DESCRIPTION
'I'itlc of Invet~tionL: UBRICATING OIL COMPOSITION
Technical field
[0001] The present invention relates to a lubricating oil composition.
5 Bacltground Art
[0002] Lubricating oils are prepared by mixing additives into a base oil
such as a mineral oil or synthetic oil according to required properties.
For example, lubricating oils prepared by mixing a sarcosine acid
derivative and an extreme pressure agent into a base oil are disclosed as
10 lubricating oils excellent in rust preventing properties and abrasion
resistance in Patent Literame 1 to 3 listed below.
Citation List
Patent Literatore
[0003] Patent Literature 1: Japanese Unexamined Patent Publication
15 NO. 2002-129180
Patent Literature 2: Japanese Unexarnined Patent Publication No.
2009-144045
Patent Literature 3: Japanese Unexamined Patent Ptrblication No.
2012-007186
20 Summary of ]Invention
Tecilriical Problem
[0004] In general, an effective amount of additive needs to be mixed
into a base oil in order that the desired effect may be obtained by
addition of the additive.
25 [0005] However, a study by the present inventors has revealed that
mixing an effective amount of sarcosine acid derivative into a base oil
can cause precipitation. In particular, precipitation may occur during
use of the lt~bricatingo il even if no precipitation occurs at the time of
preparation of the lubricating oil.
[0006] The present invention has been made in view of the above
5 problem, and has as its object to provide a lubricating oil composition
for which the effect of addition of a sarcosine acid derivative can be
effectively obtained and in which the occurrence of precipitation can be
sufficiently prevented.
Solution to Proble~n
10 [0007] The present invention provides a lubricating oil composition
comprising a hydrocarbon base oil, a sarcosine acid derivative, and an
amine salt of acidic phosphate, wherein a content of the sarcosine acid
derivative is 0.005 to 0.1 mass%, and a content of the anine salt of
acidic phosphate is 0.01 to 0.5 mass%, based on a total amount of the
15 lubricating oil composition, and wherein a ratio (BIA) between a
content (A) of the sarcosine acid derivative and a content (B) of the
alnine salt of acidic phosphate is 1 to 30 in terms of mass satio.
[0008] In the lubricating oil composition according to the present
invention, the contents of the sarcosine acid derivative and the amine
20 salt of acidic phosphate, and also the ratio between the content of the
sarcosine acid derivative and thc content of the alniue salt of acidic
phosphate, are within predetermined ranges, by virtue of which the
effect of addition of the sarcosine acid derivative can be effectively
obtained and the occurrence of precipitation can be sufficiently
25 prevented. By contrast, for a lubricating oil composition that does not
have the above feature, such as a lubricating oil composition that
contains a hydrocarbon base oil and either which does not contain 0.01
to 0.5 mass% of an amine salt of acidic phosphate or in which a ratio
(BIA) between a content @)of the sarcosine acid derivative and a
content (B) of the amine salt of acidic phosphate is outside the range of
5 1 to 30 in terms of mass ratio, the present inventors have confilmed that
precipitation can accompany the use of the lubricating oil composition.
In view of these facts, one reason why the present invention provides
the above effect is presumably that in the conlbination with the
hydrocarbon base oil, the contents of the sarcosine acid derivative and
10 the amine salt of acidic phosphate, and also the ratio between the
contents, meet the above requirements, and hence that the arnine salt of
acidic phosphate hnctions as an aid for dissolution of the sarcosine acid
derivative.
[0009] The %Cp of the hydrocarbon base oil is preferably 50 or more,
15 and the content of the hydrocarbon base oil is preferably 95 mass% or
more based on the total amount of the lubricating oil composition.
[0010] It is preferable for the sarcosine acid derivative to comprise a
co~npoundre presented by the following formula (1):
[Chemical Formula I]
wherein R' represents a linear alkenyl group having 10 to 20
carbon atoms.
