U.S. patent application number 13/145647 was filed with the patent office on 2011-11-10 for lubricant for gears.
This patent application is currently assigned to IDEMITSU KOSAN CO., LTD.. Invention is credited to Tahei Okada.
Application Number | 20110275867 13/145647 |
Document ID | / |
Family ID | 42356016 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110275867 |
Kind Code |
A1 |
Okada; Tahei |
November 10, 2011 |
LUBRICANT FOR GEARS
Abstract
The invention provides a lubricating oil for gears which
contains an .alpha.-olefin polymer having a viscosity index of 175
or higher and which has a viscosity index of 170 or higher. The
lubricating oil for gears which has high shear stability and high
oxidation resistance and which prevents malfunction during start-up
at low temperature.
Inventors: |
Okada; Tahei; (Chiba,
JP) |
Assignee: |
IDEMITSU KOSAN CO., LTD.
Tokyo
JP
|
Family ID: |
42356016 |
Appl. No.: |
13/145647 |
Filed: |
January 22, 2010 |
PCT Filed: |
January 22, 2010 |
PCT NO: |
PCT/JP2010/050833 |
371 Date: |
July 25, 2011 |
Current U.S.
Class: |
585/1 |
Current CPC
Class: |
C10M 2207/283 20130101;
C10M 2207/289 20130101; C10N 2040/02 20130101; C10N 2020/02
20130101; C10N 2030/68 20200501; C08F 210/14 20130101; C08F 4/65908
20130101; C10M 107/10 20130101; C10M 2205/0285 20130101; C10M
2215/223 20130101; C08F 4/65912 20130101; C10N 2030/02 20130101;
C08F 4/65927 20130101; C10N 2030/06 20130101; C10M 2215/064
20130101; C10N 2040/04 20130101; C10M 2209/084 20130101; C10N
2030/10 20130101; C10N 2070/00 20130101; C08F 210/14 20130101; C08F
210/14 20130101; C08F 2500/17 20130101 |
Class at
Publication: |
585/1 |
International
Class: |
C10M 105/02 20060101
C10M105/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 23, 2009 |
JP |
2009-013312 |
Claims
1. A lubricating oil for gears which contains an .alpha.-olefin
polymer having a viscosity index of 175 or higher and which has a
viscosity index of 170 or higher.
2. A lubricating oil for gears which contains an .alpha.-olefin
polymer having a viscosity index of 180 or higher and which has a
viscosity index of 175 or higher.
3. A lubricating oil for gears according to claim 1 or 2, wherein
the .alpha.-olefin polymer is produced by polymerizing a C6 to C20
.alpha.-olefin.
4. A lubricating oil for gears according to any of claims 1 to 3,
wherein the .alpha.-olefin polymer is produced in the presence of a
metallocene catalyst.
5. A lubricating oil for gears according to claim 4, wherein the
metallocene catalyst includes (A) a transition metal compound
represented by formula (I): ##STR00006## (wherein each of R.sup.1
to R.sup.6 represents a hydrogen atom, a halogen atom, a C1 to C20
hydrocarbyl group, or a C1 to C20 organic group containing at least
one element selected from among a halogen atom, a silicon atom, an
oxygen atom, a sulfur atom, a nitrogen atom, and a phosphorus atom;
at least one group selected from among R.sup.1 to R.sup.3 is a
hydrogen atom; at least one group selected from among R.sup.4 to
R.sup.6 is a hydrogen atom; each of R.sup.a and R.sup.b represents
a divalent group formed though bonding of two cyclopentadienyl
rings via 1 to 3 atoms; each of X.sup.1 and X.sup.2 represents a
hydrogen atom, a halogen atom, a C1 to C20 hydrocarbyl group, or a
C1 to C20 organic group containing at least one element selected
from among a halogen atom, a silicon atom, an oxygen atom, a sulfur
atom, a nitrogen atom, and a phosphorus atom; and M represents a
transition metal belonging to group 4 to group 6 in the periodic
table) and (B) an organic aluminumoxy compound (b-1) and/or an
ionic compound (b-2) which can transform into a cation through
reaction with the transition metal compound.
6. A lubricating oil for gears according to any of claims 1 to 5,
which is a lubricating oil for use with a step-up gear for wind
power generation.
Description
TECHNICAL FIELD
[0001] The present invention relates to a lubricating oil for gears
and, more particularly, to a lubricating oil for gears containing
an .alpha.-olefin polymer having a high viscosity index.
BACKGROUND ART
[0002] In recent years, demand for utilization of natural energy
has attracted considerable attention to cope with environmental
issues and possible exhaustion of fossil fuels. For example, an
increasing numbers of countries and regions have come to employ
wind power generation. In wind power generation, kinetic energy of
wind is transformed into electric energy by means of rotors
including propellers which are rotated by wind. In general, a wind
power generator does not operate continuously. That is, when the
wind velocity falls outside a range allowing power generation, the
wind power generator is stopped, whereas when the wind velocity
falls within that range, the generator is restarted. In wind power
generation, a step-up gear is employed to elevate power generation
efficiency, and a step-up gear oil is used for lubrication of the
gear.
[0003] One known step-up gear oil for wind power generation,
disclosed in Patent Document 1, is a lubricating oil which contains
specific additives, which is excellent in seizure resistance and
fatigue resistance, and which forms only a reduced amount of
sludge. However, wind power generation is increasingly considered
promising these days, a step-up gear oil having higher performance
is desired. Specifically, a wind power generator may be installed
at sites where temperature varies greatly; e.g., deserts and
extremely cold areas. In such a case, when a step-up gear oil
having high viscosity measured at low temperature is used, the
discharge pressure of a circulating pump increases excessively
during start-up at low temperature, readily causing problematic
malfunction. Generally, conventionally employed step-up gear oils
have a viscosity index of about 140, and the employable limit in
low temperature is thought to be about -20.degree. C. In order to
further increase the sites available for installing a wind power
generator in the future, the viscosity of a step-up gear oil at low
temperature is preferably lowered. For example, when the step-up
gear oil has a viscosity index of 170 or higher, the employable
low-temperature limit is thought to be lowered by about 10.degree.
C.
[0004] One conceivable and general approach to enhance the
viscosity index of a lubricating oil is addition of a viscosity
index improver. However, addition of a high-molecular-weight
polymer having low shear stability to a step-up gear oil is not
preferred, since such a polymer imposes high load on the step-up
gear. In the case where a polymer having lower molecular weight is
used, use of an olefin copolymer encounters difficulty in elevating
viscosity index, and use of PMA (polymethacrylate) readily causes a
drop in viscosity attributed to shear force, along with a drop in
oxidation resistance.
[0005] Thus, there is demand for a lubricating oil for gears which
can be suitable employed with a step-up gear for wind power
generation or a similar means.
PRIOR ART DOCUMENTS
Patent Documents
[0006] Patent Documents 1: WO 2008/038701
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0007] The present invention has been conceived under such
circumstances. Thus, an object of the invention is to provide a
lubricating oil for gears which has high stability against shear
(hereinafter referred to as shear stability) and high oxidation
resistance and which prevents malfunction during start-up at low
temperature.
DESCRIPTION OF EMBODIMENTS
Means for Solving the Problems
[0008] The present inventor has carried out extensive studies, and
has found that the object can be attained by a lubricating oil
containing a specific .alpha.-olefin polymer. The present invention
has been accomplished on the basis of this finding.
[0009] Accordingly, the present invention provides the
following.
[0010] 1. A lubricating oil for gears which contains an
.alpha.-olefin polymer having a viscosity index of 175 or higher
and which has a viscosity index of 170 or higher.
