[0001]The present invention relates to a lubricating oil 10 composition for industrial gears and a method for producing the same.
Background Art [0002]
15 Compared to automobile gears, there is generally a
tendency for reducer gears and transmission gears utilized in industrial equipment machinery such as machine tools and wind power generators to bear high loads, hence it is often the case that gear friction is a problem. In order to protect the
20 gears, a lubricating oil with a higher viscosity and easier oil film formation compared to the lubricating oil for automobiles, is applied. Moreover, in order to lower the maintenance cost incurred by changing the lubricating oil, a lubricating oil excellent in long-term stability is in demand

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(refer to Non-patent Literature 1). [0003]
Meanwhile, as global warming advances, it is an urgent task to cut carbon dioxide emissions, which is one of the 5 gases contributing to the greenhouse effect. In all kinds of industrial fields, reducing the amount of electric power consumption has also come to be demanded. In order to reduce the electric power consumption amount, it is necessary to reduce the lubricating oil agitation torque at low
10 temperatures to the vicinity of the utilization temperature, hence measures for lowering the viscosity of lubricating oil can be considered. However, since viscosity also ends up becoming lowered at high temperatures due to the lowering of the base oil viscosity, oil film formation becomes difficult
15 at high temperatures, and as a result, there is a possibility that sufficient gear protecting performance cannot be expressed. Moreover, particularly in cold regions, it is desirable for viscosity to be low at low temperatures, in order to reduce torque when starting engines during winter.
20 [0004]
In order to have a balance between low torque at low temperatures and oil film formation at high temperatures, certain types of polymers soluble in lubricating oil bases have been utilized as viscosity modifying agents (also called

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viscosity index improving agents), with the objective of reducing the viscosity temperature dependency. As such viscosity improving agents, α-olefin polymer and polybutene have been widely utilized in recent years (refer to Patent 5 Literature 1 and 2). However, there were problems in that the shear stability of α-olefin polymer was not sufficient, and thus had inferior long-term stability. There was moreover a problem of the polybutene having inferior temperature viscosity properties, low-temperature properties, and heat
10 resistance stability. [0005]
In order to improve this, investigation was conducted where ethylene-α-olefin copolymer having a specific kinematic viscosity (100°C kinematic viscosity of 30 to 350 mm2/s) was
15 utilized. However, there was room for improvement from the perspective of finding a balance between low torque at low temperature and oil film formation at high temperature (refer to Patent Literature 3). [0006]
20 Patent Literature 4 discloses a lubricating oil
composition containing a specific lubricant base oil and a specific ethylene-α-olefin copolymer, where this composition has a balance of these properties, and which is suitably applicable to industrial gears.

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[0007]
Moreover, Patent Literature 5 describes a method for producing a liquid random copolymer of ethylene and α-olefin, wherein further described is that this copolymer is useful as 5 a lubricating oil.
Citation List
Patent Literature
WO 2000/034420 A1
JP H08-301939 A
JP 2011-190377 A
JP 2016-069406 A
EP 2921509 A1
[0008] 10 Patent Literature 1:
Patent Literature 2:
Patent Literature 3:
Patent Literature 4:
Patent Literature 5: 15
Non-patent Literature
[0009]
Non-patent Literature 1: Illustrated guide to the
introductory basics of industrial lubricating oil (2011); 20 Author/Editor: Lubricants Department, Lubricant Technology 2nd
section of Idemitsu Kosan Co Ltd, published by Nikkan Kogyo
Shimbun, Ltd [The Daily Industrial News]
Summary of Invention

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Technical Problem [0010]
However, there was further room for improvement in conventional lubricating oil compositions, from the 5 perspective of providing a lubricating oil composition for industrial gears having remarkably excellent temperature viscosity properties; namely, having oil film retention properties at high temperatures and low-temperature viscosity properties, and further having excellent thermal and 10 oxidation stability.
Solution to Problem [0011]
The present inventors keenly investigated the
15 development of a lubricating oil composition having excellent performance, and as a result, discovered that the
aforementioned problem can be solved with a lubricating oil composition which contains, with a specific lubricant base oil, an ethylene-α-olefin (co)polymer prepared by means of a
20 specific catalyst, and satisfies specific conditions, thus arriving at the perfection of the present invention. The present invention specifically mentions the below aspect. [0012] [1]

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A lubricating oil composition for industrial gears,
comprising
10 to 90% by mass of a lubricant base oil (A) having
the properties of the below (A1) to (A3), and 5 90 to 10% by mass of a liquid random copolymer (B) of
ethylene and α-olefin, the liquid random copolymer (B) being
prepared by the below method (α), wherein the total amount of
the lubricant base oil (A) and the copolymer (B) is 100% by
mass, 10 the lubricating oil composition for industrial gears
having the properties of the below (C1).
(A1) The lubricant base oil (A) has a kinematic viscosity at
100°C of 1 to 100 mm2/s.
(A2) The lubricant base oil (A) has a viscosity index of 100 15 or more.
(A3) The lubricant base oil (A) has a pour point of 0°C or
lower.
(C1) The lubricating oil composition for industrial gears has
a kinematic viscosity at 40°C of 100 to 10,000 mm2/s. 20 (Method (α))
A method (α) for preparing a liquid random copolymer of
ethylene and α-olefin, comprising a step of carrying out
solution polymerization of ethylene and α-olefin having 3 to
20 carbon atoms, under a catalyst system comprising

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(a) a bridged metallocene compound represented by the following Formula 1, and
(b) at least one compound selected from a group consisting of
(i) an organoaluminum oxy-compound, and
5 (ii) a compound which reacts with the bridged
metallocene compound to form an ion pair. [0013]

(Formula 1)
[In Formula 1, R1, R2, R3, R4, R5, R8, R9 and R12 are 10 respectively and independently hydrogen atom, hydrocarbon
group or silicon-containing hydrocarbon group, and adjoining groups are optionally connected to each other to form a ring structure,
R6 and R11, being the same, are hydrogen atom,

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hydrocarbon group or silicon-containing hydrocarbon group,
R7 and R10, being the same, are hydrogen atom, hydrocarbon group or silicon-containing hydrocarbon group,
R6 and R7 are optionally connected to hydrocarbon having 5 2 to 3 carbon atoms to form a ring structure,
R11 and R10 are optionally connected to hydrocarbon having 2 to 3 carbon atoms to form a ring structure,
R6, R7, R10 and R11 are not hydrogen atom at the same
time;
10 Y is a carbon atom or silicon atom;
R13 and R14 are independently aryl group;
M is Ti, Zr or Hf;
Q is independently halogen, hydrocarbon group, an anionic ligand or a neutral ligand which can be coordinated 15 to a lone pair of electrons; and
j is an integer of 1 to 4.] [2]
The lubricating oil composition for industrial gears of the aforementioned [1], wherein in the metallocene compound 20 represented by the above Formula 1, at least one among
substituents (R1, R2, R3 and R4) bonded to a cyclopentadienyl group is a hydrocarbon group having 4 or more carbon atoms. [0014] [3]

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The lubricating oil composition for industrial gears of the aforementioned [1] or [2], wherein R6 and R11, being the same, are hydrocarbon groups having 1 to 20 carbon atoms. [0015] 5 [4]
The lubricating oil composition for industrial gears of any of the aforementioned [1] to [3], wherein in the metallocene compound represented by the above Formula 1, substituent (R2 or R3) bonded to the 3-position of the
10 cyclopentadienyl group is a hydrocarbon group. [0016] [5]
The Lubricating oil composition for industrial gears of the aforementioned [4], wherein in the metallocene compound
15 represented by the above Formula 1, the hydrocarbon group (R2 or R3) bonded to the 3-position of the cyclopentadienyl group is an n-butyl group. [0017] [6]
20 The lubricating oil composition for industrial gears of
any of the aforementioned [1] to [5], wherein in the metallocene compound represented by the above Formula 1, substituents (R6 and R11) bonded to the 2-position and 7-position of the fluorenyl group are all tert-butyl groups.

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[0018] [7]
The lubricating oil composition for industrial gears of any of the aforementioned [1] to [6], wherein the compound 5 which reacts with the bridged metallocene compound to form an ion pair is a compound represented by the following Formula 6. [0019]
Rg pe R B—R
R ., ■■■ (Formula 6)
10 [In Formula 6, Re+ is H+, a carbenium cation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptyltrienyl cation, or a ferrocenium cation having a transition metal, and Rf to Ri each is independently a hydrocarbon group having 1 to 20 carbon atoms.]
15 [8]
The lubricating oil composition for industrial gears of the aforementioned [7], wherein the ammonium cation is a dimethylanilinium cation. [0020]
20 [9]
The lubricating oil composition for industrial gears of

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the aforementioned [7] or [8], wherein the catalyst system further comprises an organoaluminum compound selected from a group consisting of trimethyl aluminum and triisobutyl aluminum. 5 [0021] [10]
A lubricating oil composition for industrial gears, comprising
10 to 90% by mass of a lubricant base oil (A) having 10 the properties of the below (A1) to (A3), and
90 to 10% by mass of a liquid random copolymer of ethylene and α-olefin, the liquid random copolymer having the properties of the below (B1) to (B5), wherein the total amount of the lubricant base oil (A) and the copolymer is 15 100% by mass,
the lubricating oil composition for industrial gears having the property of the below (C1).
(A1) The lubricant base oil (A) has a kinematic viscosity at 100°C of 1 to 100 mm2/s. 20 (A2) The lubricant base oil (A) has a viscosity index of 100 or more.
(A3) The lubricant base oil (A) has a pour point of 0°C or lower. (B1) The liquid random copolymer comprises 40 to 60 mol% of

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ethylene units and 60 to 40 mol% of α-olefin units having 3
to 20 carbon atoms.
(B2) The liquid random copolymer has a number average
molecular weight (Mn) of 500 to 10,000 and a molecular weight 5 distribution (Mw/Mn, Mw is the weight average molecular
weight) of 3 or less, as measured by Gel Permeation
Chromatography (GPC).
(B3) The liquid random copolymer has a kinematic viscosity at
100°C of 30 to 5,000 mm2/s. 10 (B4) The liquid random copolymer has a pour point of 30 to -
45°C
(B5) The liquid random copolymer has a Bromine Number of 0.1
g / 100 g or less.
(C1) The lubricating oil composition for industrial gears has 15 a kinematic viscosity at 40°C of 100 to 10,000 mm2/s.
[11]
The lubricating oil composition for industrial gears
according to any of the aforementioned [1] to [10], having a
kinematic viscosity at 40°C of 250 to 5,000 mm2/s. 20 [0022]
[12]
The lubricating oil composition for industrial gears
according to any of the aforementioned [1] to [11], wherein
the lubricant base oil (A) further satisfies the below (A4)

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to (A6).
(A4) The lubricant base oil (A) has a kinematic viscosity at
100°C of 1 to 10 mm2/s.
(A5) The lubricant base oil (A) has a viscosity index of 110 5 or more.
(A6) The lubricant base oil (A) has a pour point of -10°C or
lower.
[13]
The lubricating oil composition for industrial gears 10 according to any of the aforementioned [1] to [12], wherein
30 to 100% by mass of the lubricant base oil (A) is a mineral
oil.
[0023]
[14]
15 The lubricating oil composition for industrial gears
according to any of the aforementioned [1] to [13], wherein
30 to 100% by mass of the lubricant base oil (A) is a
synthetic oil, and the synthetic oil is a poly α-olefin (PAO)
and/or an ester oil. 20 [0024]
[15]
A gear oil for wind power generation, consisting of the
lubricating oil composition according to any of the
aforementioned [1] to [14].

