[0001]The present invention relates to a lubrication oil composition and a method for producing the same. More 10 particularly, the present invention relates to a lubrication oil composition comprising specific components and mainly used for industrial machines and transportation machines, and a method for producing the same. 15 BACKGROUND ART [0002] In recent years, environmental problems have been highlighted on a global scale, and as one of countermeasures, reduction of power consumption or fuel consumption in 20 industrial machines or transportation machines is taken in factories or by transportation carriers, etc. As one means to solve the above problems, there has been required a much higher effect on power saving and fuel saving by various lubrication oils used for the above machines. SF-3415 2 [0003] Lubrication oil products have a so-called temperature dependence of viscosity that the viscosity generally greatly varies as the temperature is changed. Since the working 5 temperature of equipment using lubrication oil greatly varies in certain cases, the temperature dependence of the viscosity is considered to be preferably small. Then, for the purpose of reducing the temperature dependence of the viscosity, a certain polymer that is soluble in a lubrication base oil has 10 been used as a viscosity modifier for lubrication oils. In recent years, an α-olefin polymer has been widely used as such a viscosity modifier, and in order to further improve a property balance of lubrication oil, a variety of further improvements have been made (patent literature 1). 15 Such viscosity index improvers as above are generally used for maintaining a proper viscosity at high temperatures. On the other hand, under such circumstances that energy saving and resource saving have been strongly considered to be part of reduction of environmental burden, a viscosity 20 modifier, which holds down viscosity increase particularly at low temperatures (is excellent in low-temperature characteristics) and is excellent also in durability and thermal oxidation stability, has been desired recently. In general lubrication oil applications, in order to obtain SF-3415 3 excellent low-temperature characteristics, control of a concentration of a polymer contained to the lowest is advantageous also from the economical viewpoint, and therefore, use of a polymer having a molecular weight as high 5 as possible is known. However, an α-olefin polymer having a high molecular weight tends to be disadvantageous in terms of shear stability. [0004] Particularly in gear oil applications among industrial 10 lubrication oil applications, high durability (shear stability) and thermal oxidation stability have been required, and performance given in consideration of a balance between durability and viscosity characteristics has been desired. Further, of various lubrication oils, gear oils are 15 used under particularly severe conditions, so that requirements for higher performance and longer life are strong, and also with regard to an extreme pressure agent that is a component exerting influence on formation of a stable oil film, further improvement in performance is 20 desired. [0005] As lubrication base oils, mineral oils are classified into three ranks of Groups (I) to (III), and further, poly-α-olefins (PAO) are classified as Group (IV) and the others are SF-3415 4 classified as Group (V) by the API classification. In various automotive lubrication oil applications, in order to cope with higher performance required and reduction of environmental burden, a ratio of use of Group (II) and Group 5 (III) mineral oils or synthetic oils such as poly-α-olefins has increased though Group (I) mineral oils have been hitherto widely used. On the other hand, also in the industrial lubrication oil applications, long life and high durability are desired, and the aforesaid Group (III) mineral 10 oils or poly-α-olefins have been used. Particularly in the recent industrial gear oils, shear stability is strongly desired as a main parameter of durability. It is difficult to meet the shear stability required herein by the use of conventional viscosity modifiers of high molecular weight 15 type, so that α-olefin polymers of relatively low molecular weight, such as polybutene, have been used. However, there is room for improvement in viscosity characteristics of polybutene, particularly in sufficient fluidity thereof at low temperatures, depending upon the use applications. 20 CITATION LIST PATENT LITERATURE [0006] Patent literature 1: WO 00/34420 SF-3415 5 SUMMARY OF INVENTION TECHNICAL PROBLEM [0007] 5 The aforesaid extreme pressure agent is a component that chemically reacts with, for example, a material for forming a frictional surface of a machine or the like and forms a pressure-resistant film on the frictional surface. Since the materials of such frictional surfaces are often 10 metals, the extreme pressure agent tends to be a component of high polarity. [0008] On the other hand, base oils of synthetic oils, such as poly-α-olefins, often have low polarity, and therefore, the 15 industrial gear oil applications in which high viscosity is particularly required have faced a problem that such oils have bad compatibility with the extreme pressure agent of high polarity. [0009] 20 Accordingly, the problem to be solved by the present invention is to provide industrial lubrication oil, which is excellent in compatibility with an extreme pressure agent, is excellent in a balance between viscosity characteristics and shear stability and is excellent also in durability and SF-3415 6 thermal oxidation stability. SOLUTION TO PROBLEM [0010] 5 Under such circumstances as above, the present inventors have earnestly studied, and as a result, they have found that the above problem can be solved by combining an ethylene/α-olefin copolymer produced using a specific catalyst, one or more synthetic oils and/or mineral oils 10 having specific viscosity, viscosity index and pour point that are used when needed, and a base oil, with a specific extreme pressure agent. Thus, the present inventors have accomplished the present invention. [0011] 15 The specific embodiments of the present invention are as described below. [1] A lubrication oil composition comprising (A) a liquid random copolymer of ethylene and an α- olefin, which is produced by a method (α) below, 20 (F) a sulfur-containing compound wherein at least one hydrocarbon group being adjacent to sulfur is a secondary or tertiary hydrocarbon group, and as an optional component, (G) a polymer of α-olefin having 3 to 6 carbon atoms, SF-3415 7 having a kinematic viscosity at 40°C of 450 to 51,000 mm2/s, and having a sulfur content of 0.1 to 5 parts by weight [0012] 5 (with the proviso that the total amount of the lubrication oil composition is 100 parts by weight): (Method (α)) a method (α) for producing a liquid random copolymer of ethylene and an α-olefin comprising a step of performing 10 solution polymerization of ethylene and an α-olefin having 3 to 20 carbon atoms in a catalyst system comprising (a) a bridged metallocene compound represented by the Formula 1 below, and (b) at least one compound selected from the group 15 consisting of (i) organoaluminumoxy compounds, and (ii) compounds that react with the bridged metallocene compounds to form ion pairs: [0013] 20 [Chem. 1] SF-3415 8 R9 R; (Formula 1) 10 [In Formula 1, R1, R2, R3, R4, R5, R8, R9, and R12 are respectively and independently a hydrogen atom, a hydrocarbon group, or a silicon-containing hydrocarbon group, and adjacent groups may be linked to each other to form a ring structure, 15 R6 and R11, being identical with each other, are hydrogen atoms, hydrocarbon groups, or silicon-containing hydrocarbon groups, R7 and R10, being identical with each other, are hydrogen atoms, hydrocarbon groups, or silicon-containing 20 hydrocarbon groups, R6 and R7 may bind to hydrocarbon having 2 to 3 carbon atoms to form a ring structure, R11 and R10 may bind to hydrocarbon having 2 to 3 carbon atoms to form a ring structure, SF-3415 9 R6, R7, R10, and R11 are not hydrogen atoms simultaneously, Y is a carbon atom or a silicon atom, R13 and R14 are independently aryl groups, 5 M is Ti, Zr, or Hf, Q is independently a halogen, a hydrocarbon group, an anionic ligand, or a neutral ligand that is capable of coordinating to a lone electron pair, and j is an integer of 1 to 4]. 10 [2] The lubrication oil composition described in [1], in which in the metallocene compound 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. 15 [3] The lubrication oil composition described in [1] or [2], in which R6 and R11, being the same, are hydrocarbon groups having 1 to 20 carbon atoms. [4] The lubrication oil composition described in any one of [1] to [3], in which in the metallocene compound 20 represented by the above Formula 1, a substituent (R2 or R3) bonded to the 3-position of the cyclopentadienyl group is a hydrocarbon group. [5] The lubrication oil composition described in [4], in which in the metallocene compound represented by the above SF-3415 10 Formula 1, a hydrocarbon group (R2 or R3) bonded to the 3-position of the cyclopentadienyl group is an n-butyl group. [6] The lubrication oil composition described in any one of [1] to [5], in which in the metallocene compound 5 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. [7] The lubrication oil composition described in any one of [1] to [6], in which the compound which reacts with 10 the bridged metallocene compound to form ion pairs is a compound represented by the following Formula 6: [0014] [Chem. 2] Rg R' e R1 h ■■ « (Formula 6) 15 [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 are respectively and SF-3415 11 independently a hydrocarbon group having 1 to 20 carbon atoms]. [8] The lubrication oil composition described in [7], in which the ammonium cation is a dimethylanilinium cation. 