a lubricating oil composition having even higher
cooling ability is also required.
Solution to Problem
[0008] Therefore, the present inventors have solved the problem to
be solved by the present invention by further adding an organic
molybdenum compound to a lubricating oil composition comprising a
base oil, a neutral phosphorus-based compound, an acidic
phosphorus-based compound and a sulfur-based compound.
[0009] The present invention comprises the inventions of the
following aspects.
[0010] [1]
[0011] A lubricating oil composition, comprising a lubricating base
oil (A), a neutral phosphorus-based compound (B), an acidic
phosphorus-based compound (C), a sulfur-based compound (D) and an
organic molybdenum compound (E).
[0012] [2]
[0013] A mechanical device, comprising the lubricating oil
composition according to [1].
[0014] [3]
[0015] A method for producing a lubricating oil composition,
comprising a step of mixing a lubricating base oil (A), a neutral
phosphorus-based compound (B), an acidic phosphorus-based compound
(C), a sulfur-based compound (D) and an organic molybdenum compound
(E).
Advantageous Effects of Invention
[0016] The lubricating oil composition according to an aspect of
the present invention exhibits excellent properties with respect to
all of abrasion resistance, seizure resistance, and low friction.
The lubricating oil composition according to an aspect of the
present invention further has an excellent cooling ability.
DESCRIPTION OF EMBODIMENTS
[0017] Hereinafter, the embodiments of the present invention will
be described in detail. The present invention is not limited to the
following embodiments, and optionally changes may be made in the
range without departing from the gist of the invention to practice
the present invention. All documents and publications cited in the
present specification are incorporated herein by reference in their
entirety regardless of the purpose.
[0018] The lubricating oil composition of the present invention
comprises a lubricating base oil (A), a neutral phosphorus-based
compound (B), an acidic phosphorus-based compound (C), a
sulfur-based compound (D) and an organic molybdenum compound
(E).
[0019] In the lubricating oil composition of the present invention,
the total content of a lubricating base oil (A), a neutral
phosphorus-based compound (B), an acidic phosphorus-based compound
(C), a sulfur-based compound (D) and an organic molybdenum compound
(E) is preferably 70 mass % or more, more preferably 80 mass % or
more, still more preferably 85 mass % or more, even more preferably
90 mass % or more based on the total amount of the composition.
[0020] Hereinafter, each component contained in the lubricating oil
composition will be described in detail.
[0021] [Lubricating base oil (A)]
[0022] The lubricating base oil (A) (hereinafter, also simply
referred to as "base oil") contained in the lubricating oil
composition is not particularly limited as long as it is an oil
having lubricity, and may be a mineral oil or a synthetic oil. The
types of these base oils are not particularly limited, and any type
of oil may be appropriately selected from mineral oils and
synthetic oils which are conventionally used as a base oil of a
lubricating oil for a transmission for an automobile, and may be
used.
[0023] Examples of mineral oils include, for example, a refined
mineral oil or a wax obtained by refining a lubricating oil
fraction obtained by reduced-pressure distillation of an
atmospheric residue obtained by atmospheric pressure distillation
of crude oil, using one or more treatment process of solvent
deasphalting, solvent extraction, hydrocracking, solvent dewaxing,
contact dewaxing, hydrorefining etc.; and a mineral oil (GTL)
produced by isomerizing GTL WAX (gas-to-liquid wax) produced from
natural gas by Fischer Tropsh process. Among these, a refined
mineral oil obtained by treatment process of hydrorefining and a
mineral oil (GTL) produced by isomerizing GTL WAX are preferable
from the viewpoint of % C.sub.p and viscosity index described
below.
[0024] Examples of synthetic oils include, for example, polybutene;
poly-.alpha.-olefins such as an .alpha.-olefin homopolymer and an
.alpha.-olefin copolymer (for example, ethylene-.alpha.-olefin
copolymer); various esters such as a polyol ester, a dibasic acid
ester and a phosphoric acid ester; various ethers such as
polyphenyl ether; polyglycol; alkylbenzene; and alkylnaphthalene.
Among these synthetic oils, poly-.alpha.-olefins and esters are
preferable. These synthetic oils may be used alone or in
combination of two or more.
[0025] The above base oil may contain one mineral oil or may
contain two or more mineral oils. For the base oil, one synthetic
oil may be used, or two or more synthetic oils may be used in
combination. The above base oil may contain one or more mineral
oils and one or more synthetic oils.
[0026] The base oil is a main component of the lubricating oil
composition, and the content of the base oil is usually preferably
65-98 mass %, more preferably 70-97 mass %, still more preferably
75-96 mass % based on the total amount of the composition.
[0027] Although the flash point of the lubricating base oil (A) is
not limited, it is preferable to use a base oil having a high flash
point since the obtained lubricating oil composition tends to also
have a higher flash point. Specifically, the flash point of the
lubricating base oil (A) is preferably 172.degree. C. or higher,
still more preferably the flash point is 174.degree. C. or higher,
particularly preferably the flash point is 176.degree. C. or
higher. When the lubricating base oil (A) contains more than one
mineral oils or synthetic oils etc., all of these mineral oils or
synthetic oils are not required to have a flash point of
172.degree. C. or higher, but it is sufficient that the lubricating
base oil (A) obtained by mixing these oils has a flash point of
172.degree. C. or higher.
[0028] The flash point as used herein means the value obtained by
measurement using COC method according to JIS-K-2265-4.