[0011] 2. A lubricating oil for gears which contains an
.alpha.-olefin polymer having a viscosity index of 180 or higher
and which has a viscosity index of 175 or higher.
[0012] 3. A lubricating oil for gears according to 1 or 2 above,
wherein the .alpha.-olefin polymer is produced by polymerizing a C6
to C20 .alpha.-olefin.
[0013] 4. A lubricating oil for gears according to any of 1 to 3
above, wherein the .alpha.-olefin polymer is produced in the
presence of a metallocene catalyst.
[0014] 5. A lubricating oil for gears according to 4 above, wherein
the metallocene catalyst includes (A) a transition metal compound
represented by formula (I):
##STR00001##
(wherein each of R.sup.1 to R.sup.6 represents a hydrogen atom, a
halogen atom, a C1 to C20 hydrocarbyl group, or a C1 to C20 organic
group containing at least one element selected from among a halogen
atom, a silicon atom, an oxygen atom, a sulfur atom, a nitrogen
atom, and a phosphorus atom; at least one group selected from among
R.sup.1 to R.sup.3 is a hydrogen atom; at least one group selected
from among R.sup.4 to R.sup.6 is a hydrogen atom; each of R.sup.a
and R.sup.b represents a divalent group formed though bonding of
two cyclopentadienyl rings via 1 to 3 atoms; each of X.sup.1 and
X.sup.2 represents a hydrogen atom, a halogen atom, a C1 to C20
hydrocarbyl group, or a C1 to C20 organic group containing at least
one element selected from among a halogen atom, a silicon atom, an
oxygen atom, a sulfur atom, a nitrogen atom, and a phosphorus atom;
and M represents a transition metal belonging to group 4 to group 6
in the periodic table) and (B) an organic aluminumoxy compound
(b-1) and/or an ionic compound (b-2) which can transform into a
cation through reaction with the transition metal compound.
[0015] 6. A lubricating oil for gears according to any of 1 to 5
above, which is a lubricating oil for use with a step-up gear for
wind power generation.
Effects of the Invention
[0016] The present invention enables provision of a lubricating oil
for gears which has a high viscosity index, high shear stability,
and high oxidation resistance. The lubricating oil is preferably
employed with a step-up gear for wind power generation.
MODES FOR CARRYING OUT THE INVENTION
[0017] The lubricating oil for gears of the present invention
contains an .alpha.-olefin polymer for gears having a viscosity
index of 175 or higher. No particular limitation is imposed on the
.alpha.-olefin polymer used in the present invention, and any
.alpha.-olefin polymer may be used so long as the polymer has a
viscosity index of 175 or higher. When the .alpha.-olefin polymer
has a viscosity index of 175 or higher, the viscosity index of the
lubricating oil for gears can be readily adjusted to 170 or higher.
Thus, the viscosity index of the .alpha.-olefin polymer is
preferably 180 or higher, more preferably 190 or higher. In the
present invention, no particular limitation is imposed on the upper
limit of the viscosity index of the .alpha.-olefin polymer.
However, an .alpha.-olefin polymer having a viscosity index of 300
or less is generally employed. The viscosity index of the
lubricating oil for gears is more preferably 175 or higher.
[0018] The kinematic viscosity of the .alpha.-olefin polymer
measured at 100.degree. C. is preferably 20 to 200 mm.sup.2/s. When
the kinematic viscosity measured at 100.degree. C. falls within the
range, the .alpha.-olefin can be employed as a suitable ingredient
of the lubricating oil for gears. Thus, the kinematic viscosity of
the .alpha.-olefin polymer measured at 100.degree. C. is more
preferably 25 to 150 mm.sup.2/s, particularly preferably 30 to 110
mm.sup.2/s.
[0019] The kinematic viscosity of the .alpha.-olefin polymer
measured at 40.degree. C. is generally 270 to 450 mm.sup.2/s, and
such an .alpha.-olefin polymer can be employed as a suitable
ingredient of the lubricating oil for gears.
[0020] The .alpha.-olefin polymer generally has a triad
isotacticity (in .alpha.-olefin unit chain) of 20 to 40%,
preferably 25 to 35%. The syndiotacticity thereof generally 40% or
less, preferably 15 to 35%. When the .alpha.-olefin polymer has the
aforementioned stereoregularity, the polymer readily possesses
excellent physical characteristics at low-temperature.
[0021] For the production of the .alpha.-olefin polymer, one or
more C6 to C20 .alpha.-olefins are generally employed as raw
material monomers (.alpha.-olefins). Examples of such C6 to C20
.alpha.-olefins include 1-hexene, 4-methyl-1-pentene, 1-heptene,
1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene,
1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene,
1-octadecene, 1-nonadecene, and 1-eicocene. Of these, one or more
species are employed. Among these olefins, readily available and
inexpensive C6 to C14 olefins are more preferred, with C8 to C12
olefins being particularly preferred.
[0022] The amount of the .alpha.-olefin polymer incorporated into
the lubricating oil for gears is generally 70 to 95 mass % with
respect to the total amount of the lubricating oil, preferably 80
to 90 mass %.
[0023] The aforementioned .alpha.-olefin polymer may be produced
through, for example, polymerizing an .alpha.-olefin in the
presence of a metallocene catalyst. Examples of preferred
metallocene catalysts include a catalyst formed of (A) a transition
metal compound represented by formula (I):
##STR00002##
and (B) an organic aluminumoxy compound (b-1) and/or an ionic
compound (b-2) which can transform into a cation through reaction
with the transition metal compound.
[0024] The transition metal compound represented by formula (I) is
a transition metal compound which is a double-crosslinked
bis(cyclopentadienyl) metallocene complex. In formula (I), each of
R.sup.1 to R.sup.6 represents a hydrogen atom, a halogen atom, a C1
to C20 hydrocarbyl group, or a C1 to C20 organic group containing
at least one element selected from among a halogen atom, a silicon
atom, an oxygen atom, a sulfur atom, a nitrogen atom, and a
phosphorus atom. The case where the metallocene complex is a
complex having as a ligand a condensed cyclopentadienyl group; such
as a double-crosslinked bis(indenyl) metallocene complex is not
preferred, since high-pressure conditions, addition of a large
amount of hydrogen, severe reaction conditions such as high
reaction temperature, and dilution with inert solvent are required
in production of an .alpha.-olefin polymer having a specific
viscosity. Each of R.sup.1 to R.sup.6 is preferably a hydrogen atom
or a C1 to C20 alkyl group, more preferably a hydrogen atom or a C1
to C4 alkyl group. At least one group selected from among R.sup.1
to R.sup.3 is a hydrogen atom, and at least one group selected from
among R.sup.4 to R.sup.6 is a hydrogen atom. The case where any of
R.sup.1 to R.sup.3 is not a hydrogen atom, or the case where any of
R.sup.4 to R.sup.6 is not a hydrogen atom is not preferred, since
high-pressure conditions, addition of a large amount of hydrogen,
severe reaction conditions such as high reaction temperature, and
dilution with inert solvent are required in production of an
.alpha.-olefin polymer having a specific viscosity.
[0025] Each of R.sup.a and R.sup.b is a divalent group in which two
cyclopentadienyl rings are bound via 1 to 3 atoms, and is
preferably a group represented by formula (II).
##STR00003##
[0026] In formula (II), n is an integer of 1 to 3. Each of R.sup.7
and R.sup.8 represents a hydrogen atom, a halogen atom, a C1 to C20
hydrocarbyl group, or a C1 to C20 halogen-containing hydrocarbyl
group, and is preferably a hydrogen atom or a C1 to C4 hydrocarbyl
group, more preferably a hydrogen atom or a C1 to C4 alkyl group. A
represents an atom belonging to the group 14 of the periodic table.