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[0025]
[16]
A gear oil for machine tools and molding machines,
consisting of the lubricating oil composition according to 5 any of the aforementioned [1] to [14].
[0026]
[17]
A method for producing a lubricating oil composition
for industrial gears, comprising the steps of:
10 preparing a liquid random copolymer (B) of ethylene and
α-olefin by the following method (α); and
preparing a lubricating oil composition for industrial
gears by mixing a lubricant base oil (A) in an amount of 10
to 90% by mass of the lubricating oil composition, the 15 lubricant base oil (A) having the properties of the below
(A1) to (A3), and the liquid random copolymer (B) in an
amount of 90 to 10% by mass of the lubricating oil
composition, wherein the total amount of the lubricant base
oil (A) and the copolymer (B) is 100% by mass, the 20 lubricating oil composition for industrial gears having the
property of the below (C1).
(A1) The lubricant base oil (A) has a kinematic viscosity at
100°C of 1 to 100 mm2/s.
(A2) The lubricant base oil (A) has a viscosity index of 100

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or more.
(A3) The lubricant base oil (A) has a pour point of 0°C or lower.
(C1) The lubricating oil composition for industrial gears has 5 a kinematic viscosity at 40°C of 100 to 10,000 mm2/s. (Method (α))
A method (α) for preparing a liquid random copolymer of ethylene and α-olefin, comprising a step of carrying out solution polymerization of ethylene and α-olefin having 3 to 10 20 carbon atoms, under a catalyst system comprising
(a) a bridged metallocene compound represented by the following Formula 1, and
(b) at least one compound selected from a group consisting of
(i) an organoaluminum oxy-compound, and 15 (ii) a compound which reacts with the bridged metallocene compound to form an ion pair. [0027]

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(Formula 1)
[In Formula 1, R1, R2, R3, R4, R5, R8, R9 and R12 are respectively and independently hydrogen atom, hydrocarbon group or silicon-containing hydrocarbon group, and adjoining 5 groups are optionally connected to each other to form a ring structure,
R6 and R11, being the same, are hydrogen atom, hydrocarbon group or silicon-containing hydrocarbon group,
R7 and R10, being the same, are hydrogen atom, 10 hydrocarbon group or silicon-containing hydrocarbon group,
R6 and R7 are optionally connected to hydrocarbon having 2 to 3 carbon atoms to form a ring structure,
R11 and R10 are optionally connected to hydrocarbon having 2 to 3 carbon atoms to form a ring structure,

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R6, R7, R10 and R11 are not hydrogen atom at the same time;
Y is a carbon atom or silicon atom;
R13 and R14 are independently aryl group;
5 M is Ti, Zr or Hf;
Q is independently halogen, hydrocarbon group, an anionic ligand or a neutral ligand which can be coordinated to a lone pair of electrons; and
j is an integer of 1 to 4.] 10
Advantageous Effects of Invention [0028]
The lubricating oil composition of the present invention has high temperature viscosity properties; namely 15 has oil film retention properties at high temperatures and
excellent low-temperature viscosity properties, and further has excellent thermal and oxidation stability. The lubricating oil composition is preferably applicable to industrial gear oil, and particularly to gear oil for wind 20 power generators, or gear oil for machine tools and molding machines.
Description of Embodiments
[0029]

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The lubricating oil composition for industrial gears according to the present invention (hereinafter, also referred to merely as “lubricating oil composition”) will be explained in detail below. 5 [0030]
The lubricating oil composition for industrial gears according to the present invention comprises a lubricant base oil (A), and a liquid random copolymer (B) of ethylene and α-olefin prepared by method (α) (may also be described in the
10 present specification as “ethylene-α-olefin copolymer (B)”), the lubricating oil composition having a kinematic viscosity at 40°C in a specific range. [0031] < (A) Lubricant base oil >
15 The lubricant base oil (A) has the properties of (A1) to (A3) below. [0032]
(A1) The lubricant base oil has a kinematic viscosity at 100°C of 1 to 100 mm2/s
20 The value of this kinematic viscosity is that as measured in accordance with the method described in JIS K2283. The kinematic viscosity at 100°C of the lubricant base oil (A) is 1 to 100 mm2/s, preferably 1 to 10 mm2/s, and more preferably 2 to 8 mm2/s. With a kinematic viscosity at 100°C

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in this range, the lubricating oil composition of the present invention is excellent in terms of balance between volatility and temperature viscosity properties. [0033] 5 (A2) The lubricant base oil has a viscosity index of 100 or more
The value of this viscosity index is that as measured in accordance with the method described in JIS K2283. The viscosity index of lubricant base oil (A) is 100 or more,
10 preferably 110 or more, and further preferably 120 or more. With a viscosity index in this range, the lubricating oil composition of the present invention has excellent temperature viscosity properties. [0034]
15 (A3) The lubricant base oil has a pour point of 0°C or lower The value of this pour point is that as measured in accordance with the method described in ASTM D97. The pour point of lubricant base oil (A) is 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower,
20 and furthermore preferably -30°C or lower. With a pour point
in this range, the lubricating oil composition of the present invention has excellent low-temperature viscosity properties. [0035]
In the lubricant base oil used in the present

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invention, performance and quality such as viscosity properties, heat resistance and oxidation stability, will differ depending on the producing and refining processes etc. of the lubricant base oil. In general, the lubricant base oil 5 is classified broadly into a mineral oil and a synthetic oil. Moreover, the API (American Petroleum Institute) categorizes lubricant base oil into five types: Group I, II, III, IV and V. These API categories are defined in the API Publication 1509, 15th Edition, Appendix E, April 2002, and are as shown 10 in Table 1. The lubricant base oil (A) may be either mineral oil or synthetic oil, and may be of any of the Groups I to V in the API categories. Details are described as follows. [0036]
Table 1

Group Type Viscosity index *1 Saturated
hydrocarbon
portion *2
(vol%) Sulfur
portion *3 (%
by weight)
I Mineral oil 80 to 120 < 90 > 0.03
II Mineral oil 80 to 120 ≥ 90 ≤ 0.03
III Mineral oil ≥ 120 ≥ 90 ≤ 0.03
IV Poly-a-olefin
V Lubricant base material other than the aforementioned
15 *1: Measured in accordance with ASTM D445 (JIS K2283) *2: Measured in accordance with ASTM D3238 *3: Measured in accordance with ASTM D4294 (JIS K2541)

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*4: Mineral oils whose saturated hydrocarbon portion is less than 90 vol% and sulfur portion is less than 0.03% by weight, or whose saturated hydrocarbon portion is 90 vol% or more and sulfur portion exceeds 0.03% by weight, are included in Group 5 I.
< Mineral oil >
The mineral oil is ascribed to Groups I to III of the aforementioned API categories.
10 [0037]
The quality of the mineral oil is as mentioned above, where the aforementioned respective qualities of mineral oil are obtainable depending on the refining method. Exemplifications of the mineral oil specifically include: a
15 lubricant base oil, in which a lubricating oil fraction
obtained by reduced pressure distillation of an atmospheric residue which is obtainable by the atmospheric distillation of crude oil, is refined by one or more treatments such as solvent deasphalting, solvent extraction, hydrocracking,
20 solvent dewaxing, hydrorefining; or a lubricant base oil of wax isomerized mineral oil. [0038]
Moreover, a Gas-to-Liquid (GTL) base oil obtained by the Fisher-Tropsch method is a base oil which can also be

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suitably utilized as Group III mineral oil. Such GTL base oil is also handled as Group III+ lubricant base oil, which are described e.g. in the following Patent Literatures: EP0776959, EP0668342, WO97/21788, WO00/15736, WO00/14188, 5 WO00/14187, WO00/14183, WO00/14179, WO00/08115, WO99/41332, EP1029029, WO01/18156 and WO01/57166. [0039] < Synthetic oil >
The synthetic oil is ascribed to Group IV or Group V of
10 the aforementioned API categories. [0040]
Poly-α-olefins, which are ascribed to Group IV, can be obtained by oligomerizing higher α-olefins with an acid catalyst such as a boron trifluoride catalyst or a chromic
15 acid catalyst, as described in US Patent No. 3,382,291, US
Patent No. 3,763,244, US Patent No. 5,171,908, US Patent No. 3,780,128, US Patent No. 4,032,591, JP H01-163136 A, US Patent No. 4,967,032, and US Patent No. 4,926,004. Poly-α-olefins can also be obtained by processes using a catalyst
20 system containing a complex of a transition metal such as
zirconium, titanium or hafnium, which includes a metallocene compound as described in patent literatures, JP S63-037102 A, JP 2005-200447 A, JP 2005-200448 A, JP 2009-503147 A and JP 2009-501836 A. Of these, a low molecular weight oligomer of

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at least one olefin selected from an olefin having 6 or more carbon atoms can be utilized as the poly-α-olefin. If utilizing a poly-α-olefin as the lubricant base oil (A), a lubricating oil composition having remarkably excellent 5 temperature viscosity properties, low-temperature viscosity properties, as well as heat resistance is obtainable. [0041]
Poly-α-olefins are also industrially available, where those with a 100°C kinematic viscosity of 2 mm2/s to 150 mm2/s
10 are commercially available. Among these, the use of a poly α-olefin of 2 to 100 mm2/s is preferable from the perspective of obtaining a lubricating oil composition with excellent temperature viscosity properties. Examples include the NEXBASE 2000 series (made by NESTE), Spectrasyn (made by
15 ExxonMobil Chemical), Durasyn (made by INEOS Oligomers), and Synfluid (made by Chevron Phillips Chemical). [0042]
As the synthetic oil ascribed to Group V, examples include alkyl benzenes, alkyl naphthalenes, isobutene
20 oligomers and hydrides thereof, paraffins, polyoxy alkylene glycol, dialkyl diphenylether, polyphenylether, and esters. [0043]
Most of the alkyl benzenes and alkyl naphthalenes are usually dialkyl benzene or dialkyl naphthalene whose alkyl