5 [9] The lubrication oil composition described in [7] or [8], in which the catalyst system further comprises an organoaluminum compound selected from a group consisting of trimethyl aluminum and triisobutyl aluminum. [10] The lubrication oil composition described in any 10 one of [1] to [9], which further comprises a component (B) satisfying all of the following requirements (B-1) to (B-3): (B-1) a kinematic viscosity at 100̊C is 3 to 120 mm2/s, (B-2) a viscosity index is not less than 90, and (B-3) a pour point is not higher than -10̊C. 15 [11] The lubrication oil composition described in [10], in which the component (B) is synthetic oil (C) satisfying all of the following requirements (C-1) to (C-3): (C-1) a kinematic viscosity at 100̊C is 20 to 120 mm2/s, 20 (C-2) a viscosity index is not less than 120, and (C-3) a pour point is not higher than -30̊C. [12] The lubrication oil composition described in [10], in which the component (B) is synthetic oil (D) satisfying all of the following requirements (D-1) to (D-3): SF-3415 12 (D-1) a kinematic viscosity at 100°C is 3 to 10 mm2/s, (D-2) a viscosity index is not less than 120, and (D-3) a pour point is not higher than -40°C. [13] The lubrication oil composition described in [10], 5 in which the component (B) is mineral oil (E) satisfying all of the following requirements (E-1) to (E-3): (E-1) a kinematic viscosity at 100°C is 3 to 40 mm2/s, (E-2) a viscosity index is not less than 90, and (E-3) a pour point is not higher than -10°C. 10 [14] The lubrication oil composition described in [11] or [12], in which the component (C) and/or the component (D) is synthetic oil comprising a polymer of a-olefin having 8 to 20 carbon atoms and/or an ester compound. [15] The lubrication oil composition described in [13], 15 in which the component (E) is one or more mineral oils selected from Groups (I), (II) and (III) of the API classification. [16] The lubrication oil composition described in [10], in which the component (B) is one or more selected from 20 synthetic oil (C) satisfying all of the following requirements (C-1) to (C-3), synthetic oil (D) satisfying all of the following requirements (D-1) to (D-3), and mineral oil (E) satisfying all of the following requirements (E-1) to (E- 3), and SF-3415 13 the saturated hydrocarbon content relative to the entirety of the components (A) to (E) is not less than 80% by weight: (C-1) a kinematic viscosity at 100̊C is 20 to 120 5 mm2/s, (C-2) a viscosity index is not less than 120, (C-3) a pour point is not higher than -30̊C (D-1) a kinematic viscosity at 100̊C is 3 to 10 mm2/s, (D-2) a viscosity index is not less than 120, 10 (D-3) a pour point is not higher than -40̊C (E-1) a kinematic viscosity at 100̊C is 3 to 40 mm2/s, (E-2) a viscosity index is not less than 90, and (E-3) a pour point is not higher than -10̊C. [17] A Lubrication oil composition comprising: 15 a liquid random copolymer of ethylene and an α-olefin satisfying all of the following requirements (A-1) to (A-5): (A-1) comprising 40 to 60% by mol of an ethylene unit, and 60 to 40% by mol of an α-olefin unit having 3 to 20 carbon atoms, 20 (A-2) having a number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of 500 to 10,000, and a molecular weight distribution (Mw/Mn, Mw means a weight average molecular weight) of 3 or less, (A-3) having a kinematic viscosity at 100̊C of 30 to SF-3415 14 5,000 mm2/s, (A-4) having a pour point of 30 to -45°C, and (A-5) having a bromine value of not higher than 0.1 g/100 g, 5 (F) a sulfur-containing compound in which at least one hydrocarbon group adjacent to sulfur is a secondary or tertiary hydrocarbon group, and as an optional component, (G) a polymer of α-olefin having 3 to 6 carbon atoms, 10 and having a kinematic viscosity at 40̊C of 962 to 4,570 mm2/s, and a sulfur content of 0.1 to 5 parts by weight [0015] (with the proviso that the total amount of the 15 lubrication oil composition is 100 parts by weight). [18] The lubrication oil composition described in any one of [1] to [17], which is a gear oil composition. [19] A method for producing a lubrication oil composition comprising: 20 a step of producing (A) a liquid random copolymer of ethylene and an α-olefin by a method (α) below, and a step of mixing (A) the liquid random copolymer, (F) a sulfur-containing compound in which at least one hydrocarbon group adjacent to sulfur is a secondary or tertiary SF-3415 15 hydrocarbon group, (B) a component (B) satisfying all of the following requirements (B-1) to (B-3), and as an optional component, (G) a polymer of α-olefin having 3 to 6 carbon atoms to give a lubrication oil composition having a 5 kinematic viscosity at 40°C of 450 to 51,000 mm2/s and a sulfur content of 0.1 to 5 parts by weight: (Method (α)) a method (α) for producing a liquid random copolymer of ethylene and an α-olefin, comprising a step of performing 10 solution polymerization of ethylene and an α-olefin having 3 to 20 carbon atoms in a catalyst system comprising (a) a bridged metallocene compound represented by the Formula 1 below, and (b) at least one compound selected from the group 15 consisting of (i) organoaluminumoxy compounds, and (ii) compounds that react with the bridged metallocene compounds to form ion pairs: [0016] 20 [Chem. 3] SF-3415 16 ,(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, SF-3415 17 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, 5 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 groups; M is Ti, Zr or Hf; 10 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.] 15 ADVANTAGEOUS EFFECTS OF INVENTION [0017] The lubrication oil composition of the present invention is excellent in compatibility though it contains a sulfur compound that is considered to be preferable as an 20 extreme pressure agent, that is, the lubrication oil composition is in liquid form with excellent transparency and is excellent also in viscosity characteristics and shear stability. Therefore, this lubrication oil composition is a lubrication oil composition excellent in energy saving, SF-3415 18 resource saving, etc., and further in durability and thermal oxidation stability. On this account, the lubrication oil composition is preferable as industrial lubrication oil, particularly gear oil. 5 DESCRIPTION OF EMBODIMENTS [0018] The lubrication oil composition according to the present invention is characterized by comprising a liquid 10 random copolymer of ethylene and an α-olefin produced by the method (α) below (hereinafter referred to as “ethylene/α-olefin copolymer (A)” in the present description), and a sulfur compound (F) satisfying specific requirements. Each component is described below. 15 [Ethylene/α-olefin copolymer (A)] An ethylene/α-olefin copolymer (A) in the present invention is a liquid random copolymer (A) of ethylene and an α-olefin produced by a method (α) below. (Method (α)) 20 a method (α) for producing a liquid random copolymer of ethylene and an α-olefin, comprising a step of performing solution polymerization of ethylene and an α-olefin having 3 to 20 carbon atoms in a catalyst system comprising: (a) a bridged metallocene compound represented by the SF-3415 19 Formula 1 below, and (b) at least one compound selected from the group consisting of (i) organoaluminumoxy compounds, and 5 (ii) compounds that react with the bridged metallocene compounds to form ion pairs: [0019] [Chem. 4] Ry Rtt •••(Formula 1) SF-3415 20 [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 5 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, hydrocarbon group or silicon-containing hydrocarbon group, 10 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, R6, R7, R10 and R11 are not hydrogen atom at the same 15 time; Y is a carbon atom or silicon atom; R13 and R14 are independently aryl groups; M is Ti, Zr or Hf; Q is independently halogen, hydrocarbon group, an 20 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.] Here, the hydrocarbon group has 1 to 20 carbon atoms, preferably 1 to 15 atoms, and more preferably 4 to 10 carbon SF-3415 21 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. [0020] 5 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, triphenylsilyl group etc. 10 [0021] In the bridged metallocene compound represented by Formula 1, cyclopentadienyl group may be substituted or unsubstituted. [0022] 15 In the bridged metallocene compound represented by Formula 1, (i) it is preferable that at least one among substituents (R1, R2, R3 and R4) bonded to cyclopentadienyl group is a hydrocarbon group, 20 (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, (iii) it is most preferable that substituent (R2 or R3) bonded to the 3-position of the cyclopentadienyl group is a SF-3415 22 hydrocarbon group having 4 or more carbon atoms (for example an n-butyl group). [0023] In case where at least two among R1, R2, R3 and R4 are 5 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. [0024] 10 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 poly-α-olefin, in order to improve the polymerization 15 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-position of the fluorenyl group are the same hydrocarbon group having 1 to 20 carbon atoms, and preferably all tert-20 butyl groups, and R7 and R10 are the same hydrocarbon group having 1 to 20 carbon atoms, and preferably all tert-butyl groups. [0025] SF-3415 23 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 5 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 10 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 15 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 preferably include a phenyl group. In the bridged metallocene 20 compound represented by Formula 1, preferably R13 and R14 are the same in view of easy production. [0026] In the bridged metallocene compound represented by Formula 1, Q is preferably a halogen atom or hydrocarbon SF-3415 24 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, 2,2-5 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. 