U.S. patent application number 12/933805 was filed with the patent office on 2011-01-27 for lubricant composition.
This patent application is currently assigned to JX NIPPON OIL & ENERGY CORPORATION. Invention is credited to Shozaburo Konishi, Hajime Nakao, Toshio Yoshida.
Application Number | 20110021394 12/933805 |
Document ID | / |
Family ID | 41113530 |
Filed Date | 2011-01-27 |
United States Patent
Application |
20110021394 |
Kind Code |
A1 |
Nakao; Hajime ; et
al. |
January 27, 2011 |
LUBRICANT COMPOSITION
Abstract
A lubricating oil composition comprising a lubricating base oil,
and a mixture and/or a reaction product of (A) 0.01-0.5% by mass of
at least one compound selected from among acid phosphates
represented by formula (1) or formula (2), and (B) 0.01-2% by mass
of an alkylamine represented by formula (3), based on the total
weight of the composition, wherein the acid value due to component
(A) is 0.1-1.0 mgKOH/g. [R.sup.1 and R.sup.2 represent hydrogen or
straight-chain alkyl or straight-chain alkenyl groups, with at
least one of R.sup.1 and R.sup.2 being a C6-12 straight-chain alkyl
or straight-chain alkenyl group; R.sup.3 and R.sup.4 represent
hydrogen straight-chain alkyl or straight-chain alkenyl groups,
with at least one of R.sup.3 and R.sup.4 being a C13-18
straight-chain alkyl or straight-chain alkenyl group; and R.sup.5
and R.sup.6 represent hydrogen or C4-30 branched-chain alkyl
groups, with at least one of R.sup.5 and R.sup.6 being a
branched-chain alkyl group.] ##STR00001##
Inventors: |
Nakao; Hajime; (Kanagawa,
JP) ; Konishi; Shozaburo; ( Kanagawa, JP) ;
Yoshida; Toshio; (Kanagawa, JP) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
JX NIPPON OIL & ENERGY
CORPORATION
Tokyo
JP
|
Family ID: |
41113530 |
Appl. No.: |
12/933805 |
Filed: |
March 12, 2009 |
PCT Filed: |
March 12, 2009 |
PCT NO: |
PCT/JP2009/054778 |
371 Date: |
September 21, 2010 |
Current U.S.
Class: |
508/433 |
Current CPC
Class: |
C10N 2040/20 20130101;
C10M 141/10 20130101; C10M 169/04 20130101; C10M 2223/043 20130101;
C10M 137/08 20130101; C10M 2223/04 20130101; C10M 2203/1025
20130101; C10N 2030/43 20200501; C10M 137/04 20130101; C10M 2215/04
20130101; C10N 2030/02 20130101; C10N 2020/065 20200501 |
Class at
Publication: |
508/433 |
International
Class: |
C10M 169/04 20060101
C10M169/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2008 |
JP |
2008-084307 |
Mar 27, 2008 |
JP |
2008-084377 |
Claims
1. A lubricating oil composition comprising: a lubricating base
oil, and a mixture and/or a reaction product of (A) 0.01-0.5% by
mass of at least one compound selected from among acid phosphates
represented by the following formula (1) or (2), and (B) 0.01-2% by
mass of an alkylamine represented by the following formula (3),
based on the total weight of the composition, the acid value due to
component (A) being 0.1-1.0 mgKOH/g. ##STR00009## wherein R.sup.1
and R.sup.2 may be the same or different, and each represents
hydrogen or a straight-chain alkyl or straight-chain alkenyl group,
and at least one of R.sup.1 and R.sup.2 is a C6-12 straight-chain
alkyl or straight-chain alkenyl group; wherein R.sup.3 and R.sup.4
may be the same or different, and each represents hydrogen or a
straight-chain alkyl or straight-chain alkenyl group, and at least
one of R.sup.3 and R.sup.4 is a C13-18 straight-chain alkyl or
straight-chain alkenyl group; and wherein R.sup.5 and R.sup.6 may
be the same or different, and each represents hydrogen or a C4-30
branched-chain alkyl group, and at least one of R.sup.5 and R.sup.6
is a branched-chain alkyl group.
2. A lubricating oil composition according to claim 1, wherein the
lubricating base oil is a lubricating base oil with a viscosity
index of 105 or greater, a saturated hydrocarbon component of 70%
by mass or greater and a sulfur content of not greater than 0.2% by
mass.
3. A lubricating oil composition according to claim 1, wherein the
nitrogen content of the lubricating base oil is not greater than 10
ppm by mass and the flash point of the lubricating base oil is
250.degree. C. or higher.
4. A lubricating oil composition according to claim 1, further
comprising (C) 0.01-5% by mass of a sulfur compound, based on the
total weight of the composition.
5. A lubricating oil composition according to claim 1, used in a
machine tool.
Description
TECHNICAL FIELD
[0001] The present invention relates to a lubricating oil
composition.
BACKGROUND ART
[0002] Lubricating oils for sliding guide surfaces such as machine
tool work tables must have low friction and anti stick-slip
performance to improve machining accuracy, as well as storage
stability, corrosion resistance and the like. Most machine tools
have a construction in which the lubricating oil for the sliding
guide surface is blended with the working fluid for the workpiece.
Particularly in cases where a water-soluble cutting fluid is used
as the working fluid, blending of the lubricating oil for the
sliding guide surface is one cause of deterioration of the
water-soluble cutting fluid (reduced cutting performance,
accelerated decay, shortened mineral oil life and increased waste
water disposal cost). The performance of a sliding guide surface
lubricating oil must therefore include an excellent lubrication
property, which reduces frictional coefficient and prevents
stick-slip on the sliding guide surface, and excellent separability
from the water-soluble cutting fluid, since it is blended with the
water-soluble cutting fluid, without adversely affecting the
performance of the water-soluble cutting fluid or of the
lubricating oil for the sliding guide surface.
[0003] A variety of extreme-pressure agents or oil agents have been
used to date as friction reducers. Demands for accuracy, in
particular, of machine tools have been increasing in recent years,
and phosphoric acid esters, acid phosphates, carboxylic acids,
sulfur compounds, amines and the like have been used to realize
reduced friction in the low-speed range, which has an important
effect on accuracy (see Patent documents 1, 2, 3 and 4, for
example). Also, neutralization of acid phosphates with alkylamines
has been attempted to improve stability (see Patent document 5, for
example). [0004] [Patent document 1] Japanese Unexamined Patent
Application Publication HEI No. 8-134488 [0005] [Patent document 2]
Japanese Unexamined Patent Application Publication No. 2001-104973
[0006] [Patent document 3] Japanese Unexamined Patent Application
Publication No. 2003-171684 [0007] [Patent document 4] Japanese
Unexamined Patent Application Publication No. 2003-430949 [0008]
[Patent document 5] Japanese Unexamined Patent Application
Publication No. 2007-238764
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0009] In the prior art, however, the environmental burden of
additives is high, and although the additives used allow excellent
initial friction performance and machine tool positioning
performance to be achieved, blending of water-soluble cutting
fluids with sliding guide surface lubricating oils significantly
inhibits the initial low friction, while also being a cause of poor
machining accuracy of machine tools, due to factors such as
corrosion of iron-containing sliding surfaces by acidic components
such as phosphoric acid, and continued use of such devices tends to
result in poorer positioning accuracy.
[0010] It has been attempted in the past to improve stability by
neutralizing acid phosphates with alkylamines, but it has been
difficult to continuously maintain low friction for prolonged
periods with combinations of additives in the prior art. A need
therefore exists for lubricants that continuously maintain
excellent friction performance for prolonged periods.
[0011] The present invention has been accomplished in light of
these circumstances, and its object is to provide a lubricating oil
composition which is excellent in terms of the low-friction
property, positioning property, thermal stability and
low-temperature storage stability, and that does not have a
significantly impaired initial low-friction property even when
cutting fluids are blended therewith, as well as to provide a
lubricating oil composition that also exhibits excellent corrosion
resistance.
Means for Solving the Problems
[0012] As a result of much diligent research directed toward
achieving the object stated above, the present inventors have
discovered that the aforementioned problems can be solved by a
lubricating oil composition comprising a mixture and/or a reaction
product of a specific acidic phosphoric acid ester and a specific
aliphatic amine in a specific proportion in a lubricating base oil,
wherein the acid value due to the acidic phosphoric acid ester
satisfies specific conditions, and the invention has been completed
upon this discovery.
[0013] Specifically, the lubricating oil composition of the
invention comprises a lubricating base oil, and a mixture and/or a
reaction product of (A) 0.01-0.5% by mass of at least one compound
selected from among acid phosphates represented by the following
formula (1) or the following formula (2), and (B) 0.01-2% by mass
of an alkylamine represented by the following formula (3), based on
the total weight of the composition, the acid value due to
component (A) being 0.1-1.0 mgKOH/g.
##STR00002##
wherein R.sup.1 and R.sup.2 may be the same or different, and each
represents hydrogen or a straight-chain alkyl or straight-chain
alkenyl group, with at least one of R.sup.1 and R.sup.2 being a
C6-12 straight-chain alkyl or straight-chain alkenyl group; [0014]
wherein R.sup.3 and R.sup.4 may be the same or different, and each
represents hydrogen or a straight-chain alkyl or straight-chain
alkenyl group, with at least one of R.sup.3 and R.sup.4 being a
C13-18 straight-chain alkyl or straight-chain alkenyl group; and
[0015] wherein R.sup.5 and R.sup.6 may be the same or different,
and each represents hydrogen or a C4-30 branched-chain alkyl group,
with at least one of R.sup.5 and R.sup.6 being a branched-chain
alkyl group.
[0016] In the lubricating oil composition of the invention, the
lubricating oil is preferably a lubricating base oil with a
viscosity index of 105 or greater, a saturated hydrocarbon
component of 70% by mass or greater and a sulfur content of not
greater than 0.2% by mass.
[0017] Also, the nitrogen content of the lubricating base oil is
preferably not greater than 10 ppm by mass and the flash point of
the lubricating base oil is preferably 250.degree. C. or
higher.
[0018] The lubricating oil composition of the invention preferably
further comprises (C) 0.01-5% by mass of a sulfur compound, based
on the total weight of the composition.
[0019] The lubricating oil composition of the invention may be used
for various purposes, but it is preferably used in a machine tool,
and most preferably on a machine tool sliding guide surface.
Effect of the Invention
[0020] The lubricating oil composition of the invention is
excellent in terms of low-friction property, positioning property,
thermal stability and low-temperature storage stability, does not
notably impair the initial low-friction property even when a
cutting fluid is blended therewith, can maintain machining
accuracy, and also exhibits excellent corrosion resistance. The
lubricating oil composition of the invention is therefore highly
useful from the viewpoint of stabilization of machine tool
operation, and prolongation of usable life.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a general schematic drawing showing the frictional
coefficient measuring system used for the examples.