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chain length has 6 to 14 carbon atoms, where such alkyl benzenes or alkyl naphthalenes are produced by the Friedel– Crafts alkylation reaction of benzene or naphthalene with olefin. In the production of alkyl benzenes or alkyl 5 naphthalenes, the alkylated olefin to be utilized may be a
linear or branched olefin, or may be a combination of these. These production processes are described in e.g. US Patent 3,909,432. [0044]
10 Moreover, as the ester, fatty acid esters are preferred
from the perspective of compatibility with the ethylene-α-olefin copolymer (B). [0045]
Although there are no particular limitations on the
15 fatty acid esters, examples include fatty acid esters
consisting of only carbon, oxygen or hydrogen as mentioned below, where the examples include monoesters prepared from a monobasic acid and alcohol; diesters prepared from dibasic acid and alcohol, or from a diol with a monobasic acid or an
20 acid mixture; or polyolesters prepared by reacting a
monobasic acid or an acid mixture with a diol, triol (e.g. trimethylolpropane), tetraol (e.g. pentaerythritol), hexol (e.g. dipentaerythritol) etc. Examples of these esters include ditridecyl glutarate, di-2-ethyl hexyl adipate,

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diisodecyl adipate, ditridecyl adipate, di-2-ethyl hexyl sebacate, tridecyl pelargonate, di-2-ethyl hexyl adipate, di-2-ethyl hexyl azelate, trimethylolpropane caprylate, trimethylolpropane pelargonate, trimethylolpropane 5 triheptanoate, pentaerythritol-2-ethyl hexanoate, pentaerythritol pelargonate, and pentaerythritol tetraheptanoate. [0046]
From the perspective of the compatibility with the
10 ethylene-α-olefin copolymer (B), an alcohol having two or
more functional hydroxyl groups is preferred as the alcohol moiety constituting the ester, and a fatty acid having 8 or more carbon atoms is preferred as the fatty acid moiety. However, a fatty acid having 20 or fewer carbon atoms, which
15 is easily industrially available, is superior in terms of the manufacturing cost of the fatty acid. The effect of the present invention is also sufficiently exhibited with the use of one fatty acid constituting an ester, or with the use of a fatty acid ester prepared by means of two or more acid
20 mixtures. Examples of fatty acid esters more specifically
include a mixed triester of trimethylolpropane with lauric acid and stearic acid, and diisodecyl adipate, where these are preferable in terms of compatibility of saturated hydrocarbon components such as the ethylene-α-olefin

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copolymer (B), with stabilizers such as antioxidants, corrosion preventing agents, anti-wear agents, friction modifying agents, pour point lowering agents, anti-rust agents and anti-foamers mentioned below and having a polar 5 group. [0047]
When utilizing a synthetic oil, particularly a poly-α-olefin as the lubricant base oil (A), it is preferable that the lubricating oil composition of the present invention
10 contain a fatty acid ester in an amount of 5 to 20% by mass with respect to 100% by mass of the entire weight of the lubricating oil composition. By containing a fatty acid ester of 5% by mass or more, good compatibility is obtainable with the lubricating oil sealing material such as resins and
15 elastomers inside the internal combustion engines and
industrial machinery of all types. Specifically, swelling of the lubricating oil sealing material can be suppressed. From the perspective of oxidation stability or heat resistance, the amount of ester is preferably 20% by mass or less. When
20 mineral oil is contained in the lubricating oil composition, a fatty acid ester is not necessarily required, because the mineral oil per se has a swelling suppression effect of the lubricating oil sealing agent. [0048]

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In the lubricating oil composition of the present invention, a synthetic oil or mineral oil may be used alone as the lubricant base oil (A), or any mixture etc. of two or more lubricating oils selected from the synthetic oil and 5 mineral oil may be used as the lubricant base oil (A). [0049] < (B) Ethylene-α-olefin copolymer >
The ethylene-α-olefin copolymer (B) is a liquid random copolymer (B) of ethylene and α-olefin prepared by the 10 following method (α). (Method (α))
A method (α) for preparing a liquid random copolymer of ethylene and α-olefin, comprising a step of carrying out solution polymerization of ethylene and α-olefin having 3 to 15 20 carbon atoms, under a catalyst system containing
(a) a bridged metallocene compound represented by the following Formula 1, and
(b) at least one compound selected from a group consisting of
(i) an organoaluminum oxy-compound, and 20 (ii) a compound which reacts with the bridged metallocene compound to form an ion pair. [0050]

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(Formula 1)
[In Formula 1, R1, R2, R3, R4, R5, R8, R9 and R12 are respectively and independently hydrogen atom, hydrocarbon group or silicon-containing hydrocarbon group, and adjoining 5 groups are optionally connected to each other to form a ring structure,
R6 and R11, being the same, are hydrogen atom, hydrocarbon group or silicon-containing hydrocarbon group,
R7 and R10, being the same, are hydrogen atom, 10 hydrocarbon group or silicon-containing hydrocarbon group,
R6 and R7 are optionally connected to hydrocarbon having 2 to 3 carbon atoms to form a ring structure,
R11 and R10 are optionally connected to hydrocarbon having 2 to 3 carbon atoms to form a ring structure,

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R6, R7, R10 and R11 are not hydrogen atom at the same time;
Y is a carbon atom or silicon atom;
R13 and R14 are independently aryl group;
5 M is Ti, Zr or Hf;
Q is independently halogen, hydrocarbon group, an anionic ligand or a neutral ligand which can be coordinated to a lone pair of electrons; and
j is an integer of 1 to 4.]
10 Here, the hydrocarbon group has 1 to 20 carbon atoms,
preferably 1 to 15 atoms, and more preferably 4 to 10 carbon atoms, and means for example an alkyl group, aryl group etc. The aryl group has 6 to 20 carbon atoms, and preferably 6 to 15 carbon atoms. 15 [0051]
Examples of the silicon-containing hydrocarbon group include an alkyl or aryl group having 3 to 20 carbon atoms which contains 1 to 4 silicon atoms, and in more detail includes trimethylsilyl group, tert-butyldimethylsilyl group, 20 triphenylsilyl group etc. [0052]
In the bridged metallocene compound represented by Formula 1, cyclopentadienyl group may be substituted or unsubstituted.

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[0053]
In the bridged metallocene compound represented by Formula 1,
(i) it is preferable that at least one among 5 substituents (R1, R2, R3 and R4) bonded to cyclopentadienyl group is a hydrocarbon group,
(ii) it is more preferable that at least one among
substituents (R1, R2, R3 and R4) is a hydrocarbon group having
4 or more carbon atoms,
10 (iii) it is most preferable that substituent (R2 or R3)
bonded to the 3-position of the cyclopentadienyl group is a
hydrocarbon group having 4 or more carbon atoms (for example
an n-butyl group).
[0054]
15 In case where at least two among R1, R2, R3 and R4 are
substituents (that is, being not hydrogen atom), the above-mentioned substituents may be the same or be different, and it is preferable that at least one substituent is a hydrocarbon group having 4 or more carbon atoms. 20 [0055]
In the metallocene compound represented by Formula 1, R6 and R11 bonded to fluorenyl group are the same, R7 and R10 are the same, but R6, R7, R10 and R11 are not hydrogen atom at the same time. In high-temperature solution polymerization of

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poly-α-olefin, in order to improve the polymerization activity, preferably neither R6 nor R11 is hydrogen atom, and more preferably none of R6, R7, R10 and R11 is hydrogen atom. For example, R6 and R11 bonded to the 2-position and 7-5 position of the fluorenyl group are the same hydrocarbon
group having 1 to 20 carbon atoms, and preferably all tert-butyl groups, and R7 and R10 are the same hydrocarbon group having 1 to 20 carbon atoms, and preferably all tert-butyl groups.
10 [0056]
The main chain part (bonding part, Y) connecting the cyclopentadienyl group and the fluorenyl group is a cross-linking section of two covalent bonds comprising one carbon atom or silicon atom, as a structural bridge section
15 imparting steric rigidity to the bridged metallocene compound represented by Formula 1. Cross-linking atom (Y) in the cross-linking section has two aryl groups (R13 and R14) which may be the same or different. Therefore, the cyclopentadienyl group and the fluorenyl group are bonded by the covalent bond
20 cross-linking section containing an aryl group. Examples of the aryl group include a phenyl group, naphthyl group, anthracenyl group, and a substituted aryl group (which is formed by substituting one or more aromatic hydrogen (sp2-type hydrogen) of a phenyl group, naphthyl group or

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anthracenyl group, with substituents). Examples of substituents in the aryl group include a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group having 1 to 20 carbon atoms, a halogen atom etc., and 5 preferably include a phenyl group. In the bridged metallocene compound represented by Formula 1, preferably R13 and R14 are the same in view of easy production. [0057]
In the bridged metallocene compound represented by
10 Formula 1, Q is preferably a halogen atom or hydrocarbon
group having 1 to 10 carbon atoms. The halogen atom includes fluorine, chlorine, bromine or iodine. The hydrocarbon group having 1 to 10 carbon atoms includes methyl, ethyl, n-propyl, isopropyl, 2-methylpropyl, 1,1-dimethylpropyl, 2,2-
15 dimethylpropyl, 1,1-diethylpropyl, 1-ethyl-1-methylpropyl, 1,1,2,2-tetramethylpropyl, sec-butyl, tert-butyl, 1,1-dimethylbutyl, 1,1,3-trimethylbutyl, neopentyl, cyclohexyl methyl, cyclohexyl, 1-methyl-1-cyclohexyl etc. Further, when j is an integer of 2 or more, Q may be the same or different.
20 [0058]
Examples of such bridged metallocene compounds (a) include:
ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, ethylene [η5-(3-tert-

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butyl-5-methyl cyclopentadienyl)] [η5- (3,6-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-tert-butyl-5 5-methyl cyclopentadienyl)] (octamethyl
octahydrodibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (dibenzofluorenyl)
10 zirconium dichloride, ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-tert-butyl-
15 5-methyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride;
ethylene [η5-(3-tert-butyl cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] [η5-(3,6-di-tert-butyl fluorenyl)]
20 zirconium dichloride, ethylene [η5-(3-tert-butyl
cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] (octamethyl octahydrodibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl

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cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] (octahydrodibenzofluorenyl) 5 zirconium dichloride, ethylene [η5-(3-tert-butyl
cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride;
10 ethylene [η5-(3-n-butyl cyclopentadienyl)] (η5-
fluorenyl) zirconium dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(3,6-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)]
15 zirconium dichloride, ethylene [η5-(3-n-butyl
cyclopentadienyl)] (octamethyl octahydrodibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] (dibenzofluorenyl)
20 zirconium dichloride, ethylene [η5-(3-n-butyl
cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-

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(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride;
diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, 5 diphenylmethylene [η5- (3-tert-butyl-5-methyl
cyclopentadienyl)] [η5-(3,6-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-
10 methyl cyclopentadienyl)] (octamethyl
octahydrodibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-methyl
15 cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl
20 fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-
tert-butyl-5-methyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride;
diphenylmethylene [η5-(3-tert-butyl cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-

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tert-butyl cyclopentadienyl)] [η5- (3,6-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-5 tert-butyl cyclopentadienyl)] (octamethyl
octahydrodibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl cyclopentadienyl)] (dibenzofluorenyl) zirconium
10 dichloride, diphenylmethylene [η5-(3-tert-butyl
cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-
15 tert-butyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride;
diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(3,6-di-tert-butyl fluorenyl)]
20 zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] (octamethyl octahydrodibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-n-butyl

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cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] (octahydrodibenzofluorenyl) 5 zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride;
10 di(p-tolyl) methylene [η5-(3-tert-butyl-5-methyl
cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] [η5-(3,6-di-tert-butyl fluorenyl)] zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-
15 butyl-5-methyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl
fluorenyl)] zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (octamethyl octahydrodibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)]
20 (benzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, di(p-tolyl)

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methylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl 5 fluorenyl)] zirconium dichloride;
di(p-tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)] [η5-(3,6-di-tert-butyl fluorenyl)] zirconium dichloride, di(p-
10 tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)] (octamethyl octahydrodibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)]
15 (benzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl
20 cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl
fluorenyl)] zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride; and
di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)]

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(η5-fluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(3,6-di-tert-butyl fluorenyl)] zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl 5 fluorenyl)] zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] (octamethyl
octahydrodibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl
10 cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] (2,7-diphenyl-3,6-di-tert-butyl fluorenyl) zirconium dichloride, di(p-
15 tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride. [0059]
Although compounds whose zirconium atoms were substituted with hafnium atoms, or compounds whose chloro
20 ligands were substituted with methyl groups etc. are
exemplified in these compounds, the bridged metallocene compound (a) is not limited to these exemplifications. [0060]
As the organoaluminum oxy-compound used in the catalyst

SF-3417

40

5

system in the present invention, conventional aluminoxane can be used. For example, linear or ring type aluminoxane represented by the following Formulas 2 to 5 can be used. A small amount of organic aluminum compound may be contained in the organoaluminum oxy-compound. [0061]
R—(-A1— O -)—A1R2

R

(Formula 2)

R ... (Formula 3)
n
■fAl—0-) (-A1—Oi
m

Me

Rx

(Formula 4)

In Formulae 2 to 4, R is independently a hydrocarbon group having 1 to 10 carbon atoms, Rx is independently a 10 hydrocarbon group having 2 to 20 carbon atoms, m and n are
independently an integer of 2 or more, preferably 3 or more, more preferably 10 to 70, and most preferably 10 to 50. [0062]

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41

d BC pd
R\ T ,R
Al—O—B—O—Ai:
K R.-- (Formula 5)
In Formula 5, Rc is a hydrocarbon group having 1 to 10 carbon atoms, and Rd is independently a hydrogen atom, halogen atom or hydrocarbon group having 1 to 10 carbon 5 atoms. [0063]
In Formula 2 or Formula 3, R is a methyl group (Me) of the organoaluminum oxy-compound which is conventionally referred to as "methylaluminoxane". 10 [0064]
The methylaluminoxane is easily available and has high polymerization activity, and thus it is commonly used as an activator in the polyolefin polymerization. However, the methylaluminoxane is difficult to dissolve in a saturated 15 hydrocarbon, and thus it has been used as a solution of
aromatic hydrocarbon such as toluene or benzene, which is environmentally undesirable. Therefore, in recent years, a flexible body of methylaluminoxane represented by Formula 4 has been developed and used as an aluminoxane dissolved in 20 the saturated hydrocarbon. The modified methylaluminoxane represented by Formula 4 is prepared by using a trimethyl aluminum and an alkyl aluminum other than the trimethyl

SF-3417
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aluminum as shown in US Patent 4960878 and US Patent 5041584, and for example, is prepared by using trimethyl aluminum and triisobutyl aluminum. The aluminoxane in which Rx is an isobutyl group is commercially available under the trade name 5 of MMAO and TMAO, in the form of a saturated hydrocarbon
solution. (See Tosoh Finechem Corporation, Tosoh Research &
Technology Review, Vol 47, 55 (2003)).
[0065]
As (ii) the compound which reacts with the bridged
10 metallocene compound to form an ion pair (hereinafter, referred to as "ionic compound" as required) which is contained in the present catalyst system, a Lewis acid, ionic compounds, borane, borane compounds and carborane compounds can be used. These are described in patent literatures,
15 Korean Patent No. 10-551147 A, JP H01-501950 A, JP H03-179005 A, JP H03-179006 A, JP H03-207703 A, JP H03-207704 A, US Patent 5321106 and so on. If needed, heteropoly compounds, and isopoly compound etc. can be used, and the ionic compound disclosed in JP 2004-51676 A can be used. The ionic compound
20 may be used alone or by mixing two or more. In more detail, examples of the Lewis acid include the compound represented by BR3 (R is fluoride, substituted or unsubstituted alkyl group having 1 to 20 carbon atoms (methyl group, etc.), substituted or unsubstituted aryl group having 6 to 20 carbon

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43
atoms (phenyl group, etc.), and also includes for example, trifluoro boron, triphenyl boron, tris(4-fluorophenyl) boron, tris(3,5-difluorophenyl) boron, tris(4-fluorophenyl) boron, tris(pentafluorophenyl) and boron tris(p-tolyl) boron. When 5 the ionic compound is used, its use amount and sludge amount produced are relatively small in comparison with the organoaluminum oxy-compound, and thus it is economically advantageous. In the present invention, it is preferable that the compound represented by the following Formula 6 is used 10 as the ionic compound. [0066]
Rg pe R B—R
R ., ■■■ (Formula 6)
In Formula 6, Re+ is H+, a carbenium cation, an oxonium cation, an ammonium cation, a phosphonium cation, a
15 cycloheptyltrienyl cation, or a ferrocenium cation having a transition metal, and Rf to Ri each is independently an organic group, preferably a hydrocarbon group having 1 to 20 carbon atoms, and more preferably an aryl group, for example, a penta-fluorophenyl group. Examples of the carbenium cation
20 include a tris(methylphenyl)carbenium cation and a
tris(dimethylphenyl)carbenium cation, and examples of the

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44
ammonium cation include a dimethylanilinium cation. [0067]
Examples of compounds represented by the aforementioned Formula 6 preferably include N,N-dialkyl anilinium salts, and 5 specifically include N,N-dimethylanilinium tetraphenylborate, N,N-dimethylanilinium tetrakis (pentafluorophenyl) borate, N,N-dimethylanilinium tetrakis (3,5-ditrifluoro methylphenyl) borate, N,N-diethyl anilinium tetraphenylborate, N,N-diethyl anilinium tetrakis (pentafluorophenyl) borate, N,N-diethyl
10 anilinium tetrakis (3,5-ditrifluoro methylphenyl) borate,
N,N-2,4,6-penta methylanilinium tetraphenylborate, and N,N-2,4,6-penta methylanilinium tetrakis (pentafluorophenyl) borate. [0068]
15 The catalyst system used in the present invention
further includes (c) an organoaluminum compound when it is needed. The organoaluminum compound plays a role of activating the bridged metallocene compound, the organoaluminum oxy-compound, and the ionic compound, etc. As
20 the organoaluminum compound, preferably an organoaluminum represented by the following Formula 7, and alkyl complex compounds of the Group 1 metal and aluminum represented by the following Formula 8 can be used. [0069]

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45
RamAl(ORb)nHpXq … Formula 7 In Formula 7, Ra and Rb each is independently a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms, and X is a halogen atom, m is an integer 5 of 0
The lubricating oil composition for industrial gears according to the present invention contains the lubricant base oil (A) and the ethylene-α-olefin copolymer (B), and has the property of the below (C1).
20 [0082]
(C1) The lubricating oil composition for industrial gears has a kinematic viscosity at 40°C of 100 to 10,000 mm2/s
The kinematic viscosity at 40°C (i.e. the kinematic viscosity as measured in accordance with the method described

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in JIS K2283) is 100 to 10,000 mm2/s, preferably 250 to 8,000 mm2/s, more preferably 250 to 5,000 mm2/s, and furthermore preferably 500 to 4,000 mm2/s. If the kinematic viscosity at 40°C of the lubricating oil composition for industrial gears 5 is much more than 10,000 mm2/s, the agitation torque rises
when stirring the lubricating oil composition, and hence the energy conservation performance of machinery with gears utilizing the lubricating oil composition worsens. If the kinematic viscosity at 40°C is much lower than 10 mm2/s, the
10 oil film retention of the lubricating oil composition cannot be maintained, and hence sufficient lubricity is not obtainable. [0083]
Generally, the viscosity of industrial lubricating oil
15 products is stipulated according to 40°C kinematic viscosity, and viscosity ranges are defined by JIS K2001 (in accordance with ISO3448). The permissible range is set at ± 10% for each viscosity. For example, if a lubricating oil with a 40°C kinematic viscosity of 320 mm2/s is indicated as ISO VG320,
20 the permitted range of the 40°C kinematic viscosity is 288 to 352 mm2/s. Although the optimal range differs depending on the sites where gears are utilized as well as usage conditions, ISO VG150 to ISO VG3200 is preferably utilized for gear oil. When comparing performance, lubricating oil

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compositions of equal viscosity grades are usually compared. [0084]
The lubricating oil composition for industrial gears according to the present invention preferably further has the 5 property (C2). [0085]
(C2) The lubricating oil composition for industrial gears has a viscosity index of 130 or more
This viscosity index (i.e. as measured in accordance 10 with the method described in JIS K2283) is preferably 130 or more, more preferably 150 or more, furthermore preferably 170 or more, and particularly preferably 180 or more. With a viscosity index in this range, the lubricating oil composition has excellent temperature viscosity properties. 15 [0086]
Generally, as the 40°C kinematic viscosity increases, there is a tendency for the viscosity index to also increase. Hence, the viscosity index range also changes depending on the 40°C kinematic viscosity, and is preferably within the 20 range represented in the following Formula (1), and
furthermore preferably within the range represented in the
following Formula (2).
[0087]
Y ≥ 17.64 LN(X) + 58.8 … Formula (1)

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53
Y ≥ 17.64 LN(X) + 68.8 … Formula (2) (wherein Y indicates the viscosity index, and X indicates the 40°C kinematic viscosity (unit: mm2/s). [0088] 5 The pour point of the lubricating oil composition for industrial gears according to the present invention (i.e. the pour point as measured by the method described in ASTM D97) is preferably 0°C or lower, preferably -10°C or lower, and furthermore preferably -20°C or lower. A low pour point shows 10 excellent low-temperature properties of the lubricating oil composition. [0089]
As the 40°C kinematic viscosity increases, there is also a tendency for the pour point to increase. Hence, the 15 viscosity index range also changes depending on the 40°C kinematic viscosity, and is preferably within the range represented in the following Formula (3), and furthermore preferably within the range represented in the following Formula (4). 20 [0090]
Z ≤ 10.29 LN(X) - 82.4 ••• Formula (3) Z ≤ 10.29 LN(X) - 87.4 ••• Formula (4) (wherein Z indicates the pour point (unit: degrees), and X indicates the 40°C kinematic viscosity (unit: mm2/s).