Advantageous Effects of Invention
[0011] According to the present invention, it is possible to provide a
lubricating oil co~nposition for which the effect of addition of a
sarcosiue acid derivative can be effectively obtained and in which the
occurrence of precipitation can be sufficiently prevented.
Description of Embodimer~ts
5 [0012] Hereinafter, a prefel~ed embodiment of the lubricating oil
compositio~i according to the present invention will be described in
detail.
[0013] A lubricating oil composition according to the present
embodiment comprises a hydrocarbon base oil, a sarcosine acid
10 derivative, and an amine salt of acidic phosphate. The content of the
sarcosine acid derivative is 0.005 to 0.1 mass%, and the content of the
a~niues alt of acidic phosphate is 0.01 to 0.5 mass%, based on the total
amount of the lubricating oil composition. A ratio @/A) between the
content (A) of the sarcosine acid derivative and the content (B) of the
15 amine salt of acidic phosphate is 1 to 30 in terms of mass ratio.
[0014] Examples of the hydrocarbon base oil include a mineral base oil,
a synthetic base oil, and a mixture of two or more such oils.
[0015] Examples of the mineral base oil include: a kerosene distillate
obtained by distillation of a paraffinic or naphthenic ciude oil; a normal
20 paraffin obtained by extraction &om a kerosene distillate; and a
paraffinic mineral oil, a naphthenic mineral oil, a normal paraffinic base
oil, and an isoparaffiic base oil that are obtained by one, or an
appropriate combination of two or more, of refining processes such as
solvent deasphalting, solvent extraction, hydrocracking, hydrogen
25 isomerization, solvent dewaxing, catalytic dewaxing, hydrogenation
refining, sulfuric acid washing, and white earth treatment performed
using a crude material such as: a lubricating oil distillate obtained by
distillation of a paraffi~ico r naphthcnic crude oil; or a wax such as a
slack wax obtained by dewaxing of a lubricating oil and/or a synthetic
wax such as a Fischer-Tropsch wax or GTL wax obtained by
5 gas-to-liquid (GTL) process. Among these, the paraffutlic mineral oil,
the no~mal paraffinic base oil, and the isoparaffinic base oil are
preferably used.
[0016] Examples of the synthetic base oil include: poly-a-olefins or
hydrides thereof; olefin oligoiners such as propylene oligomer,
10 isobutylene oligomer, polybutene, 1-octene oligomer, 1-decene
oligomer, and ethylene-propylene oligomer or hydrides thereof;
alkylbenzenes; and allcylnaphthalenes. Among these, poly-a-olefins or
hydrides thereof are preferably used.
[0017] The %Cp of the hydrocarbon base oil is preferably 50 or more,
15 more preferably 75 or more, and even more preferably 90 or more.
The %CN of the llydrocarbon base oil is preferably 40 or less, more
preferably 22 or less, and even more preferably 16 or less. The %CA
of the hydrocarbon base oil is preferably 10 or less, nlore preferably 5 or
t
less, and even more preferably 0.5 or less. When the %C,, %CN,
20 and %CA of the hydrocarbon base oil are within the above ranges, the
stability of the hydrocarbon base oil against oxidation or the like is high,
and the decline in its quality is likely to be prevented even under heated
conditions or the like.
[0018] In the present invention, the %C,, %CN, and %CA respectively
25 refer to values determined by a method (n-d-M ring analysis) according
to ASTM D 3238-85 (2010).
[0019] Thc kinematic viscosity of the hydrocarbon base oil at 40°C is
prefcrably 2 m d s or more, more preferably 5 mn2/s or more, and even
more preferably 32 mni21s or inore, and is preferably 1000 1mn~1osr less
and more preferably 680 m21s or less. The kmematic viscosity of the
5 hydrocarbon base oil at 100°C is preferably 2 mm2/s or more, more
preferably 3 mm2/s or more, even more preferably 5 mmn21s or more, and
is 50 mmn21s or less, more preferably 45 mm21s or less, and even more
preferably 40 mm21s or less. When the kinematic viscosities of the
hydrocarbon base oil are within the above ranges, a proper viscosity of
10 the hydrocarbon base oil can be maintained, and a good oil film can be
obtained at a practical range of use temperatures, so that a machine can
be effectively protected.