Examples of preferred groups of R.sup.a and R.sup.b include
--CR.sup.7R.sup.8--, --SiR.sup.7R.sup.8--, and
--CR.sup.7R.sup.8--CR.sup.7R.sup.8--.
[0027] Each of X.sup.1 and X.sup.2, which are .sigma.-bonding
ligands, represents a hydrogen atom, a halogen atom, a C1 to C20
hydrocarbyl group, or a C1 to C20 organic group containing at least
one element selected from among a halogen atom, a silicon atom, an
oxygen atom, a sulfur atom, a nitrogen atom, and a phosphorus atom.
Examples of preferred groups of X.sup.1 and X.sup.2 include a
halogen atom. M represents a transition metal belonging to group 4
to group 6 in the periodic table and is preferably a group 4
transition metal.
[0028] Examples of the compound represented by formula (I) include
dichloride compounds such as
(1,1'-ethylene)(2,2'-ethylene)biscyclopentadienylzirconium
dichloride,
(1,1'-ethylene)(2,2'-ethylene)bis(3-methylcyclopentadienyl)zirconium
dichloride,
(1,1'-ethylene)(2,2'-ethylene)bis(4-methylcyclopentadienyl)zirconium
dichloride,
(1,1'-ethylene)(2,2'-ethylene)bis(3,4-dimethylcyclopentadienyl)zirconium
dichloride,
(1,1'-ethylene)(2,2'-ethylene)bis(3,5-dimethylcyclopentadienyl)zirconium
dichloride,
(1,1'-dimethylsilylene)(2,2'-dimethylsilylene)biscyclopentadienylzirconiu-
m dichloride,
(1,1'-dimethylsilylene)(2,2'-dimethylsilylene)bis(3-methylcyclopentadieny-
l)zirconium dichloride,
(1,1'-dimethylsilylene)(2,2'-dimethylsilylene)bis(4-methylcyclopentadieny-
l)zirconium dichloride,
(1,1'-dimethylsilylene)(2,2'-dimethylsilylene)bis(3,4-dimethylcyclopentad-
ienyl)zirconium dichloride,
(1,1'-dimethylsilylene)(2,2'-dimethylsilylene)bis(3,5-dimethylcyclopentad-
ienyl)zirconium dichloride,
(1,1'-dimethylsilylene)(2,2'-ethylene)biscyclopentadienylzirconium
dichloride,
(1,1'-dimethylsilylene)(2,2'-ethylene)bis(3-methylcyclopentadienyl)zircon-
ium dichloride,
(1,1'-dimethylsilylene)(2,2'-ethylene)bis(4-methylcyclopentadienyl)zircon-
ium dichloride,
(1,1'-dimethylsilylene)(2,2'-ethylene)bis(3,4-dimethylcyclopentadienyl)zi-
rconium dichloride,
(1,1'-dimethylsilylene)(2,2'-ethylene)bis(3,5-dimethylcyclopentadienyl)zi-
rconium dichloride,
(1,1'-isopropylidene)(2,2'-dimethylsilylene)biscyclopentadienylzirconium
dichloride,
(1,1'-isopropylidene)(2,2'-dimethylsilylene)bis(3-methylcyclopentadienyl)-
zirconium dichloride,
(1,1'-isopropylidene)(2,2'-dimethylsilylene)bis(4-methylcyclopentadienyl)-
zirconium dichloride,
(1,1'-isopropylidene)(2,2'-dimethylsilylene)bis(3,4-dimethylcyclopentadie-
nyl)zirconium dichloride,
(1,1'-isopropylidene)(2,2'-dimethylsilylene)bis(3,5-dimethylcyclopentadie-
nyl)zirconium dichloride,
(1,1'-isopropylidene)(2,2'-isopropylidene)bis(3-methylcyclopentadienyl)zi-
rconium dichloride, (1,1'-isopropylidene)
(2,2'-isopropylidene)bis(4-methylcyclopentadienyl)zirconium
dichloride,
(1,1'-isopropylidene)(2,2'-isopropylidene)bis(3,4-dimethylcyclopentadieny-
l)zirconium dichloride, and
(1,1'-isopropylidene)(2,2'-isopropylidene)bis(3,5-dimethylcyclopentadieny-
l)zirconium dichloride. Examples also include dimethyl forms,
diethyl forms, dihydro forms, diphenyl forms, and dibenzyl forms of
these complexes, and titanium analogues and hafnium analogues.
[0029] The transition metal compounds serving as component (A) may
be used singly or in combination of two or more species.
[0030] Examples of the organic aluminumoxy compound (b-1) serving
as component (B) include chain aluminoxanes represented by formula
(III):
##STR00004##
and cyclic aluminoxanes represented by formula (IV).
##STR00005##
[0031] In formula (III) and (IV), each of R.sup.9 to R.sup.14
represents a C1 to C20 (preferably C1 to C12) hydrocarbyl group or
a halogen atom. Examples of the hydrocarbyl group include an alkyl
group, an alkenyl group, an aryl group, and an arylalkyl group. The
parameter "n" represents a polymerization degree and is generally
an integer of 2 to 50, preferably 2 to 40. Groups R.sup.9 to
R.sup.14 may be identical to or different from one another.
[0032] Examples of the aluminoxane include methylaluminoxane,
ethylaluminoxane, and isobutylaluminoxane.
[0033] No particular limitation is imposed on the method of
producing the aforementioned aluminoxane, and a known method may be
applied. For example, alkylaluminum is brought into contact with a
condensing agent (e.g., water). In one method, an organic aluminum
compound is dissolved in an organic solvent, and the solution is
brought into contact with water. In another method, an organic
aluminum compound is added to a polymerization system, and then
water is added thereto. In still another method, crystallization
water included in a metal salt or the like, or water adsorbed to an
inorganic or organic is caused to react with an organic aluminum
compound. In yet another method, trialkylaluminum is sequentially
reacted with tetraalkyldialuminoxane and water. Notably, the
aluminoxane may be insoluble in toluene. These aluminoxanes may be
used singly or in combination of two or more species.
[0034] Any compound may be employed as component (b-2), so long as
the compound is an ionic compound which can transform into a cation
through reaction with the transition metal compound serving as the
aforementioned component (A). Among such compounds, preferably
employed are compounds represented by the following formula (V) and
(VI):
([L.sup.1-R.sup.15].sup.k+).sub.a([Z].sup.-).sub.b (V)
([L.sup.2].sup.k+).sub.a([Z].sup.-).sub.b (VI).
[0035] In formula (V), L.sup.1 represents a Lewis base; and
R.sup.15 represents a hydrogen atom, a C1 to C20 alkyl group or a
C6 to C20 hydrocarbyl group selected from among an aryl group, an
alkylaryl group, and an arylalkyl group.
[0036] Specific examples of the group L.sup.1 include amines such
as ammonia, methylamine, aniline, dimethylamine, diethylamine,
N-methylaniline, diphenylamine, N,N-dimethylaniline,
trimethylamine, triethylamine, tri-n-butylamine,
methyldiphenylamine, pyridine, p-bromo-N,N-dimethylaniline, and
p-nitro-N,N-dimethylaniline; phosphines such as triethylphosphine,
triphenylphosphine, and diphenylphosphine; thioethers such as
tetrahydrothiophene; esters such as ethyl benzoate; and nitriles
such as acetonitrile and benzonitrile. Specific examples of the
group R.sup.15 include a hydrogen atom, a methyl group, an ethyl
group, a benzyl group, and a trityl group.
