Lubricant composition

Abstract

The present invention provides a lubricant composition which has a low kinematic viscosity at 100°C and a high viscosity index and therefore contributes to improved fuel efficiency, and which also has excellent shear stability.　Provided is a lubricant composition comprising a lubricant base oil and an ethylene-α-olefin copolymer (C), wherein: the content of the ethylene-α-olefin copolymer (C) is not less than 0.1 mass% but less than 30 mass% with respect to 100 mass% of the lubricant composition; kinematic viscosity at 100°C is not less than 2.0 mm2 / s but less than 6.9 mm2 / s; and the lubricant base oil comprises a mineral oil (A) and / or a synthetic oil (B).

Description

lubricating oil composition

[0001] The present invention relates to lubricating oil compositions, and more particularly to low viscosity lubricating oil compositions and ultra-low viscosity lubricating oil compositions.

[0002] Petroleum products generally have a viscosity that changes significantly with temperature, i.e., they have a so-called temperature dependency of viscosity. For example, for lubricating oils used in automobiles, etc., it is preferable that the viscosity has a small temperature dependency. Therefore, in order to reduce the temperature dependency of viscosity, certain polymers that are soluble in the lubricating oil base are used as viscosity modifiers (also called viscosity index improvers) in lubricating oils. In recent years, OCPs (olefin copolymers) have been widely used as viscosity modifiers, and various improvements have been made to OCPs to further improve the performance of lubricating oils, as exemplified in Patent Document 1.

[0003] Meanwhile, in recent years, increasing demands for reducing the environmental impact of automobiles and industrial machinery have led to a strong demand for improved energy efficiency. One solution is to lower the viscosity of lubricating oils. Lowering viscosity, for example, in engine oils, effectively reduces torque and stirring resistance, contributing to improved energy efficiency. However, it has been pointed out that technology for improving energy efficiency through lower viscosity can result in reduced lubricity, i.e., an increased risk of metal-to-metal contact due to insufficient viscosity retention at high temperatures. This risk is particularly pronounced in engine oils with viscosity grades of 0W-8 and 0W-12, as specified by the Society of Automotive Engineers (SAE) in SAE J300-Jan 2015, and in low-viscosity lubricating oils such as 70W-65, 70W-70, and 70W-75, as specified by SAE J306-2019. Furthermore, the risk is even greater with ultra-viscosity lubricating oils, which have lower viscosities than low-viscosity lubricating oils.

[0004] Viscosity modifiers are used to maintain the appropriate viscosity of lubricating oils at high temperatures, but typical viscosity index improvers have a relatively high molecular weight, which can easily cause molecular chain severance under high shear caused by pressure and friction in sliding parts, resulting in a decrease in the viscosity of the lubricating oil.In particular, low-viscosity lubricating oils have a low original viscosity, and shear causes a further decrease in viscosity, which means that oil film retention at high temperatures is not fully ensured, resulting in the problem of damage to sliding parts due to friction and wear.

[0005] On the other hand, viscosity modifiers with relatively low molecular weights can suppress viscosity reduction due to shear, but because they have low thickening properties, they tend to require larger amounts to be added, and they tend to have inferior low-temperature viscosity characteristics compared to when high-molecular-weight viscosity modifiers are used.

[0006] Patent Document 2 describes a method for producing a liquid random copolymer of ethylene and an α-olefin, and states that this copolymer is useful as a lubricating oil.

[0007] WO 00 / 34420 EP 2921509

[0008] Conventional lubricating oil compositions have room for further improvement in terms of providing lubricating oil compositions that have a high viscosity index despite a low or ultra-low viscosity, and also have excellent shear stability that suppresses viscosity reduction.

[0009] As a result of extensive research into the development of a lubricating oil composition with excellent performance, the present inventors have found that a lubricating oil composition that contains a specific ethylene-α-olefin copolymer in a specific lubricating base oil and satisfies specific conditions can solve the above-mentioned problems, and have thus completed the present invention. Specific embodiments of the present invention include the following.