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The aforementioned Formulae (1) to (4) were derived based on the data of the below-mentioned Examples. [0091]
The lubricating oil composition for industrial gears of 5 the present invention contains the components in the ratio of 10 to 90% by mass of the lubricant base oil (A), and 90 to 10% by mass of the ethylene-α-olefin copolymer (B), wherein the total of the lubricant base oil (A) and the ethylene-α-olefin copolymer (B) is 100% by mass. The lubricating oil
10 composition for industrial gears of the present invention
contains the components in the ratios of: preferably 20 to 90% by mass of the lubricant base oil (A) and 80 to 10% by mass of the ethylene-α-olefin copolymer (B); more preferably 30 to 85% by mass of the lubricant base oil (A) and 70 to 15%
15 by mass of the ethylene-α-olefin copolymer (B); and
furthermore preferably 40 to 80% by mass of the lubricant base oil (A) and 60 to 20% by mass of the ethylene-α-olefin copolymer (B). [0092]
20 A preferable embodiment includes an aspect where 30 to
100% by mass of a lubricant base oil is a mineral oil. With a high ratio of the mineral oil in the lubricant base oil (A), there is excellent dissolvability of the below-mentioned additives, as well as superior economy since the mineral oil

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55
is easily obtained. It is more preferable for 50 to 100% by mass to be the mineral oil, and furthermore preferable for 80 to 100% by mass to be the mineral oil. Of the mineral oils, those of Group III in the API category are preferable because 5 of excellent temperature viscosity properties, and because a balance can be found between oil film retention at high temperatures and low torque at low temperatures. [0093]
Another preferable embodiment includes an aspect where 10 30 to 100% by mass of a lubricant base oil is a synthetic
oil, and the synthetic oil is a poly-α-olefin and/or an ester oil. A high ratio of the synthetic oil in the lubricant base oil (A) is preferable because of excellent thermal resistance, temperature viscosity properties and low-15 temperature properties. It is more preferable for 50 to 100% by mass to be the synthetic oil, and furthermore preferable for 80 to 100% by mass to be the synthetic oil. [0094]
Moreover, additives such as extreme pressure agents, 20 detergent dispersants, viscosity index improving agents,
antioxidants, corrosion preventing agents, anti-wear agents, friction modifying agents, pour point lowering agents, anti-rust agents and anti-foamers may be contained in the lubricating oil composition for automobile industrial gears

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of the present invention. [0095]
Below are exemplifications of additives which can be utilized in the lubricating oil composition of the present 5 invention, where these can be used alone, or used in combination of two or more. [0096]
The extreme pressure agent is the generic name for agents having a seizure preventing effect when the metals of
10 gears and the like are exposed to a high load condition, and although there are no particular limitations on the agent, sulfur-based extreme pressure agents such as sulfides, sulfoxides, sulfones, thiophosphinates, thiocarbonates, sulfurized oils and sulfurized olefins; phosphoric acids such
15 as phosphate esters, phosphite esters, phosphate ester amine salts, and phosphite ester amines; and halogen-based compounds such as chlorinated hydrocarbons can be
exemplified. Moreover, two or more types of these compounds may be used together.
20 [0097]
Until extreme pressure lubricating conditions are attained, hydrocarbon or other organic components constituting lubricating oil composition may become carbonized before reaching extreme pressure lubricating

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57
conditions due to heating or shearing, and thus there is a possibility that a carbide film could be formed on a metal surface. Therefore, with the use of the extreme pressure agent alone, contact of a metal surface with the extreme 5 pressure agent could be inhibited due to the carbide film, and thus a possibility that a sufficient effect of the extreme pressure agent cannot be expected. [0098]
Although the extreme pressure agent may be added alone,
10 because a saturated hydrocarbon such as the copolymer
constitutes a main component in the industrial gear oil in the present invention, from the perspective of
dispersibility, it is preferable to add the agent to the lubricant base oil such as mineral oil or synthetic
15 hydrocarbon oil, together with the other additives to be
used, in a dissolved state beforehand. Specifically, more preferable is a method of selecting the so-called additive package to be added to the lubricating oil composition, in which the various components such as the extreme pressure
20 agent components are mixed in advance, and further dissolved in the lubricant base oil such as mineral oil or synthetic hydrocarbon oil. [0099]
Preferred additive packages include Anglamol-98A,

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Anglamol-6043, Angramol 6085U and LUBRIZOL 1047U (made by
LUBRIZOL), HITEC 1532 (made by AFTON CHEMICAL), HITEC 307
(made by AFTON CHEMICAL), HITEC 3339 (made by AFTON
CHEMICAL), and Additin RC 9410 (made by RHEIN CHEMIE). 5 [0100]
The extreme pressure agent may be used as required in a
range of 0 to 10% by mass, to 100% by mass of the lubricating
oil composition.
[0101]
10 Exemplifications of the anti-wear agent include
inorganic or organic molybdenum compounds such as molybdenum
disulfide, graphite, antimony sulfide, and
polytetrafluoroethylene. The anti-wear agent may be used as
required in a range of 0 to 3% by mass with respect to 100% 15 by mass of the lubricating oil composition.
[0102]
Exemplifications of the friction modifying agent
include amine compounds, imide compound, fatty acid esters,
fatty acid amides, and fatty acid metal salts having at least 20 one alkyl group or alkenyl group having 6 to 30 carbon atoms,
particularly linear alkyl groups or linear alkenyl groups
having 6 to 30 carbon atoms, in a molecule.
[0103]
Exemplifications of the amine compound include a

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linear- or branched-, preferably linear-, aliphatic monoamine, or a linear- or branched-, preferably linear-, aliphatic polyamine having 6 to 30 carbon atoms, or alkylene oxide adducts of these aliphatic amines. Examples of the 5 imide compound include imide succinate with linear- or
branched- alkyl group or alkenyl group having 6 to 30 carbon atoms and/or compounds thereof modified by a carboxylic acid, boric acid, phosphoric acid, sulfuric acid etc. Exemplifications of the fatty acid ester include esters of a
10 linear- or branched-, preferably linear-, fatty acid having 7 to 31 carbon atoms with an aliphatic monohydric alcohol or aliphatic polyhydric alcohol. Exemplifications of the fatty acid amide include amides of a linear- or branched-, preferably linear-, fatty acid having 7 to 31 carbon atoms
15 with an aliphatic monoamine or aliphatic polyamine. Examples of fatty acid metal salts include alkaline-earth metal salts (e.g. magnesium salts and calcium salts) and zinc salts of a linear- or branched-, preferably linear-, fatty acid having 7 to 31 carbon atoms.
20 [0104]
The friction modifying agent may be used as required in a range of 0.01 to 5.0% by mass with respect to 100% by mass of the lubricating oil composition. [0105]

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Exemplifications of the detergent dispersants include metal sulfonates, metal phenates, metal phosphonates, and imide succinate. The detergent dispersant may be used as required in a range of 0 to 15% by mass with respect to 100% 5 by mass of the lubricating oil composition. [0106]
In addition to ethylene-α-olefin copolymers (excluding the ethylene-α-olefin copolymer (B)), known viscosity index improving agents such as olefin copolymers whose molecular 10 weights exceed 50,000, poly-α-olefins with a 100°C kinematic
viscosity of 101 mm2/s or more, methacrylate-based copolymers and liquid polybutene, can be used together as the viscosity index improving agent. The viscosity index improving agent may be used as required in a range of 0 to 50% by mass with 15 respect to 100% by mass of the lubricating oil composition. [0107]
Examples of the antioxidant include phenol-based or amine-based compounds such as 2,6-di-t-butyl-4-methylphenol. The antioxidant may be used as required in a range of 0 to 3% 20 by mass with respect to 100% by mass of the lubricating oil composition. [0108]
Examples of the corrosion preventing agent include compounds such as benzotriazole, benzoimidazole, and

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thiadiazole. The corrosion preventing agent may be used as
required in a range of 0 to 3% by mass with respect to 100%
by mass of the lubricating oil composition.
[0109]
5 Examples of the anti-rust agent include compounds such
as amine compounds, carboxylic acid metal salts, polyhydric alcohol esters, phosphorus compounds, and sulfonates. The anti-rust agent may be used as required in a range of 0 to 3% by mass with respect to 100% by mass of the lubricating oil 10 composition. [0110]
Exemplifications of the anti-foamer include silicone-based compounds such as dimethyl siloxane and silica gel dispersions, and alcohol- or ester-based compounds. The anti-15 foamer may be used as required in a range of 0 to 0.2% by mass with respect to 100% by mass of the lubricating oil composition. [0111]
A variety of known pour point lowering agents may be 20 used as the pour point lowering agent. Specifically, high
molecular compounds containing an organic acid ester group may be used, and in particular, vinyl polymers containing an organic acid ester group are suitably used. Examples of the vinyl polymer containing an organic acid ester group include