[0029] The viscosity of the base oil is not particularly limited,
and the kinetic viscosity at a temperature of 100.degree. C. is
preferably 21-30 mm.sup.2/s, more preferably 21.5-15 mm.sup.2/s,
still more preferably 2-10 mm.sup.2/s though it varies depending on
the intended use of the lubricating oil composition. When the
kinetic viscosity at 100.degree. C. is 2 mm.sup.2/s or more,
vaporization loss is lower. When the kinetic viscosity is 30
mm.sup.2/s or less, power loss due to viscous resistance is lower,
which results in the effect of improvement of fuel efficiency.
[0030] The kinetic viscosity of the base oil at 40.degree. C. is
not particularly limited, and preferably 5-65 mm.sup.2/s, more
preferably 8-40 mm.sup.2/s, still more preferably 10-25 mm.sup.2/s.
When the kinetic viscosity at 40.degree. C. is 5 mm.sup.2/s or
more, vaporization loss is lower. When the kinetic viscosity is 65
mm.sup.2/s or less, power loss due to viscous resistance is lower,
which results in the effect of improvement of fuel efficiency.
[0031] Herein, "kinetic viscosity at 100.degree. C." and "kinetic
viscosity at 40.degree. C." can be measured by the method according
to JIS-K-2283:2000. When the lubricating base oil (A) contains two
or more oils, "kinetic viscosity at 100.degree. C." and "kinetic
viscosity at 40.degree. C." mean the kinetic viscosity of the whole
mixed base oil.
[0032] The viscosity index of the base oil is not particularly
limited, and preferably 70 or more, more preferably 80 or more,
still more preferably 90 or more. In the base oil having the above
viscosity index of 70 or more, viscosity change due to temperature
change is smaller. When the viscosity index of the base oil is
within the above range, better viscosity properties of the
lubricating oil composition can be obtained, and the effect of
improvement of fuel efficiency can be obtained. Herein, "viscosity
index" can be calculated by the method according to
JIS-K-2283:2000.
[0033] The content of aromatic moieties (% C.sub.A) of the base oil
obtained by ring analysis and the sulfur content are not
particularly limited, and the base oil having % C.sub.A of 3.0 or
less and the sulfur content of 10 mass ppm or less is preferably
used. In this context, % C.sub.A obtained by ring analysis refers
to a ratio of aromatic moieties (percentage) calculated by the ring
analysis n-d-M method in which measurement is conducted according
to ASTM D 3238. The base oil having the above % C.sub.A of 3.0 or
less and the sulfur content of 10 mass ppm or less can provide a
lubricating oil composition having good oxidation stability and
capable of suppressing increase in acid value and production of
sludge. More preferably % C.sub.A is 1.0 or less, still more
preferably % C.sub.A is 0.5 or less. More preferably the sulfur
content is 7 mass ppm or less, still more preferably the sulfur
content is 5 mass ppm or less.
[0034] The paraffin content (% C.sub.p) of the base oil obtained by
ring analysis is not particularly limited, and preferably 70 or
more, more preferably 75 or more, still more preferably 79 or more.
When the above % C.sub.p is 70 or more, the oxidation stability of
the base oil is better. The upper limit of % C.sub.p is not
particularly limited, and is for example 98 or less. In this
context, % C.sub.p obtained by ring analysis refers to a ratio of
paraffin component (percentage) calculated by the ring analysis
n-d-M method in which measurement is conducted according to ASTM D
3238.
[0035] NOACK evaporation amount of the base oil is not particularly
limited, and preferably 15.0 mass % or less, more preferably 14.0
mass % or less, more preferably 13.0 mass % or less. NOACK
evaporation amount can be measured according to ASTM D 5800
(250.degree. C., 1 hour).
[0036] [Neutral Phosphorus-Based Compound (B)]
[0037] The neutral phosphorus-based compound (B) is added for the
purpose of improving the abrasion resistance between metals. The
abrasion resistance between metals cannot be enhanced without using
the neutral phosphorus-based compound (B).
[0038] The neutral phosphorus-based compound (B) is not
particularly limited as long as it is a compound which is neutral
and contains a phosphorus atom, but a compound represented by the
following general formula (2) or (3) is preferably used.
##STR00001##
[0039] In the above general formulae (2) and (3), hydrocarbon
groups R.sup.5, R.sup.6 and R.sup.7 each independently represent an
aryl group having 6 to 30 carbon atoms, an alkyl group having 1 to
30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
preferably an aryl group having 8 to 28 carbon atoms, an alkyl
group having 2 to 28 carbon atoms or an alkenyl group having 4 to
28 carbon atoms, still more preferably represent an aryl group
having 10 to 26 carbon atoms, an alkyl group having 4 to 26 carbon
atoms or an alkenyl group having 6 to 26 carbon atoms, and
particularly preferably an aryl group having 12 to 24 carbon atoms,
an alkyl group having 6 to 24 carbon atoms or an alkenyl group
having 6 to 24 carbon atoms. R.sup.5, R.sup.6 and R.sup.7 may be
the same or may be different.
[0040] Examples of the neutral phosphorus-based compound (B)
include, for example, neutral aromatic phosphoric acid esters such
as tricresyl phosphate, triphenyl phosphate, trixylenyl phosphate,
tricresylphenyl phosphate, tricresyl thiophosphate and triphenyl
thiophosphate; neutral aliphatic phosphoric esters such as tributyl
phosphate, tri(2-ethylhexyl) phosphate, tributoxy phosphate and
tributyl thiophosphate; neutral aromatic phosphite esters such as
triphenyl phosphite, tricresyl phosphite, trisnonylphenyl
phosphite, diphenyl mono(2-ethylhexyl) phosphite, diphenyl
monotridecyl phosphite, tricresyl thiophosphite and triphenyl
thiophosphite; and neutral aliphatic phosphorous esters such as
tributyl phosphite, trioctyl phosphite, trisdecyl phosphite,
tris(trydecyl) phosphite, trioleyl phosphite, tributyl
thiophosphite and trioctyl thiophosphite. Among these neutral
phosphorus-based compounds, neutral aromatic phosphoric acid
esters, neutral aliphatic phosphoric acid esters etc. are
preferably used from the viewpoint of abrasion resistance between
metals. Furthermore, these neutral phosphorus-based compounds may
be used alone or may be used in combination of two or more.