[0020] The viscosity index of the hydrocarbon base oil is preferably 70
or more, more preferably 120 or more, and even more preferably 135 or
15 more. When the viscosity index is within the above range, the
viscosity stability against external temperature is maintained, and thus
an oil film can be formed stably against variation in external
temperature during use.
[0021] The kinematic viscosities at 40°C and 100°C and the viscosity
20 index in the present invention respectively refer to values measured
according to US K 2283: 2000 "Crude petsole~un and petroleum
products-Determination of kinematic viscosity and calculation of
viscosity index ftom kinematic viscosity".
[0022] The content of the hydrocarbon base oil is preferably 90 mass%
25 or more, more preferably 95 mass% or more, and even more preferably
98 mass% or more, based on the total amount of the lubricating oil
comnposition.
[0023] The sarcosine acid derivative is not paiticularly limited and, for
example, a co~npoundr epresented by the following fos~nula( 1) is used.
[0024] [Chemical Formula 21
0
I I
R'-C-N-CH~-COOH (1)
5
I
CH3
[0025] In the fonnula (I), R' represents an aryl, alkyl, or alkenyl group
having 6 to 24 carbon atoms, preferably a linear alkenyl group having
10 to 20 carbon atoms.
[0026] In view of the lust preventing ability, the content of the
10 sarcosine acid derivative is 0.005 mass% or more, preferably 0.01
mass% or more, and more preferably 0.02 mass% or more, based on the
total amount of the lubricating oil composition. In view of preventing
the occurrence of precipitation associated with degradation of the
lubricating oil conlposition during use, the content of the sarcosine acid
15 derivative is 0.1 inass% or less, preferably 0.08 mass% or less, and
more preferably 0.05 mass% or less, based on the total amount of the
lubricating oil composition.
[0027] The amine salt of acidic phosphate is not particularly limited
and, for example, a salt of an acidic phosphate represented by the
20 following formula (2) with an amine represented by the following
foimula (3) is used.
[0028] [Chemical Formula 31
[0029] In the formula (2), K' each independently represent an a~yl,
alkyl, or alkenyl group having 6 to 24 carbon atoms, preferably an allcyl
or alke~~gyrlo up having 6 to 18 carbon atoms, inore preferably a linear
alkyl group having 6 to 12 carbon atoms. m represents 1 or 2. It is
5 preferable that the acidic phosphate represented by the formula (2) be a
mixture of an acidic phosphate represented by the formula (2) wherein
m is 1 and an acidic pliospliate represented by the formula (2) wherein
m is 2.
[0030] [Chemical Formula 41
10 R33+1NHn (3)
[0031] In the formula (3), R~ each independently represent an aryl,
alkyl, or alkenyl group having 6 to 24 carbon atoms, preferably a linear
or branched alkyl or alkenyl group having 6 to 18 carbon atoms, more
preferably a linear alkyl group having 12 to 18 carbon atonis. 11
15 represents an integer of 0 to 3, preferably 2.
[0032] In view of rust preventing effect and impartatioil of extreme
pressure properties, the content of the amine salt of acidic phosphate is
0.01 mass% or more, preferably 0.02 mass% or more, and more
preferably 0.05 mass% or more, based on the total amount of the
20 lubricating oil composition. In view of preventing the occurrence of
precipitation associated with degradation of the lubricating oil
composition during use, the content of the amine salt of acidic
phosphate is 0.5 mass% or less, preferably 0.4 mass% or less, and more
preferably 0.3 mass% or less, based on the total amount of the
25 lubricating oil composition.
[0033] In view of preventing the occurrence of precipitation associated
with degadation of the lubricating oil co1nposition during use, the ratio
(BIA) between the content (A) of the sarcosine acid derivative and the
content (B) of the atnine salt of acidic phosphate is 1 to 30, preferably 2
to 25, more preferably 3 to 20, and even more preferably 4 to 10, in
5 terms of mass ratio.