[0010] [1] A lubricating oil composition comprising a lubricating base oil and an ethylene-α-olefin copolymer (C) having the following characteristics (C1) to (C3), wherein the content of the ethylene-α-olefin copolymer (C) is 0.1% by mass or more and less than 30% by mass, based on 100% by mass of the lubricating oil composition, and the kinematic viscosity of the lubricating oil composition at 100°C is 2.0 mm 2 / s or more 6.9 mm 2 / s, and the lubricating base oil is a mineral oil (A) having the following characteristics (A1) to (A3) and / or a synthetic oil (B) having the following characteristics (B1) to (B3). (A1) A lubricating oil composition having a kinematic viscosity at 100°C of 2 to 7 mm 2 (A2) The viscosity index is 95 or more. (A3) The pour point is -10°C or less. (B1) The kinematic viscosity at 100°C is 1 to 7 mm 2 (B2) The kinematic viscosity at 40°C is 4 to 40 mm 2 (B3) The pour point is -30°C or lower. (C1) The content of structural units (i) derived from ethylene is 30 to 80 mol%, and the content of structural units (ii) derived from an α-olefin having 3 to 20 carbon atoms is 70 to 20 mol% (provided that the total content of structural units (i) and (ii) is 100 mol%). (C2) The kinematic viscosity at 100°C is 10 to 5,000 mm 2 (C3) The number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 500 to 10,000, and the molecular weight distribution (Mw / Mn, Mw is the weight average molecular weight) is 2.5 or less. [2] The kinematic viscosity of the lubricating oil composition at 100°C is 4.0 mm 2 / s or more 6.9 mm 2 [3] The lubricating oil composition according to item [1], wherein the kinematic viscosity at 100°C of the lubricating oil composition is less than 2.0 mm / s. 2 / s or more 4.0mm 2 [4] The lubricating oil composition according to any one of items [1] to [3], wherein the mineral oil (A) has a viscosity index of 105 or more. [5] The lubricating oil composition according to any one of items [1] to [4], wherein the ethylene-α-olefin copolymer (C) has a content of ethylene-derived structural units (i) in the range of 40 to 70 mol %. [6] The ethylene-α-olefin copolymer (C) has a kinematic viscosity at 100°C of 15 to 2,500 mm 2 / s. [7] The lubricating oil composition according to any one of items [1] to [5], wherein the α-olefin of the ethylene-α-olefin copolymer (C) is propylene. [8] An automobile engine oil comprising the lubricating oil composition according to any one of items [1] to [7]. [9] An automobile gear oil comprising the lubricating oil composition according to any one of items [1] to [7].

[10] An automobile transmission oil comprising the lubricating oil composition according to any one of items [1] to [7].

[11] An industrial lubricating oil comprising the lubricating oil composition according to any one of items [1] to [7].

[0011] The lubricating oil composition of the present invention has a low kinematic viscosity at 100° C. and a high viscosity index, which contributes to fuel economy and also provides excellent shear stability.

[0012] The lubricating oil composition according to the present invention comprises a lubricating base oil and an ethylene-α-olefin copolymer (C), the content of the ethylene-α-olefin copolymer (C) being 0.1% by mass or more and less than 30% by mass based on 100% by mass of the lubricating oil composition, the lubricating base oil being composed of a mineral oil (A) and / or a synthetic oil (B), and the lubricating base oil has a kinematic viscosity at 100°C of 2.0 mm 2 / s or more 6.9 mm 2 / s or less.

[0013] The lubricating oil composition of the present invention has a kinematic viscosity of 2.0 mm at 100°C. 2 / s or more 6.9 mm 2 The lubricating oil composition of the present invention has a kinematic viscosity at 100°C of 4.0 mm / s or less, which is suitable for use as a low-viscosity lubricating oil. ２ / s or more 6.9 mm ２ / s) (hereinafter also referred to as "low viscosity lubricating oil composition (X)") and a lubricating oil composition (X) having a viscosity of less than 2.0 mm suitable for ultra-low viscosity lubricating oils with even lower viscosities. ２ / s or more 4.0mm ２ The lubricating oil composition (Y) (hereinafter also referred to as "ultra-low viscosity lubricating oil composition (Y)") has a kinematic viscosity at 100°C of less than 6.9 mm / s. ２If the kinematic viscosity of the lubricating oil composition at 100°C is 2.0 mm / s or less, the agitation resistance of the lubricating oil to each part of the internal combustion engine increases. 2 If the kinematic viscosity is too low, metal wear may occur. This kinematic viscosity value is measured by the method described in JIS K2283.

[0014] The kinematic viscosity of the lubricating oil composition at 100°C is preferably 2.0 mm 2 / s or more 6.5mm 2 / s or less, more preferably 2.0 mm 2 / s or more 5.9 mm 2 / s or less, more preferably 2.0 mm 2 / s or more 4.9 mm 2 / s or less, particularly preferably 2.0 mm 2 / s or more 4.2mm 2 / s or less.