EXPLANATION OF SYMBOLS
[0022] 1: Table, 2: A/C servomotor, 3: feed screw, 4: movable jig,
5: load cell, 6: bed, 7: computer, 8: control panel, 9: weight.
BEST MODES FOR CARRYING OUT THE INVENTION
[0023] Preferred embodiments of the invention will now be described
in detail.
[0024] There are no particular restrictions on the method of
producing the mineral base oil for use according to the invention,
and for example, it may be a paraffin-based or naphthene-based
mineral oil obtained by applying an appropriate combination of one
or more refining means such as solvent deasphalting, solvent
extraction, hydrocracking, solvent dewaxing, catalytic dewaxing,
hydrorefming, sulfuric acid washing or white clay treatment, on a
lube-oil, distillate obtained from atmospheric distillation and
vacuum distillation of crude oil. A fat or oil and/or synthetic oil
may also be added to the lubricating base oil of the invention.
[0025] The fat or oil may be beef tallow, lard, soybean oil,
rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel
oil, or hydrogenated forms of the foregoing.
[0026] Examples of synthetic oils include poly-.alpha.-olefins
(ethylene-propylene copolymer, polybutene, 1-octene oligomer,
1-decene oligomer, and hydrides thereof), as well as synthetic
hydrocarbon oils such as alkylbenzenes and alkylnaphthalenes. The
methods for producing these are not particularly restricted, and
may be any methods commonly employed for production.
[0027] Examples of synthetic oils other than the aforementioned
synthetic hydrocarbon oils include monoesters (butyl stearate,
octyl laurate and the like), diesters (ditridecyl glutarate,
di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate,
di-2-ethylhexyl sebacate and the like), polyesters (trimellitic
acid ester and the like), polyol esters (trimethylolpropane
caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethyl
hexanoate, pentaerythritol pelargonate and the like),
polyoxyalkylene glycols, polyphenyl ethers, dialkyldiphenyl ethers,
phosphoric acid esters (tricresyl phosphate and the like),
fluorinated compounds (perfluoropolyethers, fluorinated polyolefins
and the like), and silicone oils.
[0028] The lubricating base oil of the invention may contain one or
a combination of two or more of these fats or oils and/or synthetic
oils.
[0029] There are no particular restrictions on the viscosity of the
lubricating base oil used for the invention, but the kinematic
viscosity at 40.degree. C. is preferably in the range of 10-700
mm.sup.2/s and more preferably in the range of 15-500 mm.sup.2/s.
The lubricating base oil content is also not particularly
restricted but is preferably in the range of 50-99.98% by mass
based on the total weight of the composition.
[0030] A preferred example of a lubricating base oil to be used for
the invention is a lubricating base oil with a viscosity index of
105 or greater, a saturated hydrocarbon component of 70% by mass or
greater and a sulfur content of not greater than 0.2% by mass
(hereinafter referred to as "lubricating base oil of the
invention"). The lubricating base oil of the invention will now be
described in detail.
[0031] The lubricating base oil of the invention is not
particularly restricted so long as the viscosity index, saturated
hydrocarbon component and sulfur content satisfy the aforementioned
conditions, but it is preferably a lubricating base oil prepared by
hydrocracking/hydroisomerization of a mineral oil or a normal
paraffin-containing stock oil (hereinafter also referred to as "wax
isomerized base oil"), a synthetic hydrocarbon oil or a mixture of
two or more selected from among them, having a viscosity index of
105 or greater, a saturated hydrocarbon component of 70% by mass or
greater and a sulfur content of not greater than 0.2% by mass.
[0032] If the viscosity index of the lubricating base oil is 105 or
greater it will be possible to obtain a lubricating oil composition
that can more satisfactorily exhibit both oil film formability and
fluid resistance lowering performance. If the saturated hydrocarbon
component is less than 70% by mass, the oxidation stability will be
notably lowered and sludge will tend to be generated. If the sulfur
content exceeds 0.2, the thermal stability will be impaired and the
frictional coefficient will be more adversely affected.
[0033] The viscosity index for the purpose of the invention is the
viscosity index measured according to JIS K 2283-1993. The
saturated hydrocarbon component content is the value measured
according to ASTM D 2007-93 (units: % by mass).
[0034] The nitrogen content of the lubricating base oil of the
invention is preferably not greater than 10 ppm by mass. If the
nitrogen content exceeds 10 ppm by mass, the oxidation stability or
thermal stability will tend to be reduced. The nitrogen content for
the purpose of the invention is the nitrogen content measured
according to JIS K 2609-1990.
[0035] The flash point of the lubricating base oil of the invention
is preferably 250.degree. C. or higher. An oil with a flash point
of 250.degree. C. or higher does not qualify as a "flammable
liquid" within the definition of a Type 4 hazardous material under
the Japan Fire Service Law, and is classified as a designated
"combustible liquid", the storage and handling of which is much
less restricted than a Type 4 hazardous material. The flash point
for the purpose of the invention is the flash point measured
according to JIS K 2265.
[0036] The lubricating oil composition of the invention may also
contain base oils other than the lubricating base oil of the
invention, such as fats or oils and/or synthetic oils other than
those of the invention.
[0037] A wax isomerized base oil to be used for the invention is a
lubricating base oil prepared by hydrocracking/hydroisomerization
of a normal paraffin-containing stock oil, described below.
[0038] An example of a preferred embodiment of the method for
production of a wax isomerized base oil of the invention is a
method for production of a wax isomerized base oil comprising a
step of hydrocracking/hydroisomerization of a stock oil containing
normal paraffins, until the urea adduct value of the obtained
treatment product is not greater than 4% by mass, the viscosity
index is 130 or higher and the NOACK evaporation is not greater
than 15% by mass.
[0039] The urea adduct value according to the invention is measured
by the following method. A 100 g weighed portion of sample oil (wax
isomerized base oil) is placed in a round bottom flask, 200 g of
urea, 360 ml of toluene and 40 ml of methanol are added and the
mixture is stirred at room temperature for 6 hours. This produces
white particulate crystals as urea adduct in the reaction mixture.
The reaction mixture is filtered with a 1 micron filter to obtain
the produced white particulate crystals, and the crystals are
washed 6 times with 50 ml of toluene. The recovered white crystals
are placed in a flask, 300 ml of purified water and 300 ml of
toluene are added and the mixture is stirred at 80.degree. C. for 1
hour. The aqueous phase is separated and removed with a separatory
funnel, and the toluene phase is washed 3 times with 300 ml of
purified water. After dewatering treatment of the toluene phase by
addition of a desiccant (sodium sulfate), the toluene is distilled
off. The proportion (weight percentage) of urea adduct obtained in
this manner with respect to the sample oil is defined as the urea
adduct value.
[0040] The NOACK evaporation for the purpose of the invention is
the evaporation loss as measured according to ASTM D 5800-95.
[0041] Another preferred embodiment of the method for production of
a lubricating base oil of the invention is a method for production
of a wax isomerized base oil comprising a step of
hydrocracking/hydroisomerization of a normal paraffin-containing
stock oil, until the urea adduct value of the obtained treatment
product is not greater than 4% by mass, the viscosity index is 130
or higher, the CCS viscosity at -35.degree. C. is not greater than
2000 mPas, and the product of the kinematic viscosity at 40.degree.
C. (units: mm.sup.2/s) and the NOACK evaporation (units: % by mass)
is not greater than 250.
[0042] In the process for production of a wax isomerized base oil
according to the invention, it is preferred for the stock oil to
contain at least 50% by mass slack wax obtained by solvent dewaxing
of the wax isomerized base oil.
[0043] Also, from the viewpoint of improving the low-temperature
viscosity characteristic without impairing the
viscosity-temperature characteristic, the urea adduct value of the
wax isomerized base oil of the invention must be not greater than
4% by mass as mentioned above, and it is preferably not greater
than 3.5% by mass, more preferably not greater than 3% by mass and
even more preferably not greater than 2.5% by mass. The urea adduct
value of the wax isomerized base oil may even be 0% by mass.
However, it is preferably 0.1% by mass or greater, more preferably
0.5% by mass or greater and most preferably 0.8% by mass or
greater, from the viewpoint of obtaining a wax isomerized base oil
with a sufficient low-temperature viscosity characteristic and a
higher viscosity index, and also of relaxing the dewaxing
conditions for increased economy.
[0044] From the viewpoint of improving the viscosity-temperature
characteristic, the viscosity index of the wax isomerized base oil
of the invention must be 105 or greater as mentioned above, and it
is preferably 110 or greater, more preferably 120 or greater, even
more preferably 130 or greater and most preferably 140 or
greater.
[0045] The stock oil used for production of the wax isomerized base
oil of the invention may include normal paraffins or normal
paraffin-containing wax. The stock oil may be a mineral oil or a
synthetic oil, or a mixture of two or more thereof.
[0046] The stock oil used for the invention preferably is a
wax-containing starting material that boils in the range of
lubricating oils according to ASTM D86 or ASTM D2887. The wax
content of the stock oil is preferably between 50% by mass and 100%
by mass based on the total weight of the stock oil. The wax content
of the starting material can be measured by a method of analysis
such as nuclear magnetic resonance spectroscopy (ASTM D5292), n-d-M
method(ASTM D3238) or the solvent method (ASTM D3235).
[0047] As examples of wax-containing starting materials there may
be mentioned oils derived from solvent refining methods, such as
raffmates, partial solvent dewaxed oils, deasphalted oils,
distillates, vacuum gas oils, coker gas oils, slack waxes, foot
oil, Fischer-Tropsch waxes and the like, among which slack waxes
and Fischer-Tropsch waxes are preferred.
[0048] Slack wax is typically derived from hydrocarbon starting
materials by solvent or propane dewaxing. Slack waxes may contain
residual oil. The residual oil can be removed by deoiling. Foot oil
corresponds to deoiled slack wax.
[0049] Fischer-Tropsch waxes are produced by so-called
Fischer-Tropsch synthesis.
[0050] Commercial normal paraffin-containing stock oils are also
available. Specifically, there may be mentioned Paraflint 80
(hydrogenated Fischer-Tropsch wax) and Shell MDS Waxy Raffinate
(hydrogenated and partially isomerized heart cut distilled
synthetic wax raffinate).
[0051] Stock oil from solvent extraction is obtained by feeding a
high boiling point petroleum fraction from atmospheric distillation
to a vacuum distillation apparatus and subjecting the distillation
fraction to solvent extraction. The residue from vacuum
distillation may also be deasphalted. In solvent extraction
methods, the aromatic components are dissolved in the extract phase
while leaving more paraffinic components in the raffinate phase.