[0037] In formula (VI), L.sup.2 represents M.sup.1,
R.sup.16R.sup.17M.sup.2, R.sup.18C, or R.sup.19M.sup.2. Each of
R.sup.16 and R.sup.17 represents a cyclopentadienyl group, a
substituted cyclopentadienyl group, an indenyl group, or a
fluorenyl group. R.sup.18 represents a C1 to C20 alkyl group, or a
a C6 to C20 hydrocarbyl group selected from among an aryl group, an
alkylaryl group, and an arylalkyl group. R.sup.19 represents a
large cyclic ligand such as tetraphenylporphyrin and
phthalocyanine.
[0038] M.sup.1 represents an element belonging to any of group 1 to
group 3, group 11 to group 13, and group 17 of the periodic table,
and M.sup.2 represents an element belonging to group 7 to group 12
of the periodic table.
[0039] Specific examples of the group R.sup.16 or R.sup.17 include
a cyclopentadienyl group, a methylcyclopentadienyl group, an
ethylcyclopentadienyl group, and a pentamethylcyclopentadienyl
group. Specific examples of the group R.sup.18 include a phenyl
group, a p-tolyl group, and a p-methoxyphenyl group. Specific
examples of the group R.sup.19 include tetraphenylporphyrin and
phthalocyanine. Specific examples of the group M.sup.1 include
L.sup.1, Na, K, Ag, Cu, Br, I, and I.sub.3, and specific examples
of the group M.sup.2 include Mn, Fe, Co, Ni, and Zn.
[0040] In formulas (V) and (VI), k represents an ion valence of
[L.sup.1-R.sup.15] and [L.sup.2], and is an integer of 1 to 3; a is
an integer of 1 or more; and b is (kxa).
[0041] [Z].sup.- represents a non-coordinating anion
[Z.sup.1].sup.- or [Z.sup.2].sup.-.
[0042] [Z.sup.1].sup.- represents an anion in which a plurality of
groups are bonded to an element; i.e., [M.sup.3G.sup.1G.sup.2 . . .
G.sup.f].sup.-. M.sup.3 represents an element belonging to group 5
to group 15 (preferably group 13 to group 15) of the periodic
table. Each of G.sup.1 to G.sup.f represents a hydrogen atom, a
halogen atom, a C1 to C20 alkyl group, a C2 to C40 dialkylamino
group, a C1 to C20 alkoxy group, a C6 to C20 aryl group, a C6 to
C20 aryloxy group, a C7 to C40 alkylaryl group, a C7 to C40
arylalkyl group, a C1 to C20 halo-substituted hydrocarbyl group, a
C1 to C20 acyloxy group or organic metalloid group, or a C2 to C20
heteroatom-containing hydrocarbyl group. Two or more groups of
G.sup.1 to G.sup.f may form a ring structure. The "f" represents an
integer [(valence of center metal M.sup.3)+1].
[0043] [Z.sup.2].sup.- represents a conjugate base of a Broensted
acid having a pKa (logarithm of reciprocal acid dissociation
constant) of -10 or lower, a conjugate base of the Broensted acid
and a Lewis acid, or a conjugate base of a generally defined
super-strong acid. To the conjugate base, a Lewis base may be
coordinated.
[0044] Specific examples of the group M.sup.3 of [Z.sup.1].sup.-;
i.e., [M.sup.3G.sup.1G.sup.2 . . . G.sup.f].sup.-, include B, Al,
Si, P, As, and Sb. Among them, B and Al are preferred. Specific
examples of the groups G.sup.1 and G.sup.2 to G.sup.f include
dialkylamino groups such as dimethylamino and diethylamino; alkoxy
or aryloxy groups such as methoxy, ethoxy, n-propoxy, and phenoxy;
hydrocarbyl groups such as methyl, ethyl, n-propyl, isopropyl,
n-butyl, isobutyl, n-octyl, n-eicosyl, phenyl, p-tolyl, benzyl,
4-t-butylphenyl, and 3,5-dimethylphenyl; halogen atoms such as
fluorine, chlorine, bromine, and iodine; heteroatom-containing
hydrocarbyl groups such as p-fluorophenyl, 3,5-difluorophenyl,
pentachlorophenyl, 3,4,5-trifluorophenyl, pentafluorophenyl,
3,5-bis(trifluoromethyl)phenyl, and bis(trimethylsilyl)methyl;
organic metalloid groups such as pentamethylantimony,
trimethylsilyl, trimethylgermyl, diphenylarsine,
dicyclohexylantimony, and diphenylboron.
[0045] Specific examples of the conjugate base [Z.sup.2].sup.- of a
Broensted acid having a pKa (logarithm of reciprocal acid
dissociation constant) of -10 or lower or the conjugate base of the
Broensted acid and a Lewis acid include trifluoromethane sulfonate
anion (CF.sub.3SO.sub.3).sup.-, bis(trifluoromethanesulfonyl)methyl
anion, bis(trifluoromethanesulfonyl)benzyl anion,
bis(trifluoromethanesulfonyl)amide, perchlorate anion
(ClO.sub.4).sup.-, trifluoroacetate anion (CF.sub.3COO).sup.-,
hexafluoroantimonate anion (SbF.sub.6).sup.-, fluorosulfonate anion
(FSO.sub.3).sup.-, chlorosulfonate anion (ClSO.sub.3).sup.-,
fluorosulfonate anion/pentafluoroantimonate anion
(FSO.sub.3/SbF.sub.5).sup.-, fluorosulfonate
anion/pentafluoroarsenate anion (FSO.sub.3/AsF.sub.5).sup.-, and
trifluoromethanesulfonate anion/pentafluoroantominate anion
(CF.sub.3SO.sub.3/SbF.sub.5).sup.-.
[0046] Specific examples of such compounds of component (b-2)
include triethylammonium tetraphenylborate, tri-n-butylammonium
tetraphenylborate, trimethylammonium tetraphenylborate,
tetraethylammonium tetraphenylborate, methyl(tri-n-butyl)ammonium
tetraphenylborate, benzyl(tri-n-butyl)ammonium tetraphenylborate,
dimethyldiphenylammonium tetraphenylborate,
triphenyl(methyl)ammonium tetraphenylborate, trimethylanilinium
tetraphenylborate, methylpyridinium tetraphenylborate,
benzylpyridinium tetraphenylborate, methyl(2-cyanopyridinium)
tetraphenylborate, triethylammonium
tetrakis(pentafluorophenyl)borate, tri-n-butylammonium
tetrakis(pentafluorophenyl)borate, tri-n-butylammonium
tetrakis(pentafluorophenyl)borate, triphenylammonium
tetrakis(pentafluorophenyl)borate, tetra-n-butylammonium
tetrakis(pentafluorophenyl)borate, tetraethylammonium
tetrakis(pentafluorophenyl)borate, benzyl(tri-n-butyl)ammonium
tetrakis(pentafluorophenyl)borate, methyldiphenylammonium
tetrakis(pentafluorophenyl)borate, triphenyl(methyl)ammonium
tetrakis(pentafluorophenyl)borate, methylanilinium
tetrakis(pentafluorophenyl)borate, dimethylanilinium
tetrakis(pentafluorophenyl)borate, trimethylanilinium
tetrakis(pentafluorophenyl)borate, methylpyridinium
tetrakis(pentafluorophenyl)borate, benzylpyridinium
tetrakis(pentafluorophenyl)borate, methyl(2-cyanopyridinium)
tetrakis(pentafluorophenyl)borate, benzyl(2-cyanopyridinium)
tetrakis(pentafluorophenyl)borate, methyl(4-cyanopyridinium)
tetrakis(pentafluorophenyl)borate, triphenylphosphonium
tetrakis(pentafluorophenyl)borate, dimethylanilinium
tetrakis[bis(3,5-ditrifluoromethyl)phenyl]borate, ferrocenium
tetraphenylborate, silver tetraphenylborate, trityl
tetraphenylborate, tetraphenylporphyrinmanganese tetraphenylborate,
ferrocenium tetrakis(pentafluorophenyl)borate,
(1,1'-dimethylferrocenium) tetrakis(pentafluorophenyl)borate,
decamethylferrocenium tetrakis(pentafluorophenyl)borate, silver
tetrakis(pentafluorophenyl)borate, trityl
tetrakis(pentafluorophenyl)borate, lithium
tetrakis(pentafluorophenyl)borate, sodium
tetrakis(pentafluorophenyl)borate, tetraphenylporphyrinmanganese
tetrakis(pentafluorophenyl)borate, silver tetrafluoroborate, silver
hexafluorophosphate, silver hexafluoroarsenate, silver perchlorate,
silver trifluoroacetate, and silver trifluoromethanesulfonate.