[0015] <Lubricant Base Oil> The lubricant base oil used in the present invention has different performance and quality, such as viscosity characteristics, heat resistance, and oxidation stability, depending on its production method, refining method, etc. The API (American Petroleum Institute) classifies lubricant base oils into five types: Group I, II, III, IV, and V. These API categories are defined in API 1509, Engine Oil Licensing and Certification System, 22nd Edition, October 2023, and are as shown in Table 1.

[0016]

[0017] In the lubricating oil composition of the present invention, the mineral oil (A) or the synthetic oil (B) may be used alone as the lubricating base oil, or an arbitrary mixture of two or more lubricating oils selected from the mineral oil (A) and the synthetic oil (B) may be used.

[0018] <(A) Mineral Oil> The mineral oil (A) has the following characteristics (A1) to (A3): The mineral oil (A) in the present invention belongs to Groups I to III in the above-mentioned API category.

[0019] (A1) Kinematic viscosity at 100 ° C. is 2 to 7 mm 2 This kinematic viscosity value is measured according to the method described in JIS K2283. The kinematic viscosity of the mineral oil (A) at 100°C is 2 to 7 mm / s. 2 / s, preferably 2 to 6.8 mm 2 / s, more preferably 2 to 6.5 mm 2 When the kinematic viscosity at 100°C is within this range, the lubricating oil composition of the present invention is excellent in terms of volatility and temperature-viscosity characteristics.

[0020] (A2) Viscosity index of 95 or higher This viscosity index value is measured according to the method described in JIS K2283. The viscosity index of the mineral oil (A) is 95 or higher, preferably 105 or higher, more preferably 108 or higher, and even more preferably 110 or higher. The viscosity index of the mineral oil (A) in the low-viscosity lubricating oil composition (X), which is one embodiment of the lubricating oil composition of the present invention, is preferably 105 or higher, more preferably 108 or higher, and even more preferably 110 or higher. The viscosity index of the mineral oil (A) in the ultra-low viscosity lubricating oil composition (Y), which is one embodiment of the lubricating oil composition of the present invention, is 95 or higher, preferably 96 or higher, more preferably 97 or higher, even more preferably 105 or higher, and particularly preferably 108 or higher. The viscosity index of the mineral oil (A) is preferably at least 150 or lower, more preferably 130 or lower, and even more preferably 114 or lower. When the viscosity index is within this range, the lubricating oil composition of the present invention has excellent temperature-viscosity characteristics.

[0021] (A3) Pour point of -10°C or lower This pour point value is measured according to the method described in ASTM D97. The pour point of the mineral oil (A) is -10°C or lower, preferably -13°C or lower. It is also preferable that the pour point of the mineral oil (A) is at least -40°C or higher. When the pour point is within this range, the lubricating oil composition of the present invention will have excellent low-temperature viscosity characteristics when the mineral oil (A) is used in combination with a pour point depressant.

[0022] The qualities of mineral oils are as described above, and mineral oils of the respective qualities can be obtained by the refining method. Specific examples of mineral oil (A) include lubricating oil fractions obtained by vacuum distillation of atmospheric residue obtained by atmospheric distillation of crude oil, and then refined by one or more processes such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, and hydrorefining, as well as lubricating base oils such as wax isomerized mineral oil.

[0023] Gas-to-liquid (GTL) base oils obtained by the Fischer-Tropsch process are also suitable for use as Group III mineral oils. Such GTL base oils are sometimes referred to as Group III+ lubricant base oils, and are described, for example, in patent documents such as EP 776959, EP 668342, WO 97 / 21788, WO 00 / 15736, WO 00 / 14188, WO 00 / 14187, WO 00 / 14183, WO 00 / 14179, WO 00 / 08115, WO 99 / 41332, EP 1029029, WO 01 / 18156, and WO 01 / 57166.

[0024] <(B) Synthetic Oil> The synthetic oil (B) has the following characteristics (B1) to (B3): The synthetic oil (B) in the present invention belongs to Group IV or Group V in the above-mentioned API category.

[0025] (B1) Kinematic viscosity at 100 ° C. is 1 to 7 mm 2 This kinematic viscosity value is measured according to the method described in JIS K2283. The kinematic viscosity of the synthetic oil (B) at 100°C is 1 to 7 mm / s. 2 / s, preferably 1.0 to 6.8 mm 2 / s, more preferably 1.0 to 6.5 mm 2 When the kinematic viscosity at 100°C is within this range, the lubricating oil composition of the present invention is excellent in terms of volatility and temperature-viscosity characteristics.