Naphthenes are distributed in the extract phase and raffinate
phase. The preferred solvents for solvent extraction are phenols,
furfurals and N-methylpyrrolidone. By controlling the solvent/oil
ratio, extraction temperature and method of contacting the solvent
with the distillate to be extracted, it is possible to control the
degree of separation between the extract phase and raffinate phase.
There may also be used as the starting material a bottom fraction
obtained from a fuel oil hydrocracker, using a fuel oil
hydrocracker with higher hydrocracking performance.
[0052] The wax isomerized base oil of the invention may be obtained
through a step of hydrocracking/hydroisomerization of the stock oil
until the treatment product has a urea adduct value of not greater
than 4% by mass and a viscosity index of 100 or higher. The
hydrocracking/hydroisomerization step is not particularly
restricted so long as it satisfies the aforementioned conditions
for the urea adduct value and viscosity index of the treatment
product. A preferred hydrocracking/hydroisomerization step
according to the invention comprises: [0053] a first step in which
a normal paraffin-containing stock oil is subjected to
hydrotreatment using a hydrotreatment catalyst, [0054] a second
step in which the treatment product from the first step is
subjected to hydrodewaxing using a hydrodewaxing catalyst, and
[0055] a third step in which the treatment product from the second
step is subjected to hydrorefining using a hydrorefming
catalyst.
[0056] Conventional hydrocracking/hydroisomerization also includes
a hydrotreatment step in an early stage of the hydrodewaxing step,
for the purpose of desulfurization and denitrification to prevent
poisoning of the hydrodewaxing catalyst. In contrast, the first
step (hydrotreatment step) according to the invention is carried
out to decompose a portion (for example, about 10% by mass and
preferably 1-10% by mass) of the normal paraffins in the stock oil
at an early stage of the second step (hydrodewaxing step), thus
allowing desulfurization and denitrification in the first step as
well, although the purpose differs from that of conventional
hydrotreatment. The first step is preferred in order to reliably
limit the urea adduct value of the treatment product obtained after
the third step (the wax isomerized base oil) to not greater than 4%
by mass.
[0057] As hydrogenation catalysts to be used in the first step
there may be mentioned catalysts containing Group 6 metals and
Group 8-10 metals, as well as mixtures thereof. As preferred metals
there may be mentioned nickel, tungsten, molybdenum and cobalt, and
mixtures thereof. The hydrogenation catalyst may be used in a form
with the aforementioned metals supported on a heat-resistant metal
oxide carrier, and normally the metal will be present on the
carrier as an oxide or sulfide. When a mixture of metals is used,
it may be used as a bulk metal catalyst with an amount of metal of
at least 30% by mass based on the total weight of the catalyst. The
metal oxide carrier may be an oxide such as silica, alumina,
silica-alumina or titania, with alumina being preferred. Preferred
alumina is .gamma. or .beta. porous alumina. The loading weight of
the metal is preferably 0.5-35% by mass based on the total weight
of the catalyst. When a mixture of a metal of Groups 9-10 and a
metal of Group 6 is used, preferably the metal of Group 9 or 10 is
present in an amount of 0.1-5% by mass and the metal of Group 6 is
present in an amount of 5-30% by mass based on the total weight of
the catalyst. The loading weight of the metal may be measured by
atomic absorption spectrophotometry or inductively coupled plasma
emission spectroscopy, or the individual metals may be measured by
other ASTM methods.
[0058] The acidity of the metal oxide carrier can be controlled by
controlling the addition of additives and the nature of the metal
oxide carrier (for example, controlling the amount of silica
incorporated in a silica-alumina carrier). As examples of additives
there may be mentioned halogens, especially fluorine, and
phosphorus, boron, yttria, alkali metals, alkaline earth metals,
rare earth oxides and magnesia. Co-catalysts such as halogens
generally raise the acidity of metal oxide carriers, while weakly
basic additives such as yttria and magnesia can be used to lower
the acidity of the carrier.
[0059] As regards the hydrotreatment conditions, the treatment
temperature is preferably 150-450.degree. C. and more preferably
200-400.degree. C., the hydrogen partial pressure is preferably
1400-20,000 kPa and more preferably 2800-14,000 kPa, the liquid
hourly space velocity (LHSV) is preferably 0.1-10 and more
preferably 0.1-5 hr.sup.-1, and the hydrogen/oil ratio is
preferably 50-1780 m.sup.3/m.sup.3 and more preferably 89-890
m.sup.3/m.sup.3. These conditions are only for example, and the
hydrotreatment conditions in the first step may be appropriately
selected for different starting materials, catalysts and
apparatuses, in order to obtain the specified urea adduct value and
viscosity index for the treatment product obtained after the third
step.
[0060] The treatment product obtained by hydrotreatment in the
first step may be directly supplied to the second step, but a step
of stripping or distillation of the treatment product and
separating removal of the gas product from the treatment product
(liquid product) is preferably conducted between the first step and
second step. This can reduce the nitrogen and sulfur contents in
the treatment product to levels that will not affect prolonged use
of the hydrodewaxing catalyst in the second step. The main objects
of separating removal by stripping and the like are gaseous
contaminants such as hydrogen sulfide and ammonia, and stripping
can be accomplished by ordinary means such as a flash drum,
distiller or the like.
[0061] When the hydrotreatment conditions in the first step are
mild, residual polycyclic aromatic components can potentially
remain depending on the starting material used, and such
contaminants may be removed by hydrorefming in the third step.
[0062] The hydrodewaxing catalyst used in the second step may
contain crystalline or amorphous materials. Examples of crystalline
materials include molecular sieves having 10- or 12-membered ring
channels, composed mainly of aluminosilicates (zeolite) or
silicoaluminophosphates (SAPO). Specific examples of zeolites
include ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, ferrierite, ITQ-13,
MCM-68, MCM-71 and the like. ECR-42 may be mentioned as an example
of an aluminophosphate. Examples of molecular sieves include
zeolite beta and MCM-68. Among the above there are preferably used
one or more selected from among ZSM-48, ZSM-22 and ZSM-23, with
ZSM-48 being particularly preferred. The molecular sieves are
preferably hydrogen-type. Reduction of the hydrodewaxing catalyst
may occur at the time of hydrodewaxing. Alternatively, a
hydrodewaxing catalyst that has been previously subjected to
reduction treatment may be used for the hydrodewaxing.
[0063] As amorphous materials for the hydrodewaxing catalyst there
may be mentioned alumina doped with Group 3 metals, fluorinated
alumina, silica-alumina, fluorinated silica-alumina, silica-alumina
and the like.
[0064] A preferred mode of the dewaxing catalyst is a bifunctional
catalyst, i.e. one carrying a metal hydrogenated component which is
at least one metal of Group 6, at least one metal of Groups 8-10 or
a mixture thereof. Preferred metals are precious metals of Groups
9-10, such as Pt, Pd or mixtures thereof. Such metals are supported
at preferably 0.1-30% by mass based on the total weight of the
catalyst. The method for preparation of the catalyst and loading of
the metal may be, for example, an ion-exchange method or
impregnation method using a decomposable metal salt.
[0065] When molecular sieves are used, they may be compounded with
a binder material that is heat resistant under the hydrodewaxing
conditions, or they may be binderless (self-binding). As binder
materials there may be mentioned inorganic oxides, including
silica, alumina, silica-alumina, two-component combinations of
silica with other metal oxides such as titania, magnesia, yttria
and zirconia, and three-component combinations of oxides such as
silica-alumina-yttria, silica-alumina-magnesia and the like. The
amount of molecular sieves in the hydrodewaxing catalyst is
preferably 10-100% by mass and more preferably 35-100% by mass
based on the total weight of the catalyst. The hydrodewaxing
catalyst may be formed by a method such as spray-drying or
extrusion. The hydrodewaxing catalyst may be used in sulfided or
non-sulfided form, although a sulfided form is preferred.
[0066] As regards the hydrodewaxing conditions, the temperature is
preferably 250-400.degree. C. and more preferably 275-350.degree.
C., the hydrogen partial pressure is preferably 791-20,786 kPa
(100-3000 psig) and more preferably 1480-17,339 kPa (200-2500
psig), the liquid hourly space velocity is preferably 0.1-10
hr.sup.-1 and more preferably 0.1-5 hr.sup.-1, and the hydrogen/oil
ratio is preferably 45-1780 m.sup.3/m.sup.3 (250-10,000 scf/B) and
more preferably 89-890 m.sup.3/m.sup.3 (500-5000 scf/B). These
conditions are only for example, and the hydrodewaxing conditions
in the second step may be appropriately selected for different
starting materials, catalysts and apparatuses, in order to obtain
the specified urea adduct value and viscosity index for the
treatment product obtained after the third step.
[0067] The treatment product that has been hydrodewaxed in the
second step is then supplied to hydrorefining in the third step.
Hydrorefining is a form of mild hydrotreatment aimed at removing
residual heteroatoms and color components while also saturating the
olefins and residual aromatic compounds by hydrogenation. The
hydrorefining in the third step may be carried out in a cascade
fashion with the dewaxing step.
[0068] The hydrorefining catalyst used in the third step is
preferably one comprising a Group 6 metal, a Group 8-10 metal or a
mixture thereof supported on a metal oxide support. As preferred
metals there may be mentioned precious metals, and especially
platinum, palladium and mixtures thereof. When a mixture of metals
is used, it may be used as a bulk metal catalyst with an amount of
metal of 30% by mass or greater based on the weight of the
catalyst. The metal content of the catalyst is preferably not
greater than 20% by mass non-precious metals and preferably not
greater than 1% by mass precious metals. The metal oxide support
may be either an amorphous or crystalline oxide. Specifically,
there may be mentioned low acidic oxides such as silica, alumina,
silica-alumina and titania, with alumina being preferred. From the
viewpoint of saturation of aromatic compounds, it is preferred to
use a hydrorefming catalyst comprising a metal with a relatively
powerful hydrogenating function supported on a porous carrier.
[0069] As preferred hydrorefining catalysts there may be mentioned
meso-microporous materials belonging to the M41S class or line of
catalysts. M41S line catalysts are meso-microporous materials with
high silica contents, and specific ones include MCM-41, MCM-48 and
MCM-50. The hydrorefming catalyst has a pore size of 15-100 .ANG.,
and MCM-41 is particularly preferred. MCM-41 is an inorganic porous
non-laminar phase with a hexagonal configuration and pores of
uniform size. The physical structure of MCM-41 manifests as
straw-like bundles with straw openings (pore cell diameters) in the
range of 15-100 angstroms. MCM-48 has cubic symmetry, while MCM-50
has a laminar structure. MCM-41 may also have a structure with pore
openings having different meso-microporous ranges. The
meso-microporous material may contain metal hydrogenated components
consisting of one or more Group 8, 9 or 10 metals, and preferred as
metal hydrogenated components are precious metals, especially Group
10 precious metals, and most preferably Pt, Pd or their
mixtures.