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(co)polymers of methacrylic acid alkyl, (co)polymers of
acrylic acid alkyl, (co)polymers of fumaric acid alkyl,
(co)polymers of maleic acid alkyl, and alkylated naphthalene.
[0112]
5 Such pour point lowering agents have a melting point of
-13°C or lower, preferably -15°C, and furthermore preferably -17°C or lower. The melting point of the pour point lowering agent is measured by means of differential scanning calorimetry (DSC). Specifically, a sample of about 5 mg is
10 packed into an aluminum pan and temperature is raised to
200°C, where the temperature is maintained at 200°C for 5 minutes. This is then cooled at 10°C/minute until reaching -40°C, where the temperature is maintained at -40°C for 5 minutes. The temperature is then raised at 10°C/minute during
15 which the melting point is obtained from the heat absorption curve. [0113]
The pour point lowering agent has a polystyrene conversion weight average molecular weight obtainable by gel
20 permeation chromatography in the range of 20,000 to 400,000, preferably 30,000 to 300,000, more preferably 40,000 to 200,000. [0114]
The pour point lowering agent may be used as required

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in a range of 0 to 2% by mass with respect to 100% by mass of
the lubricating oil composition.
[0115]
In addition to the aforementioned additives, anti-5 emulsifying agents, coloring agents, oiliness agents
(oiliness improving agents) and the like may also be used as
required.
[0116]
< Use >
10 The lubricating oil composition of the present
invention can be suitably utilized in the industrial gear oil of a variety of industrial equipment machinery, and this composition has remarkably excellent temperature viscosity properties; namely, oil film retention properties at high
15 temperatures and low-temperature viscosity properties, and can greatly contribute to the energy conservation of industrial equipment machinery. In particular, the lubricating oil composition of the present invention is remarkably useful as gear oil for wind power generation, and
20 gear oil for machine tools and molding machines.
Examples
[0117]

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The present invention is further specifically explained based on the below Examples. However, the present invention is not limited to these Examples. [0118] 5 [Evaluation method]
In the below Examples and Comparative Examples etc., the physical properties etc. of the ethylene-α-olefin copolymer and the industrial gear oil were measured by the below methods.
10 [0119]
< Ethylene content (mol%) >
Using a Fourier transform infrared spectrometer FT/IR-610 or FT/IR-6100 (made by JASCO), the absorbance ratio of the absorption in the vicinity of 721 cm-1 based on the
15 horizontal vibration of the long chain methylene group, and the absorption in the vicinity of 1155 cm-1 based on the skeletal vibration of propylene (D1155 cm-1 / D721 cm-1) was calculated, and the ethylene content (% by weight) was obtained by the calibration curve created beforehand (created
20 using the ASTM D3900 reference sample). Using the ethylene content (% by weight) thus obtained, the ethylene content (mol%) was obtained according to the following Formula. [0120]

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Ethylene content (mol%)
= [ethylene content (% by weight) / 28]
[ethylene content (% by weight) / 28] + [propylene content (% by weight) / 42]
< B-value >
Employing o-dichloro benzene / benzene-d6 (4/1 5 [vol/vol%]) as a measurement solvent, the 13C-NMR spectrum was measured under the measuring conditions (100 MHz, ECX 400P, made by JEOL Ltd) of temperature of 120°C, spectral width of 250 ppm, pulse repeating time of 5.5 seconds, and a pulse width of 4.7 μsec (45° pulse), or under the measuring
10 conditions (125 MHz, AVANCE III Cryo-500 made by Bruker
Biospin Inc) of temperature of 120°C, spectral width of 250 ppm, pulse repeating time of 5.5 seconds, and a pulse width of 5.0 μsec (45° pulse), and the B-value was calculated based on the following Formula [1]. The peak attribution was

In Formula [1], PE indicates the molar fraction 20 contained in the ethylene component, PO indicates the molar
15 performed by reference to the aforementioned known literature. [0121]

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fraction contained in the α-olefin component, and POE indicates the molar fraction of the ethylene-α-olefin sequences of all dyad sequences. [0122] 5 < Molecular weight distribution >
Employing the HLC-8320 GPC (gel permeation chromatography) device produced by Tosoh Corporation, the molecular weight distribution was measured as below. Four TSK gel Super Multipore HZ-M columns were used as separation
10 columns, the column temperature was 40°C, tetrahydrofuran (made by Wako Pure Chemical Industries) was used as the mobile phase, with a development rate of 0.35 ml/minute, a sample concentration of 5.5 g/L, a sample injection amount of 20 microliters, and a differential refractometer was used as
15 a detector. PStQuick MP-M; made by Tosoh Corporation) was used as the reference polystyrene. In accordance with general-purpose calibration procedures, weight average molecular weight (Mw) and number average molecular weight (Mn) were calculated in terms of polystyrene molecular
20 weight, and the molecular weight distribution (Mw/Mn) was calculated from those values. [0123] < Viscosity properties >
The 100°C kinematic viscosity, 40°C kinematic viscosity

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and the viscosity index were measured and calculated by the
method described in JIS K2283.
[0124]
< Pour point >
5 The pour point was measured by the method described in
ASTM D97. Pour points lower than -50°C were described as -50°C or lower. [0125]
< -40°C viscosity >
10 Low-temperature viscosity properties were conducted in
accordance with ASTM D2983, and the -40°C viscosity was measured at -40°C with a Brookfield viscometer. [0126]
< Thermal and oxidation stability >
15 Regarding thermal and oxidation stability, a test was
conducted in accordance with the Oxidation Stability Test of Lubricating Oil for Internal Combustion Engines (ISOT) method described in JIS K2514, and the lacquer rating was evaluated 72 hours after the test time.
20 [0127]
[Production of ethylene-α-olefin copolymer (B)]
Ethylene-α-olefin copolymers (B) were prepared in accordance with the Polymerization Examples below. [0128]

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[Polymerization Example 1]
760 ml of heptane and 120 g of propylene were charged into a stainless steel autoclave with a volume of 2 L sufficiently substituted with nitrogen, and the temperature 5 in the system was raised to 150°C, and then 0.85 MPa of
hydrogen and 0.19 MPa of ethylene were supplied to raise the total pressure to 3 MPaG. Then, 0.4 mmol of triisobutyl aluminum, 0.0002 mmol of diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)]
10 zirconium dichloride, and 0.002 mmol of N,N-dimethylanilinium tetrakis (pentafluorophenyl) borate were injected with nitrogen, and polymerization was started by stirring with a rotation of 400 rpm. Ethylene was then continuously supplied to keep the total pressure at 3 MPaG, and polymerization took
15 place at 150°C for 5 minutes. Polymerization was stopped by adding a small amount of ethanol in the system, and the unreacted ethylene, propylene and hydrogen were purged. The resulting polymer solution was washed 3 times with 1000 ml of a 0.2 mol/L solution of hydrochloric acid, further washed 3
20 times with 1000 ml of distilled water, dried with magnesium
sulfate, and the solvent was then distilled off under reduced pressure. The resulting polymer was dried at 80°C under reduced pressure for 10 hours. The resulting polymer had an ethylene content of 49.5 mol%, an Mw of 5,100, an Mw/Mn of

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1.7, a B-value of 1.2, and a 100°C kinematic viscosity of 150 mm2/s. [0129]
[Polymerization Example 2] 5 710 mL of heptane and 145 g of propylene were charged into a stainless steel autoclave with a volume of 2L sufficiently substituted with nitrogen, and the temperature in the system was raised to 150°C, and then 0.40 MPa of hydrogen and 0.27 MPa of ethylene were supplied to raise the
10 total pressure to 3 MPaG. Then, 0.4 mmol of triisobutyl
aluminum, 0.0001 mmol of diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, and 0.001 mmol of N,N-dimethylanilinium tetrakis (pentafluorophenyl) borate were injected with
15 nitrogen, and polymerization was started by stirring with a rotation of 400 rpm. Ethylene only was then continuously supplied to keep the total pressure at 3 MPaG, and polymerization took place at 150°C for 5 minutes. Polymerization was stopped by adding a small amount of
20 ethanol in the system, and the unreacted ethylene, propylene and hydrogen were purged. The resulting polymer solution was washed 3 times with 1000 ml of a 0.2 mol/L solution of hydrochloric acid, further washed 3 times with 1000 ml of distilled water, dried with magnesium sulfate, and the

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solvent was then distilled off under reduced pressure. The resulting polymer was dried overnight at 80°C under reduced pressure to obtain 52.2 g of an ethylene-propylene copolymer. The resulting polymer had an ethylene content of 52.9 mol%, 5 an Mw of 8,600, an Mw/Mn of 1.8, a B-value of 1.2, and a 100°C kinematic viscosity of 600 mm2/s. [0130] [Polymerization Example 3]
250 mL of heptane was charged into a glass
10 polymerization vessel with a volume of 1 L sufficiently
substituted with nitrogen, and the temperature in the system was raised to 50°C, and then 25 L/h of ethylene, 75 L/h of propylene, and 100 L/h of hydrogen were continuously supplied into the polymerization vessel, and stirred with a rotation
15 of 600 rpm. Then, 0.2 mmol of triisobutyl aluminum was
charged into the polymerization vessel, and 0.023 mmol of N,N-dimethylanilinium tetrakis (pentafluorophenyl) borate and 0.00230 mmol of diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)]
20 zirconium dichloride, which were pre-mixed in toluene for 15 minutes or more, were charged into the polymerization vessel to start the polymerization. Ethylene, propylene and hydrogen were then continuously supplied, and polymerization took place at 50°C for 15 minutes. Polymerization was stopped by

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adding a small amount of isobutyl alcohol in the system, and the unreacted monomers were purged. The resulting polymer solution was washed 3 times with 100 mL of a 0.2 mol/L solution of hydrochloric acid, further washed 3 times with 5 100 mL of distilled water, dried with magnesium sulfate, and the solvent was then distilled off under reduced pressure. The resulting polymer was dried overnight at 80°C under reduced pressure to obtain 1.43 g of an ethylene-propylene copolymer. The resulting polymer had an ethylene content of
10 52.4 mol%, an Mw of 13,600, an Mw/Mn of 1.9, a B-value of 1.2, and a 100°C kinematic viscosity of 2,000 mm2/s. [0131] [Polymerization Example 4]
760 ml of heptane and 120 g of propylene were charged
15 into a stainless steel autoclave with a volume of 2 L
sufficiently substituted with nitrogen, and the temperature in the system was raised to 150°C, and then 0.85 MPa of hydrogen and 0.19 MPa of ethylene were supplied to raise the total pressure to 3 MPaG. Then, 0.4 mmol of triisobutyl
20 aluminum, 0.0002 mmol of dimethylsilyl bis(indenyl) zirconium dichloride, and 0.059 mmol of MMAO were injected with nitrogen, and polymerization was started by stirring with a rotation of 400 rpm. Ethylene was then continuously supplied to keep the total pressure at 3 MPaG, and polymerization took