[0047] The compounds serving as component (b-2) may be used singly
or in combination of two or more species. When component (b-1) is
employed as component (B), the ratio by mole of amount of component
(A) to amount of component (B) is preferably 1:1 to 1:1,000,000,
more preferably 1:10 to 1:10,000. When component (b-2) is employed,
the ratio by mole of amount of component (A) to amount of component
(B) is preferably 10:1 to 1:100, more preferably 2:1 to 1:10. As
component (B), compounds serving as (b-1) and those serving as
(b-2) may be used singly or in combination of two or more
species.
[0048] The aforementioned catalyst may contain, as predominant
ingredients, the aforementioned components (A) and (B), or may
contain, as predominant ingredients, the aforementioned components
(A) and (B) and (C) an organic aluminum compound. The organic
aluminum compound serving as component (C) and employed in the
invention is a compound represented by formula (VII):
(R.sup.20).sub.vAlQ.sub.3-v (VII)
(wherein R.sup.20 represents a C1 to C10 alkyl group; Q represents
a hydrogen atom, a C1 to C20 alkoxy group, a C6 to C20 aryl group,
or a halogen atom; and v is an integer of 1 to 3).
[0049] Specific examples of the compound represented by formula
(VII) include trimethylaluminum, triethylaluminum,
triisopropylaluminum, triisobutylaluminum, dimethylaluminum
chloride, diethylaluminum chloride, methylaluminum dichloride,
ethylaluminum dichloride, dimethylaluminum fluoride,
diisobutylaluminum hydride, diethylaluminum hydride, and
ethylaluminum sesquichloride. These organic aluminum compounds may
be used singly or in combination of two or more species. The ratio
by mole of amount of component (A) to amount of component (C) is
preferably 1:1 to 1:10,000, more preferably 1:5 to 1:2,000, still
more preferably 1:10 to 1:1,000. Although use of component (C)
results in enhancement in catalytic activity on the basis of the
amount of transition metal, when the organic aluminum compound is
used in an excessive amount, the excess compound cannot be
utilized, and a large amount thereof remains in the formed
.alpha.-olefin polymer, which is not preferred.
[0050] In use the aforementioned catalyst, at least one catalyst
component may be supported by an appropriate carrier. No particular
limitation is imposed on the type of the carrier, and any of
inorganic oxide carriers and other inorganic and organic carriers
may be employed. Among them, an inorganic oxide carrier and a
non-oxide inorganic carrier are preferred, from the viewpoint of
control of the morphology.
[0051] Specific examples of the inorganic oxide carrier include
SiO.sub.2, Al.sub.2O.sub.3, MgO, ZrO.sub.2, TiO.sub.2,
Fe.sub.2O.sub.3, B.sub.2O.sub.3, CaO, ZnO, BaO, ThO.sub.2 and
mixtures thereof (e.g., silica-alumina, zeolite, ferrite, and glass
fiber). Among them, SiO.sub.2 and Al.sub.2O.sub.3 are particularly
preferred. The inorganic oxide carrier may contain a small amount
of a carbonate salt, a nitrate salt, a sulfate salt, or the like.
Examples of the non-oxide carrier include magnesium compounds and
complexes thereof represented by Mg(R.sup.21).sub.aX.sub.b,
typically being magnesium compounds such as MgCl.sub.2 and
Mg(OC.sub.2H.sub.5).sub.2. In the formula, R.sup.21 represents a C1
to C20 alkyl group, a C1 to C20 alkoxy group, or a C6 to C20 aryl
group; X represents a halogen atom or a C1 to C20 alkyl group; a is
0 to 2; b is 0 to 2; and a+b is 2. A plurality of R.sup.21 or X may
be identical to or different from one another.
[0052] Examples of the organic carrier include polymers such as
polystyrene, styrene-divinylbenzene copolymer, polyethylene,
polypropylene, substituted polystyrene, and polyarylate; starch;
and carbon. The carrier employed in the aforementioned catalyst is
preferably MgCl.sub.2, MgCl(OC.sub.2H.sub.5),
Mg(OC.sub.2H.sub.5).sub.2, SiO.sub.2, Al.sub.2O.sub.3, etc. The
carrier generally has a dimensional characteristic (mean particle
size), which varies depending on the type and production method, of
1 to 300 preferably 10 to 200 .mu.m, more preferably 20 to 100
.mu.m. When the particle size is small, the amount of micropowder
in the formed .alpha.-olefin polymer increases, whereas when the
particle size is large, the amount of coarse particles in the
.alpha.-olefin polymer increases, thereby causing reduction in bulk
density and plugging of a hopper. Also, the carrier generally has a
specific surface area of 1 to 1,000 m.sup.2/g, preferably 50 to 500
m.sup.2/g, a micropore volume of 0.1 to 5 cm.sup.3/g, preferably
0.3 to 3 cm.sup.3/g. In the case where one of the specific surface
area and micropore volume falls outside the corresponding range,
the catalytic activity may decrease. The specific surface area and
micropore volume may be determined from, for example, the volume of
nitrogen gas adsorbed by the carrier through the BET method (see J.
Am. Chem. Soc., 60, 309 (1983)). Before use, the carrier is
generally fired at 150 to 1,000.degree. C., preferably 200 to
800.degree. C.
[0053] When at least one catalyst component is caused to be
supported by the aforementioned carrier, at least one of components
(A) and (B), preferably both components (A) and (B) are supported.
No particular limitation is imposed on the method for supporting at
least one of components (A) and (B), and there may be employed the
following methods: a method in which at least one of components (A)
and (B) is mixed with the carrier; a method in which the carrier is
treated with an organic aluminum compound or a halogen-containing
silicon compound, and the product is mixed with at least one of
components (A) and (B) in an inert solvent; a method in which the
carrier is reacted with component (A) and/or component (B) and with
an organic aluminum compound or a halogen-containing silicon
compound; a method in which component (A) or component (B) is
caused to be supported by the carrier, and the carrier is mixed
with component (B) or component (A); a method in which a contact
reaction product between component (A) and component (B) is mixed
with the carrier; and a method in which the contact reaction
between component (A) and component (B) is performed in the
co-presence of the carrier. In the above reaction, the organic
aluminum compound (C) may be added to the reaction system.
[0054] Before use in polymerization, the thus-produced catalyst may
be separated as a solid through evaporation of solvent, or the
catalyst as is may be used. In the catalyst preparation, the
catalyst may be produced by at least one of components (A) and (B)
is caused to be supported on the carrier in the polymerization
system. In one specific procedure, an olefin (e.g., ethylene) is
subjected to preliminary polymerization for about 1 minute to about
2 hours at -20.degree. C. to 200.degree. C. under normal pressure
to 2 MPa in the presence of at least one of components (A) and (B),
the carrier, and an optional organic aluminum compound (C), to
thereby form catalyst particles.