[0070] As regards the hydrorefining conditions, the temperature is
preferably 150-350.degree. C. and more preferably 180-250.degree.
C., the total pressure is preferably 2859-20,786 kPa (approximately
400-3000 psig), the liquid hourly space velocity is preferably
0.1-5 hr.sup.-1 and more preferably 0.5-3 hr.sup.-1, and the
hydrogen/oil ratio is preferably 44.5-1780 m.sup.3/m.sup.3
(250-10,000 scf/B). These conditions are only for example, and the
hydrorefining conditions in the third step may be appropriately
selected for different starting materials and treatment
apparatuses, so that the urea adduct value and viscosity index for
the treatment product obtained after the third step satisfy the
respective conditions specified above.
[0071] The treatment product obtained after the third step may be
subjected to distillation or the like as necessary for separating
removal of certain components.
[0072] The wax isomerized base oil of the invention obtained by the
production method described above is not restricted in terms of its
other properties so long as the urea adduct value and viscosity
index satisfy their respective conditions. The wax isomerized base
oil of the invention preferably also satisfies the conditions
specified below.
[0073] The saturated component content of the wax isomerized base
oil of the invention is 70% by mass or greater, preferably 90% by
mass or greater, more preferably 93% by mass or greater and even
more preferably 95% by mass or greater, based on the total weight
of the wax isomerized base oil. The proportion of cyclic saturated
components among the saturated components is preferably 0.1-50% by
mass, more preferably 0.5-40% by mass, even more preferably 1-30%
by mass and most preferably 5-20% by mass. If the saturated
component content and proportion of cyclic saturated components
among the saturated components both satisfy these respective
conditions, it will be possible to achieve adequate levels for the
viscosity-temperature characteristic and heat and oxidation
stability, while additives added to the wax isomerized base oil
will be kept in a sufficiently stable dissolved state in the wax
isomerized base oil, and it will be possible for the functions of
the additives to be exhibited at a higher level. In addition, a
saturated component content and proportion of cyclic saturated
components among the saturated components satisfying the
aforementioned conditions can improve the frictional properties of
the wax isomerized base oil itself, resulting in a greater friction
reducing effect and thus increased energy savings.
[0074] If the saturated component content is less than 70% by mass,
the viscosity-temperature characteristic, heat and oxidation
stability and frictional properties will tend to be inadequate. If
the proportion of cyclic saturated components among the saturated
components is less than 0.1% by mass, the solubility of the
additives included in the wax isomerized base oil will be
insufficient and the effective amount of additives kept dissolved
in the wax isomerized base oil will be reduced, making it
impossible to effectively achieve the function of the additives. If
the proportion of cyclic saturated components among the saturated
components is greater than 50% by mass, the efficacy of additives
included in the wax isomerized base oil will tend to be
reduced.
[0075] According to the invention, a proportion of 0.1-50% by mass
cyclic saturated components among the saturated components is
equivalent to 99.9-50% by mass acyclic saturated components among
the saturated components. Both normal paraffins and isoparaffins
are included by the term "acyclic saturated components". The
proportions of normal paraffins and isoparaffins in the wax
isomerized base oil of the invention are not particularly
restricted so long as the urea adduct value satisfies the condition
specified above. The proportion of isoparaffins is preferably
50-99.9% by mass, more preferably 60-99.9% by mass, even more
preferably 70-99.9% by mass and most preferably 80-99.9% by mass
based on the total weight of the wax isomerized base oil. If the
proportion of isoparaffins in the wax isomerized base oil satisfies
the aforementioned conditions it will be possible to further
improve the viscosity-temperature characteristic and heat and
oxidation stability, while additives added to the wax isomerized
base oil will be kept in a sufficiently stable dissolved state in
the lubricating base oil and it will be possible for the functions
of the additives to be exhibited at an even higher level.
[0076] The saturated component content for the purpose of the
invention is the value measured according to ASTM D 2007-93 (units:
% by mass).
[0077] The proportions of the cyclic saturated components and
acyclic saturated components among the saturated components for the
purpose of the invention are the naphthene portion (measured:
monocyclic-hexacyclic naphthenes, units: % by mass) and alkane
portion (units: % by mass), respectively, both measured according
to ASTM D 2786-91.
[0078] The proportion of normal paraffins in the wax isomerized
base oil for the purpose of the invention is the value obtained by
analyzing saturated components separated and fractionated by the
method of ASTM D 2007-93 by gas chromatography under the following
conditions, and calculating the value obtained by identifying and
quantifying the proportion of normal paraffins among those
saturated components, with respect to the total weight of the wax
isomerized base oil. For identification and quantitation, a C5-50
straight-chain normal paraffin mixture sample is used as the
reference sample, and the normal paraffin content among the
saturated components is determined as the proportion of the total
of the peak areas corresponding to each normal paraffin, with
respect to the total peak area of the chromatogram (subtracting the
peak area for the diluent).
(Gas Chromatography Conditions)
[0079] Column: Liquid phase nonpolar column (length: 25 cm, inner
diameter: 0.3 mm.phi., liquid phase film thickness: 0.1 .mu.m),
temperature elevating conditions: 50.degree. C.-400.degree. C.
(temperature-elevating rate: 10.degree. C./min). [0080] Carrier
gas: helium (linear speed: 40 cm/min) [0081] Split ratio: 90/1
[0082] Sample injection rate: 0.5 .mu.L (injection rate of sample
diluted 20-fold with carbon disulfide).
[0083] The proportion of isoparaffins in the wax isomerized base
oil is the value of the difference between the acyclic saturated
components among the saturated components and the normal paraffins
among the saturated components, based on the total weight of the
wax isomerized base oil.
[0084] Other methods may be used for separation of the saturated
components or for compositional analysis of the cyclic saturated
components and acyclic saturated components, so long as they
provide similar results. Examples of other methods include the
method according to ASTM D 2425-93, the method according to ASTM D
2549-91, methods of high performance liquid chromatography (HPLC),
and modified forms of these methods.
[0085] When the bottom fraction obtained from a fuel oil
hydrocracker is used as the starting material for the wax
isomerized base oil of the invention, the obtained base oil will
have a saturated component content of 90% by mass or greater, a
proportion of cyclic saturated components in the saturated
components of 30-50% by mass, a proportion of acyclic saturated
components in the saturated components of 50-70% by mass, a
proportion of isoparaffins in the wax isomerized base oil of 40-70%
by mass and a viscosity index of 100-135 and preferably 120-130.
When the urea adduct value satisfies the conditions specified above
it will be possible to obtain a wax isomerized composition with the
effect of the invention, i.e. an excellent low-temperature
viscosity characteristic wherein the -40.degree. C. MR viscosity is
not greater than 20,000 mPas and especially not greater than 10,000
mPas. When a slack wax or Fischer-Tropsch wax having a high wax
content (for example, a normal paraffin content of 50% by mass or
greater) is used as the starting material for the wax isomerized
base oil of the invention, the obtained base oil will have a
saturated component content of 90% by mass or greater, a proportion
of cyclic saturated components in the saturated components of
0.1-40% by mass, a proportion of acyclic saturated components in
the saturated components of 60-99.9% by mass, a proportion of
isoparaffins in the wax isomerized base oil of 60-99.9% by mass and
a viscosity index of 100-170 and preferably 135-160. When the urea
adduct value satisfies the conditions specified above it will be
possible to obtain a wax isomerized composition with very excellent
properties in terms of the effect of the invention, and especially
the high viscosity index and low-temperature viscosity
characteristic, wherein the -40.degree. C. MR viscosity is not
greater than 12,000 mPas and especially not greater than 7000
mPas.
[0086] If the 20.degree. C. refractive index is represented as
n.sub.20 and the 100.degree. C. kinematic viscosity is represented
as kv100, the value of n.sub.20-0.002.times.kv100 for the wax
isomerized base oil of the invention is preferably 1.435-1.450,
more preferably 1.440-1.449, even more preferably 1.442-1.448 and
yet more preferably 1.444-1.447. If n.sub.20-0.002.times.kv100 is
within the range specified above it will be possible to achieve an
excellent viscosity-temperature characteristic and excellent heat
and oxidation stability, while additives added to the wax
isomerized base oil will be kept in a sufficiently stable dissolved
state in the wax isomerized base oil so that the functions of the
additives can be exhibited at an even higher level. A
n.sub.20-0.002.times.kv100 value within the aforementioned range
can also improve the frictional properties of the wax isomerized
base oil itself, resulting in a greater friction reducing effect
and thus increased energy savings.
[0087] If the n.sub.20-0.002.times.kv100 value exceeds the
aforementioned upper limit, the viscosity-temperature
characteristic, heat and oxidation stability and frictional
properties will tend to be insufficient, and the efficacy of
additives when added to the wax isomerized base oil will tend to be
reduced. If the n.sub.20-0.002.times.kv100 value is less than the
aforementioned lower limit, the solubility of the additives
included in the wax isomerized base oil will be insufficient and
the effective amount of additives kept dissolved in the wax
isomerized base oil will be reduced, tending to interfere with
effective function of the additives.
[0088] The 20.degree. C. refractive index (n.sub.20) for the
purpose of the invention is the refractive index measured at
20.degree. C. according to ASTM D1218-92. The 100.degree. C.
kinematic viscosity (kv100) for the purpose of the invention is the
kinematic viscosity measured at 100.degree. C. according to JIS K
2283-1993.
[0089] The aromatic content of the wax isomerized base oil of the
invention is preferably not greater than 5% by mass, more
preferably 0.05-3% by mass, even more preferably 0.1-1% by mass and
most preferably 0.1-0.5% by mass based on the total weight of the
wax isomerized base oil. If the aromatic content exceeds the
aforementioned upper limit, the viscosity-temperature
characteristic, heat and oxidation stability, frictional
properties, resistance to volatilization and low-temperature
viscosity characteristic will tend to be reduced, while the
efficacy of additives when added to the wax isomerized base oil
will also tend to be reduced. The wax isomerized base oil of the
invention may be free of aromatic components. The solubility of
additives can be further increased with an aromatic content of
0.05% by mass or greater.
[0090] The aromatic content in this case is the value measured
according to ASTM D 2007-93. The aromatic portion normally includes
alkylbenzenes and alkylnaphthalenes, as well as anthracene,
phenanthrene and their alkylated forms, compounds with four or more
fused benzene rings, and heteroatom-containing aromatic compounds
such as pyridines, quinolines, phenols, naphthols and the like.