[0041] The content of the neutral phosphorus-based compound (B) in
the lubricating oil composition is preferably 2.5 mass % or less,
more preferably 0.12 mass % or more and 2.5 mass % or less,
particularly preferably 0.25 mass % or more and 1.3 mass % or less
based on the total amount of the composition. When the content of
the phosphorus-based compound (B) is 0.12 mass % or more based on
the total amount of the composition, abrasion resistance between
metals provided by the lubricating oil composition can be further
enhanced. On the other hand, when the content of the neutral
phosphorus-based compound (B) is 2.5 mass % or less based on the
total amount of the composition, solubility of the neutral
phosphorus-based compound (B) to the base oil can be enhanced.
[0042] The content of the neutral phosphorus-based compound (B) in
terms of phosphorus atom is preferably 2000 mass ppm or less, more
preferably 100 mass ppm or more and 2000 mass ppm or less,
particularly preferably 200 mass ppm or more and 1000 mass ppm or
less based on the total amount of the composition. When the content
of the neutral phosphorus-based compound (B) in terms of phosphorus
atom is 2000 mass ppm or less based on the total amount of the
composition, solubility of the neutral phosphorus-based compound
(B) to the base oil can be enhanced. When the content of the
neutral phosphorus-based compound (B) in terms of phosphorus atom
is 100 mass ppm or more based on the total amount of the
composition, abrasion resistance between metals provided by the
lubricating oil composition can be further enhanced.
[0043] Herein, the content of phosphorus atom means the value
obtained by measurement according to JPI-5S-38-92.
[0044] [Acidic Phosphorus-Based Compound (C)]
[0045] The acidic phosphorus-based compound (C) is added for the
purpose of enhancement of seizure resistance. When the acidic
phosphorus-based compound (C) is not used, seizure resistance
cannot be enhanced.
[0046] The acidic phosphorus-based compound (C) is not particularly
limited as long as it is a compound which is acidic and contains a
phosphorus atom, but is preferably at least one acidic
phosphorus-based compound selected from the group consisting of
acidic phosphoric acid esters represented by the following general
formula (4) and the group consisting of acidic phosphorous acid
esters represented by the following general formula (5).
##STR00002##
[0047] In the above general formula (4) and the above general
formula (5), R.sup.8 and R.sup.9 represent a hydrogen atom or a
hydrocarbon group having 8 to 30 carbon atoms. R.sup.8 and R.sup.9
may be the same or may be different. At least one of R.sup.8 and
R.sup.9 is a hydrocarbon group having 8 to 30 carbon atoms,
preferably both of them are hydrocarbon groups having 8 to 30
carbon atoms, still more preferably 10 to 28 carbon atoms,
particularly preferably 12 to 26 carbon atoms. When the number of
carbon atoms in the above hydrocarbon group is 8 or more, oxidation
stability of the lubricating oil composition enhances, and on the
other hand, when the number or carbon atoms in the above
hydrocarbon group is 30 or less, seizure resistance between metals
becomes satisfactory. Examples of hydrocarbon groups of R.sup.8 and
R.sup.9 include, for example, an alkyl group, an alkenyl group, an
aryl group, an alkylaryl group and arylalkyl group.
[0048] Examples of acidic phosphoric acid esters represented by the
above general formula (4) and amine salts thereof include, for
example, acidic aliphatic phosphoric acid esters such as
di-2-ethylhexyl acid phosphate, dilauryl acid phosphate and dioleyl
acid phosphate; acidic aromatic phosphoric acid esters such as
diphenyl acid phosphate and dicresyl acid phosphate; and
sulfur-containing acidic phosphoric acid esters such as S-octyl
thioethyl acid phosphate and S-dodecyl thioethyl acid phosphate.
These acidic phosphoric acid esters and amine salts thereof may be
used alone or may be used in combination of two or more.
[0049] Examples of acidic phosphorous acid esters represented by
the above general formula (5) and amine salts thereof include, for
example, acidic aliphatic phosphorous acid esters such as dibutyl
hydrogen phosphite, di-2-ethylhexyl hydrogen phosphite, dilauryl
hydrogen phosphite and dioleyl hydrogen phosphite; acidic aromatic
phosphite esters such as diphenyl hydrogen phosphite and dicresyl
hydrogen phosphite; and sulfur-containing acidic phosphorous acid
esters such as S-octyl thioethyl hydrogen phosphite and S-dodecyl
thioethyl hydrogen phosphite. The lubricating oil composition may
contain these acidic phosphorous acid esters as amine salts
thereof. These acidic phosphorous acid esters and amine salts
thereof may be used alone or may be used in combination of two or
more.
[0050] In the lubricating oil composition, the content of the
acidic phosphorus-based compound (C) is preferably 0.8 mass % or
less, more preferably 0.1 mass % or more and 0.8 mass % or less,
particularly preferably 0.1 mass % or more and 0.5 mass % or less
based on the total amount of the composition. When the content of
the acidic phosphorus-based compound (C) is 0.8 mass % or less
based on the total amount of the composition, volume resistivity of
the lubricating oil composition may become satisfactory. When the
content of the acidic phosphorus-based compound (C) is 0.1 mass %
or more based on the total amount of the composition, seizure
resistance between metals provided by the lubricating oil
composition can be further enhanced.