[0055] The ratio by mass of component (b-1) to the carrier is
preferably 1:0.5 to 1:1,000, more preferably 1:1 to 1:50, and the
ratio by mass of component (b-2) to the carrier is preferably 1:5
to 1:10,000, more preferably 1:10 to 1:500. In the case where two
or more species are employed in combination as catalyst component
(B), the ratio by mass of each component (B) species to the carrier
preferably falls within the aforementioned range. The ratio by mass
of component (A) to the carrier is preferably 1:5 to 1:10,000, more
preferably 1:10 to 1:500. The catalyst employed in polymerization
may contain the aforementioned components (A), (B), and (C), as
predominant ingredients. Preferably, the ratio by mass of component
(B) to the carrier and the ratio by mass of component (A) to the
carrier fall within the aforementioned ranges. In this case, as
mentioned above, the ratio by mole of amount of component (C) to
amount of component (A) is preferably 1:1 to 1:10,000, more
preferably 1:5 to 1:2,000, still more preferably 1:10 to 1:1,000.
In the case where the ratio of component (B) (component (b-1) or
(b-2)) to carrier, the ratio of component (A) to carrier, or the
ratio of component (C) to component (A) falls outside the
aforementioned range, the catalytic activity may be reduced. The
thus-prepared catalyst generally has a mean particle size of 2 to
200 .mu.m, preferably 10 to 150 .mu.l, particularly preferably 20
to 100 .mu.m, a specific surface area of 20 to 1,000 m.sup.2/g,
preferably 50 to 500 m.sup.2/g. When the mean particle size is
smaller than 2 .mu.m, the amount of micropowder in the formed
polymer may increase, whereas when the particle size is in excess
of 200 .mu.m, the amount of coarse particles in the polymer may
increase. When the specific surface area is less than 20 m.sup.2/g,
the catalytic activity may decrease, whereas when the specific
surface area is in excess of 1,000 m.sup.2/g, the bulk density of
the formed polymer may decrease. In the aforementioned catalyst,
the carrier (100 g) generally contains transition metal in an
amount of 0.05 to 10 g, particularly preferably 0.1 to 2 g. When
the transition metal content falls outside the range, the catalytic
activity may decrease. Through supporting the catalyst component(s)
on such a carrier, industrially advantageous production method can
be realized.
[0056] No particular limitation is imposed on the polymerization
method employing the aforementioned catalyst, and any
polymerization method such as bulk polymerization, solution
polymerization, suspension polymerization, slurry polymerization,
or vapor-phase polymerization may be employed. Regarding
polymerization conditions, the polymerization temperature is
generally 0 to 200.degree. C., preferably 30 to 150.degree. C.,
more preferably 40 to 120.degree. C. The amount of catalyst
employed with respect to the raw material monomer, i.e., raw
material monomer/component (A) (by mole) is preferably 1 to
10.sup.8, particularly preferably 100 to 10.sup.5. The time of
polymerization is generally 5 minutes to 20 hours, and the pressure
at the reaction is preferably normal pressure to 0.2 MPaG,
particularly preferably normal pressure to 0.1 MPaG.
[0057] The method for producing an .alpha.-olefin oligomer
employing the aforementioned catalyst is preferably carried out in
the absence of solvent, from the viewpoint of productivity.
However, a solvent may also be used. Examples of the solvent which
may be employed in the production method include aromatic
hydrocarbons such as benzene, toluene, xylene, and ethylbenzene;
alicyclic hydrocarbons such as cyclopentane, cyclohexane, and
methylcyclohexane; aliphatic hydrocarbons such as pentane, hexane,
heptane, and octane; halogenated hydrocarbon such as chloroform and
dichloromethane. These solvent may be used singly or in combination
of two or more species. Alternatively, a monomer such as 1-butene
may be employed as a solvent.
[0058] In the method for producing an .alpha.-olefin polymer
employing the aforementioned catalyst, the catalytic activity is
enhanced by adding hydrogen to the C6 to C20 .alpha.-olefin
polymerization system. When hydrogen is used, the pressure thereof
is generally 0.2 MPaG or lower, preferably 0.001 to 0.1 MPaG, more
preferably 0.01 to 0.1 MPaG.
[0059] In the method for producing an .alpha.-olefin polymer
employing the aforementioned catalyst, preliminary polymerization
may be carried out in the presence of the aforementioned catalyst.
Preliminary polymerization may be carried out through, for example,
causing a small amount of olefin into contact with the catalyst
component(s). However, no particular limitation is imposed the
method, and any known method may be employed. No particular
limitation is imposed on the olefin used in preliminary
polymerization, and examples of the olefin include ethylene, a C3
to C20 .alpha.-olefin, and mixtures thereof. In an advantageous
manner, the same olefin as employed in the main polymerization is
used. Preliminary polymerization is generally performed at -20 to
200.degree. C., preferably -10 to 130.degree. C., more preferably 0
to 80.degree. C. In the preliminary polymerization, a solvent such
as an inert hydrocarbon, an aliphatic hydrocarbon, an aromatic
hydrocarbon, a monomer, etc. may be used. Among them, an aliphatic
hydrocarbon is particularly preferred. Alternatively, the
preliminary polymerization may be performed in the absence of
solvent. Preferably, preliminary polymerization conditions are
tuned such that the amount of preliminary polymerization product
with respect to 1 mmol of the transition metal component in the
catalyst is adjusted to 1 to 10,000 g, particularly preferably 1 to
1,000 g.
[0060] In the production method of the present invention, the
molecular weight of the formed polymer is controlled by selecting
the type and amount of each catalyst component or polymerization
temperature or by adding hydrogen or an inert gas (e.g., nitrogen)
to the polymerization system.
[0061] After completion of the aforementioned production step, the
.alpha.-olefin polymer employed in the present invention may be
purified by removing C.ltoreq.24 .alpha.-olefin compounds
(.alpha.-olefin and .alpha.-olefin oligomers). Examples of the
removal method include distillation under reduced pressure.
[0062] In order to enhance the stability of the lubricating oil for
gears, the .alpha.-olefin polymer is preferably subjected to
hydrogenation treatment. No particular limitation is imposed on the
hydrogenation, and any known technique may be employed.
[0063] When polymerization is performed in the presence of the
catalyst containing the aforementioned components (A) and (B),
isomerization is more effectively suppressed, as compared to
conventional Friedel Crafts reaction. Therefore, the formed
.alpha.-olefin polymer exhibits enhanced oxidation resistance and
has high viscosity index and high fluidity, at low temperature.
Thus, the .alpha.-olefin polymer is particularly preferred as an
ingredient of a lubricating oil for gears.
[0064] The lubricating oil for gears of the present invention
contains the aforementioned .alpha.-olefin polymer and has a
viscosity index of 170 or higher. Since the lubricating oil for
gears has a viscosity index of 170 or higher, malfunction during
start-up at low temperature can be suppressed. No particular
limitation is imposed on the upper limit of the viscosity index.
For example, according to the present invention, a lubricating oil
for gears having a viscosity index of 300 or less can be
produced.
[0065] Thus, the lubricating oil for gears of the present invention
attains such a high viscosity index without containing a viscosity
index improver. Therefore, the lubricating oil of the invention
exhibits excellent shear stability.