10 [0027] Examples of such bridged metallocene compounds (a) include: ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, ethylene [η5-(3-tert- 15 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-methyl cyclopentadienyl)] (octamethyl 20 octahydrodibenzfluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] SF-3415 25 (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-5-methyl cyclopentadienyl)] [η5-5 (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)] 10 zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] (octamethyl octahydrodibenzfluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl 15 cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, ethylene [η5-(3-tert-butyl 20 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; SF-3415 26 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 5 cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] (octamethyl octahydrodibenzfluorenyl) zirconium dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, 10 ethylene [η5-(3-n-butyl cyclopentadienyl)] (dibenzofluorenyl) 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 15 dichloride, ethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride; diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (η5-fluorenyl) zirconium dichloride, 20 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- SF-3415 27 methyl cyclopentadienyl)] (octamethyl octahydrodibenzfluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, 5 diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (octahydrodibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl-5-methyl 10 cyclopentadienyl)] [η5-(2,7-diphenyl-3,6-di-tert-butyl 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)] 15 (η5-fluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-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- 20 tert-butyl cyclopentadienyl)] (octamethyl octahydrodibenzfluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-tert-butyl cyclopentadienyl)] (dibenzofluorenyl) zirconium SF-3415 28 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 5 fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-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- 10 butyl cyclopentadienyl)] [η5-(3,6-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-di-tert-butyl fluorenyl)] zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] (octamethyl octahydrodibenzfluorenyl) 15 zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] (dibenzofluorenyl) zirconium dichloride, diphenylmethylene [η5-(3-n-butyl cyclopentadienyl)] (octahydrodibenzofluorenyl) 20 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; SF-3415 29 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)] 5 zirconium dichloride, di(p-tolyl) methylene [η5-(3-tert-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 octahydrodibenzfluorenyl) zirconium dichloride, di(p-tolyl) 10 methylene [η5-(3-tert-butyl-5-methyl cyclopentadienyl)] (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)] 15 (octahydrodibenzofluorenyl) zirconium dichloride, di(p-tolyl) 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 20 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- SF-3415 30 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 octahydrodibenzfluorenyl) zirconium dichloride, 5 di(p-tolyl) methylene [η5-(3-tert-butyl cyclopentadienyl)] (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 10 dichloride, di(p-tolyl) methylene [η5-(3-tert-butyl 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 15 di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] (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 20 fluorenyl)] zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] (octamethyl octahydrodibenzfluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] (benzofluorenyl) zirconium dichloride, di(p-tolyl) methylene [η5-(3-n-butyl SF-3415 31 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)] [η5-(2,7-diphenyl-5 3,6-di-tert-butyl fluorenyl) zirconium dichloride, di(p- tolyl) methylene [η5-(3-n-butyl cyclopentadienyl)] [η5-(2,7-dimethyl-3,6-di-tert-butyl fluorenyl)] zirconium dichloride. [0028] Although compounds whose zirconium atoms were 10 substituted with hafnium atoms, or compounds whose chloro ligands were substituted with methyl groups etc. are exemplified in these compounds, the bridged metallocene compound (a) is not limited to these exemplifications. [0029] 15 As the organoaluminum oxy-compound used in the catalyst system according to 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 20 contained in the organoaluminum oxy-compound. [0030] [Chem. 5] SF-3415 32 R—(-A1— O -)—AIR R (Formula 2) (-A1—O n •- (Formula 3) ^Al—o^-ui—o-) 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 hydrocarbon group having 2 to 20 carbon atoms, m and n are 5 independently an integer of 2 or more, preferably 3 or more, more preferably 10 to 70, and most preferably 10 to 50. [0031] [Chem. 6] SF-3415 33 Rdv Y Rd Al—O—B—O—Al Rd "R( 1 » r\ (Formula 5) In Formula 5, Rc is a hydrocarbon group having 1 to 10 carbon atoms, and Rd is independently a hydrogen atom, 5 halogen atom or hydrocarbon group having 1 to 10 carbon atoms. [0032] In Formula 2 or Formula 3, R is a methyl group (Me) of the organoaluminum oxy-compound which is conventionally 10 referred to as "methylaluminoxane". [0033] 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 15 methylaluminoxane is difficult to dissolve in a saturated 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 20 has been developed and used as an aluminoxane dissolved in SF-3415 34 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 aluminum as shown in US Patent 4960878 and US Patent 5041584, 5 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 of MMAO and TMAO, in the form of a saturated hydrocarbon solution. (See Tosoh Finechem Corporation, Tosoh Research & 10 Technology Review, Vol 47, 55 (2003)). [0034] As (ii) the compound which reacts with the bridged metallocene compound to form ion pairs (hereinafter, referred to as "ionic compound" as required) which is contained in the 15 present catalyst system, a Lewis acid, ionic compounds, borane, borane compounds and carborane compounds can be used. These are described in Korean Patent No. 10-551147, Japanese Unexamined Publication H01-501950, Japanese Unexamined Publication H03-179005, Japanese Unexamined Publication H03-20 179006, Japanese Unexamined Publication H03-207703, Japanese Unexamined Publication H03-207704, USP 5321106 and so on. If needed, heteropoly compounds, and isopoly compound etc. can be used, and the ionic compound disclosed in Japanese Unexamined Publication 2004-051676 can be used. The ionic SF-3415 35 compound 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 5 group, etc.), substituted or unsubstituted aryl group having 6 to 20 carbon 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 10 tris(p-tolyl) boron. When 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 15 Formula 6 is used as the ionic compound. [0035] [Chem. 7] Rg R e R B h (Formula 6) SF-3415 36 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 an 5 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 include a tris(methylphenyl)carbenium cation and a tris(dimethylphenyl)carbenium cation, and examples of the 10 ammonium cation include a dimethylanilinium cation. [0036] Examples of compounds represented by the aforementioned Formula 6 preferably include N,N-dialkyl anilinium salts, and specifically include N,N-dimethylanilinium tetraphenylborate, 15 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 anilinium tetrakis (3,5-ditrifluoro methylphenyl) borate, 20 N,N-2,4,6-penta methylanilinium tetraphenylborate, and N,N-2,4,6-penta methylanilinium tetrakis (pentafluorophenyl) borate. [0037] SF-3415 37 The catalyst system used in the present invention further includes a (c) organoaluminum compound when it is needed. The organoaluminum compound plays a role of activating the bridged metallocene compound, the 5 organoaluminum oxy-compound, and the ionic compound, etc. As 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. 10 [0038] 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 15 of 00.03 (II) Mineral oil 80 - 120 >90 <0.03 (III) Mineral oil >120 >90 <0.03 (IV) Poly-a-olefin (V) Lubrication base oils other than those listed above *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) *4: mineral oils in which a saturated hydrocarbon content is 15 less than 90 (vol%) and a sulfur content is less than 0.03% by weight, or a saturated hydrocarbon content is 90 (vol%) or higher and a sulfur content is more than 0.03% by weight are SF-3415 45 also included in group (I). The mineral oil (E) is mineral oil having the following properties (E-1) to (E-3), and is preferably high-viscosity index mineral oil, which is obtained by refining through 5 hydrocracking or the like and belongs to any one of Groups (I) to (III) of the API classification, preferably Group (III). [0057] (E-1) The kinematic viscosity at 100̊C is 3 to 40 10 mm2/s, preferably 5 to 35 mm2/s. (E-2) The viscosity index is not less than 90, preferably not less than 95. (E-3) The pour point is not higher than -10̊C, preferably not higher than -15̊C. 15 The synthetic oil (D) that is used in the present invention when needed is synthetic oil having the following properties (D-1) to (D-3), and is preferably a poly-α-olefin (PAO) of a relatively low viscosity and/or a polyol ester, a fatty acid ester or the like. 20 [0058] (D-1) The kinematic viscosity at 100̊C is 3 to 10 mm2/s, preferably 4 to 8 mm2/s. (D-2) The viscosity index is not less than 120, preferably not less than 125. SF-3415 46 (D-3) The pour point is not higher than -40̊C, preferably not higher than -50̊C. The poly-α-olefin (PAO) belonging to Group (IV) in Table 1 is a hydrocarbon polymer obtained by polymerizing an 5 α-olefin of 8 or more carbon atoms as at least a raw material monomer, and includes, for example, polydecene obtained by polymerizing decene-1. Such a poly-α-olefin is a more preferred embodiment of the synthetic oil (D). [0059] 10 Such an α-olefin oligomer can be produced by cationic polymerization, thermal polymerization or radical polymerization using a Ziegler catalyst or a Lewis acid as a catalyst. As a matter of course, the α-olefin oligomer can be also obtained by polymerizing the corresponding olefin in the 15 presence of the catalyst described in the aforesaid patent literature 1. [0060] Examples of the base oils belonging to Group (V) in Table 1 include alkylbenzenes, alkylnaphthalenes and ester 20 oils. [0061] The alkylbenzenes or the alkylnaphthalenes are usually dialkylbenzenes or dialkylnaphthalenes, most of which have an alkyl chain length of 6 to 14 carbon atoms, and such SF-3415 47 alkylbenzenes or alkylnaphthalenes are produced by Friedel-Crafts alkylation reaction of benzene or naphthalene with an olefin. The alkylation olefin used in the production of alkylbenzenes