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place at 150°C for 5 minutes. Polymerization was stopped by adding a small amount of ethanol in the system, and the unreacted ethylene, propylene and hydrogen were purged. The resulting polymer solution was washed 3 times with 1000 ml of 5 a 0.2 mol/L solution of hydrochloric acid, further washed 3 times with 1000 ml of distilled water, dried with magnesium sulfate, and the solvent was then distilled off under reduced pressure. The resulting polymer was dried at 80°C under reduced pressure for 10 hours. The resulting polymer had an 10 ethylene content of 48.5 mol%, an Mw of 5,000, an Mw/Mn of
1.8, a B-value of 1.2, and a 100°C kinematic viscosity of 150 mm2/s.
[0132]
[Polymerization Example 5]
15 710 mL of heptane and 145 g of propylene were charged
into a stainless steel autoclave with a volume of 2L sufficiently substituted with nitrogen, and the temperature in the system was raised to 150°C, and then 0.40 MPa of hydrogen and 0.27 MPa of ethylene were supplied to raise the
20 total pressure to 3 MPaG. Then, 0.4 mmol of triisobutyl
aluminum, 0.0001 mmol of dimethylsilyl bis(indenyl) zirconium dichloride, and 0.029 mmol of MMAO were injected with nitrogen, and polymerization was started by stirring with a rotation of 400 rpm. Ethylene only was then continuously

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supplied to keep the total pressure at 3 MPaG, and polymerization took place at 150°C for 5 minutes. Polymerization was stopped by adding a small amount of ethanol in the system, and the unreacted ethylene, propylene 5 and hydrogen were purged. The resulting polymer solution was washed 3 times with 1000 ml of a 0.2 mol/L solution of hydrochloric acid, further washed 3 times with 1000 ml of distilled water, dried with magnesium sulfate, and the solvent was then distilled off under reduced pressure. The
10 resulting polymer was dried overnight at 80°C under reduced
pressure to obtain 52.2 g of an ethylene-propylene copolymer. The resulting polymer had an ethylene content of 53.3 mol%, an Mw of 8,500, an Mw/Mn of 1.9, a B-value of 1.2, and a 100°C kinematic viscosity of 600 mm2/s.
15 [0133]
[Polymerization Example 6]
250 mL of heptane was charged into a glass polymerization vessel with a volume of 1 L sufficiently substituted with nitrogen, and the temperature in the system
20 was raised to 50°C, and then 25 L/h of ethylene, 75 L/h of
propylene, and 100 L/h of hydrogen were continuously supplied into the polymerization vessel, and stirred with a rotation of 600 rpm. Then, 0.2 mmol of triisobutyl aluminum was charged into a polymerization vessel, and 0.688 mmol of MMAO

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and 0.00230 mmol of dimethylsilyl bis(indenyl) zirconium dichloride, which were pre-mixed in toluene for 15 minutes or more, were charged into a polymerization vessel to start the polymerization. Ethylene, propylene and hydrogen were then 5 continuously supplied, and polymerization took place at 50°C for 15 minutes. Polymerization was stopped by adding a small amount of isobutyl alcohol in the system, and the unreacted monomers were purged. The resulting polymer solution was washed 3 times with 100 mL of a 0.2 mol/L solution of
10 hydrochloric acid, further washed 3 times with 100 mL of distilled water, dried with magnesium sulfate, and the solvent was then distilled off under reduced pressure. The resulting polymer was dried overnight at 80°C under reduced pressure to obtain 1.43 g of an ethylene-propylene copolymer.
15 The resulting polymer had an ethylene content of 52.1 mol%, an Mw of 13,800, an Mw/Mn of 2.0, a B-value of 1.2, and a 100°C kinematic viscosity of 2,000 mm2/s. [0134]
The copolymer obtained by Polymerization Example 1, the
20 copolymer obtained by Polymerization Example 2, the copolymer obtained by Polymerization Example 3, the copolymer obtained by Polymerization Example 4, the copolymer obtained by Polymerization Example 5, and the copolymer obtained by Polymerization Example 6, are respectively described below as

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Polymer 1, Polymer 2, Polymer 3, Polymer 4, Polymer 5, and Polymer 6. [0135]
[Preparation of lubricating oil composition for industrial 5 gears]
The components used other than the ethylene-α-olefin copolymer in the preparation of the below lubricating oil compositions are as follows. [0136] 10 Lubricant base oil;
The below lubricant base oils were used as the mineral oils.
Mineral oil-A: API (American Petroleum Institute) Group III mineral oil with a 100°C kinematic viscosity of 6.5 15 mm2/s, a viscosity index of 131, and a pour point of -12.5°C (Yubase-6; made by SK Lubricants),
Mineral oil-B: API (American Petroleum Institute) Group I mineral oil with a 100°C kinematic viscosity of 6.8 mm2/s, a viscosity index of 108, and a pour point of -12.5°C (Super 20 Oil N-32, made by JX Nippon Oil & Energy Corporation),
Moreover, the below lubricant base oils were used as the synthetic oils.
Synthetic oil-A: Synthetic oil poly-α-olefin with a 100°C kinematic viscosity of 4.0 mm2/s, a viscosity index of

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123, and a pour point of -50°C or lower (NEXBASE 2004; made by Neste),
Synthetic oil-B: Synthetic oil poly-α-olefin with a 100°C kinematic viscosity of 5.8 mm2/s, a viscosity index of 5 138, and a pour point of -50°C or lower (NEXBASE 2006; made by Neste, synthetic oil-A), and
Synthetic oil-C: Ester-based synthetic oil trimethylolpropane caprylate (TMTC) with a 100°C kinematic viscosity of 4.5 mm2/s, a viscosity index of 142, and a pour 10 point -50°C or lower, (SYNATIVETM ES TMTC, made by Cognis). [0137]
In addition to the lubricant base oil and ethylene-α-olefin copolymer, the below types of additives were used.
Pour point lowering agent - A; IRGAFLOW 720P made by 15 BASF
Pour point lowering agent - B; IRGAFLOW 649P made by BASF
Additive package – A; HITEC-3339 made by AFTON
CHEMICAL,
20 Additive package – B; Anglamol-6085U made by LUBRIZOL,
Additive package – C; LUBRIZOL 1047U made by LUBRIZOL,
Antioxidant; Phenol-based antioxidant (Irganox L135 made by BASF), and
Polybutene; Liquid polybutene with a weight average

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molecular weight of 8,400 and a 100°C kinematic viscosity of 3,800 mm2/s, as measured by GPC in the same way as the ethylene-α-olefin copolymer (Nisseki Polybutene HV-1900 made by JX Nippon Oil & Energy Corporation). 5 [0138]
< Lubricating oil composition for industrial gears > [Example 1]
Synthetic oil-A was used as the lubricant base oil (A), and the copolymer obtained in Polymerization Example 2
10 (Polymer 2) was used as the ethylene-α-olefin copolymer (B).
These were mixed together with an antioxidant and adjusted to 100% by mass, thereby preparing a lubricating oil composition for industrial gear oil. The addition amounts of the respective components are as shown in Table 2. The physical
15 properties of the lubricating oil composition are shown in Table 2. [0139] [Examples 2 to 14, Comparative Examples 1 to 9]
Except for changing the types of components and
20 addition amounts to those as described in Table 2, the lubricating oil compositions for industrial gears were prepared in the same way as in Example 1. The physical properties etc. of the obtained lubricating oil compositions are as shown in Table 2.

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[0140]
Table 2

Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5
Polymer 1 % by mass
Polymer 2 % by mass 21.0 24.0 25.0
Polymer 3 % by mass 16.0 17.0
Polymer 4 % by mass
Polymer 5 % by mass
Polymer 6 % by mass
Polybutene % by mass
Mineral oil - A % by mass 73.0
Mineral oil - B % by mass
Synthetic oil - A % by mass 78.8 83.8
Synthetic oil - B % by mass 64.8 71.8
Synthetic oil - C % by mass
Antioxidant % by mass 0.2 0.2
Additive Package - A % by mass 1.2 1.2
Additive Package - B % by mass 1.5
Additive Package - C % by mass
Pour point lowering agent - A % by mass 0.5
Pour point lowering agent - B % by mass
40°C kinematic viscosity mm2/s 148 160 228 239 230
Viscosity index - 166 175 169 175 168
Pour point °C -43 -45 -40 -40 -35
-40°C viscosity mPa･s 75,000 77,000 160,000 130,000
ISOT Lacquer rating Adhered
substance
(thin) Adhered
substance
(thin) Adhered
substance
(thin) Adhered
substance
(thin) Adhered substance (medium)

Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12
48.0 56.0
31.0 37.0
18.0 23.0 27.0




80.0 67.5 75.5
51.5 42.5 61.5 71.5





1.5
1.0 1.0 1.0 1.0 1.0 1.0
0.5
0.5 0.5 0.5 0.5 0.5 0.5
226 325 325 338 455 468 462
171 154 165 172 155 173 178
-33 -25 -25 -25 -23 -24 -23

Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) Adhered substance (medium)

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[0141]
Table 2 (continued)

Ex. 13 Ex. 14 Comp. Ex. 1 Comp. Ex. 2 Comp. Ex. 3 Comp. Ex. 4 Comp. Ex. 5 Comp. Ex. 6 Comp. Ex. 7 Comp. Ex. 8 Comp. Ex. 9
Polymer 1 % by mass
Polymer 2 % by mass 48.0
Polymer 3 % by mass 35.0
Polymer 4 % by mass 48.0
Polymer 5 % by mass 21.0 31.0 48.0
Polymer 6 % by mass 16.0 23.0 35.0
Polybutene % by mass 24.0 24.0
Mineral oil - A % by mass 67.5 75.5 74.5
Mineral oil - B % by mass 51.5
Synthetic oil - A % by mass 40.5 53.5 78.8 83.8 40.5 53.5
Synthetic oil - B % by mass 64.8
Synthetic oil - C % by mass 10.0 10.0 10.0 10.0 10.0
Antioxidant % by mass 0.2 0.2
Additive Package - A % by mass 1.2
Additive Package - B % by mass 1.5 1.5 1.5 1.5
Additive Package - C % by mass 1.0 1.0 1.0 1.0
Pour point lowering agent - A % by mass
Pour point lowering agent - B % by mass 0.5 0.5 0.5
40°C kinematic viscosity mm2/s 695 662 147 162 324 325 336 698 658 225 221
Viscosity index - 190 199 166 175 154 165 172 191 197 150 144
Pour point °C -29 -30 -43 -46 -25 -25 -25 -29 -30 -38 -30
-40°C viscosity mPa･s 76,000 75,000 190,000
ISOT Lacquer rating Adhered
substance
(thin) Adhered
substance
(thin) Adhered
substance
(thick) Adhered
substance
(thick) Adhered
substance
(thick) Adhered
substance
(thick) Adhered
substance
(thick) Adhered
substance
(thick) Adhered
substance
(thick) Adhered
substance
(thick) Adhered
substance
(thick)