[0066] The lubricating oil for gears of the present invention
preferably has a kinematic viscosity at -20.degree. C. of 20,000
mm.sup.2/s or lower. Under the conditions, malfunction during
start-up at low temperature can be suppressed. From this viewpoint,
the kinematic viscosity at -20.degree. C. is more preferably 18,000
mm.sup.2/s or less, particularly preferably 17,000 mm.sup.2/s or
less. For gaining an appropriate lube action, the lubricating oil
for gears of the present invention preferably has a kinematic
viscosity at 40.degree. C. of 300 to 340 mm.sup.2/s.
[0067] So long as the object of the present invention is not
impaired, the lubricating oil for gears of the present invention
may be mixed with a conventionally known base oil in use or may
further contain various additives.
[0068] Either mineral oil or synthetic oil may be used as a base
oil. Examples of the mineral oil include paraffin-base mineral oil,
intermediate mineral oil, and naphthene-base mineral oil. Specific
examples include solvent-refined or hydrogenated light neutral oil,
medium neutral oil, heavy neutral oil, and bright stock. Examples
of the synthetic oil which may be employed include polybutene,
polyol ester, dibasic acid esters, phosphate esters, polyphenyl
ethers, alkylbenzenes, alkylnaphthalenes, polyoxyalkylene glycols,
neopentyl glycol, silicone oil, trimethylolpropane,
pentaerythritol, and hindered esters. These base oils may be used
singly or in combination of two or more species, and mineral oil
and synthetic oil may be used in combination.
[0069] Examples such additives include an extreme pressure agent,
an oiliness agent, an anti-wear agent, an ashless
detergent-dispersant, an antioxidant, a rust inhibitor, a metal
deactivator, a viscosity index improver, a pour point depressant,
and a defoaming agent.
[0070] Examples of the extreme pressure agent, the oiliness agent,
and the anti-wear agent include sulfur compounds such as olefin
sulfide, dialkyl polysulfide, diarylalkyl polysulfide, and diaryl
polysulfide; phosphorus compounds such as acidic phosphate esters,
phosphate esters, thiophosphate esters, phosphite esters, alkyl
hydrogenphosphites, and amine salts thereof; chlorine compounds
such as chlorinated fats and oils, chlorinated paraffins,
chlorinated fatty acid esters, and chlorinated fatty acids; ester
compounds such as maleic acid alkyl or alkenyl esters, succinic
acid alkyl or alkenyl esters, and polyol esters; organic acid
compounds such as alkyl or alkeylmaleic acids and alkyl or
alkenylsuccinic acids; and organometallic compounds such as
naphthenate salts, zinc dithiophosphate (ZnDTP), zinc
dithiocarbamate (ZnDTC), molybdenum oxysulfide
organophosphorodithioate (MoDTP), and molybdenum oxysulfide
dithiocarbamate (MoDTC).
[0071] Examples of the ashless detergent-dispersant include
succinimides, boron-containing succinimides, benzylamines,
boron-containing benzylamines, succinate esters, and mono- or
divalent carboxamides including fatty acid amides and
succinamides.
[0072] The antioxidant employed may be an amine-based antioxidant,
a phenol-based antioxidant, or a sulfur-containing antioxidant,
which are conventionally employed in lubricating oil. These
antioxidants may be used singly or in combination of two or more
species. Examples of the amine-based antioxidant include
monoalkyldiphenylamine compounds such as monooctyldiphenylamine and
monononyldiphenylamine; dialkyldiphenylamine compounds such as
4,4'-dibutyldiphenylamine, 4,4'-dipentyldiphenylamine,
4,4'-dihexyldiphenylamine, 4,4'-diheptyldiphenylamine,
4,4'-dioctyldiphenylamine, and 4,4'-dinonyldiphenylamine;
polyalkyldiphenylamine compounds such as tetrabutyldiphenylamine,
tetrahexyldiphenylamine, tetraoctyldiphenylamine, and
tetranonyldiphenylamine; and naphthylamine compounds such as
.alpha.-naphthylamine, phenyl-.alpha.-naphthylamine,
butylphenyl-.alpha.-naphthylamine,
pentylphenyl-.alpha.-naphthylamine,
hexylphenyl-.alpha.-naphthylamine,
heptylphenyl-.alpha.-naphthylamine,
octylphenyl-.alpha.-naphthylamine, and
nonylphenyl-.alpha.-naphthylamine.
[0073] Examples of the phenol-based antioxidant include monophenol
compounds such as 2,6-di-tert-butyl-4-methylphenol,
2,6-di-tert-butyl-4-ethylphenol, and octadecyl
3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; and diphenol
compounds such as 4,4'-methylenebis(2,6-di-tert-butylphenol) and
2,2'-methylenebis(4-ethyl-6-tert-butylphenol).
[0074] Examples of the sulfur-containing antioxidant include
2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol;
thioterpene compounds such as a reaction product between phosphorus
pentasulfide and pinene; and dialkyl thiodipropionates such as
dilauryl thiodipropionate and distearyl thiodipropionate.
[0075] Examples of the rust inhibitor include metal sulfonates and
succinic acid esters, and examples of the metal deactivator include
benzotriazole and thiadiazole.
[0076] Examples of the viscosity index improver include
polymethacrylates, dispersion-type polymethacrylates, olefin
copolymers (e.g., ethylene-propylene copolymer), dispersion-type
olefin copolymers, and styrene copolymers (e.g., styrene-diene
hydrogenated copolymer).
[0077] Examples of the pour point depressant which may be employed
in the invention include polymethacrylates having a weight average
molecular weight of about 50,000 to about 150,000.
[0078] The defoaming agent is preferably a high-molecular-weight
silicone defoaming agent or a polyacrylate defoaming agent.
Incorporation of a defoaming agent such as a high-molecular-weight
silicone defoaming agent into the composition of the invention
effectively attains defoaming property.
[0079] Examples of the high-molecular-weight silicone defoaming
agent include organopolysiloxanes. Of these, fluorine-containing
organopolysiloxanes such as trifluoropropylmethyl silicone oil are
particularly preferred.
[0080] The lubricating oil for gears of the present invention is a
lubricating oil having a high viscosity index and exhibiting
excellent shear stability and oxidation resistance. Thus, the
lubricating oil is preferably employed as, for example, an
automotive gear oil and an industrial gear oil, particularly
preferably as a wind power generation step-up gear.
EXAMPLES
[0081] The present invention will next be described in more detail
by way of examples, which should not be construed as limiting the
invention thereto.
Production Example 1
[0082] To a stainless steel autoclave (capacity: 5 L) purged with
nitrogen, 1-decene (2.5 L), which had been degassed and dehydrate
through nitrogen bubbling in advance, was fed. The temperature of
the autoclave was elevated to 105.degree. C., and a 1.0-mol/L
triisobutylaluminum/toluene solution (6.3 mL) and a 10-mmol/L
N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate/toluene
suspension (5 mL) were added to the autoclave.
[0083] Subsequently, a 10-mmol/L
(1,1'-dimethylsilylene)(2,2'-dimethylsilylene)-bis(cyclopentadienyl)zirco-
nium dichloride/toluene solution (2.5 mL) was added to the
autoclave, and the contents were allowed to react at 105.degree. C.
for 6 hours, while hydrogen (50 kPa) was continuously added
thereto.
[0084] In the above reaction, the ratio of metallocene compound to
1-decene was 0.025 mmol/L(1-decene); the ratio by mole of
triisobutylaluminum/metallocene compound was 100; and the ratio by
mole of borate compound/metallocene compound was 2. The reaction
was terminated with 1% dilute HCl (500 mL), and the reaction
product was washed twice with deionized water (100 mL), whereby the
remaining catalysts components were decomposed and removed from the
reaction product. The element analysis of the obtained solution
revealed that all the Cl level, Al level, and Zr level were less
than 2 mass ppm, indicating that the product contained
substantially no catalyst residue.