or alkylnaphthalenes may be a linear or 5 branched olefin or a combination of these olefins. Such a production process is described in, for example, U.S. Patent No. 3,909,432. [0062] Examples of the esters include monoesters produced from 10 monobasic acids and alcohols; diesters produced from dibasic acids and alcohols or from diols and monobasic acids or acid mixtures; and polyol esters produced by bringing diols, triols (e.g., trimethylolpropane), tetraols (e.g., pentaerythritol), hexaols (e.g., dipentaerythritol) or the 15 like to react with monobasic acids or acid mixtures. Examples of these esters include tridecyl pelargonate, di-2-ethylhexyl adipate, di-2-ethylhexyl azelate, trimethylolpropnane triheptanoate and pentaerythritol tetraheptanoate. [0063] 20 The synthetic oil (C) that is used in the present invention when needed is synthetic oil satisfying the following properties (C-1) to (C-3) and is preferably a poly-α-olefin (PAO) belonging to Group (IV), but it may contain synthetic oil such as an ester belonging to Group (V). SF-3415 48 [0064] (C-1) The kinematic viscosity at 100̊C is 20 to 120 mm2/s, preferably 30 to 110 mm2/s. (C-2) The viscosity index is not less than 120, 5 preferably not less than 130. (C-3) The pour point is not higher than -30̊C, preferably not higher than -35̊C. The component (B) that is preferably used as a lubrication base oil of a low viscosity in the present 10 invention comprises one or more kinds selected from the synthetic oils (C), the synthetic oils (D) or the mineral oils (E), and may comprise one or more kinds selected from the synthetic oils (C), the synthetic oils (D) and the mineral oils (E), or may be a mixture of the synthetic oil 15 (C) or (D) and the mineral oil (E). [0065] When the total amount of the ethylene/α-olefin copolymer (A) and the later-described sulfur compound (F) is 100 parts by weight, these components (B) to (E) can be used 20 preferably in an amount of 2 to 80 parts by weight, more preferably 3 to 60 parts by weight, particularly preferably 4 to 40 parts by weight. [0066] In the lubrication oil composition of the present SF-3415 49 invention, the saturated hydrocarbon content based on the total amount of the hydrocarbon components in the components (A) to (E) is preferably not less than 80% by weight, more preferably not less than 90%, still more preferably not less 5 than 95%, particularly preferably not less than 96%. [0067] If the saturated hydrocarbon content is too low, durability for lubrication oil sometimes becomes insufficient. 10 [0068] The polymer of α-olefin having 3 to 6 carbon atoms (G), which is used in the present invention when needed, is an α-olefin polymer in which the amount of structural units of an α-olefin selected from α-olefins of 3 to 6 carbon atoms 15 exceeds 70% by mol, and when the total amount of the lubrication oil composition is 100 parts by weight, the amount of the polymer of α-olefin (G) is not more than 15 parts by weight, preferably not more than 12 parts by weight, more preferably not more than 10 parts by weight, still more 20 preferably not more than 5 parts by weight, particularly preferably not more than 2 parts by weight. The lower limit is preferably 0 part by weight. [0069] If the content of the polymer of α-olefinhaving 3 to 6 SF-3415 50 carbon atoms (G) is too high, shear viscosity is sometimes lowered with time. [Sulfur compound (F)] The sulfur compound (F) for use in the present 5 invention is characterized in that the carbon atom adjacent to sulfur is secondary or tertiary carbon. Examples of substituents containing such carbon include isopropyl group (i-Pr), s-butyl group (s-Bu), t-butyl group (t-Bu), 2-hexyl group, 3-hexyl group, 2-methyl-2-pentyl group and 3-methyl-3- 10 pentyl group. [0070] The sulfur compound (F) having a substituent of such structures is generally used as an extreme pressure agent, and it is surprising that the sulfur compound has good 15 compatibility with the ethylene/α-olefin copolymer (A) though it maintains strong polarity, and it can form a lubrication oil composition having excellent transparency. Further, compatibility of the sulfur compound (F) is rarely impaired even if various oil agents have high viscosity, and as the 20 later-described lubrication oil composition, a product of high transparency tends to be easily obtained. It is thought that the coexistence of compatibility and polarity is derived from the structure of the above-described bulky hydrocarbon-containing substituent. SF-3415 51 [0071] In the sulfur compound (F) for use in the present invention, the ratio of the number of carbon atoms to the number of sulfur atoms is preferably 1.5 to 20, more 5 preferably 1.8 to 15, particularly preferably 2 to 10. It is thought that since the sulfur compound satisfying such a range has high polarity, it exhibits strong interaction with, for example, a surface of a gear of metal equipment and can form a strong coated film. 10 [0072] If the ratio of the number of atoms is too high, polarity sometimes becomes insufficient. On the other hand, if the ratio of the number of atoms is too low, compatibility of the sulfur compound with the ethylene/α-olefin copolymer 15 (A) is sometimes lowered. [0073] As a preferred example of such a sulfur compound as above, a compound of a structure wherein the aforesaid hydrocarbon substituents of a secondary or tertiary structure 20 are present at both ends of a sulfur chain can be mentioned. Specific examples of such compounds include compounds having structures of t-Bu2-S, s-Bu2-S, i-Pr2-S, t-Bu-S-S-t-Bu, s-Bu-S-S-s-Bu, i-Pr-S-S-i-Pr, t-Bu-S-S-S-t-Bu, s-Bu-S-S-S-s-Bu, i-Pr-S-S-S-i-Pr, t-Bu-S-S-S-S-t-Bu, s-Bu-S-S-S-S-s-Bu and i-Pr- SF-3415 52 S-S-S-S-i-Pr. (Here, Bu represents a butyl group, Pr represents a propyl group, s- represents secondary, and t-represents tertiary. As a matter of course, S is sulfur.) When the total amount of the lubrication oil 5 composition of the present invention is 100 parts by weight, the content of sulfur in the lubrication oil composition is 0.1 to 5 parts by weight, preferably 0.5 to 4 parts by weight, still more preferably 1 to 3 parts by weight. [0074] 10 When the above range is satisfied, transparency is imparted, and transparency and lubricating performance such as film formation can be allowed to coexist on a high level. If the content of sulfur is too low, lubrication oil performance sometimes becomes insufficient, and if the 15 content of sulfur is too high, transparency for lubrication oil is sometimes impaired. [Lubrication oil composition] The lubrication oil composition of the present invention comprises the ethylene/α-olefin copolymer (A), and 20 preferably comprises a component (B) comprising one or more kinds selected from the synthetic oil (C), the synthetic oil (D), the mineral oil (E) and the like, when needed. The lubrication oil composition of the present invention further comprises the sulfur compound (F). The ratio of these SF-3415 53 components contained is as previously described. [0075] To the lubrication oil composition of the present invention, publicly known additives, such as pour point 5 depressant, extreme pressure agent, friction modifier, oiliness agent, antioxidant, rust proofing agent and corrosion inhibitor, can be added in an amount of not more than 20 parts by weight based on 100 parts by weight of the composition, when needed. 10 [0076] Such a lubrication oil composition is characterized by exhibiting excellent viscosity characteristics and shear stability with a good balance. [0077] 15 [Pour point depressant] Examples of the pour point depressants include a polymer or copolymer of alkyl methacrylate, a polymer or copolymer of alkyl acrylate, a polymer or copolymer of alkyl fumarate, a polymer or copolymer of alkyl maleate and an 20 alkyl aromatic compound. Of these, a polymethacrylate pour point depressant that is a pour point depressant comprising a polymer or copolymer of alkyl methacrylate is particularly preferable. The number of carbons of the alkyl group in the alkyl methacrylate is preferably 12 to 20, and the content of SF-3415 54 the alkyl methacrylate is 0.05 to 2% by weight of the total amount of the composition. As such pour point depressants, products that are on the market as pour point depressants are obtainable. Examples of brand names of such commercial 5 products include Aclube 146 and Aclube 136 available from Sanyo Chemical Industries, Ltd., and Lubran 141 and Lubran 171 available from Toho Chemical Industry Co., Ltd. [0078] These components can be used by dissolving them in 10 mineral oils, esters or the like or diluting them. The concentration is preferably 10 to 80%, more preferably 30 to 70%. [0079] [Extreme pressure agent] 15 As the extreme pressure agents, not only the aforesaid sulfur compounds but also sulfurized olefins, sulfurized oils and fats, sulfides, phosphates, phosphites, phosphate amine salts and phosphite amine salts can be mentioned. [0080] 20 These components can be used by dissolving them in esters, solvents comprising the aforesaid olefin polymers or the like or diluting them. The concentration is preferably 10 to 80%, more preferably 30 to 70%. [0081] SF-3415 55 [Friction modifier] As the friction modifiers, organometal-based friction modifiers, typically organomolybdenum compounds such as molybdenum dithiophosphate and molybdenum dithiocarbamate, 5 can be mentioned. [0082] These components can be used by dissolving them in esters or the like or diluting them. The concentration is preferably 10 to 80%, more preferably 30 to 70%. 