[0034] The lubricating oil composition can further include another base
oil and another additive in addition to the hydrocarbon base oil, the
sarcosine acid derivative, and the amine salt of acidic phosphate.
[0035] Examples of the other base oil include an ester, a polyalkylene
10 glycol, a polyvinyl ether, a ketone, a silicone, and a perfluoroether.
Examples of the other additive include a phenol-based or amine-based
antioxidant, an extreme pressure ageni, a metal deactivator, an
anti-foaming agent, a corsosion inhibitor, a wetting agent, a film
forming agent, and a surfactant. The contents of the other base oil and
15 the other additive are not particularly limited and, for example, it is
preferable that the contents be 10 mass% or less based on the total
amount of the lubricating oil con~position.
[0036] Among the other additives, the phenol-based or amine-based
antioxidant and the extreme pressure agent are preferably used. The
20 phenol-based or amine-based antioxidant is not particularly limited and,
for example, 2,6-di-t-butyl-p-cresol, 4,4'-methylenebis(2,6-di-tbutylphenol),
phenylnaphthylarnine, or diphenylamine is used. The
extreme pressure agent is not particularly limited and, for example,
triphenyl phosphorothionate is used.
25 [0037] The lubricatiug oil cornposition is suitable for use, for example,
as a lubricating oil for tnacline tools, an engine oil, a lubricating oil for
drive systems, a grease, a wet brake oil, a liydraulic oil, a turbine oil, or
a colnpressor oil.
Examples
[0038] Hereinaftel; the present invention will be more specifically
5 described based on examples; however, the present invention is not
limited to the examples.
100391 Lubricating oil compositions having the cotnpositions sl~ownin
Tables 1 to 4 were prepared using base oils and additives listed below.
In the tables, B/A represents the ratio (mass ratio) between the content
10 (A) of the sarcosine acid derivative and the content @) of the alnine salt
of acidic phosphate.
[0040] (Base oil)
Base oil 1: Poly-a-oleh (decene, dodecene derivative,
kinematic viscosity at 40°C: 44.1 m&s, kinematic viscosity at 100°C:
15 7.8 d s , viscosity index: 146, %Cp: 100)
Base oil 2: Mineral oil (kinematic viscosity at 40°C: 47.7 m2/s,
kinematic viscosity at 100°C: 7.8 mrn2/s, viscosity index: 131, %C,:
79.7, %CN: 20.3, %CA: 0.0)
Base oil 3: Mineral oil (kinematic viscosity at 40°C: 47.4 mnm2/s,
20 kinematic viscosity at 100°C: 6.9 mni2/s, viscosity index: 101, %Cp:
67.5, %CN: 25.7, %CA: 6.8)
[0041] (Additive)
Additive 121: N-oleoyl sarcosine
Additive 131: Amine salt of acidic phosphate (a mixture of a
25 con~pound represented by the f o d a (2) wherein R~ is a linear alky1
group having 6 carbon atoms and m is 1 and a compound represented by
the for~nula (2) wherein R' is a linear alkyl group having 6 carbon
atoms and m is 2, and a colnpound rcpresented by the formula (3)
wherein R3 is a linear or branched alkyl group having 10 to 14 carbon
atoms and n is 1 or 2)
5 Additive B2: Amine salt of acidic phosphate (a mixture of a
compound represented by the formula (2) wherein R' is a linear alkenyl
group having 18 carbon atoms and 1n is 1 and a compound represented
by the formula (2) wherein R2 is a linear alkenyl group having 18
carbon atoms and m is 2, and a compound represented by the fon~iula
10 (3) wherein R~ is a linear alkyl group having 18 carbon atoms and n is
2)
Additive bl: 2-ethylhexyl phosphate
Additive b2: Tricresyl phosphate
Additive C1: Other additives (an amhe-based antioxidant, a
15 metal deactivator, and an anti-foaming agent)
[0042] Rust prevention evaluation test, extreme pressure property
evaluation test, and precipitation evaluation test, which will be
described below, were camried out on the lubricating oil comnpositions.