[0085] The solution from which the decomposed catalyst components
had been removed was distilled under reduced pressure, to thereby
remove remaining monomers and dimers. Subsequently, the
thus-treated solution was fed into a stainless steel autoclave
(capacity: 5 L) purged with nitrogen, and a palladium/alumina
catalyst (5% Pd-deposited) (1 mass %) was added to the autoclave.
While hydrogen (0.8 MPa) was continuously fed thereto under
stirring, reaction was performed at 85.degree. C. for 5 hours.
After completion of reaction, the reaction mixture was filtered
through filter paper (No. 2), to thereby remove the catalyst and
yield a target product.
Production Example 2
[0086] A stainless steel autoclave (capacity: 2 L) was sufficiently
dried and purged with nitrogen. Under nitrogen, 1-dodecene (780 mL)
and 1-octene (420 mL) were added to the autoclave, and the
temperature thereof was elevated to 105.degree. C. Subsequently,
under nitrogen, triisobutylaluminum (0.3 mmol) (1 mmol/mL toluene
solution; 0.3 mL),
(1,1'-dimethylsilylene)(2,2'-dimethylsilylene)-bis(cyclopentadienyl)zirco-
nium dichloride (15 .mu.mol) (5 .mu.mol/mL toluene solution; 3 mL),
and N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate (60
.mu.mol) (20 .mu.mol/mL slurry in toluene; 3 mL) were added to the
autoclave, and the mixture was stirred for a while. Then, hydrogen
(0.05 MPaG) was fed thereto, and polymerization was initiated. The
polymerization reaction was performed at 105.degree. C. for 120
minutes, and the polymerization was terminated through addition of
methanol (10 mL) to the polymerization system. The contents were
removed from the autoclave and added to 1 mass % aqueous NaOH (500
mL) with stirring. The solution was transferred to a separating
funnel, to thereby recover an organic layer. The organic layer was
washed with water and then, filtered through filter paper (2C,
product of Toyo Roshi Kaisha, Ltd.), to thereby remove solid
matter. From the thus-obtained solution, toluene, remaining raw
materials, methanol, etc. were removed by means of a rotary
evaporator (reduced pressure of about 1.0.times.10.sup.-4 MPa, oil
bath at 100.degree. C.), to thereby yield a clear liquid (666 g).
The liquid was further distilled under reduced pressure
(5.times.10.sup.-6 MPa) at 180.degree. C. by means of a thin-film
distillatior (product of Sibata Scientific Technology Ltd.,
molecular distillation apparatus MS-300, with high-vacuum pumping
system DS-212Z), to thereby yield a polymerization product (631 g),
from which C.ltoreq.24 component had been removed. The
thus-obtained polymerization product was fed to a stainless steel
autoclave (capacity: 2 L), and a stabilized nickel catalyst (SN750,
product of Sakai Chemical Industry Co., Ltd.) was added thereto in
an amount of 1 mass %. In the presence of hydrogen (2 MPa), the
reaction system was allowed to react at 130.degree. C. for 6 hours.
After completion of reaction, the temperature of the contents was
lowered to about 80.degree. C., and the contents were removed. The
contents were filtered at 70.degree. C. through a 1-.mu.m filter,
to thereby yield 630 g of a target product.
Preparation of Lubricating Oil
[0087] Lubricating oils having formulations (parts by mass) shown
in Table 1 were prepared. In the preparation, the kinematic
viscosity at 60.degree. C. of each lubricating oil was adjusted to
about 125 mm.sup.2/s, in consideration of the temperature at use in
practice. Table 2 shows the characteristics and performances of the
prepared lubricating oils.
TABLE-US-00001 TABLE 1 Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 1 Ex. 2
Ex. 3 PAO1 86.16 -- -- -- -- PAO2 -- 86.16 -- -- -- PAO3 -- --
86.16 -- -- PAO4 -- -- -- 56.16 -- PMA -- -- -- 30 70.16 OCP -- --
-- -- 16 Ester 10 10 10 10 10 Additives 3.84 3.84 3.84 3.84
3.84
[0088] The detailed information of the compounds shown in Table 1
is as follows.
PAO1: .alpha.-Olefin polymer produced in Production Example 1
(kinematic viscosity (40.degree. C.): 345.9 mm.sup.2/s, kinematic
viscosity (100.degree. C.): 45.82 mm.sup.2/s, viscosity index 192)
PAO2: .alpha.-Olefin polymer produced in Production Example 2
(kinematic viscosity (40.degree. C.): 440.0 mm.sup.2/s, kinematic
viscosity (100.degree. C.): 51.00 mm.sup.2/s, viscosity index 179)
PAO3: Durasyn 174 (product of INEOS Oligomers) (kinematic viscosity
(40.degree. C.): 395 mm.sup.2/s, kinematic viscosity (100.degree.
C.): 40 mm.sup.2/s, viscosity index 149) PAO4: Durasyn 172 (product
of INEOS Oligomers) (kinematic viscosity (40.degree. C.): 63
mm.sup.2/s, kinematic viscosity (100.degree. C.): 9.8 mm.sup.2/s,
viscosity index 139) PMA: Polymethacrylate (Mw: 3,700) diluted with
PAO4 (50:50) OCP: Lucant HC2000 (product of Mitsui Chemicals, Inc.)
Ester: Ester between trimethylolpropane and isostearic acid (1:2 by
mole) Additives: (Octadecyl
3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and
4,4'-dioctyldiphenylamine, dialkylaminomethylbenzotriazole
TABLE-US-00002 TABLE 2 Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 1 Ex. 2
Ex. 3 Kinematic viscosity (40.degree. C.): 285.2 291.3 317.7 288.1
298.7 mm.sup.2/s Kinematic viscosity (100.degree. C.): 36.72 35.88
32.39 36.25 34.86 mm.sup.2/s Viscosity index 178 171 142 175 163
Kinematic viscosity (60.degree. C.): 124.8 124.9 124.8 124.7 124.9
mm.sup.2/s Kinematic viscosity (0.degree. C.): 2,995 3,286 4,934
3,140 3,683 mm.sup.2/s Kinematic viscosity (-10.degree. C.): 6,640
7,494 12,800 7,064 8,701 mm.sup.2/s Kinematic viscosity
(-20.degree. C.): 16,500 19,300 38,500 17,900 23,400 mm.sup.2/s
Kinematic viscosity (-30.degree. C.): 47,100 57,400 139,000 52,100
73,300 mm.sup.2/s Shear stability 0.0 0.0 0.0 6.4 0.8 (40.degree.
C. viscosity drop) Shear stability 0.0 0.0 0.0 5.1 0.6 (100.degree.
C. viscosity drop) Shell four ball test 1,961 1,961 1,961 1,569
1,961 RBOT 2,320 2,650 2,180 1,680 1,460
[0089] The tests in the Examples were performed according to the
following methods.
Kinematic viscosity and viscosity index: JIS K 2283 Shear
stability: JPI-5S-29 Shell four ball test: ASTM D 2783 RBOT
(rotating bomb oxidation test): JIS K 2514
INDUSTRIAL APPLICABILITY
[0090] The present invention enables provision of a lubricating oil
for gears which has a high viscosity index, high shear stability,
and high oxidation resistance. The lubricating oil for gears of the
invention is preferably employed as a step-up gear oil for wind
power generation. Thus, the employable low-temperature limit can be
lowered, whereby the sites available for wind power generation
increases.
* * * * *