[0051] The content of the acidic phosphorus-based compound (C) in
terms of phosphorus atom is preferably 400 mass ppm or less, more
preferably 50 mass ppm or more and 400 mass ppm or less,
particularly preferably 50 mass ppm or more and 250 mass ppm or
less based on the total amount of the composition. When the content
of the acidic phosphorus-based compound (C) in terms of phosphorus
atom is 400 mass ppm or less based on the total amount of the
composition, volume resistivity of the lubricating oil composition
may become satisfactory. When the content of the acidic
phosphorus-based compound (C) in terms of phosphorus atom is 50
mass ppm or more based on the total amount of the composition,
abrasion resistance between metals provided by the lubricating oil
composition may be further enhanced.
[0052] [Sulfur-Based Compound (D)]
[0053] The sulfur-based compound (D) is added for the purpose of
enhancement of seizure resistance. When the sulfur-based compound
(D) is not used, seizure resistance may not be enhanced.
[0054] The sulfur-based compound (D) is not particularly limited as
long as it is a compound which contains a sulfur atom. As the
sulfur-based compound (D), a known compound can be used, but
specifically, a thiadiazole-based compound, a polysulfide-based
compound, a thiocarbamate-based compound, a sulfurized fat and
oil-based compound, a sulfurized olefin-based compound etc. can be
exemplified. Among these sulfur-based compounds, a
thiadiazole-based compound and a polysulfide-based compound are
preferable from the viewpoint of seizure resistance between metals
and abrasion resistance between metals. These sulfur-based
compounds may be used alone or may be used in combination of two or
more.
[0055] As the above thiadiazole-based compound, a known compound
can be used as necessary, but for example, a compound represented
by the following general formula (6) can be exemplified.
##STR00003##
[0056] In the above general formula (6), R.sup.10 and R.sup.11 each
independently represent an alkyl group having 1 to 30 carbon atoms,
but are preferably alkyl groups having 6 to 20 carbon atoms, still
more preferably alkyl groups having 8 to 18 carbon atoms. The alkyl
group may be linear or branched. R.sup.10 and R.sup.11 may be the
same or may be different. X1 and X2 each independently represent an
integer of 1 to 3, and refer to the number of sulfur atoms, but a
compound having the number of sulfur atoms of 2 is preferably
used.
[0057] As a thiadiazole-based compound represented by the above
general formula (6), 2,5-bis(n-hexyldithio)-1,3,4-thiadiazole,
2,5-bis(n-octyldithio)-1,3,4-thiadiazole,
2,5-bis(n-nonyldithio)-1,3,4-thiadiazole,
2,5-bis(1,1,3,3-tetramethylbutyldithio)-1,3,4-thiadiazole,
3,5-bis(n-hexyldithio)-1,2,4-thiadiazole,
3,6-bis(n-octyldithio)-1,2,4-thiadiazole,
3,5-bis(n-nonyldithio)-1,2,4-thiadiazole,
3,5-bis(1,1,3,3-tetramethylbutyldithio)-1,2,4-thiadiazole,
4,5-bis(n-octyldithio)-1,2,3-thiadiazole,
4,5-bis(n-nonyldithio)-1,2,3-thiadiazole and
4,5-bis(1,1,3,3-tetramethylbutyldithio)-1,2,3-thiadiazole are
preferable, 2,5-bis(n-hexyldithio)-1,3,4-thiadiazole,
2,5-bis(n-octyldithio)-1,3,4-thiadiazole,
2,5-bis(n-nonyldithio)-1,3,4-thiadiazole and
2,5-bis(1,1,3,3-tetramethylbutyldithio)-1,3,4-thiadiazole are more
preferable, and
2,5-bis(1,1,3,3-tetramethylbutyldithio)-1,3,4-thiadiazole is
particularly preferable.
[0058] As the above polysulfide-based compound, a known compound
can be used as necessary, but for example, a compound represented
by the following general formula (7) can be exemplified.
R.sup.12--(S).sub.y--R.sup.13 (7)
[0059] In the above general formula (7), R.sup.12 and R.sup.13 each
independently represent an alkyl group having 1 to 24 carbon atoms,
an aryl group having 6 to 20 carbon atoms or an alkylaryl group
having 7 to 20 carbon atoms. The number of carbon atoms in the
alkyl group is preferably 3 or more and 20 or less, still more
preferably 6 or more and 16 or less. The number of carbon atoms in
the aryl group is preferably 6 or more and 20 or less, still more
preferably 6 or more and 16 or less. The number of carbon atoms in
the alkylaryl group is preferably 8 or more and 20 or less, still
more preferably 9 or more and 18 or less. R.sup.12 and R.sup.13 may
be the same or may be different.
[0060] Y represents the number of sulfur atoms, and is preferably
an integer of 2 or more and 8 or less taking into consideration of
abrasion resistance, fatigue life, availability and corrosion,
etc., more preferably an integer of 2 or more and 7 or less, still
more preferably an integer of 2 or more and 6 or less.
[0061] Examples of a group represented by R.sup.12 and R.sup.13
include aryl groups such as a phenyl group, a naphthyl group, a
benzyl group, a tolyl group and a xyl group; and alkyl groups such
as a methyl group, an ethyl group, a propyl group, a butyl group, a
pentyl group, a hexyl group, a heptyl group, an octyl group, a
nonyl group, a decyl group, a dodecyl group, a cyclohexyl group and
a cyclooctyl group. These groups may be linear or branched. These
groups may be used alone or may be used in combination of two or
more.
[0062] Among the polysulfide-based compounds represented by the
above general formula (7), dibenzyl polysulfide, di-tert-nonyl
polysulfide, didodecyl polysulfide, di-tert-butyl polysulfide,
dioctyl polysulfide, diphenyl polysulfide and dicyclohexyl
polysulfide are more preferred, and disulfides of these compounds
are particularly preferred.