10 [0083] Examples of the oiliness agents include fatty acids having an alkyl group of 8 to 22 carbon atoms, fatty acid esters and higher alcohols. [0084] 15 [Antioxidant] Specific examples of the antioxidants include phenol- based antioxidants, such as 2,6-di-t-butyl-4-methylphenol; and amine-based antioxidants, such as dioctyldiphenylamine. [0085] 20 Examples of anti-foaming agents include silicon-based anti-foaming agents, such as dimethylsiloxane and silica gel dispersion; and alcohol- and ester-based anti-foaming agents. [0086] These components can be used by dissolving them in SF-3415 56 esters or the like or diluting them. The concentration is preferably 10 to 80%, more preferably 30 to 70%. [0087] [Rust proofing agent] 5 Examples of the rust proofing agents include carboxylic acids, carboxylates, esters, and phosphoric acid. Examples of the corrosion inhibitors include benzotriazole, derivatives thereof and thiazole-based compounds. [0088] 10 Further, benzotriazole-based, thiadiazole-based and imidazole-based compounds can be also mentioned as the corrosion inhibitors. [0089] The lubrication oil composition of the present 15 invention is excellent particularly in viscosity characteristics and shear stability, and further in durability and thermal oxidation stability, and is effective as industrial lubrication oil. [0090] 20 The kinematic viscosity of the lubrication oil composition of the present invention at 40̊C is in the range of 450 to 51,000 mm2/s. As industrial lubrication oil, the lubrication oil composition having a viscosity of ISO-500 to ISO-46,000 is preferable, and this is particularly effective SF-3415 57 as open type gear oil. [0091] The lubrication oil composition of the present invention can be favorably used as industrial lubrication oil 5 for various industrial machines and transportation machines. The lubrication oil composition of the present invention is favorable particularly for gear oil. Further, the lubrication oil composition of the present invention can be favorably used as gear oil for construction machines. 10 [0092] The lubrication oil composition of the present invention is expected to be excellent in film-forming ability on a metal surface, has high lubricating performance and can become lubrication oil having excellent transparency also at 15 low temperatures. By using the lubrication oil composition continuously, its transparency tends to be gradually lowered, but conversely, the transparency can be regarded as an index of deterioration or time for replacement. On this account, transparency is also one of the important properties for 20 lubrication oils. EXAMPLES [0093] The present invention will be further described with SF-3415 58 reference to the following examples. Various properties in the examples were measured in the following manner. [0094] [Ethylene content] 5 Using a JEOL LA500-model nuclear magnetic resonance spectrometer, the ethylene content was measured in a mixed solvent of orthodichlorobenzene and benzene-d6 (orthodichlorobenzene/benzene-d6 = 3/1 to 4/1 (ratio by volume)) under the conditions of 120̊C, a pulse width of 45̊ 10 pulse and a pulse repetition interval of 5.5 seconds. The number of repeated measurements is 1000 or more, preferably 10000 or more. [0095] [B-value] 15 Employing o-dichloro benzene/benzene-d6 (4/1 [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 20 width of 4.7 μsec (45o pulse), or under the measuring 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 (45o pulse), and the B-value was calculated based SF-3415 59 on the following Formula [1]. [0096] [Formula 1] 5 In Formula [1], PE indicates the molar fraction contained in the ethylene component, PO indicates the molar fraction contained in the α-olefin component, and POE indicates the molar fraction of the ethylene-α-olefin sequences of all dyad sequences. 10 [0097] [Saturated hydrocarbon content] An ECX400-model nuclear magnetic resonance spectrometer manufactured by JEOL Ltd., was used, and as a solvent, deuterated orthodichlorobenzene, deuterated chloroform or 15 deuterated benzene was appropriately used. [0098] A sample concentration of 50 to 60 mg/0.5 mL and a measuring temperature of room temperature to 120̊C were appropriately selected. Measurement was carried out under the 20 conditions of an observed nucleus of 1H (400 MHz), a single pulse sequence, a pulse width of 5.12 μsec (45̊ pulse), a repetition interval of 7.0 seconds, a cumulative number of SF-3415 60 500 or more and a chemical shift reference value of 7.10 ppm. Peaks of 1H, etc. derived from vinyl group, methyl group and the like were assigned in the usually way, and using the result of the above ethylene content together, the saturated 5 hydrocarbon content was calculated. [0099] In the polyolefins used in the experimental examples of the present invention, peaks derived from unsaturated carbon- carbon bonds were rarely observed. 10 [Kinematic viscosity (40̊C, 100̊C)] Measurement was carried out in accordance with ASTM D445. In the examples, the viscosity of a formulated oil was adjusted in the following manner on the basis of each ISO classification. 15 [0100] (1) ISO 460: A formulated oil was prepared by carrying out formulation so that the kinematic viscosity (40̊C) can be 460±46 mm2/s. [0101] 20 (2) ISO 1000: A formulated oil was prepared by carrying out formulation so that the kinematic viscosity (40̊C) can be 1000±100 mm2/s. [0102] (3) ISO 2200: A formulated oil was prepared by carrying SF-3415 61 out formulation so that the kinematic viscosity (40̊C) can be 2200±220 mm2/s. (4) ISO 3200: A formulated oil was prepared by carrying out formulation so that the kinematic viscosity (40̊C) can be 5 3200±320 mm2/s. [0103] (5) ISO 4600: A formulated oil was prepared by carrying out formulation so that the kinematic viscosity (40̊C) can be 4600±460 mm2/s. 10 [0104] (6) ISO 6800: A formulated oil was prepared by carrying out formulation so that the kinematic viscosity (40̊C) can be 6800±680 mm2/s. (7) ISO 10000: A formulated oil was prepared by 15 carrying out formulation so that the kinematic viscosity (40̊C) can be 10000±1000 mm2/s. [0105] (8) ISO 22000: A formulated oil was prepared by carrying out formulation so that the kinematic viscosity 20 (40̊C) can be 22000±2200 mm2/s. [Viscosity index] Viscosity index was measured and calculated by the method described in JIS K2283. [0106] SF-3415 62 [Molecular weight distribution (Mw/Mn)] A pump for liquid chromatography, a sampling apparatus, columns for gel permeation chromatography (GPC) and a differential refractive index detector (RI detector) 5 described below were connected, and GPC measurement was carried out to determine a molecular weight distribution. [0107] Liquid chromatography apparatus: 515 HPLC Pump manufactured by Waters Corporation 10 Sampling apparatus: 717 plus Autosampler manufactured by Waters Corporation Mobile phase: THF (containing stabilizer, grade for liquid chromatography) Column: One column of MIXED-D manufactured by Polymer 15 Laboratories Ltd. and one column of 500 Å manufactured by Polymer Laboratories Ltd. were connected in series. [0108] Sample concentration: 5 mg/mL Mobile phase flow rate: 1.0 mL/min 20 Measuring temperature: ordinary temperature Standard sample for calibration curve: EasiCal PS-1 manufactured by Polymer Laboratories Ltd. [0109] [Shear stability (viscosity reduction rate %)] SF-3415 63 Using a KRL shearing test machine, a test was carried out in accordance with CEC-L-45 (CEC: an organization for the management of test procedure for the performance testing of automotive fuels & lubricants in Europe) to evaluate a 5 reduction rate of viscosity at 40̊C. [0110] Shear stability is an index of kinematic viscosity loss attributable to cleavage of a molecular chain caused by that a copolymer component in lubrication oil suffers shear at the 10 metal sliding part. [0111] [Compatibility (solubility of extreme pressure agent)] 10 days after the formulated oil was heated and stirred at a temperature of 60̊C, appearance of the oil was observed 15 and evaluated by the following grades. [0112] grade A: transparent, grade B: slightly turbid, grade C: turbid [Analysis of extreme pressure agent (GC/MS method)] 20 The structure of a sulfur compound contained in an extreme pressure agent was measured by a so-called GC/MS method using gas chromatography and a mass spectrometer in combination. The measuring conditions are described below. Apparatus: Jms-Q1000GC K9 type apparatus manufactured SF-3415 64 by JEOL Ltd. Column: DB5MS + DG (inner diameter: 0.25 mm, length: 30 m) Column temperature control pattern: The temperature was 5 maintained at 40̊C for 3 minutes and raised at a rate of 10̊C/min, and after the temperature reached 320̊C, this temperature was maintained for 29 minutes to complete the temperature control. [0113] 10 Mobile phase: helium (flow rate: 0.7 ml/min) Sample injection temperature: 280̊C, split (1/20) Sample injection quantity: 1 μL (diluting solvent: hexane) Ionization method: EI (electron ionization), ionization 15 temperature: 200̊C [0114] [Thermal oxidation stability] The thermal oxidation stability was conducted in accordance with the Oxidation Stability Test of Lubrication 20 Oil for Internal Combustion Engines method described in JIS K2514, and the lacquer rating was evaluated 72 hours after the test time. [0115] [Components used in the present invention] SF-3415 65 Components used in the examples and the comparative examples, such as lubrication base oils, are set forth in Table 2. [0116] 5 [Table 2] Table 2 Note on Component (Main Component) Viscosity 100°C (mm2/s) Viscosity 40°C (mm2/s) Viscosity Index Pour Point (°C) Chevron NEXBASE 2006 polydecene (saturation ratio~100%) 5.83 30.5 137 -65.0 BFS TMTC polyol ester 4.40 19.5 140 -50.0 JX bright stock N460 mineral oil (API Group I) 29.9 460 97 -10.0 JX HV1900 polybutene (main component) 3950 UNICHEMA PRIOLUBE 3986 polyol ester 2030 54900 264 Shell Chemicals SV251 Viscosity modifier 1480 15500 346 Extreme pressure agents used in the examples and the comparative examples are as follows. ∙HITEC (trademark)-3339 available from Afton Chemical 10 sulfur content: 32.6% by weight, phosphorus content: 1.19% by weight (catalogue values) As a sulfur-containing component, di-t-butyl polysulfide was detected by the GC/MS method. In addition, a component suggesting mineral oil was contained. 