[0026] (B2) Kinematic viscosity at 40 ° C. is 4 to 40 mm 2This kinematic viscosity value is measured in accordance with the method described in JIS K2283. The kinematic viscosity of the synthetic oil (B) at 40°C is 4 to 40 mm 2 / s, preferably 4 to 38 mm 2 / s, more preferably 4 to 35 mm 2 When the kinematic viscosity at 40°C is within this range, the lubricating oil composition of the present invention is excellent in terms of flowability and handleability at room temperature.

[0027] (B3) Pour point of -30°C or lower This pour point value is measured according to the method described in ASTM D97. The pour point of synthetic oil (B) is -30°C or lower, preferably -40°C or lower, and more preferably -50°C or lower. It is also preferable that the pour point of synthetic oil (B) is at least -80°C or higher. When the pour point is within this range, the lubricating oil composition of the present invention has excellent low-temperature viscosity characteristics.

[0028] The synthetic oil (B) of the present invention may be a single synthetic oil or two or more synthetic oils, and preferably contains a synthetic oil belonging to Group IV or Group V, and more preferably contains an ester and a synthetic oil other than an ester.

[0029] Poly-α-olefins belonging to Group IV can be obtained by oligomerizing higher α-olefins with an acid catalyst, as described in U.S. Pat. Nos. 3,780,128 and 4,032,591, and Japanese Patent Laid-Open Publication No. 1-163136. Among these, the poly-α-olefin can be a low-molecular-weight oligomer of at least one olefin selected from olefins having 8 or more carbon atoms. When a poly-α-olefin is used as the lubricating base oil, a lubricating oil composition having excellent temperature viscosity characteristics, low-temperature viscosity characteristics, and heat resistance can be obtained.

[0030] Poly-α-olefin is commercially available and has a kinematic viscosity of 1.7 mm at 100°C. 2 / s ~ 10mm 2Examples of commercially available fluororesin include Spectrasyn manufactured by ExxonMobil Chemical, Durasyn manufactured by Ineos Oligomers, and Synfluid manufactured by Chevron Phillips Chemical.

[0031] Examples of synthetic oils belonging to Group V include alkylbenzenes, alkylnaphthalenes, isobutene oligomers or hydrogenated products thereof, paraffins, polyoxyalkylene glycols, dialkyldiphenyl ethers, polyphenyl ethers, esters, and the like.

[0032] The majority of alkylbenzenes and alkylnaphthalenes are dialkylbenzenes or dialkylnaphthalenes, typically having alkyl chain lengths of 6 to 14 carbon atoms, and such alkylbenzenes or alkylnaphthalenes are produced by the Friedel-Crafts alkylation reaction of benzene or naphthalene with an olefin. The alkylated olefin used in the production of alkylbenzenes or alkylnaphthalenes may be a linear or branched olefin or a combination thereof. The production method thereof is described, for example, in U.S. Pat. No. 3,909,432.

[0033] Furthermore, the ester is preferably a fatty acid ester from the viewpoint of compatibility with the ethylene-α-olefin copolymer (C). The fatty acid ester is not particularly limited, but examples thereof include fatty acid esters consisting only of carbon, oxygen, and hydrogen, such as the following: monoesters produced from a monobasic acid and an alcohol; diesters produced from a dibasic acid and an alcohol, or from a diol and a monobasic acid or an acid mixture; and polyol esters produced by reacting a diol, a triol (e.g., trimethylolpropane), a tetraol (e.g., pentaerythritol), a hexaol (e.g., dipentaerythritol), or the like with a monobasic acid or an acid mixture. Examples of these esters include ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, tridecyl pelargonate, di-2-ethylhexyl adipate, di-2-ethylhexyl azelate, trimethylolpropane caprylate, trimethylolpropane pelargonate, trimethylolpropane triheptanoate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate, pentaerythritol tetraheptanoate, and the like.

[0034] From the viewpoint of compatibility with the ethylene-α-olefin copolymer (C), the alcohol moiety constituting the ester is preferably an alcohol having a hydroxyl group with two or more functionalities, and the fatty acid moiety is preferably a fatty acid having eight or more carbon atoms. However, with regard to the fatty acid, fatty acids having 20 or fewer carbon atoms, which are easily available industrially, are advantageous in terms of production costs. The ester may be composed of a single fatty acid, or the effects of the present invention can be fully achieved even when a fatty acid ester produced using a mixture of two or more acids is used. More specific examples of fatty acid esters include trimethylolpropane lauric acid stearic acid mixed triester and diisodecyl adipate. These are preferred from the viewpoint of compatibility with saturated hydrocarbon components such as the ethylene-α-olefin copolymer (C) and antioxidants, corrosion inhibitors, antiwear agents, friction modifiers, pour point depressants, rust inhibitors, and antifoaming agents having polar groups, as described below. A preferred form of the lubricating base oil used in the present invention is a synthetic oil (B) from the viewpoint of quality stability.