[0063] In the lubricating oil composition, the content of the
sulfur-based compound (D) is preferably 0.3 mass % or less, more
preferably 0.03 mass % or more and 0.3 mass % or less, particularly
preferably 0.03 mass % or more and 0.15 mass % or less based on the
total amount of the composition. When the content of the
sulfur-based compound (D) is 0.3 mass % or less based on the total
amount of the composition, volume resistivity of the lubricating
oil composition can be expected to be maintained. When the content
of the sulfur-based compound (D) is 0.03 mass % or more based on
the total amount of the composition, seizure resistance between
metals provided by the lubricating oil composition can be further
enhanced.
[0064] The content of the sulfur-based compound (D) in terms of
sulfur atom preferably 1000 mass ppm or less based on the total
amount of the composition, more preferably 125 mass ppm or more and
1000 mass ppm or less and furthermore, particularly preferably 125
mass ppm or more and 500 mass ppm or less from the viewpoint of
achievement of both volume resistivity and seizure resistance of
the lubricating oil composition. When the content of the
sulfur-based compound (D) in terms of sulfur atom is 1000 mass ppm
or less based on the total amount of the composition, volume
resistivity of the lubricating oil composition can be expected to
allow to be maintained. When the content of the sulfur-based
compound (D) in terms of sulfur atom is 125 mass ppm or more based
on the total amount of the composition, seizure resistance between
metals provided by the lubricating oil composition can be further
enhanced.
[0065] As used herein, the content of sulfur refers to the value
obtained by measurement according to JIS K2541-6.
[0066] [Organic Molybdenum Compound (E)]
[0067] The lubricating oil composition is characterized in that it
further contains the organic molybdenum compound (E) in addition to
the lubricating base oil (A), the neutral phosphorus-based compound
(B), the acidic phosphorus-based compound (C) and the sulfur-based
compound (D). By adding the organic molybdenum compound (E), the
lubricating oil composition can provide low friction in addition to
seizure resistance and abrasion resistance. When the organic
molybdenum compound (E) is not used, low friction may not be
provided.
[0068] As the molybdenum-based friction modifier (E), any organic
compound having a molybdenum atom can be used, but the organic
compound represented by formula (1) is preferable.
##STR00004##
[0069] In formula (1), R.sup.1 to R.sup.4 are each independently a
hydrocarbon group having 4 to 18 carbon atoms, preferably an alkyl
group having 4 to 18 carbon atoms, an alkenyl group having 4 to 18
carbon atoms, a cycloalkyl group having 4 to 18 carbon atoms, an
aryl group having 6 to 18 carbon atoms, an alkylaryl group having 7
to 18 carbon atoms or an arylalkyl group having 7 to 18 carbon
atoms.
[0070] Examples of hydrocarbon group of R.sup.1 to R.sup.4 include,
for example, alkyl groups having 5 to 18 carbon atoms such as
pentyl group, hexyl group, heptyl group, octyl group, nonyl group,
decyl group, undecyl group, dodecyl group, tridecyl group,
tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl
group and octadecyl group; alkenyl groups having 5 to 18 carbon
atoms such as octenyl group, nonenyl group, decenyl group,
undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl
group and pentadecenyl group; cycloalkyl groups having 5 to 18
carbon atoms such as a cyclohexyl group, a dimethylcyclohexyl
group, an ethylcyclohexyl group, a methylcyclohexylmethyl group, a
cyclohexylethyl group, a propylcyclohexyl group, a butylcyclohexyl
group and a heptylcyclohexyl group; aryl groups having 6 to 18
carbon atoms such as a phenyl group, a naphthyl group, an
anthracenyl group, a biphenyl group and a terphenyl group;
alkylaryl groups such as a tolyl group, a dimethylphenyl group, a
butylphenyl group, a nonylphenyl group, a methylbenzyl group and a
dimethylnaphthyl group; and arylalkyl groups having 7 to 18 carbon
atoms such as a phenylmethyl group, a phenylethyl group and a
diphenylmethyl group.
[0071] In formula (1), X.sup.1 to X.sup.4 are each independently an
oxygen atom or a sulfur atom. The molar ratio of sulfur atoms to
oxygen atoms [sulfur atoms/oxygen atoms] in X.sup.1 to X.sup.4 is
preferably 1/3-3/1, more preferably 1.5/2.5-3/1 from the viewpoint
of enhancement of solubility to the lubricating base oil (A).
[0072] In the lubricating oil composition, the content of the
organic molybdenum compound (E) is preferably 0.01 mass % or more
and 1.0 mass % or less, still more preferably 0.1 mass % or more
and 0.9 mass % or less, particularly preferably 0.2 mass % or more
and 0.8 mass % or less based on the total amount of the lubricating
oil composition from the viewpoint of achievement of low friction
of the lubricating oil composition.
[0073] The ratio of the content (mass %) of the sulfur-based
compound (D) to the content of the organic molybdenum compound (E)
(sulfur-based compound (D)/organic molybdenum compound (E)) is
preferably within the range of 1-10, since low friction of the
lubricating oil composition is enhanced.
[0074] The ratio of the total content(mass %) of the acidic
phosphorus-based compound (C) and the sulfur-based compound (D) to
the content (mass %) of the organic molybdenum compound (E)
((acidic phosphorus-based compound (C)+sulfur-based compound
(D))/organic molybdenum compound (E)) is preferably within the
range of 0.3-1, since abrasion resistance of the lubricating oil
composition is enhanced.