15 ∙HITEC (trademark) 343 available from Afton Chemical A peak suggesting a sulfur compound having a secondary or tertiary alkyl group was not detected by the GC/MS method. SF-3415 66 [0117] [Method for polymerizing an ethylene/α-olefin copolymer (A)] [Polymerization Example 1] 5 250 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 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 10 into the polymerization vessel, and stirred with a rotation 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 15 cyclopentadienyl)(η5-2,7-di-t-butyl fluorenyl)] 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 20 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 hydrochloric acid, further washed 3 times with SF-3415 67 100 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 5 copolymer. The ethylene content of the resulting polymer (polymer 1) was 52.4 mol%, Mw was 13,600, Mw/Mn was 1.9, B-value was 1.2, and kinematic viscosity at 100°C was 2,000 mm2/s. [0118] 10 [Polymerization Example 2] 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 was raised to 50°C, and then 25 L/h of ethylene, 75 L/h of 15 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 and 0.00230 mmol of dimethylsilyl bis(indenyl) zirconium 20 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 adding a SF-3415 68 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 ethylene content of the resulting polymer 10 (polymer 2) was 52.1 mol%, Mw was 13,800, Mw/Mn was 2.0, B-value was 1.2, and 100°C kinematic viscosity was 2,000 mm2/s. [0119] [Polymerization Example 3] 250 mL of decane was charged into a glass 15 polymerization vessel with a volume of 1 L sufficiently substituted with nitrogen, and the temperature in the system was raised to 130°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 20 of 600 rpm. Then, 0.2 mmol of triisobutyl aluminum was charged into the polymerization vessel, and 1.213 mmol of MMAO and 0.00402 mmol of [[diphenylmethylene (η5-(3-n-butyl cyclopentadienyl) (η5-2,7-di-t-butyl fluorenyl)] zirconium dichloride, which were pre-mixed in toluene for 15 minutes or SF-3415 69 more, were charged into the polymerization vessel to start the polymerization. Ethylene, propylene and hydrogen were then continuously supplied, and polymerization took place at 130°C for 15 minutes. Polymerization was stopped by adding a 5 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 100 mL of distilled water, dried with magnesium sulfate, and 10 the solvent was then distilled off under reduced pressure. The resulting polymer was dried overnight at 80°C under reduced pressure to obtain 0.77 g of an ethylene-propylene copolymer. The ethylene content of the resulting polymer (polymer 3) was 48.8 mol%, Mw was 4,100, Mw/Mn was 1.7, B-15 value was 1.2, and 100°C kinematic viscosity was 100 mm2/s. [0120] [Polymerization Example 4] 250 mL of decane was charged into a glass polymerization vessel with a volume of 1 L sufficiently 20 substituted with nitrogen, and the temperature in the system was raised to 130°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 SF-3415 70 charged into the polymerization vessel, and 1.213 mmol of MMAO and 0.00402 mmol of dimethylsilyl bis(indenyl) zirconium dichloride, which were pre-mixed in toluene for 15 minutes or more, were charged into the polymerization vessel to start 5 the polymerization. Ethylene, propylene and hydrogen were then continuously supplied, and polymerization took place at 130°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 10 solution was washed 3 times with 100 mL of a 0.2 mol/L solution of 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 15 reduced pressure to obtain 0.77 g of an ethylene-propylene copolymer. The ethylene content of the resulting polymer (polymer 4) was 48.7 mol%, Mw was 4,200, Mw/Mn was 1.8, B-value was 1.2, and 100°C kinematic viscosity was 100 mm2/s. [0121] 20 (Example 1) Using 93.0% by weight of the polymer 3 obtained in Polymerization Example 3 as the ethylene/propylene copolymer (A) serving as a viscosity modifier, 5.0% by weight of a polyol ester (TMTC available from BFS) classified as API SF-3415 71 Group (V) and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton Chemical), formulation was carried out to prepare a formulated oil having a viscosity equivalent to ISO 1000. Lubrication oil 5 properties of the formulated oil are set forth in Table 3. [0122] (Example 2) Using 9.5% by weight of the polymer 1 obtained in Polymerization Example 1 and 83.5% by weight of the polymer 3 10 obtained in Polymerization Example 3 as the ethylene/propylene copolymers (A), 5.0% by weight of a polyol ester (TMTC available from BFS) as the synthetic oil (D), and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton Chemical), formulation 15 was carried out to prepare a formulated oil having a viscosity equivalent to ISO 2200. Lubrication oil properties of the formulated oil are set forth in Table 3. [0123] (Example 3) 20 A formulated oil having a viscosity equivalent to ISO 3200 was prepared by carrying out formulation in the same manner as described in Example 2, except for using 28.0% by weight of the copolymer 1 obtained in Polymerization Example 1, and 65.0% by weight of the polymer 3 obtained in SF-3415 72 Polymerization Example 3 as the ethylene/propylene copolymers (A). Lubrication oil properties of the formulated oil are set forth in Table 3. [0124] 5 (Example 4) A formulated oil having a viscosity equivalent to ISO 6800 was prepared by carrying out formulation in the same manner as described in Example 2, except for using 48.0% by weight of the polymer 1 obtained in Polymerization Example 1, 10 and 45.0% by weight of the polymer 3 obtained in Polymerization Example 3 as the ethylene/propylene copolymers (A). Lubrication oil properties of the formulated oil are set forth in Table 3. [0125] 15 (Example 5) Using 4.0% by weight of the polymer 1 obtained in Polymerization Example 1, and 84.0% by weight of the polymer 3 obtained in Polymerization Example 3 as the ethylene/propylene copolymers (A), 10.0% by weight of a poly 20 α-olefin (NEXBASE 2006, available from CHEVRON) as the synthetic oil (D), and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton Chemical), formulation was carried out to prepare a formulated oil having a viscosity equivalent to ISO 1000. Lubrication oil SF-3415 73 properties of the formulated oil are set forth in Table 3. [0126] (Example 6) A formulated oil having a viscosity equivalent to ISO 5 3200 was prepared by carrying out formulation in the same manner as described in Example 5, except for using 30.0% by weight of the polymer 1 obtained in Polymerization Example 1, and 58.0% by weight of the polymer 3 obtained in Polymerization Example 3 as the ethylene/propylene copolymers 10 (A). Lubrication oil properties of the formulated oil are set forth in Table 3. [0127] (Example 7) Using 10.0% by weight of the polymer 1 obtained in 15 Polymerization Example 1, and 73.0% by weight of the polymer 3 obtained in Polymerization Example 3 as the ethylene/propylene copolymers (A), and 10.0% by weight of a poly α-olefin (NEXBASE 2006, available from CHEVRON) as the synthetic oil (D), 5.0% by weight of a polyol ester (TMTC 20 available from BFS), and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton Chemical), formulation was carried out to prepare a formulated oil having a viscosity equivalent to ISO 1000. Lubrication oil properties of the formulated oil are set SF-3415 74 forth in Table 3. [0128] (Example 8) A formulated oil having a viscosity equivalent to ISO 5 2200 was prepared by carrying out formulation in the same manner as described in Example 7, except for using 30.0% by weight of the polymer 1 obtained in Polymerization Example 1, and 53.0% by weight of the polymer 3 obtained in Polymerization Example 3 as the ethylene/propylene copolymers 10 (A). Lubrication oil properties of the formulated oil are set forth in Table 3. [0129] (Example 9) Using 18.0% by weight of the polymer 1 obtained in 15 Polymerization Example 1 as the ethylene/propylene copolymer (A), 80.0% by weight of a highly viscous poly α-olefin (DURASYN 180 available from INEOS) as the synthetic oil (C), and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton Chemical), formulation 20 was carried out to prepare a formulated oil having a viscosity equivalent to ISO 2200. Lubrication oil properties of the formulated oil are set forth in Table 3. [0130] (Example 10) SF-3415 75 A formulated oil having a viscosity equivalent to ISO 3200 was prepared by carrying out formulation in the same manner as described in Example 9, except for using 27.0% by weight of the polymer 1 obtained in Polymerization Example 1 5 as the ethylene/propylene copolymer (A), and 71.0% by weight of a highly viscous poly α-olefin (DURASYN 180 available from INEOS) as the synthetic oil (C). Lubrication oil properties of the formulated oil are set forth in Table 3. [0131] 10 (Example 11) Using 20.0% by weight of the polymer 1 obtained in Polymerization Example 1 as the ethylene/propylene copolymer (A), 73.0% by weight of a highly viscous poly α-olefin (DURASYN 180 available from INEOS) as the synthetic oil (C), 15 5.0% by weight of a polyol ester (TMTC available from BFS) as the synthetic oil (D), and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton Chemical), formulation was carried out to prepare a formulated oil having a viscosity equivalent to ISO 2200. 20 Lubrication oil properties of the formulated oil are set forth in Table 3. [0132] (Example 12) A formulated oil having a viscosity equivalent to ISO SF-3415 76 3200 was prepared by carrying out formulation in the same manner as described in Example 11, except for using 30.0% by weight of the polymer 1 obtained in Polymerization Example 1 as the ethylene/propylene copolymer (A), and 63.0% by weight 5 of a highly viscous poly α-olefin (DURASYN 180 available from INEOS) as the synthetic oil (C). Lubrication oil properties of the formulated oil are set forth in Table 3. [0133] (Example 13) 10 Using 30.0% by weight of the polymer 1 obtained in Polymerization Example 1 as the ethylene/propylene copolymer (A), 53.0% by weight of a high viscosity poly α-olefin (DURASYN 180 available from INEOS) as the synthetic oil (C), 10.0% by weight of a low viscosity poly α-olefin (NEXBASE 15 2006 available from CHEVRON) as the synthetic oil (D), 5.0% by weight of a polyol ester (TMTC available from BFS) as the synthetic oil (D), and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton Chemical), formulation was carried out to prepare a formulated oil 20 having a viscosity equivalent to ISO 2200. Lubrication oil properties of the formulated oil are set forth in Table 3. [0134] (Example 14) A formulated oil having a viscosity equivalent to ISO SF-3415 77 3200 was prepared by carrying out formulation in the same manner as described in Example 13, except for using 40.0% by weight of the polymer 1 obtained in Polymerization Example 1 as the ethylene/propylene copolymer (A), and 43.0% by weight 5 of a highly viscous poly α-olefin (DURASYN 180 available from INEOS) as the synthetic oil (C). Lubrication oil properties of the formulated oil are set forth in Table 3. [0135] (Example 15) 10 Using 20.0% by weight of the polymer 1 obtained in Polymerization Example 1 as the ethylene/propylene copolymer (A), 78.0% by weight of a bright stock (N460 available from JX) as the mineral oil (E), and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton 15 Chemical), formulation was carried out to prepare a formulated oil having a viscosity equivalent to ISO 2200. Lubrication oil properties of the formulated oil are set forth in Table 3. [0136] 20 (Example 16) A formulated oil having a viscosity equivalent to ISO 4600 was prepared by carrying out formulation in the same manner as described in Example 15, except for using 40.0% by weight of the polymer 1 obtained in Polymerization Example 1 SF-3415 78 as the ethylene/propylene copolymer (A), and 58.0% by weight of a bright stock (N460 available from JX) as the mineral oil (E). Lubrication oil properties of the formulated oil are set forth in Table 3. 