[0035] <(C) Ethylene-α-olefin copolymer> The ethylene-α-olefin copolymer (C) has the following characteristics (C1) to (C3).

[0036] (C1) The content of structural units (i) derived from ethylene is 30 to 80 mol %, and the content of structural units (ii) derived from an α-olefin having 3 to 20 carbon atoms is 70 to 20 mol % (where the total content of structural units (i) and (ii) is 100 mol %). The content of structural units (i) in the ethylene-α-olefin copolymer (C) is usually 30 to 80 mol %, preferably 35 to 70 mol %, more preferably 40 to 70 mol %, and particularly preferably 40 to 60 mol %. If it is excessively lower than this, the viscosity-temperature characteristics of the lubricating oil composition will deteriorate, and if it is excessively higher than this, the ethylene chains in the molecule will be extended, which may result in the development of crystallinity and the deterioration of the low-temperature viscosity characteristics of the lubricating oil composition.

[0037] The content of the ethylene-derived structural unit (i) in the ethylene-α-olefin copolymer (C) (hereinafter also referred to as "ethylene content (mol%)") can be determined according to the method described in "Polymer Analysis Handbook" (published by Asakura Publishing, pp. 163-170). 13 It is also possible to measure the sample determined by this method as a known sample using Fourier transform infrared spectroscopy (FT-IR).

[0038] The content of the structural unit (ii) in the ethylene-α-olefin copolymer (C) (hereinafter also referred to as the "α-olefin content (mol %)") is usually 70 to 20 mol %, preferably 65 to 30 mol %, more preferably 60 to 30 mol %, and particularly preferably 60 to 40 mol %. When the content of the structural unit (ii) is within the above range, crystalline components are less likely to form, and solubility in the base oil is improved.

[0039] (C2) Kinematic viscosity at 100 ° C. is 10 to 5,000 mm 2 This value of kinematic viscosity is measured by the method described in JIS K2283. The kinematic viscosity of the ethylene-α-olefin copolymer (C) at 100°C is 10 to 5,000 mm 2 / s, preferably 15 to 2,500 mm 2 / s, more preferably 20 to 2,500 mm 2 If the kinematic viscosity at 100° C. of the ethylene-α-olefin copolymer (C) is within the above range, it is preferable in terms of the low-temperature viscosity characteristics of the lubricating oil composition.

[0040] (C3) The number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 500 to 10,000, and the molecular weight distribution (Mw / Mn) is 2.5 or less. The molecular weight distribution (Mw / Mn) of the ethylene-α-olefin copolymer (C) is measured by gel permeation chromatography (GPC) according to the method described below, and calculated as the ratio (Mw / Mn) of the weight average molecular weight (Mw) obtained in terms of standard polystyrene to the number average molecular weight (Mn). The number average molecular weight (Mn) of the present invention is 500 to 10,000, preferably 750 to 8,000, and more preferably 1,000 to 7,500. A number average molecular weight (Mn) within this range provides an excellent balance between thickening properties and shear stability. The molecular weight distribution (Mw / Mn) of the present invention is 2.5 or less, preferably 2.3 or less, and more preferably 2.0 or less. If the molecular weight distribution excessively exceeds this range, the viscosity of the lubricating oil composition will change due to volatilization of low molecular weight components when used in a high-temperature environment, or the shear stability of the lubricating oil composition will deteriorate. Furthermore, the molecular weight distribution of the ethylene-α-olefin copolymer (C) is preferably at least 1.4. With the molecular weight distribution within this range, the lubricating oil composition will have excellent viscosity-temperature characteristics and low-temperature viscosity characteristics.

[0041] The ethylene-α-olefin copolymer (C) preferably further has one or more of the characteristics (C4) to (C6), more preferably has two or more of the characteristics, and even more preferably has three of the characteristics.

[0042] (C4) B Value of 1.1 or More The B value of the ethylene-α-olefin copolymer (C), represented by the following formula [1], is 1.1 or more, preferably 1.2 or more.