[0075] [Additives]
[0076] A viscosity index enhancer, a detergent dispersant, an
antioxidant, a metal deactivator, an anti-rust agent, a
surfactant/demulsifying agent, an anti-foaming agent, a corrosion
inhibitor, an oiliness improver, an acid scavenger, etc. can be
appropriately added to the lubricating oil composition within the
range not inhibiting the effect of the present invention.
[0077] Examples of a viscosity index enhancer include, for example,
a non-dispersion type polymethacrylate, a dispersion type
polymethacrylate, an olefin-based copolymer, a dispersion type
olefin-based copolymer and a styrene-based copolymer. The mass
average molecular weight of these viscosity index enhancers is
preferably 5000 or more and 300000 or less for a dispersion type
and a non-dispersion type polymethacrylate, for example. For an
olefin-based copolymer, the mass average molecular weight is
preferably 800 or more and 100000 or less. These viscosity index
enhancers may be used alone or may be used in combination of two or
more. The amount of the viscosity index enhancer to be added is not
particularly limited, and preferably 0.5 mass % or more and 15 mass
% or less, more preferably 1 mass % or more and 10 mass % or less
based on the total amount of the composition.
[0078] As a detergent dispersant, an ashless dispersant and a
metal-based detergent dispersant can be used.
[0079] Examples of an ashless dispersant include, for example, a
succinimide compound, a boron-based imide compound, a Mannich
dispersant and an acid amide-based compound. These may be used
alone or may be used in combination of two or more. The amount of
an ashless dispersant to be added is not particularly limited, and
is preferably 0.1 mass % or more and 20 mass % or less based on the
total amount of the composition.
[0080] Examples of a metal-based detergent dispersant include, for
example, an alkali metal sulfonate, an alkali metal phenate, an
alkali metal salicylate, an alkali metal naphthenate, an alkali
earth metal sulfonate, an alkali earth metal phenate, an alkali
earth metal salicylate and an alkali earth metal naphthenate. These
may be used alone or may be used in combination of two or more. The
amount of a metal-based detergent dispersant to be added is not
particularly limited, and is preferably 0.1 mass % or more and 10
mass % or less based on the total amount of the composition.
[0081] Examples of an antioxidant include, for example, an
amine-based antioxidant, phenol-based antioxidant and sulfur-based
antioxidant. These may be used alone or may be used in combination
of two or more. The amount of an antioxidant to be added is not
particularly limited, and preferably 0.05 mass % or more and 7 mass
% or less based on the total amount of the composition.
[0082] Examples of a pour point depressant include a
polymethacrylate, an ethylene-vinyl acetate copolymer, a condensate
of chlorinated paraffin and naphthalene, a condensate of
chlorinated paraffin and phenol, a polyalkylstyrene and a
poly(meth)acrylate. The mass average molecular weight (Mw) of the
pour point depressant is preferably 20,000-100,000, more preferably
30,000-80,000, still more preferably 40,000-60,000. The molecular
weight distribution (Mw/Mn) is preferably 5 or less, more
preferably 3 or less, still more preferably 2 or less. The content
of a pour point depressant may be appropriately determined
depending on the desired MRV viscosity etc., and is preferably 0.01
mass % or more and 5 mass % or less, more preferably 0.02 mass % or
more and 2 mass % or less based on the total amount of the
composition.
[0083] Examples of the metal deactivator include, for example, a
benzotriazole-based metal deactivator, a tolyltriazole-based metal
deactivator, a thiadiazole-based metaldeactivator and an
imidazole-based metal deactivator. These may be used alone or may
be used in combination of two or more. The amount of the metal
deactivator to be added is not particularly limited, and is
preferably 0.01 mass % or more and 3 mass % or less, more
preferably 0.01 mass % or more and 1 mass % or less based on the
total amount of the composition.
[0084] Examples of the anti-rust agent include, for example, a
petroleum sulfonate, an alkylbenzene sulfonate, a
dinonylnaphthalene sulfonate, an alkenylsuccinate ester and a
polyhydric alcohol ester. These may be used alone or may be used in
combination of two or more. The amount of the anti-rust agent to be
added is not particularly limited, and preferably 0.01 mass % or
more and 1 mass % or less, more preferably 0.05 mass % or more and
0.5 mass % or less based on the total amount of the
composition.
[0085] Examples of a surfactant/demulsifying agent include, for
example, a polyalkylene glycol-based nonionic surfactant.
Specifically, polyoxyethylene alkyl ether, polyoxyethylene
alkylphenyl ether and polyoxyethylene alkylnaphthyl ether can be
exemplified. These may be used alone or may be used in combination
of two or more. The amount of the surfactant to be added is not
particularly limited, and is preferably 0.01 mass % or more and 3
mass % or less, more preferably 0.01 mass % or more and 1 mass % or
less based on the total amount of the composition.
[0086] Examples of an anti-foaming agent include, for example, a
fluorosilicone oil and a fluoroalkyl ether. These may be used alone
or may be used in combination of two or more. The amount of the
anti-foaming agent to be added is not particularly limited, and is
preferably 0.005 mass % or more and 0.5 mass % or less, more
preferably 0.01 mass % or more and 0.2 mass % or less based on the
total amount of the composition.
[0087] Examples of the corrosion inhibitor include, for example, a
benzotriazole-based corrosion inhibitor, a benzimidazole-based
corrosion inhibitor, a benzothiazole-based corrosion inhibitor and
a thiadiazole-based corrosion inhibitor. These may be used alone or
may be used in combination of two or more. The amount of the
corrosion inhibitor to be added is not particularly limited, and is
preferably within the range of 0.01 mass % or more and 1 mass % or
less based on the total amount of the composition.