5 [0137] [Table 3] 5 SF-3415 79 Table 3 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Polymer 1 % by weight 9.5 28.0 48.0 4.0 30.0 10.0 30.0 18.0 Polymer 2 % by weight Polymer 3 % by weight 93.0 83.5 65.0 45.0 84.0 58.0 73.0 53.0 Polymer 4 % by weight DURASYN 180 % by weight 80.0 NEXBASE 2006 % by weight 10.0 10.0 10.0 10.0 TMTC % by weight 5.0 5.0 5.0 5.0 5.0 5.0 Bright stock N460 % by weight HITEC 3339 % by weight 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 40°C kinematic viscosity mm2/s 962 2,010 3,120 6,300 1,100 2,980 1,050 2,300 2,120 Viscosity index - 163 185 200 220 168 200 170 200 155 Shear test viscosity reduction rate % 0 7 9 7 10 7 11 10 Compatibility (appearance) A A A A A A A A A ISOT Lacquer rating Adhered substance (thin) Adhered substance (thin) Adhered substance (thin) Adhered substance (thin) Adhered substance (thin) Adhered substance (thin) Adhered substance (thin) Adhered substance (thin) Adhered substance (medium) SF-3415 80 [Table 3] (continued) Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Polymer 1 % by weight 27.0 20.0 30.0 30.0 40.0 20.0 40.0 Polymer 2 % by weight Polymer 3 % by weight Polymer 4 % by weight DURASYN 180 % by weight 71.0 73.0 63.0 53.0 43.0 NEXBASE 2006 % by weight 10.0 10.0 TMTC % by weight 5.0 5.0 5.0 5.0 Bright stock N460 % by weight 78.0 58.0 HITEC 3339 % by weight 2.0 2.0 2.0 2.0 2.0 2.0 2.0 40°C kinematic viscosity mm2/s 3,300 2,100 3,100 2,120 3,150 2,120 4,600 Viscosity index - 230 161 225 170 295 151 188 Shear test viscosity reduction rate % 10 10 11 11 11 10 10 Compatibility (appearance) A A A A A A A ISOT Lacquer rating Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) Adhered substance (medium) SF-3415 81 (Comparative Example 1) Using 20.0% by weight of polybutene (HV-1900 available from JX) as a viscosity modifier, 78.0% by weight of the polymer 3 obtained in Polymerization Example 3 as the 5 ethylene/propylene copolymer (A) and 2.0% by weight of an extreme pressure agent HITEC (trademark)-3339 (available from Afton Chemical), formulation was carried out to prepare a formulated oil having a viscosity equivalent to ISO 2200. Lubrication oil properties of the formulated oil are set 10 forth in Table 4. [0138] (Comparative Example 2) A formulated oil having a viscosity equivalent to ISO 6800 was prepared by carrying out formulation in the same 15 manner as described in Comparative Example 1, except for using 42.0% by weight of polybutene (HV-1900 available from JX), and 56.0% by weight of the polymer 3 obtained in Polymerization Example 3 as the ethylene/propylene copolymer (A). Lubrication oil properties of the formulated oil are set 20 forth in Table 4. [0139] (Comparative Example 3) A formulated oil having a viscosity equivalent to ISO 1000 was prepared by carrying out formulation in the same SF-3415 82 manner as described in Example 1, except for using HITEC (trademark) 343 (available form Afton Chemical) instead of HITEC (trademark)-3339 (available form Afton Chemical) as an extreme pressure agent. The result of compatibility 5 evaluation of the formulated oil is set forth in Table 4. [0140] (Comparative Example 4) A formulated oil having a viscosity equivalent to ISO 2200 was prepared by carrying out formulation in the same 10 manner as described in Example 2, except for using HITEC (trademark) 343 (available form Afton Chemical) instead of HITEC (trademark)-3339 (available form Afton Chemical) as an extreme pressure agent. The result of compatibility evaluation of the formulated oil set forth in Table 4. 15 [0141] (Comparative Example 5) A formulated oil having a viscosity equivalent to ISO 3200 was prepared by carrying out formulation in the same manner as described in Example 3, except for using HITEC 20 (trademark) 343 (available form Afton Chemical) instead of HITEC (trademark)-3339 (available form Afton Chemical) as an extreme pressure agent. The result of compatibility evaluation of the formulated oil of the formulated oil are set forth in Table 4. SF-3415 83 [0142] (Comparative Example 6) A formulated oil having a viscosity equivalent to ISO 6800 was prepared by carrying out formulation in the same 5 manner as described in Example 4, except for using HITEC (trademark) 343 (available form Afton Chemical) instead of HITEC (trademark)-3339 (available form Afton Chemical) as an extreme pressure agent. The result of compatibility evaluation of the formulated oil of the formulated oil are 10 set forth in Table 4. [0143] (Comparative Example 7) A formulated oil having a viscosity equivalent to ISO 2200 was prepared by carrying out formulation in the same 15 manner as described in Example 15, except for using HITEC (trademark) 343 (available form Afton Chemical) instead of HITEC (trademark)-3339 (available form Afton Chemical) as an extreme pressure agent. The result of compatibility evaluation of the formulated oil of the formulated oil are 20 set forth in Table 4. [0144] (Comparative Example 8) A formulated oil having a viscosity equivalent to ISO 4600 was prepared by carrying out formulation in the same SF-3415 84 manner as described in Example 16, except for using HITEC (trademark) 343 (available form Afton Chemical) instead of HITEC (trademark)-3339 (available form Afton Chemical) as an extreme pressure agent. The result of compatibility 5 evaluation of the formulated oil of the formulated oil are set forth in Table 4. [0145] (Comparative Example 9) A formulated oil having a viscosity equivalent to ISO 10 1000 was prepared by carrying out formulation in the same manner as described in Example 1, except for using the polymer 4 obtained in Polymerization Example 4 instead of the polymer 3. Lubrication oil properties of the formulated oil are set forth in Table 4. 15 [0146] (Comparative Example 10) A formulated oil having a viscosity equivalent to ISO 2200 was prepared by carrying out formulation in the same manner as described in Example 2, except for using the 20 polymer 2 obtained in Polymerization Example 2 instead of the polymer 1, and using the polymer 4 obtained in Polymerization Example 4 instead of the polymer 3. Lubrication oil properties of the formulated oil are set forth in Table 4. [0147] SF-3415 85 (Comparative Example 11) A formulated oil having a viscosity equivalent to ISO 6800 was prepared by carrying out formulation in the same manner as described in Example 4, except for using the 5 polymer 2 obtained in Polymerization Example 2 instead of the polymer 1, and using the polymer 4 obtained in Polymerization Example 4 instead of the polymer 3. Lubrication oil properties of the formulated oil are set forth in Table 4. [0148] 10 (Comparative Example 12) A formulated oil having a viscosity equivalent to ISO 2200 was prepared by carrying out formulation in the same manner as described in Example 8, except for using the polymer 2 obtained in Polymerization Example 2 instead of the 15 polymer 1, and using the polymer 4 obtained in Polymerization Example 4 instead of the polymer 3. Lubrication oil properties of the formulated oil are set forth in Table 4. [0149] (Comparative Example 13) 20 A formulated oil having a viscosity equivalent to ISO 3200 was prepared by carrying out formulation in the same manner as described in Example 14, except for using the polymer 2 obtained in Polymerization Example 2 instead of the polymer 1. Lubrication oil properties of the formulated oil SF-3415 86 are set forth in Table 4. [0150] (Comparative Example 14) A formulated oil having a viscosity equivalent to ISO 5 2200 was prepared by carrying out formulation in the same manner as described in Example 15, except for using the polymer 2 obtained in Polymerization Example 2 instead of the polymer 1. Lubrication oil properties of the formulated oil are set forth in Table 4. 