[0043]

[0044] In the formula, P E indicates the ethylene content (mol%), Po indicates the α-olefin content (mol%), and P OE indicates the content (mol %) of ethylene-α-olefin chains in all dyad chains.

[0045] The larger the B value, the fewer block-like sequences there are, the more uniform the distribution of ethylene and α-olefin, and the narrower the composition distribution of the copolymer. The length of these block-like sequences affects the physical properties of the copolymer, and the larger the B value, the shorter the block-like sequences and the lower the pour point of the ethylene-α-olefin copolymer (C), and the lubricating oil composition will exhibit good low-temperature viscosity characteristics.

[0046] The B value is an index showing the randomness of the copolymerization monomer sequence distribution in the copolymer, and is expressed as P in the above formula [1]. E , P O and P OE teeth, 13 The B value can be determined by measuring a C-NMR spectrum based on the reports of J. C. Randall [Macromolecules, 15, 353 (1982)], J. Ray [Macromolecules, 10, 773 (1977)], etc. Specific conditions for measuring the B value are as described in the Examples.

[0047] (C5) 1 The number of unsaturated bonds measured by H-NMR is less than 0.5 per 1000 carbon atoms. The ethylene-α-olefin copolymer (C) has the following properties: 1 The total number of double bonds derived from vinyl, vinylidene, disubstituted olefins, trisubstituted olefins, etc. (hereinafter also referred to as "unsaturated bond amount") measured by H-NMR is less than 0.5, preferably less than 0.3, more preferably less than 0.2, and even more preferably less than 0.1 per 1,000 carbon atoms. When the unsaturated bond amount is within this range, the heat resistance of the lubricating oil composition is good. Specific conditions for measuring the unsaturated bond amount are as described in the Examples.

[0048] (C6) No Melting Point Observed It is preferable that the ethylene-α-olefin copolymer (C) has no melting point observed by differential scanning calorimetry (DSC). Here, "no melting point (Tm) observed" means that the heat of fusion (ΔH) (unit: J / g) measured by differential scanning calorimetry (DSC) is not substantially measured. "No heat of fusion (ΔH) is substantially not measured" means that no peak is observed in differential scanning calorimetry (DSC) measurement, or the observed heat of fusion is 1 J / g or less. The melting point (Tm) and heat of fusion (ΔH) of the ethylene-α-olefin copolymer (C) can be determined by analyzing the DSC curve obtained by differential scanning calorimetry (DSC) measurement, cooling to -100°C, and then heating to 150°C at a heating rate of 10°C / min, with reference to JIS K7121. If no melting point is observed, no crystalline components are formed at low temperatures, and therefore the increase in low-temperature viscosity is suppressed, resulting in the lubricating oil composition having excellent low-temperature viscosity characteristics.

[0049] Examples of the α-olefin used in the ethylene-α-olefin copolymer (C) include linear or branched α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, and vinylcyclohexane. As the α-olefin, linear or branched α-olefins having 3 to 10 carbon atoms are preferred, with propylene, 1-butene, 1-hexene, and 1-octene being more preferred, and propylene being most preferred in terms of the shear stability of the lubricating oil composition using the resulting copolymer. These α-olefins may be used alone or in combination of two or more.

[0050] The ethylene and the α-olefin having 3 to 20 carbon atoms, which are monomers constituting the ethylene-α-olefin copolymer (C), may consist solely of monomers obtained from a biomass-derived raw material, or may consist solely of monomers obtained from a fossil fuel-derived raw material, or may be a mixture of monomers obtained from a biomass-derived raw material and monomers obtained from a fossil fuel-derived raw material.

[0051] The polymerization can also be carried out in the presence of at least one other monomer selected from an aromatic vinyl compound and a cyclic olefin in the reaction system. The other monomer can be used in an amount of, for example, 20 parts by mass or less, preferably 10 parts by mass or less, per 100 parts by mass of the total of ethylene and the α-olefin having 3 to 20 carbon atoms.

[0052] Examples of aromatic vinyl compounds include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, methoxystyrene, vinylbenzoic acid, methyl vinylbenzoate, vinylbenzyl acetate, hydroxystyrene, p-chlorostyrene, divinylbenzene, α-methylstyrene, and allylbenzene.

[0053] Examples of the cyclic olefin include cyclic olefins having 3 to 30 carbon atoms, preferably 3 to 20 carbon atoms, such as cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, and tetracyclododecene.