[0088] Examples of the oiliness improver include, for example, an
aliphatic monocarboxylic acid, a polymerized fatty acid, a hydroxyl
fatty acid, an aliphatic monoalcohol, an aliphatic monoamine, an
aliphatic monocarboxylic acid amide, a partial ester of a
polyhydric alcohol and an aliphatic monocarboxylic acid. These may
be used alone or may be used in combination of two or more. The
amount of the oiliness improver to be added is not particularly
limited, and is preferably within the range of 0.01 mass % or more
and 10 mass % or less based on the total amount of the
composition.
[0089] As the acid scavenger, an epoxy compound can be used.
Specifically, phenyl glycidyl ether, an alkyl glycidyl ether, an
alkylene glycol glycidyl ether, cyclohexene oxide, an
.alpha.-olefin oxide and an epoxydized soybean oil can be
exemplified. These may be used alone or may be used in combination
of two or more. The amount of the acid capturing agent to be added
is not particularly limited, and is preferably within the range of
0.005 mass % or more and 5 mass % or less based on the total amount
of the composition.
[0090] [Properties of Lubricating Oil Composition and the Like]
[0091] The kinetic viscosity of the lubricating oil composition can
be measured by the method according to JIS-K-2283:2000.
[0092] The kinetic viscosity of the lubricating oil composition at
100.degree. C. is preferably 14.0 mm.sup.2/s or less, more
preferably 12.5 mm.sup.2/s or less, still more preferably 10.0
mm.sup.2/s or less, and preferably 2.0 mm.sup.2/s or more, more
preferably 2.2 mm.sup.2/s or more, still more preferably 2.5
mm.sup.2/s or more from the viewpoint of enhancement of lubricity,
viscosity property and fuel-saving performance.
[0093] The kinetic viscosity of the lubricating oil composition at
40.degree. C. is preferably 80.0 mm.sup.2/s or less, more
preferably 70.0 mm.sup.2/s or less, still more preferably 65.0
mm.sup.2/s or less, and preferably 5.0 mm.sup.2/s or more, more
preferably 7.0 mm.sup.2/s or more, still more preferably 10.0
mm.sup.2/s or more from the viewpoint of enhancement of lubricity,
viscosity property and fuel-saving performance.
[0094] The viscosity index of the lubricating oil composition can
be calculated by the method according to JIS-K-2283:2000. The
viscosity index of the lubricating oil composition is preferably 90
or more, more preferably 100 or more, still more preferably 103 or
more so that viscosity change due to temperature change is
suppressed and fuel saving performance is enhanced.
[0095] [Flash Point]
[0096] The flash point means the value according to JIS-K-2265-4
and obtained by measurement using COC method. The flash point of
the lubricating oil composition is preferably 172.degree. C. or
higher, still more preferably 174.degree. C. or higher,
particularly preferably 176.degree. C. or higher.
[0097] When the flash point of the lubricating oil composition is
172.degree. C. or higher, the ability of cooling the mechanical
device in which the lubricating oil composition is used can be
better. Increase in the flash point of the lubricating oil
composition can be achieved by, for example, using an oil having
high flash point as each oil constituting the lubricating base oil
(A).
[0098] [Application of Lubricating Oil Composition]
[0099] The above described lubricating oil composition of the
present invention has a flash point within the specified range, and
can exhibit lubricity (abrasion resistance, seizure resistance, low
friction). Therefore, the lubricating oil composition of the
present invention can be preferably applied to a device in which a
motor and a speed reducer are integrated, for example mechanical
devices such as a hydraulic system, a stationary transmission
device, an automobile transmission device and a cooling device of a
motor/battery.
[0100] [Method for Producing Lubricating Oil Composition]
[0101] A method for producing the lubricating oil composition of
the present invention is not particularly limited, and it
preferably comprises a step of mixing the lubricating base oil (A),
the neutral phosphorus-based compound (B), the acidic
phosphorus-based compound (C), the sulfur-based compound (D) and
the organic molybdenum compound (E).
[0102] [Mechanical Device]
[0103] The lubricating oil composition enhances lubricity of the
mechanical device, and can be used for mechanical devices which are
a hydraulic system, a stationary transmission device, an automobile
transmission device and a cooling device of a motor/battery. For
example, the lubricating oil composition can be used for a motor
mounted in a hybrid automobile, electric automobile etc., an engine
for a diesel engine or a gasoline engine, a transmission of an
automobile etc. and the like. In particular, it is preferably used
for a transmission mounted in a hybrid automobile, electric
automobile and the like.
EXAMPLES
[0104] Hereinafter, the present invention will be described in more
detail with reference to Examples, but the present invention is not
limited to these Examples.
[0105] The properties and abilities in Examples and Comparative
Examples were measured as follows.
[0106] (1) Kinetic Viscosity
[0107] The kinetic viscosity at 40.degree. C. and the kinetic
viscosity at 100.degree. C. were measured according to
JIS-K-2283:2000 using a glass capillary type viscometer.
[0108] (2) Viscosity Index
[0109] The viscosity index was calculated by the method according
to JIS-K-2283:2000.
[0110] (3) Flash Point
[0111] The flash point was measured by COC method according to
JIS-K-2265-4.
[0112] (4) Abrasion Resistance
[0113] The abrasion resistance was evaluated by Four-ball wear
test. Specifically, the abrasion resistance between metals was
evaluated by measuring a diameter of an abrasion mark (unit: mm)
under the test condition of revolution number of 1800 rpm, test
temperature of 80.degree. C., load of 392 N, and test time of 30
minutes, according to the method described in ASTM D4172. When the
diameter of the abrasion mark is smaller, the abrasion resistance
between metals is more excellent.