[0091] The % C.sub.p of the wax isomerized base oil of the
invention is preferably 80 or greater, more preferably 82-99, even
more preferably 85-98 and most preferably 90-97. If the % C.sub.p
value of the wax isomerized base oil is less than 80, the
viscosity-temperature characteristic, heat and oxidation stability
and frictional properties will tend to be reduced, while the
efficacy of additives when added to the wax isomerized base oil
will also tend to be reduced. If the % C.sub.p value of the wax
isomerized base oil is greater than 99, on the other hand, the
additive solubility will tend to be lower.
[0092] The % C.sub.N of the wax isomerized base oil of the
invention is preferably not greater than 20, more preferably not
greater than 15, even more preferably 1-12 and most preferably
3-10. If the % C.sub.N value of the wax isomerized base oil exceeds
20, the viscosity-temperature characteristic, heat and oxidation
stability and frictional properties will tend to be reduced. If the
% C.sub.N is less than 1, however, the additive solubility will
tend to be lower.
[0093] The % C.sub.A of the wax isomerized base oil of the
invention is preferably not greater than 0.7, more preferably not
greater than 0.6 and even more preferably 0.1-0.5. If the % C.sub.A
value of the wax isomerized base oil exceeds 0.7, the
viscosity-temperature characteristic, heat and oxidation stability
and frictional properties will tend to be reduced. The % C.sub.A
value of the wax isomerized base oil of the invention may be zero.
The solubility of additives can be further increased with a %
C.sub.A value of 0.1 or greater.
[0094] The ratio of the % C.sub.P and % C.sub.N values for the wax
isomerized base oil of the invention is % C.sub.P/% C.sub.N of
preferably 7 or greater, more preferably 7.5 or greater and even
more preferably 8 or greater. If the % C.sub.P/% C.sub.N ratio is
less than 7, the viscosity-temperature characteristic, heat and
oxidation stability and frictional properties will tend to be
reduced, while the efficacy of additives when added to the wax
isomerized base oil will also tend to be reduced. The % C.sub.P/%
C.sub.N ratio is preferably not greater than 200, more preferably
not greater than 100, even more preferably not greater than 50 and
most preferably not greater than 25. The additive solubility can be
further increased if the % C.sub.P/% C.sub.N ratio is not greater
than 200.
[0095] The % C.sub.P, % C.sub.N and % C.sub.A values for the
purpose of the invention are, respectively, the percentage of
paraffinic carbons with respect to total carbon atoms, the
percentage of naphthenic carbons with respect to total carbons and
the percentage of aromatic carbons with respect to total carbons,
as determined by the method of ASTM D 3238-85 (n-d-M method). That
is, the preferred ranges for % C.sub.P, % C.sub.N and % C.sub.A are
based on values determined by these methods, and for example, %
C.sub.N may be a value exceeding 0 according to these methods even
if the wax isomerized base oil contains no naphthene portion.
[0096] The iodine value of the wax isomerized base oil of the
invention is preferably not greater than 0.5, more preferably not
greater than 0.3 and even more preferably not greater than 0.15,
and although it may be less than 0.01, it is preferably 0.001 or
greater and more preferably 0.05 or greater in consideration of
achieving a commensurate effect, and in terms of economy. Limiting
the iodine value of the wax isomerized base oil to not greater than
0.5 can drastically improve the heat and oxidation stability. The
"iodine value" for the purpose of the invention is the iodine value
measured by the indicator titration method according to HS K 0070,
"Test methods for acid value, saponification value, ester value,
iodine value, hydroxyl value and unsaponifiable matter of chemical
products".
[0097] The sulfur content in the wax isomerized base oil of the
invention will depend on the sulfur content of the starting
material. For example, when using a substantially sulfur-free
starting material as for synthetic wax components obtained by
Fischer-Tropsch reaction, it is possible to obtain a substantially
sulfur-free wax isomerized base oil. When using a sulfur-containing
starting material, such as slack wax obtained by a wax isomerized
base oil refining process or microwax obtained by a wax refining
process, the sulfur content of the obtained wax isomerized base oil
will normally be 100 ppm by mass or greater. From the viewpoint of
further improving the heat and oxidation stability and reducing
sulfur, the sulfur content in the wax isomerized base oil of the
invention is preferably not greater than 10 ppm by mass, more
preferably not greater than 5 ppm by mass and even more preferably
not greater than 3 ppm by mass.
[0098] From the viewpoint of cost reduction it is preferred to use
slack wax or the like as the starting material, in which case the
sulfur content of the obtained wax isomerized base oil is
preferably not greater than 50 ppm by mass and more preferably not
greater than 10 ppm by mass. The sulfur content for the purpose of
the invention is the sulfur content measured according to JIS K
2541-1996.
[0099] The nitrogen content in the wax isomerized base oil of the
invention is not greater than 10 ppm, preferably not greater than 5
ppm by mass, more preferably not greater than 3 ppm by mass and
even more preferably not greater than 1 ppm by mass. If the
nitrogen content exceeds 10 ppm by mass, the heat and oxidation
stability will tend to be reduced. The nitrogen content for the
purpose of the invention is the nitrogen content measured according
to JIS K 2609-1990.
[0100] The kinematic viscosity of the wax isomerized base oil
according to the invention, as the 100.degree. C. kinematic
viscosity, is preferably 1.5-20 mm.sup.2/s and more preferably
2.0-11 mm.sup.2/s. A 100.degree. C. kinematic viscosity of lower
than 1.5 mm.sup.2/s for the wax isomerized base oil is not
preferred from the standpoint of evaporation loss. If it is
attempted to obtain a wax isomerized base oil having a 100.degree.
C. kinematic viscosity of greater than 20 mm.sup.2/s, the yield
will be reduced and it will be difficult to increase the cracking
severity even when using a heavy wax as the starting material.
[0101] According to the invention, wax isomerized base oils having
a 100.degree. C. kinematic viscosity in the following ranges are
preferably used after fractionation by distillation or the
like.
[0102] Wax isomerized base oils having a 100.degree. C. kinematic
viscosity of 4.5-20 mm.sup.2/s, more preferably 4.8-11 mm.sup.2/s
and most preferably 5.5-8.0 mm.sup.2/s.
[0103] The 40.degree. C. kinematic viscosity of the wax isomerized
base oil of the invention is preferably 6.0-80 mm.sup.2/s and more
preferably 8.0-50 mm.sup.2/s. According to the invention, wax
isomerized fractions having a 40.degree. C. kinematic viscosity in
the following ranges are preferably used after fractionation by
distillation or the like.
[0104] Wax isomerized base oils having a 40.degree. C. kinematic
viscosity of 28-50 mm.sup.2/s, more preferably 29-45 mm.sup.2/s and
most preferably 30-40 mm.sup.2/s.
[0105] The wax isomerized base oil, having a urea adduct value and
viscosity index satisfying the respective conditions specified
above, can exhibit high levels for both the viscosity-temperature
characteristic and low-temperature viscosity characteristic
compared to a conventional lubricating base oil of the same
viscosity grade, and in particular it has an excellent
low-temperature viscosity characteristic, and superior heat and
oxidation stability, lubricity and resistance to
volatilization.
[0106] The 15.degree. C. density (.rho..sub.15) of the wax
isomerized base oil of the invention will also depend on the
viscosity grade of the wax isomerized base oil. It is preferably
not greater than the value of .rho. as represented by the following
formula (1), i.e., .rho..sub.15.ltoreq..rho..
.rho.=0.0025.times.kv100+0.816 (1)
[In this equation, kv100 represents the 100.degree. C. kinematic
viscosity (mm.sup.2/s) of the wax isomerized base oil.]
[0107] If .rho..sub.15>.rho., the viscosity-temperature
characteristic, heat and oxidation stability, resistance to
volatilization and low-temperature viscosity characteristic of the
wax isomerized base oil will tend to be reduced, while the efficacy
of additives when added to the lubricating base oil will also tend
to be reduced.
[0108] The 15.degree. C. density for the purpose of the invention
is the density measured at 15.degree. C. according to JIS K
2249-1995.
[0109] The aniline point (AP (.degree. C.)) of the wax isomerized
base oil of the invention will also depend on the viscosity grade
of the wax isomerized base oil. It is preferably greater than or
equal to the value of A as represented by the following formula
(2), i.e., AP.gtoreq.A.
A=4.3.times.kv100+100 (2)
[0110] [In this equation, kv100 represents the 100.degree. C.
kinematic viscosity (mm.sup.2/s) of the wax isomerized base
oil.]
[0111] If AP<A, the viscosity-temperature characteristic, heat
and oxidation stability, resistance to volatilization and
low-temperature viscosity characteristic of the wax isomerized base
oil will tend to be reduced, while the efficacy of additives when
added to the lubricating base oil will also tend to be reduced.
[0112] For example, the AP value of the wax isomerized base oil is
preferably 125.degree. C. or higher and more preferably 128.degree.
C. or higher. The aniline point for the purpose of the invention is
the aniline point measured according to ES K 2256-1985.
[0113] The NOACK evaporation of the wax isomerized base oil is
preferably 0% by mass or greater and more preferably 1% by mass or
greater, and preferably not greater than 6% by mass, more
preferably not greater than 5% by mass and even more preferably not
greater than 4% by mass. If the NOACK evaporation is below the
aforementioned lower limit it will tend to be difficult to improve
the low-temperature viscosity characteristic. If the NOACK
evaporation is above the respective upper limit, the evaporation
loss of the wax isomerized oil will be increased when the wax
isomerized base oil is used as a lubricating oil for an internal
combustion engine, and catalyst poisoning will be undesirably
accelerated as a result.
[0114] For the distillation property of the wax isomerized base
oil, the initial boiling point (IBP) is preferably 440-480.degree.
C., more preferably 430-470.degree. C. and even more preferably
420-460.degree. C. The 10% distillation temperature (T10) is
preferably 450-510.degree. C., more preferably 460-500.degree. C.
and even more preferably 460-480.degree. C. The 50% running point
(T50) is preferably 470-540.degree. C., more preferably
480-530.degree. C. and even more preferably 490-520.degree. C. The
90% running point (T90) is preferably 470-560.degree. C., more
preferably 480-550.degree. C. and even more preferably
490-540.degree. C. The final boiling point (FBP) is preferably
505-565.degree. C., more preferably 515-555.degree. C. and even
more preferably 525-565.degree. C. T90-T10 is preferably
35-80.degree. C., more preferably 45-70.degree. C. and even more
preferably 55-80.degree. C. FBP-IBP is preferably 50-130.degree.
C., more preferably 60-120.degree. C. and even more preferably
70-110.degree. C. T10-IBP is preferably 5-65.degree. C., more
preferably 10-55.degree. C. and even more preferably 10-45.degree.
C. FBP-T90 is preferably 5-60.degree. C., more preferably
5-50.degree. C. and even more preferably 5-40.degree. C.