10 [0151] [Table 4] SF-3415 87 Table 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Polymer 1 % by weight 9.5 28.0 48.0 20.0 40.0 Polymer 2 % by weight Polymer 3 % by weight 78.0 56.0 93.0 83.5 65.0 45.0 Polymer 4 % by weight HV 1900 % by weight 20.0 42.0 DURASYN 180 % by weight NEXBASE 2006 % by weight TMTC % by weight 5.0 5.0 5.0 5.0 Bright stock N460 % by weight 78.0 58.0 HITEC 3339 % by weight 2.0 2.0 HITEC 343 % by weight 2.0 2.0 2.0 2.0 2.0 2.0 40°C kinematic viscosity mm2/s 2,360 6,800 Viscosity index - 144 166 Shear test viscosity reduction rate % 13 Compatibility (appearance) A A C C C C C C ISOT Lacquer rating Adhered substance (thick) Adhered substance (thick) Adhered substance (thick) SF-3415 88 [Table 4] (continued) Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 Comparative Example 13 Comparative Example 14 Polymer 1 % by weight Polymer 2 % by weight 9.5 48.0 30.0 40.0 20.0 Polymer 3 % by weight Polymer 4 % by weight 93.0 83.5 45.0 53.0 HV 1900 % by weight DURASYN 180 % by weight 43.0 NEXBASE 2006 % by weight 10.0 10.0 TMTC % by weight 5.0 5.0 5.0 5.0 5.0 Bright stock N460 % by weight 78.0 HITEC 3339 % by weight 2.0 2.0 2.0 2.0 2.0 2.0 HITEC 343 % by weight 40°C kinematic viscosity mm2/s 966 2,000 6,600 2,250 3,200 2,180 Viscosity index - 165 181 225 196 300 152 Shear test viscosity reduction rate % 0 8 9 12 12 Compatibility (appearance) A A A A A A ISOT Lacquer rating Adhered substance (thick) Adhered substance (thick) Adhered substance (thick) Adhered substance (thick) Adhered substance (thick) Adhered substance (thick) WE CLAIMS A lubrication oil composition comprising (A) a liquid random copolymer of ethylene and an α-5 olefin, which is produced by a method (α) below, (F) a sulfur-containing compound wherein at least one hydrocarbon group being adjacent to sulfur is a secondary or tertiary hydrocarbon group, and as an optional component, (G) a polymer of α-olefin 10 having 3 to 6 carbon atoms, having a kinematic viscosity at 40°C of 450 to 51,000 mm2/s, and having a sulfur content of 0.1 to 5 parts by weight (with the proviso that the total amount of the lubrication 15 oil composition is 100 parts by weight): (Method (α)) a method (α) for producing a liquid random copolymer of ethylene and an α-olefin comprising a step of performing solution polymerization of ethylene and an α-olefin having 3 20 to 20 carbon atoms in a catalyst system comprising (a) a bridged metallocene compound represented by the Formula 1 below, and (b) at least one compound selected from the group consisting of SF-3415 90 (i) organoaluminumoxy compounds, and (ii) compounds that react with the bridged metallocene compounds to form ion pairs: [Chem. 1] R2 *3 (Formula 1) [wherein R1, R2, R3, R4, R5, R8, R9, and R12 are respectively 15 and independently a hydrogen atom, a hydrocarbon group, or a silicon-containing hydrocarbon group, and adjacent groups may be linked to each other to form a ring structure, R6 and R11, being identical with each other, are hydrogen atoms, hydrocarbon groups, or silicon-containing 20 hydrocarbon groups, R7 and R10, being identical with each other, are hydrogen atoms, hydrocarbon groups, or silicon-containing hydrocarbon groups, R6 and R7 may bind to hydrocarbon having 2 to 3 carbon SF-3415 91 atoms to form a ring structure, R11 and R10 may bind to hydrocarbon having 2 to 3 carbon atoms to form a ring structure, R6, R7, R10, and R11 are not hydrogen atoms 5 simultaneously, Y is a carbon atom or a silicon atom, R13 and R14 are independently aryl groups, M is Ti, Zr, or Hf, Q is independently a halogen, a hydrocarbon group, an 10 anionic ligand, or a neutral ligand that is capable of coordinating to a lone electron pair, and j is an integer of 1 to 4]. 2. The lubrication oil composition according to claim 1, 15 wherein in the metallocene compound 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. 20 3. The lubrication oil composition according to claim 1 or 2, wherein R6 and R11, being the same, are hydrocarbon groups having 1 to 20 carbon atoms. 4. The lubrication oil composition according to any one of SF-3415 92 claims 1 to 3, wherein in the metallocene compound represented by the above Formula 1, a substituent (R2 or R3) bonded to the 3-position of the cyclopentadienyl group is a hydrocarbon group. 5 5. The lubrication oil composition according to claim 4, wherein in the metallocene compound represented by the above Formula 1, a hydrocarbon group (R2 or R3) bonded to the 3- position of the cyclopentadienyl group is an n-butyl group. 10 6. The lubrication oil composition 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-position of the fluorenyl 15 group are all tert-butyl groups. 7. The lubrication oil composition according to any one of claims 1 to 6, wherein the compound which reacts with the bridged metallocene compound to form ion pairs is a compound 20 represented by the following Formula 6: [Chem. 2] SF-3415 93 Rg + R e R f h (Formula 6) 5 [wherein 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 are respectively and independently a hydrocarbon group having 1 to 20 carbon atoms]. 8. The lubrication oil composition according to claim 7, 10 wherein the ammonium cation is a dimethylanilinium cation. 9. The lubrication oil composition according to claim 7 or 15 8, wherein the catalyst system further comprises an organoaluminum compound selected from a group consisting of trimethyl aluminum and triisobutyl aluminum. 10. The lubrication oil composition according to claim 1, further comprising a component (B) satisfying all of the SF-3415 94 following requirements (B-1) to (B-3): (B-1) a kinematic viscosity at 100̊C is 3 to 120 mm2/s, (B-2) a viscosity index is not less than 90, and (B-3) a pour point is not higher than -10̊C. 5 11. The lubrication oil composition according to claim 10, wherein the component (B) is synthetic oil (C) satisfying all of the following requirements (C-1) to (C-3): (C-1) a kinematic viscosity at 100̊C is 20 to 120 10 mm2/s, (C-2) a viscosity index is not less than 120, and (C-3) a pour point is not higher than -30̊C. 12. The lubrication oil composition according to claim 10, 15 wherein the component (B) is synthetic oil (D) satisfying all of the following requirements (D-1) to (D-3): (D-1) a kinematic viscosity at 100̊C is 3 to 10 mm2/s, (D-2) a viscosity index is not less than 120, and (D-3) a pour point is not higher than -40̊C. 20 13. The lubrication oil composition according to claim 10, wherein the component (B) is mineral oil (E) satisfying all of the following requirements (E-1) to (E-3): (E-1) a kinematic viscosity at 100̊C is 3 to 40 mm2/s, SF-3415 95 (E-2) a viscosity index is not less than 90, and (E-3) a pour point is not higher than -10°C. 14. The lubrication oil composition according to claim 11 5 or 12, wherein the component (C) and/or the component (D) is synthetic oil comprising a polymer of a-olefin having 8 to 20 carbon atoms and/or an ester compound. 15. The lubrication oil composition according to claim 13, 10 wherein the component (E) is one or more mineral oils selected from Groups (I), (II) and (III) of the API classification. 16. The lubrication oil composition according to any one of 15 claims 1 to 9, wherein the component (B) is one or more selected from synthetic oil (C) satisfying all of the following requirements (C-1) to (C-3), synthetic oil (D) satisfying all of the following requirements (D-1) to (D-3), and mineral oil (E) satisfying all of the following 20 requirements (E-1) to (E-3), and the saturated hydrocarbon content relative to the entirety of the components (A) to (E) is not less than 80% by weight: (C-1) a kinematic viscosity at 100°C is 20 to 120 SF-3415 96 mm2/s, (C-2) a viscosity index is not less than 120, (C-3) a pour point is not higher than -30°C (D-1) a kinematic viscosity at 100°C is 3 to 10 mm2/s, 5 (D-2) a viscosity index is not less than 120, (D-3) a pour point is not higher than -40°C (E-1) a kinematic viscosity at 100°C is 3 to 40 mm2/s, (E-2) a viscosity index is not less than 90, and (E-3) a pour point is not higher than -10°C. 10 17. A lubrication oil composition comprising: a liquid random copolymer of ethylene and an a-olefin satisfying all of the following requirements (A-1) to (A-5): (A-1) comprising 40 to 60% by mol of an ethylene unit, 15 and 60 to 40% by mol of an a-olefin unit having 3 to 20 carbon atoms, (A-2) having a number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of 500 to 10,000, and a molecular weight distribution (Mw/Mn, Mw means 20 a weight average molecular weight) of 3 or less, (A-3) having a kinematic viscosity at 100°C of 30 to 5,000 mm2/s, (A-4) having a pour point of 30 to -45°C, and (A-5) having a bromine value of not higher than 0.1 SF-3415 97 g/100 g, (F) a sulfur-containing compound in which at least one hydrocarbon group adjacent to sulfur is a secondary or tertiary hydrocarbon group, and 5 as an optional component, (G) a polymer of a-olefin having 3 to 6 carbon atoms, and having a kinematic viscosity at 40°C of 450 to 51,000 mm2/s, and a sulfur content of 0.1 to 5 parts by weight 10 (with the proviso that the total amount of the lubrication oil composition is 100 parts by weight). 18. The lubrication oil composition according to any one of claims 1 to 17, which is a gear oil composition. 15 19. A method for producing a lubrication oil composition comprising: a step of producing (A) a liquid random copolymer of ethylene and an a-olefin by a method (a) below, and 20 a step of mixing (A) the liquid random copolymer, (F) a sulfur-containing compound in which at least one hydrocarbon group adjacent to sulfur is a secondary or tertiary hydrocarbon group, and as an optional component, (G) a polymer of a-olefin having 3 to 6 carbon atoms to give a SF-3415 98 lubrication oil composition having a kinematic viscosity at 40°C of 450 to 51,000 mm2/s and a sulfur content of 0.1 to 5 parts by weight: (Method (α)) 5 a method (α) for producing a liquid random copolymer of ethylene and an α-olefin, comprising a step of performing solution polymerization of ethylene and an α-olefin having 3 to 20 carbon atoms in a catalyst system comprising (a) a bridged metallocene compound represented by the 10 Formula 1 below, and (b) at least one compound selected from the group consisting of (i) organoaluminumoxy compounds, and (ii) compounds that react with the bridged metallocene 15 compounds to form ion pairs: [Chem. 3] SF-3415 99 (Formula 1) [wherein R1, R2, R3, R4, R5, R8, R9, and R12 are respectively and independently a hydrogen atom, a hydrocarbon group, or a silicon-containing hydrocarbon group, and adjacent groups may be linked to each other to form a ring structure, 15 R6 and R11, being identical with each other, are hydrogen atoms, hydrocarbon groups, or silicon-containing hydrocarbon groups, R7 and R10, being identical with each other, are hydrogen atoms, hydrocarbon groups, or silicon-containing 20 hydrocarbon groups, R6 and R7 may bind to hydrocarbon having 2 to 3 carbon atoms to form a ring structure, R11 and R10 may bind to hydrocarbon having 2 to 3 carbon atoms to form a ring structure, SF-3415 100 R6, R7, R10, and R11 are not hydrogen atoms simultaneously, Y is a carbon atom or a silicon atom, R13 and R14 are independently aryl groups, 5 M is Ti, Zr, or Hf, Q is independently a halogen, a hydrocarbon group, an anionic ligand, or a neutral ligand that is capable of coordinating to a lone electron pair, and j is an integer of 1 to 4].