WE CLAIMS

A lubricating oil composition for industrial gears,
comprising 5 10 to 90% by mass of a lubricant base oil (A) having
the properties of the below (A1) to (A3), and
90 to 10% by mass of a liquid random copolymer (B) of
ethylene and α-olefin, the liquid random copolymer (B) being
prepared by the below method (α), wherein the total amount of 10 the lubricant base oil (A) and the copolymer (B) is 100% by
mass,
the lubricating oil composition for industrial gears
having the property of the below (C1).
(A1) The lubricant base oil has a kinematic viscosity at 15 100°C of 1 to 100 mm2/s.
(A2) The lubricant base oil has a viscosity index of 100 or
more.
(A3) The lubricant base oil has a pour point of 0°C or lower.
(C1) The lubricating oil composition for industrial gears has 20 a kinematic viscosity at 40°C of 100 to 10,000 mm2/s.
(Method (α))
A method (α) for preparing a liquid random copolymer of
ethylene and α-olefin, comprising a step of carrying out
solution polymerization of ethylene and α-olefin having 3 to

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20 carbon atoms, under a catalyst system comprising
(a) a bridged metallocene compound represented by the
following Formula 1, and
(b) at least one compound selected from a group consisting of
5 (i) an organoaluminum oxy-compound, and
(ii) a compound which reacts with the bridged metallocene compound to form an ion pair.

(Formula 1)
[In Formula 1, R1, R2, R3, R4, R5, R8, R9 and R12 are 10 respectively and independently hydrogen atom, hydrocarbon
group or silicon-containing hydrocarbon group, and adjoining groups are optionally connected to each other to form a ring structure,
R6 and R11, being the same, are hydrogen atom,

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hydrocarbon group or silicon-containing hydrocarbon group,
R7 and R10, being the same, are hydrogen atom, hydrocarbon group or silicon-containing hydrocarbon group,
R6 and R7 are optionally connected to hydrocarbon having 5 2 to 3 carbon atoms to form a ring structure,
R11 and R10 are optionally connected to hydrocarbon having 2 to 3 carbon atoms to form a ring structure,
R6, R7, R10 and R11 are not hydrogen atom at the same
time;
10 Y is a carbon atom or silicon atom;
R13 and R14 are independently aryl group;
M is Ti, Zr or Hf;
Q is independently halogen, hydrocarbon group, an anionic ligand or a neutral ligand which can be coordinated 15 to a lone pair of electrons; and
j is an integer of 1 to 4.]
2. The lubricating oil composition for industrial gears according to Claim 1, wherein in the metallocene compound 20 represented by the above Formula 1, at least one among
substituents (R1, R2, R3 and R4) bonded to a cyclopentadienyl group, is a hydrocarbon group having 4 or more carbon atoms.
3. The lubricating oil composition for industrial gears

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according to Claim 1 or 2, wherein R6 and R11, being the same, are hydrocarbon groups having 1 to 20 carbon atoms.
4. The lubricating oil composition for industrial gears 5 according to any one of Claims 1 to 3, wherein in the
metallocene compound represented by the above Formula 1, substituent (R2 or R3) bonded to the 3-position of the cyclopentadienyl group is a hydrocarbon group.
10 5. The lubricating oil composition for industrial gears according to Claim 4, wherein in the metallocene compound represented by the above Formula 1, the hydrocarbon group (R2 or R3) bonded to the 3-position of the cyclopentadienyl group is an n-butyl group.
15
6. The lubricating oil composition for industrial gears
according to any one of Claims 1 to 5, wherein in the
metallocene compound represented by the above Formula 1,
substituents (R6 and R11) bonded to the 2-position and 7-
20 position of the fluorenyl group are all tert-butyl groups.
7. The lubricating oil composition for industrial gears
according to any one of Claims 1 to 6, wherein the compound
which reacts with the bridged metallocene compound to form an

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ion pair is a compound represented by the following Formula 6.
Rg
+e Rf—B—Rh
R ., ■■■ (Formula 6)
[In Formula 6, Re+ is H+, a carbenium cation, an oxonium 5 cation, an ammonium cation, a phosphonium cation, a
cycloheptyltrienyl cation, or a ferrocenium cation having a transition metal, and Rf to Ri each is independently a hydrocarbon group having 1 to 20 carbon atoms.]
10 8. The lubricating oil composition for industrial gears according to Claim 7, wherein the ammonium cation is a dimethylanilinium cation.
9. The lubricating oil composition for industrial gears 15 according to Claim 7 or 8, wherein the catalyst system
further comprises an organoaluminum compound selected from a group consisting of trimethyl aluminum and triisobutyl aluminum.
20 10. A lubricating oil composition for industrial gears,
comprising

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10 to 90% by mass of a lubricant base oil (A) having
the properties of the below (A1) to (A3), and
90 to 10% by mass of a liquid random copolymer of
ethylene and α-olefin, the liquid random copolymer having the 5 properties of the below (B1) to (B5), wherein the total
amount of the lubricant base oil (A) and the copolymer is
100% by mass,
the lubricating oil composition for industrial gears
having the property of the below (C1). 10 (A1) The lubricant base oil (A) has a kinematic viscosity at
100°C of 1 to 100 mm2/s.
(A2) The lubricant base oil (A) has a viscosity index of 100
or more.
(A3) The lubricant base oil (A) has a pour point of 0°C or 15 lower.
(B1) The liquid random copolymer comprises 40 to 60 mol% of
ethylene units and 60 to 40 mol% of α-olefin units having 3
to 20 carbon atoms.
(B2) The liquid random copolymer has a number average 20 molecular weight (Mn) of 500 to 10,000 and a molecular weight
distribution (Mw/Mn, Mw is the weight average molecular
weight) of 3 or less, as measured by Gel Permeation
Chromatography (GPC).
(B3) The liquid random copolymer has a kinematic viscosity at

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100°C of 30 to 5,000 mm2/s.
(B4) The liquid random copolymer has a pour point of 30 to -45°C.
(B5) The liquid random copolymer has a Bromine Number of 0.1 5 g / 100 g or less.
(C1) The lubricating oil composition for industrial gears has a kinematic viscosity at 40°C of 100 to 10,000 mm2/s.
11. The lubricating oil composition for industrial gears
10 according to any one of Claims 1 to 10, having a kinematic
viscosity at 40°C of 250 to 5,000 mm2/s.
12. The lubricating oil composition for industrial gears
according to any one of Claims 1 to 11, wherein the lubricant
15 base oil (A) further satisfies the below (A4) to (A6).
(A4) The lubricant base oil (A) has a kinematic viscosity at
100°C of 1 to 10 mm2/s.
(A5) The lubricant base oil (A) has a viscosity index of 110
or more.
20 (A6) The lubricant base oil (A) has a pour point of -10°C or
lower.

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13. The lubricating oil composition for industrial gears according to any one of Claims 1 to 12, wherein 30 to 100% by mass of the lubricant base oil (A) is a mineral oil.
5 14. The lubricating oil composition for industrial gears
according to any one of Claims 1 to 13, wherein 30 to 100% by mass of the lubricant base oil (A) is a synthetic oil, and the synthetic oil is a poly α-olefin (PAO) and/or an ester oil. 10
15. A gear oil for wind power generation, consisting of the lubricating oil composition according to any one of Claims 1 to 14.
15 16. A gear oil for machine tools and molding machines,
consisting of the lubricating oil composition according to any one of Claims 1 to 14.
17. A method for producing a lubricating oil composition 20 for industrial gears, comprising the steps of:
preparing a liquid random copolymer (B) of ethylene and α-olefin by the following method (α); and
preparing a lubricating oil composition for industrial gears by mixing a lubricant base oil (A) in an amount of 10

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to 90% by mass of the lubricating oil composition, the
lubricant base oil (A) having the properties of the below
(A1) to (A3), and the liquid random copolymer (B) in an
amount of 90 to 10% by mass of the lubricating oil 5 composition, wherein the total amount of the lubricant base
oil (A) and the copolymer (B) is 100% by mass, the
lubricating oil composition for industrial gears having the
property of the below (C1).
(A1) The lubricant base oil (A) has a kinematic viscosity at 10 100°C of 1 to 100 mm2/s.
(A2) The lubricant base oil (A) has a viscosity index of 100
or more.
(A3) The lubricant base oil (A) has a pour point of 0°C or
lower. 15 (C1) The lubricating oil composition for industrial gears has
a kinematic viscosity at 40°C of 100 to 10,000 mm2/s.
(Method (α))
A method (α) for preparing a liquid random copolymer of
ethylene and α-olefin, comprising a step of carrying out 20 solution polymerization of ethylene and α-olefin having 3 to
20 carbon atoms, under a catalyst system comprising
(a) a bridged metallocene compound represented by the following Formula 1, and
(b) at least one compound selected from a group consisting of

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(i) an organoaluminum oxy-compound, and (ii) a compound which reacts with the bridged metallocene compound to form an ion pair.

(Formula 1)
5 [In Formula 1, R1, R2, R3, R4, R5, R8, R9 and R12 are
respectively and independently hydrogen atom, hydrocarbon
group or silicon-containing hydrocarbon group, and adjoining
groups are optionally connected to each other to form a ring
structure,
10 R6 and R11, being the same, are hydrogen atom,
hydrocarbon group or silicon-containing hydrocarbon group,
R7 and R10, being the same, are hydrogen atom, hydrocarbon group or silicon-containing hydrocarbon group,
R6 and R7 are optionally connected to hydrocarbon having

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2 to 3 carbon atoms to form a ring structure,
R11 and R10 are optionally connected to hydrocarbon
having 2 to 3 carbon atoms to form a ring structure,
R6, R7, R10 and R11 are not hydrogen atom at the same

5

time;

Y is a carbon atom or silicon atom;
R13 and R14 are independently aryl group;
M is Ti, Zr or Hf;
Q is independently halogen, hydrocarbon group, an

10

anionic ligand or a neutral ligand which can be coordinated

to a lone pair of electrons; and
j is an integer of 1 to 4.]