[0054] It is desirable that the ethylene-α-olefin copolymer (C) is substantially free of carboxy groups, ester groups, and carboxylic anhydride groups. "Substantially free" means that carboxy group and ester group components are not actively added from the outside as monomers constituting the ethylene-α-olefin copolymer (C) or additives for modification, and excludes trace amounts of these groups as impurities that are inevitably mixed in from raw materials, etc. In other words, it is preferable that the ethylene-α-olefin copolymer (C) is not modified with at least one selected from carboxy groups, ester groups, and carboxylic anhydride groups, and it is more preferable that it is unmodified.

[0055] The method for producing the ethylene-α-olefin copolymer (C) is not particularly limited, but examples include methods using a vanadium catalyst comprising a vanadium compound and an organoaluminum compound, as described in JP-B-2-1163 and JP-B-2-7998. Furthermore, methods for producing copolymers with high polymerization activity may also be used, such as those described in JP-A-61-221207, JP-B-7-121969, and Japanese Patent No. 2796376, which use a catalyst system comprising a metallocene compound such as zirconocene and an organoaluminum oxy compound (aluminoxane). These methods are more preferred because they can reduce the chlorine content of the resulting copolymer and the 2,1-insertion of propylene. Compared to methods using metallocene catalysts, methods using vanadium catalysts use a larger amount of chlorine compound as a co-catalyst, which may result in trace amounts of chlorine remaining in the resulting ethylene-α-olefin copolymer (C).

[0056] On the other hand, in the method using a metallocene catalyst, substantially no chlorine remains, so there is no need to consider the possibility of corrosion of metal parts in internal combustion engines, machines, etc. The chlorine content is preferably 100 ppm or less, more preferably 50 ppm or less, even more preferably 20 ppm or less, and particularly preferably 5 ppm or less. The chlorine content can be quantified by various known methods. Specific measurement methods in the present invention are as described in the examples.

[0057] Furthermore, the reduction in 2,1-insertion of propylene makes it possible to further reduce the ethylene chains in the copolymer molecule, and suppress the intramolecular crystallinity of ethylene, thereby improving the viscosity-temperature characteristics and low-temperature viscosity characteristics of the lubricating oil composition. The amount of 2,1-insertion of propylene can be determined according to the method described in JP-A-7-145212. 13 It is determined by analysis of C-NMR measurement, and is preferably less than 1%, more preferably 0 to 0.5%, and even more preferably 0 to 0.1%. It is particularly preferable that no peak is observed in the range of 15.0 to 17.5 ppm.

[0058] In particular, by using the following method, an ethylene-α-olefin copolymer (C) having a good balance of performance in terms of molecular weight control, molecular weight distribution, amorphousness and B value can be obtained.

[0059] The ethylene-α-olefin copolymer (C) can be produced by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of an olefin polymerization catalyst containing a bridged metallocene compound (P) represented by the following general formula [I], and at least one compound (Q) selected from the group consisting of an organometallic compound (Q-1), an organoaluminum oxy compound (Q-2), and a compound (Q-3) that reacts with the bridged metallocene compound (P) to form an ion pair:

[0060]

[0061] [Bridged Metallocene Compound (P)] The bridged metallocene compound (P) is represented by the above formula [I]. 1 ~R 14 , Q, n and j are explained below.

[0062] (Y, M, R 1 ~R 14 , Q, n and j) Y is a Group 14 atom, for example, a carbon atom, a silicon atom, a germanium atom or a tin atom, preferably a carbon atom or a silicon atom, more preferably a carbon atom.

[0063] M is a titanium atom, a zirconium atom or a hafnium atom, and is preferably a zirconium atom.

[0064] R 1 ~R 12 are atoms or substituents selected from the group consisting of hydrogen atoms, hydrocarbon groups having 1 to 20 carbon atoms, silicon-containing groups, nitrogen-containing groups, oxygen-containing groups, halogen atoms and halogen-containing groups, and may be the same or different. 1 From R 12 Adjacent substituents up to may be bonded to each other to form a ring, or may not be bonded to each other.

[0065] Examples of the hydrocarbon group having 1 to 20 carbon atoms include an alkyl group having 1 to 20 carbon atoms, a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, a linear unsaturated hydrocarbon group having 2 to 20 carbon atoms, a cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms, an alkylene group having 1 to 20 carbon atoms, and an arylene group having 6 to 20 carbon atoms.