[0115] By setting IBP, T10, T50, T90, FBP, T90-T10, FBP-IBP, T10-MP
and FBP-T90 within the preferred ranges specified above for the wax
isomerized base oil, it is possible to further improve the low
temperature viscosity and further reduce the evaporation loss. If
the distillation ranges for T90-T10, FBP-IBP, T10-IBP and FBP-T90
are too narrow, the wax isomerized base oil yield will be poor
resulting in low economy.
[0116] The IBP, T10, T50, T90 and FBP values for the purpose of the
invention are the running points measured according to ASTM D
2887-97.
[0117] Component (A) is, specifically, a compound represented by
the following formula (1) or formula (2).
##STR00003##
[In the formulas, R.sup.1 and R.sup.2 may be the same or different,
and each represents hydrogen or a straight-chain alkyl or
straight-chain alkenyl group, and at least one of R.sup.1 and
R.sup.2 is a C6-12 straight-chain alkyl or straight-chain alkenyl
group.]
##STR00004##
[In the formulas, R.sup.3 and R.sup.4 may be the same or different,
and each represents hydrogen or a straight-chain alkyl or
straight-chain alkenyl group, and at least one of R.sup.3 and
R.sup.4 is a C13-18 straight-chain alkyl or straight-chain alkenyl
group.]
[0118] The straight-chain alkyl or straight-chain alkenyl groups of
R.sup.1 and R.sup.2 are, specifically, straight-chain hexyl,
straight-chain hexenyl, straight-chain heptyl, straight-chain
heptenyl, straight-chain octyl, straight-chain octenyl,
straight-chain nonyl, straight-chain nonenyl, straight-chain decyl,
straight-chain decenyl, straight-chain undecyl, straight-chain
undecenyl, straight-chain dodecyl or straight-chain dodecenyl
groups, and the alkyl or straight-chain alkenyl groups of R.sup.3
and R.sup.4 are, specifically, straight-chain tridecyl,
straight-chain tridecenyl, straight-chain tetradecyl,
straight-chain tetradecenyl, straight-chain pentadecyl,
straight-chain pentadecenyl, straight-chain hexadecyl,
straight-chain hexadecenyl, straight-chain heptadecyl,
straight-chain heptadecenyl, straight-chain octadecyl,
straight-chain octadecenyl or oleyl groups.
[0119] Component (A) used for the invention includes compounds
wherein one of R.sup.1 and R.sup.2 in formula (1) or one of R.sup.3
and R.sup.4 in formula (2) is hydrogen while the other is a
straight-chain alkyl or straight-chain alkenyl group (phosphoric
acid monoesters), and compounds wherein both R.sup.1 and R.sup.2 or
both R.sup.3 and R.sup.4 are straight-chain alkyl and/or
straight-chain alkenyl groups (phosphoric acid diesters). According
to the invention, either a phosphoric acid monoester or phosphoric
acid diester may be used alone, or a mixture of a phosphoric acid
monoester and a phosphoric acid diester may be used, although from
the viewpoint of frictional properties it is preferred to use a
mixture of a phosphoric acid monoester and a phosphoric acid
diester. When a mixture is used, the phosphoric acid
monoester/phosphoric acid diester mixing ratio is preferably
10/90-90/10, more preferably 20/80-80/20 and even more preferably
30/70-70/30, as the molar ratio.
[0120] The content of component (A) in the lubricating oil
composition of the invention will usually be 0.01-0.5% by mass
based on the total weight of the composition. From the viewpoint of
excellent low-friction performance it is preferably 0.05% by mass
or greater and more preferably 0.1% by mass or greater based on the
total weight of the composition. From the viewpoint of excellent
corrosion resistance of the obtained lubricating oil composition,
the content of component (A) is not greater than 0.5% by mass and
preferably not greater than 0.4% by mass, based on the total weight
of the composition. The content of component (A) as phosphorus
element will differ depending on the molecular weight of component
(A), but it will usually be 0.0005-0.06% by mass, preferably
0.003-0.06% by mass and most preferably 0.005-0.05 as phosphorus
element, based on the total weight of the composition.
[0121] The acid value due to component (A) in the lubricating oil
composition of the invention is 0.1-1.0 mg/KOH, because if it is
less than 0.1 the friction reducing effect of the additive will be
undesirably reduced, and if it is greater than 1.0, corrosion of
the sliding materials will increase and in terms of friction
performance it will not be possible to maintain low friction for
prolonged periods, which is also undesirable.
[0122] Component (B) according to the invention is an alkylamine
represented by the following formula (3).
##STR00005##
[In formula (3), R.sup.5 and R.sup.6 may be the same or different,
and each represents hydrogen or a C4-30 branched-chain alkyl group,
and at least one of R.sup.5 and R.sup.6 is a branched-chain alkyl
group.]
[0123] The amine represented by formula (3) may be a monoamine,
diamine or polyamine having one or more C4-30 and preferably C4-20
branched-chain alkyl groups, but it is preferably a monoamine
having a C4-20 branched-chain alkyl group or a secondary amine of a
monoamine having two C4-20 branched-chain alkyl groups. From the
viewpoint of obtaining excellent low-temperature storage stability
when mixed with component (A) and excellent low-friction
performance when a cutting fluid is blended therewith, the
branched-chain alkyl groups are more preferably C6 or greater
branched-chain alkyl groups. From the viewpoint of solubility in
the lubricating base oil, the branched-chain alkyl groups are
preferably not greater than C20, more preferably not greater than
C16 and even more preferably not greater than C14.
[0124] Specific preferred C4-20 branched-chain alkyl groups are
branched-chain alkyl groups such as isobutyl, isopentyl, isohexyl,
isooctyl, isononyl, isodecyl, isoundecyl, isododecyl, isotridecyl,
isotetradecyl, isopentadecyl, isohexadecyl, isoheptadecyl,
isooctadecyl, isononadecyl and isoeicosyl.
[0125] The content of component (B) in the lubricating oil
composition of the invention will usually be 0.01-2% by mass based
on the total weight of the composition, but from the viewpoint of
excellent corrosion resistance when mixed with component (A), it is
preferably 0.05% by mass or greater and most preferably 0.1% by
mass or greater based on the total weight of the composition. From
the viewpoint of low-temperature storage stability and excellent
low-friction performance when a cutting fluid is blended therewith,
the content of component (B) is not greater than 2% by mass, more
preferably not greater than 1.0% by mass and most preferably not
greater than 0.5% by mass, based on the total weight of the
composition. The content of component (B) as nitrogen element will
differ depending on the molecular weight of component (B), but it
will usually be 0.0002-0.4% by mass, preferably 0.001-0.2% by mass
and most preferably 0.002-0.1% by mass as nitrogen element, based
on the total weight of the composition.
[0126] The optimal combination of component (A) and component (B)
in the lubricating oil composition of the invention is a
combination of an acidic phosphoric acid ester with a C6-18
straight-chain alkyl group and an amine with a C4-30 branched-chain
alkyl group, and most preferably it is a combination of
mono-n-octyl acid phosphate and/or di-n-octyl acid phosphate or
monooleyl acid phosphate and/or dioleyl acid phosphate, with
di-2-ethylhexylamine and/or diisotridecylamine.
[0127] The lubricating oil composition of the invention, comprising
a specific lubricating base oil, component (A) and component (B),
has an excellent low-friction property and excellent
low-temperature storage stability, and can maintain machining
accuracy without significant impairment of the initial low-friction
property even when a cutting fluid is blended therewith.
[0128] The lubricating oil composition of the invention may also
contain (C) a sulfur compound or other additives known in the field
of lubricating oils, in order to increase its performance or to
impart performance required of lubricating oil compositions for
various purposes, and especially machine tool sliding surface
lubricating oil compositions.
[0129] The lubricating oil composition of the invention preferably
further comprises (C) a sulfur compound, from the viewpoint of
obtaining excellent corrosion resistance, maintaining an even lower
frictional coefficient, and helping to maintain machining accuracy
for prolonged periods.
[0130] Examples of the (C) sulfur compound include sulfurized fats
and oils, sulfurized fatty acids, sulfurized esters, olefin
sulfides, dihydrocarbylpolysulfides, thiadiazole compounds,
alkylthiocarbamoyl compounds, thiocarbamate compounds, thioterpene
compounds, dialkylthiodipropionate compounds and the like. Any of
these compounds may be used alone, or mixtures of two or more
thereof may be used.
[0131] Sulfurized fats and oils are obtained by reacting sulfur or
sulfur-containing compounds with fats or oils (lard oil, whale oil,
vegetable oil, fish oil and the like), and although the sulfur
content is not particularly restricted it is usually preferred to
be 5-30% by mass. Specific examples include sulfurized lard,
sulfurized rapeseed oil, sulfurized castor oil, sulfurized soybean
oil, sulfurized rice bran oil, and mixtures of the foregoing.
[0132] Examples of sulfurized fatty acids include oleic sulfide and
the like, and examples of sulfurized esters include sulfurized
methyl oleate, sulfurized rice bran fatty acid octyl esters, and
their mixtures.
[0133] Examples of olefin sulfides include compounds represented by
the following formula (4):
R.sup.7--S.sub.a--R.sup.8 (4)
(wherein R.sup.7 represents a C2-15 alkenyl group, R.sup.8
represents a C2-15 alkyl group or alkenyl group, and a represents
an integer of 1-8). The compound is obtained by reacting a C2-15
olefin or its 2-4mer with a sulfidizing agent such as sulfur or
sulfur chloride, where the olefin is preferably propylene,
isobutene, diisobutene or the like.
[0134] A dihydrocarbylpolysulfide is a compound represented by the
following formula (5):
R.sup.9--S.sub.b--R.sup.10 (5)
(wherein R.sup.9 and R.sup.10 each represent a C1-20 alkyl or
cycloalkyl group, a C6-20 aryl group, a C7-20 alkylaryl group or a
C7-20 arylalkyl group, and may be the same or different, and b
represents an integer of 1-8). When R.sup.9 and R.sup.10 are alkyl
groups, the compound is an alkyl sulfide.
[0135] Specific examples for R.sup.9 and R.sup.10 in formula (5)
above include methyl, ethyl, n-propyl, isopropyl, n-butyl,
isobutyl, sec-butyl, tert-butyl, pentyls, hexyls, heptyls, octyls,
nonyls, decyls, dodecyls, cyclohexyl, cyclooctyl, phenyl, naphthyl,
tolyl, xylyl, benzyl and phenethyl.
[0136] Preferred examples of the dihydrocarbylpolysulfide include
dibenzylpolysulfide, dinonylpolysulfides, didodecylpolysulfides,
dibutylpolysulfides, dioctylpolysulfides, diphenylpolysulfide,
dicyclohexylpolysulfide, and mixtures of the foregoing.