[0114] (5) Seizure Resistance
[0115] The fusion load WL (N) was measured by conducting a test
according to ASTM D2783-03(2014) under the condition of revolution
number of 1800 rpm at room temperature (25.degree. C.). When this
value is higher, the seizure resistance is more excellent.
[0116] (6) Friction Property
[0117] The inter-metal friction coefficient was measured by LFW-1
test according to JASO method (high load method) M358:2005. When
this value is lower, the seizure resistance is more excellent.
Examples 1-3, Comparative Examples 1-4
[0118] The lubricating oil composition was prepared according to
the composition shown in Table 1 using the lubricating base oil
(A), the neutral phosphorus-based compound (B), the acidic
phosphorus-based compound (C), the sulfur-based compound (D), the
organic molybdenum compound (E) etc. described below. Each
component constituting the lubricating oil composition and
described in Table 1 is as follows.
[0119] [Lubricating Base Oil (A)]
[0120] Mineral oil-1: The mineral oil having a kinetic viscosity at
100.degree. C. of 2.4 mm.sup.2/s, a viscosity index of 110 and a
flash point of 186.degree. C.
[0121] Mineral oil-2: The mineral oil having a kinetic viscosity at
100.degree. C. of 2.4 mm.sup.2/s, a viscosity index of 105 and a
flash point of 176.degree. C.
[0122] Synthetic oil-1: The synthetic oil having a kinetic
viscosity at 100.degree. C. of 2.4 mm.sup.2/s, a viscosity index of
110 and a flash point of 186.degree. C.
[0123] [Neutral Phosphorus-Based Compound (B)]
[0124] Tricresyl phosphate (TCP) (the compound of the above general
formula (2) wherein R.sup.5--R.sup.7 are methylphenyl groups)
[0125] [Acidic Phosphorus-Based Compound (C)]
[0126] Dioleyl acid phosphate (acidic phosphoric acid ester of the
above general formula (4) wherein R.sup.8 and R.sup.9 are oleyl
groups)
[0127] [Sulfur-Based Compound (D)]
[0128] 2,5-bis(1,1,3,3-tetramethylbutyldithio)-1,3,4-thiadiazole
(the thiadiazole-based compound of the above general formula (6)
wherein X1 and X2 are 2, R.sup.10 and R.sup.11 are
1,1,3,3-tetramethylbutyl groups)
[0129] [Organic Molybdenum Compound (E)]
[0130] Molybdenum dithiocarbamate (MoDTC) (The compound of the
formula (1) wherein R.sup.1 to R.sup.4 are each independently a
hydrocarbon group having 8 or 13 carbon atoms, X.sup.1 to X.sup.4
are oxygen atoms. The content of molybdenum atoms=10.0 mass %, the
content of sulfur atoms=11.5 mass %)
[0131] Other additives (balance) contained in the composition of
Examples and Comparative Examples consist of a viscosity index
enhancer, an antioxidant, a detergent dispersant, a pour point
depressant, an anti-foaming agent and the like.
TABLE-US-00001 TABLE 1 Compara- Compara- Compara- Compara- Exam-
Exam- Exam- tive Exam- tive Exam- tive Exam- tive Exam- Lubricating
base oil (A) ple 1 ple 2 ple 3 ple 1 ple 2 ple 3 ple 4 Composition
Mineral oil-1 95.00 95.80 95.20 95.10 95.10 of components Mineral
oil-2 95.00 (mass %) Synthetic oil-1 95.00 Neutral phosphorus-based
compound (B) 0.80 0.80 0.80 0.80 0.80 0.80 Content of component (B)
mass ppm 660 660 660 0 660 660 660 in terms of phosphorus atom
Acidic phosphorus-based compound (C) 0.20 0.20 0.20 0.20 0.20 0.20
Content of component (C) mass ppm 120 120 120 120 0 120 120 in
terms of phosphorus atom Sulfur-based compound (D) 0.10 0.10 0.10
0.10 0.10 0.10 Content of component (D) mass ppm 300 300 300 300
300 0 300 in terms of sulfur atom Orqanic molybdenum compound (E)
0.40 0.40 0.40 0.40 0.40 0.40 Other additives Balance Balance
Balance Balance Balance Balance Balance Total 100 100 100 100 100
100 100 Property Kinetic viscosity at 40.degree. C. mm.sup.2/s
10.81 10.81 10.79 10.60 10.70 10.71 10.74 Kinetic viscosity at
100.degree. C. mm.sup.2/s 2.86 2.83 2.85 2.81 2.82 2.82 2.82
Viscosity index 111 107 112 110 109 108 108 Flash point .degree. C.
186 178 188 186 188 186 186 Ability Abrasion resistance mm 0.45
0.46 0.43 0.64 0.48 0.48 0.48 Seizure resistance N 618 618 618 618
490 490 618 Friction property 0.046 0.046 0.047 0.044 0.044 0.046
0.110
[0132] As shown in Table 1, when Examples 1-3 and Comparative
Examples 1-4 were compared, it was found that the lubricating oil
compositions containing all of the lubricating base oil (A), the
neutral phosphorus-based compound (B), the acidic phosphorus-based
compound (C), the sulfur-based compound (D) and the organic
molybdenum compound (E) had excellent abilities with respect to all
of abrasion resistance, seizure resistance and friction
property.
[0133] When Examples 1-3 and Comparative Example 4 were compared,
it was found that the friction property of the obtained lubricating
oil composition was enhanced by using the organic molybdenum
compound (E).
[0134] In Examples 1-3, the flash point of the lubricating oil
composition increased when the base oil having a high flash point
was used as the lubricating base oil (A). In particular, since the
lubricating base oil (A) had a flash point of 176.degree. C. or
higher in Examples 1 and 3, the flash point of the obtained
lubricating oil composition was also higher.
* * * * *