The results are show11 in Tables 1 to 4.
20 [0043] (Rust prevention evaluation test)
Whether rust was "present" or "absent" was determined
according to JIS K 2510: 1998 "Lubricants-Determination of
rust-preventing characteristics".
[0044] (Extreme pressure property evaluation test)
25 Extreme pressure properties were evaluated according to
Tirnken method specified in JIS K 2519 "Lubricating oil-Testing
methods for load carlying capacity". Extreme pressure propelties can
be col~sideredg ood when the OK load is 5.44 kgf or nore.
[0045] (Precipitation evaluatiotl test)
A satnple oil weighing 45 g and an iron-copper catalyst in the
form of a wire were put in a 50 ml beaker, which was left in a
the~mostaticc hamber at 120°C for 3 days. Afterwards, the appearance
of the sanlple oil was observed to determine whether a precipitate was
"present" or "absent".
[0046] [Table I]
Example Example Example Example Example
I 2 3 4 5
1 Balance Balance Balatse
-.
Absent / Absent
1
:me pressure propew
latioil test
Extrt I I I I I
cvali
Rust prevention evaluation test / Absent Absent / Absent
Precivitatio~ei valuation test 1 Absent 1 Absent I Absent I Absent I Absent
5 .44 5.44 5.44 5.44 5.44
100471 [Table 21
Example
7
Balance
Example
G
Balauce
0.10
0.15
1.52
Cotnposition
(mass%
based on
total atnolult
of
li~bricating
oil)
Comparative
Example 2
Balance
Base oil
Additive
[0048] [Table 31
1
2
3
Al
B1
B2
bl
b2
C1
Rust prevention evaluatiorl
test
Extreme pressure property
evaluation test
I Comparative Coniparative Comparative Comparative Comparative
Exaniule 4 I Examule 5 I Examule 6 Examnle 7 1 Examnle 8 I
I I I 1 I Balance I Balance I Balance I Balance I Balauce 1
I l ~ a soei l 1 2 1 1
Absent
5.44
Present
5.44
Abseut
5.44
Composition
(massyo
based on
lnfal atnnnnt
-. -
Rust prevention evaluatio~te~s t Present Absent Abseut Absent Absent
Present
5.44
. . .-. ..... . -. .
I of lubricating I B2 Additive 1 -
Absent
5.44
3
A1
BI
bl I . - - I I 1 0.15
Extreme pressme property
evaluatiotl test -
Precipitation evaluation test
0.01
1.08
Absent
0.02
4.08
Present
0.03
4.08 I 4.08 1 5.44 I
hesent Present Present
0.10 0.02

C L A M S
1. A lubricating oil conlposition comprising:
a hydrocarbon base oil;
a sarcosine acid derivative; and
5 an amine salt of acidic phosphate,
wherein a content of the sarcosine acid derivative is 0.005 to 0.1
mass%, and a content of the a&e salt of acidic phosphate is 0.01 to 0.5
mass%, b&ed on a total amount of the lubricating oil comnposition, and
wherein a ratio @/A) between a content (A) of the sarcosine
10 acid derivative and a content (B) of the amine salt of acidic phosphate is
1 to 30 in terms of mass ratio.
2. The lubricating oil composition according to claim 1,
wherein %Cp of the hydrocarbon base oil is 50 or more, and a content of
the hydrocarbon base oil is 95 mass% or more based on the total amount
15 of the lubricating oil composition.
3. The lubricating oil composition according to claim 1 or 2,
wherein the sarcosine acid derivative comprises a compound
represented by the following fo~mula(1 ):
[Chemical Formula 11
I * A I:
0
I I
R~--C-N-CH~-COOH (1)~ - .I ~ ~
20 . CH. 3 1-5
' wherein R' represents a linear alkenyl group having 10 to 20
carbon atoms.