[0137] Examples of preferred thiadiazole compounds include
1,3,4-thiadiazoles, 1,2,4-thiadiazole compounds and
1,4,5-thiadiazoles represented by the following formulas (6), (7)
and (8):
##STR00006##
(wherein R.sup.11 and R.sup.12 each represent hydrogen or a C1-20
hydrocarbon group, and c and d each represent an integer of 0-8).
Specific preferred examples of such thiadiazole compounds include
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,
3,5-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-hexyldithio)-1,2,3-thiadiazole,
4,5-bis(n-octyldithio)-1,2,3-thiadiazole,
4,5-bis(n-nonyldithio)-1,2,3-thiadiazole,
4,5-bis(1,1,3,3-tetramethylbutyldithio)-1,2,3-thiadiazole, and
mixtures of the foregoing.
[0138] Examples of alkylthiocarbamoyl compounds include compounds
represented by the following formula (9):
##STR00007##
[wherein R.sup.13-R.sup.16 each represent a C1-20 alkyl group, and
e represents an integer of 1-8]. Specific preferred examples of
such alkylthiocarbamoyl compounds include
bis(dimethylthiocarbamoyl)monosulfide,
bis(dibutylthiocarbamoyl)monosulfide,
bis(dimethylthiocarbamoyl)disulfide,
bis(dibutylthiocarbamoyl)disulfide,
bis(diamylthiocarbamoyl)disulfide,
bis(dioctylthiocarbamoyl)disulfide, and mixtures of the
foregoing.
[0139] Examples of alkylthiocarbamate compounds include compounds
represented by the following formula (10):
##STR00008##
[wherein R.sup.13-R.sup.16 each represent a C1-20 alkyl group, and
R.sup.17 represents a C1-10 alkyl group]. Specific preferred
examples of such alkylthiocarbamate compounds include
methylenebis(dibutyl dithiocarbamate) and
methylenebis[di(2-ethylhexyl)dithiocarbamate].
[0140] Examples of thioterpene compounds include reaction products
of phosphorus pentasulfide and pinene, and examples of
dialkylthiodipropionate compounds include dilaurylthiodipropionate,
distearylthiodipropionate, and their mixtures.
[0141] The content of the (C) sulfur compound in the lubricating
oil composition of the invention, from the viewpoint of the
frictional properties of the obtained lubricating oil composition,
is preferably 0.01% by mass or greater, more preferably 0.05% by
mass or greater and even more preferably 0.1% by mass or greater,
based on the total weight of the composition. Also, the content of
sulfur-based additives is preferably not greater than 5% by mass,
more preferably not greater than 3% by mass and even more
preferably not greater than 2% by mass based on the total weight of
the composition, from the viewpoint of excellent separability of
the obtained lubricating oil composition from water-soluble cutting
fluids, and because greater amounts will often fail to provide
further improvement in the frictional properties.
[0142] Examples of other known additives include monohydric
alcohols or polyhydric alcohols, monobasic or polybasic acids,
esters of these alcohols and acids, oil agents including amine
compounds such as amines and alkanolamines other than those of the
present claim 1, antioxidants including phenol-based compounds such
as di-tert-butyl-p-cresol and bisphenol A, and amine-based
compounds such as phenyl-.alpha.-naphthylamine and
N,N'-di(2-naphthyl)-p-phenylenediamine; metal inactivating agents
such as benzotriazoles or alkylthiadiazoles; antifoaming agents
such as silicone oils and fluorosilicon oils; phosphorus-based
additives other than acid phosphates (orthophosphoric acid esters,
phosphites, amine salts of acid phosphate or phosphite, and the
like); oil agents such as carboxylic acids; rust-preventive
additives such as alkenylsuccinic acids and sorbitan monooleate;
pour point depressants such as polymethacrylates; and viscosity
index improvers such as polymethacrylates, polybutenes,
polyalkylstyrenes, olefin copolymers, styrene-diene copolymers and
styrene-maleic anhydride copolymers.
[0143] The lubricating oil composition of the invention having the
construction described above is excellent in terms of low-friction
performance and low-temperature storage stability, does not notably
impair the initial low-friction property even when a cutting fluid
is blended therewith, and also exhibits excellent corrosion
resistance. It can therefore be suitably used for various purposes
in the field of lubricating oils in which low-friction properties,
low-temperature storage stability and corrosion resistance are
required. The effect of the invention is exhibited even more
notably when it is used as a lubricating oil for sliding guide
surfaces (sliding surfaces) of machine tools and the like.
Examples
[0144] The present invention will now be explained in greater
detail based on examples and comparative examples, with the
understanding that these examples are in no way limitative on the
invention.
[0145] [Examples A-1 to A-8 and Comparative Examples A-1 to A-4]
The lubricating oil compositions listed in Tables 1 and 2 were
prepared for Examples A-1 to A-8 and Comparative Examples A-1 to
A-4. The components used to prepare each composition were as
follows. The viscosity index for the purpose of the invention is
the viscosity index measured according to JIS K 2283-1993. The
saturated hydrocarbon component content is the weight percentage of
saturated hydrocarbon components, fractionated by the
silica-alumina gel chromatography method described in Analytical
Chemistry, Vol. 44, No. 6(1972), p. 915-919, "Separation of
High-Boiling Petroleum Distillates Using Gradient Elution Through
Dual-Packed (Silica Gel-Alumina Gel) Adsorption Columns" using
n-hexane instead of the n-pentane that is used for elution of the
saturated hydrocarbon components in the method, with respect to the
total sample.
Lubricating Base Oil:
[0146] Base oil 1: Solvent refined mineral oil VG68 (viscosity
index: 101, sulfur content: 0.51% by mass, saturated hydrocarbon
content: 65.6 vol %, 40.degree. C. kinematic viscosity: 68.7
mm.sup.2/s, flash point 248.degree. C., 15.degree. C. density:
0.882 g/cm.sup.3)
(A) Acid Phosphates:
[0147] A1: Mixture of mono-n-octyl acid phosphate and di-n-octyl
acid phosphate (phosphorus content: 11.6% by mass) [0148] A2:
Mixture of monooleyl acid phosphate and dioleyl acid phosphate
(phosphorus content: 6.6% by mass) [0149] A3: Mono-n-hexyl acid
phosphate (phosphorus content: 17% by mass) [0150] A4: Mixture of
mono-2-ethylhexyl acid phosphate and di-2-ethylhexyl acid phosphate
(phosphorus content: 12.0% by mass)
(B) Alkylamines:
[0150] [0151] B1: Di-2-ethylhexylamine [0152] B2:
Diisotridecylamine [0153] B3: 2-Ethylhexylamine [0154] B4:
Oleylamine (C) Sulfur compounds: [0155] C1: Polysulfide (sulfur
content: 22.0% by mass) [0156] C2: Sulfurized fats and oils (sulfur
content: 11.4% by mass)
[0157] The lubricating oil compositions of each of Examples A-1
to
[0158] A-8 and Comparative Examples A-1 to A-4 were then subjected
to the following tests.
[0159] (Frictional Property Evaluation Test)
[0160] FIG. 1 is a general schematic drawing of a frictional
coefficient measurement system used for the frictional property
evaluation test. In
[0161] FIG. 1, a table 1 and a movable jig 4 connected through a
load cell 5 are placed on a bed 6, and a weight 9 is situated on
the table 1 in place of a working tool. The table 1 and bed 6 are
both made of cast iron. The movable jig 4 has a bearing section,
and the bearing section is connected to an A/C servomotor 2 via a
feed screw 3. The feed screw 3 is driven by the A/C servomotor 2,
thus allowing the movable jig 4 to reciprocally move in the axial
direction of the feed screw 3 (the direction of the arrows in the
drawing). Also, the load cell 5 is electrically connected to a
computer 7 while the computer 7 and A/C servomotor 2 are each
electrically connected to a control panel 8, through which are
effected control of the reciprocal movement of the movable jig 4
and measurement of the load between the table 1 and movable jig 4.
In this frictional coefficient measuring system, the lubricating
oil composition is dropped on top of the bed 6, and the contact
pressure between the table 1 and bed 6 is adjusted to 200 kPa by
selecting the table weight 9, after which the movable jig 4 is
reciprocally moved at a sliding rate of 0.1 mm/min and a sliding
length of 15 mm. The load between the table 1 and the movable jig 4
during this time was measured with the load cell 5 (load meter),
and the measured value was used to determine the frictional
coefficient of the guide surface (table 1/bed 6=cast iron/cast
iron). The test was carried out after 3 warm-up runs. The
frictional coefficients of the obtained lubricating oil
compositions are shown in Tables 1 and 2.
[0162] (Frictional Property Evaluation Test with Cutting Fluid
Blending)
[0163] In a 1000 mL beaker there were placed 500 mL of the
lubricating oil composition and 25 mL of a water-soluble cutting
fluid (emulsion-type cutting fluid by Nippon Oil Corp.,
corresponding to Type W1#1 Product according to "Cutting Fluids" of
JISK 2241, dilution ratio: 10.times.). The mixture was gently
stirred in the beaker with a magnetic rotor for 1 minute at room
temperature. After stirring, it was allowed to stand for 1 hour and
the upper layer was used as the measuring sample. The results of
the frictional property evaluation test described above are shown
in Tables 1 and 2. With blending of the cutting fluid, a frictional
coefficient of greater than 0.110 was judged as outside of the
allowable range, a value of up to 0.110 was judged as within the
allowable range, and a value of up to 0.09 was judged as highly
superior.
[0164] (Phosphorus Residue with Blending of Cutting Fluid)
[0165] In a 1000 mL beaker there were placed 500 mL of the
lubricating oil composition and 25 mL of a water-soluble cutting
fluid (emulsion-type cutting fluid by Nippon Oil Corp.,
corresponding to Type W1#1 Product according to "Cutting Fluids" of
JISK 2241, dilution ratio: 10.times.). The mixture was gently
stirred in the beaker with a magnetic rotor for 1 minute at room
temperature. After stirring, it was allowed to stand for 1 hour and
the upper layer (oil layer) was used as the measuring sample for
quantitative analysis of the P content based on "Lubricating
Oils--Determination of Additive Elements--Inductively Coupled
Plasma Atomic Emission Spectrometry" of JPI test method 5S-38-03 of
the Japan Petroleum Institute. The value of (phosphorus content
before test/phosphorus content after test).times.100 was calculated
as the phosphorus residue (%). The obtained results are shown in
Tables 1 and 2.
[0166] (Corrosion Resistance Test with Blending of Cutting
Fluid)
[0167] In a 1000 mL beaker there were placed 500 mL of the
lubricating oil composition and 25 mL of a water-soluble cutting
fluid (emulsion-type cutting fluid by Nippon Oil Corp.,
corresponding to Type W1#1 Product according to "Cutting Fluids" of
JISK 2241, dilution ratio: 10.times.). The mixture was gently
stirred in the beaker with a magnetic rotor for 1 minute at room
temperature. After stirring, it was allowed to stand for 1 hour and
used as the measuring sample, placing 200 ml in a glass beaker, and
immersing a methanol-degreased 7 cm-square SPC material (thickness:
0.2 mm, #80 dull finish) in the container at ordinary temperature.
After 20 days had elapsed, the test piece was rinsed with solvent
and then the outer appearance was visually observed, evaluating the
corrosion resistance based on the presence or absence of
discoloration at the gas/liquid boundary. The evaluation criteria
were as follows. The obtained results are shown in Tables 1 and 2.
[0168] A: No discoloration [0169] B: Tendency toward some
discoloration [0170] C: Distinct discoloration
TABLE-US-00001 [0170] TABLE 1 Example Example Example Example
Example Example Example Example A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8
Composition Base oil Base remainder remainder remainder remainder
remainder remainder remainder remainder [% by mass] oil 1 Component
A1 0.1 -- 0.1 0.1 0.1 0.1 0.1 0.1 (A) A2 -- 0.2 -- -- 0.2 0.2 0.2
0.2 A3 -- -- -- -- -- -- -- -- A4 -- -- -- -- -- -- -- 0.5
Component B1 0.05 0.1 -- -- 0.15 0.15 -- -- (B) B2 -- -- 0.1 -- --
-- 0.2 0.2 B3 -- -- -- 0.1 -- -- -- -- B4 -- -- -- -- -- -- -- --
Component C1 -- -- -- -- -- 1.0 -- -- (C) C2 -- -- -- -- -- -- --
0.5 Acid value due to component 0.33 0.33 0.32 0.33 0.66 0.66 0.66
0.65 (A) [mgKOH/g] Frictional coefficient 0.080 0.075 0.080 0.080
0.075 0.065 0.070 0.075 Frictional coefficient when 0.085 0.085
0.085 0.090 0.080 0.075 0.080 0.080 blended with cutting fluid
Phosphorus residue when 75 70 80 70 75 80 80 80 blended with
cutting fluid [%] Corrosion resistance when A A A A A A A A blended
with cutting fluid
TABLE-US-00002 TABLE 2 Comp. Ex. Comp. Ex. Comp. Ex. Comp. Ex. A-1
A-2 A-3 A-4 Composition Base oil Base oil 1 remainder remainder
remainder remainder [% by mass] Component (A) A1 -- -- -- -- A2 --
-- -- -- A3 0.2 -- -- 0.6 A4 -- 0.3 0.3 -- Component (B) B1 -- --
0.25 0.5 B2 -- -- -- -- B3 -- -- -- -- B4 0.3 0.3 -- -- Component
(C) C1 -- -- -- -- C2 -- -- -- -- Acid value due to component (A)
0.77 0.96 0.96 2.30 [mgKOH/g] Frictional coefficient 0.105 0.140
0.135 0.095 Frictional coefficient when blended 0.125 0.150 0.145
0.135 with cutting fluid Phosphorus residue when blended 65 65 75
65 with cutting fluid [%] Corrosion resistance when blended A A A B
with cutting fluid
[0171] As is clear from the results shown in Tables 1 and 2, the
lubricating oil compositions of Examples A-1 to A-8 were superior
to the compositions of Comparative Examples A-1 to A-4 in terms of
low-friction performance (low frictional coefficient), maintaining
low-friction performance when blended with cutting fluids, and
exhibiting satisfactory corrosion resistance as well.
Examples B-1 to B-11
[0172] Lubricating oil compositions having the compositions listed
in Tables 3 and 4 were prepared for Examples B-1 to B-11. The
components used to prepare each lubricating oil composition were as
follows.
Lubricating Base Oil:
[0173] Base oil 1: Poly-.alpha.-olefin VG32 (viscosity index: 138,
sulfur content: <1 ppm by mass, 40.degree. C. kinematic
viscosity: 31.00 mm.sup.2/s, flash point: 246.degree. C.,
15.degree. C. density: 0.827 g/cm.sup.3, nitrogen content: <3
ppm) [0174] Base oil 2: Wax isomerized base oil VG32 (viscosity
index: 154, sulfur content: <1 ppm by mass, saturated
hydrocarbon content: 99.1% by mass, 40.degree. C. kinematic
viscosity: 31.10 mm.sup.2/s, 100.degree. C. kinematic viscosity:
6.215 mm.sup.2/s, aniline point: 124.9.degree. C., flash point
258.degree. C., 15.degree. C. density: 0.827 g/cm.sup.3, nitrogen
content: <3 ppm) [0175] Base oil 3: Hydrorefined base oil VG32
(viscosity index: 135, sulfur content: 0.01% by mass, saturated
hydrocarbon content: 97.4% by mass, 40.degree. C. kinematic
viscosity: 31.11 mm.sup.2/s flash point: 246.degree. C., 15.degree.
C. density: 0.840 g/cm.sup.3, nitrogen content: <3 ppm) [0176]
Base oil 4: Poly-.alpha.-olefin VG68 (viscosity index: 150, sulfur
content: <1 ppm by mass, 40.degree. C. kinematic viscosity:
69.90 mm.sup.2/s, flash point: 270.degree. C., 15.degree. C.
density: 0.842 g/cm.sup.3, nitrogen content: <3 ppm) [0177] Base
oil 5: Hydrorefined base oil VG68 (viscosity index: 110, sulfur
content: 0.08% by mass, saturated hydrocarbon content: 76.9% by
mass, 40.degree. C. kinematic viscosity: 66.09 mm.sup.2/s flash
point: 258.degree. C., 15.degree. C. density: 0.869 g/cm.sup.3,
nitrogen content: 10 ppm) [0178] Base oil 6: Poly-.alpha.-olefin
VG220 (viscosity index: 141, sulfur content: <1 ppm, 40.degree.
C. kinematic viscosity: 216.0 mm.sup.2/s, flash point: 262.degree.
C., 15.degree. C. density: 0.842 g/cm.sup.3, nitrogen content:
<3 ppm) [0179] Base oil 7: Solvent refined mineral oil VG32
(viscosity index: 102, sulfur content: 0.27% by mass, saturated
hydrocarbon content: 67.0% by mass, 40.degree. C. kinematic
viscosity: 31.54 mm.sup.2/s flash point: 220.degree. C., 15.degree.
C. density: 0.844 g/cm.sup.3, nitrogen content: 30 ppm) [0180] Base
oil 8: Solvent refined base oil VG68 (viscosity index: 98, sulfur
content: 0.62% by mass, saturated hydrocarbon content: 63.9% by
mass, 40.degree. C. kinematic viscosity: 68.69 mm.sup.2/s flash
point: 252.degree. C., 15.degree. C. density: 0.885 g/cm.sup.3,
nitrogen content: 40 ppm) [0181] Base oil 9: Solvent refined
mineral oil VG220 (viscosity index: 95, sulfur content: 0.56% by
mass, saturated hydrocarbon content: 60.1% by mass, 40.degree. C.
kinematic viscosity: 215.9 mm.sup.2/s flash point: 270.degree. C.,
15.degree. C. density: 0.894 g/cm.sup.3, nitrogen content: 110 ppm)
[0182] The notations VG32, VG68 and VG220 for the base oils are the
viscosity grades according to JIS K 2001, "Industrial
Lubricants--ISO Viscosity Classification".
(A) Acid Phosphates:
[0182] [0183] A1: Mixture of mono-n-octyl acid phosphate and
di-n-octyl acid phosphate (phosphorus content: 11.6% by mass)
[0184] A2: Mixture of monooleyl acid phosphate and dioleyl acid
phosphate (phosphorus content: 6.6% by mass)
(B) Alkylamines:
[0184] [0185] B1: Di-2-ethylhexylamine
Other Additives:
[0185] [0186] C1: Polysulfide (sulfur content: 22.0% by mass)
[0187] Each of the lubricating oil compositions of Examples B-1 to
B-11 were then subjected to a frictional property evaluation test,
a frictional property evaluation test with cutting fluid blending,
phosphorus residue measurement with cutting fluid blending and a
corrosion resistance test with cutting fluid blending, in the same
manner as Examples A-1 to A-8. The obtained results are shown in
Tables 3 and 4.
TABLE-US-00003 TABLE 3 Example Example Example Example Example
Example B-1 B-2 B-3 B-4 B-5 B-6 Composition, Lubricant Base oil 1
remainder -- -- -- -- -- % by mass base oil Base oil 2 -- remainder
-- -- -- -- Base oil 3 -- -- remainder -- -- -- Base oil 4 -- -- --
remainder -- remainder Base oil 5 -- -- -- -- remainder -- Base oil
6 -- -- -- -- -- -- Base oil 7 -- -- -- -- -- -- Base oil 8 -- --
-- -- -- -- Base oil 9 -- -- -- -- -- -- Component A1 0.1 0.1 0.1
0.1 0.1 0.1 (A) A2 0.2 0.2 0.2 -- -- 0.2 Component B1 0.15 0.15
0.15 0.05 0.05 0.15 (B) Other C1 1.0 1.0 1.0 -- -- 1.0 additives
Acid value due to component (A), 0.66 0.66 0.33 0.33 0.33 0.66
mgKOH/g Frictional coefficient 0.060 0.060 0.070 0.075 0.070 0.065
Frictional coefficient when blended 0.075 0.065 0.080 0.080 0.080
0.070 with cutting fluid Phosphorus residue when blended 75 80 75
75 80 80 with cutting fluid, % by mass Corrosion resistance when
blended A A A A A A with cutting fluid
TABLE-US-00004 TABLE 4 Example Example Example Example Example B-7
B-8 B-9 B-10 B-11 Composition, Lubricant Base oil 1 -- -- -- -- --
wt % base oil Base oil 2 -- -- -- -- -- Base oil 3 -- -- -- -- --
Base oil 4 -- -- -- -- -- Base oil 5 remainder -- -- -- -- Base oil
6 -- remainder -- -- -- Base oil 7 -- -- remainder -- -- Base oil 8
-- -- -- remainder -- Base oil 9 -- -- -- -- remainder Component
(A) A1 0.1 0.1 0.1 0.1 0.1 A2 0.2 0.2 0.2 0.2 0.2 Component (B) B1
0.15 0.15 0.15 0.15 0.15 Other additives C1 1.0 1.0 1.0 1.0 1.0
Acid value due to component (A), mgKOH/g 0.66 0.66 0.66 0.66 0.66
Frictional coefficient 0.060 0.080 0.085 0.090 0.095 Frictional
coefficient when blended 0.070 0.095 0.090 0.095 0.100 with cutting
fluid Phosphorus residue when blended 80 75 80 75 75 with cutting
fluid, wt % Corrosion resistance when blended A A A A A with
cutting fluid
* * * * *