[0066] Examples of alkyl groups having 1 to 20 carbon atoms include linear saturated hydrocarbon groups such as methyl, ethyl, n-propyl, allyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decanyl, and branched saturated hydrocarbon groups such as isopropyl, isobutyl, s-butyl, t-butyl, t-amyl, neopentyl, 3-methylpentyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-methyl-1-propylbutyl, 1,1-propylbutyl, 1,1-dimethyl-2-methylpropyl, 1-methyl-1-isopropyl-2-methylpropyl, and cyclopropylmethyl. The alkyl group preferably has 1 to 6 carbon atoms.

[0067] Examples of cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms include cyclic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornenyl, 1-adamantyl, and 2-adamantyl, and groups in which a hydrogen atom of a cyclic saturated hydrocarbon group is replaced with a hydrocarbon group having 1 to 17 carbon atoms such as 3-methylcyclopentyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 4-cyclohexylcyclohexyl, and 4-phenylcyclohexyl. The number of carbon atoms in the cyclic saturated hydrocarbon group is preferably 5 to 11.

[0068] Examples of linear unsaturated hydrocarbon groups having 2 to 20 carbon atoms include alkenyl groups such as ethenyl (vinyl), 1-propenyl, 2-propenyl (allyl), and 1-methylethenyl (isopropenyl), and alkynyl groups such as ethynyl, 1-propynyl, and 2-propynyl (propargyl). The linear unsaturated hydrocarbon group preferably has 2 to 4 carbon atoms.

[0069] Examples of cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms include cyclic unsaturated hydrocarbon groups such as cyclopentadienyl, norbornyl, phenyl, naphthyl, indenyl, azulenyl, phenanthryl, and anthracenyl; groups in which hydrogen atoms of cyclic unsaturated hydrocarbon groups are replaced with hydrocarbon groups having 1 to 15 carbon atoms, such as 3-methylphenyl (m-tolyl), 4-methylphenyl (p-tolyl), 4-ethylphenyl, 4-t-butylphenyl, 4-cyclohexylphenyl, biphenylyl, 3,4-dimethylphenyl, 3,5-dimethylphenyl, and 2,4,6-trimethylphenyl (mesityl); and groups in which hydrogen atoms of linear or branched saturated hydrocarbon groups are replaced with cyclic saturated or unsaturated hydrocarbon groups having 3 to 19 carbon atoms, such as benzyl and cumyl. The number of carbon atoms in the cyclic unsaturated hydrocarbon group is preferably 6 to 10.

[0070] Examples of alkylene groups having 1 to 20 carbon atoms include methylene, ethylene, dimethylmethylene (isopropylidene), ethylmethylene, methylethylene, n-propylene, etc. The alkylene group preferably has 1 to 6 carbon atoms.

[0071] Examples of the arylene group having 6 to 20 carbon atoms include an o-phenylene group, an m-phenylene group, a p-phenylene group, a 4,4'-biphenylylene group, etc. The number of carbon atoms in the arylene group is preferably 6 to 12.

[0072] Examples of silicon-containing groups include alkylsilyl groups such as trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, and triisopropylsilyl, which are hydrocarbon groups having 1 to 20 carbon atoms in which a carbon atom has been replaced with a silicon atom, arylsilyl groups such as dimethylphenylsilyl, methyldiphenylsilyl, and t-butyldiphenylsilyl, pentamethyldisilanyl, and trimethylsilylmethyl. The alkylsilyl group preferably has 1 to 10 carbon atoms, and the arylsilyl group preferably has 6 to 18 carbon atoms.

[0073] Examples of the nitrogen-containing group include an amino group, a group in which the =CH- structural unit in the above-mentioned hydrocarbon group having 1 to 20 carbon atoms or silicon-containing group is replaced with a nitrogen atom, a group in which the -CH2- structural unit is replaced with a nitrogen atom to which a hydrocarbon group having 1 to 20 carbon atoms is bonded, or a group in which the -CH3 structural unit is replaced with a nitrogen atom to which a hydrocarbon group having 1 to 20 carbon atoms is bonded or a nitrile group, such as a dimethylamino group, diethylamino group, N-morpholinyl group, dimethylaminomethyl group, cyano group, pyrrolidinyl group, piperidinyl group, pyridinyl group, N-morpholinyl group, and nitro group. Preferred nitrogen-containing groups are dimethylamino group and N-morpholinyl group.

[0074] Examples of the oxygen-containing group include a hydroxyl group, a group in which the -CH2- structural unit in the above-mentioned hydrocarbon group having 1 to 20 carbon atoms, silicon-containing group, or nitrogen-containing group is replaced with an oxygen atom or a carbonyl group, or a group in which the -CH3 structural unit is replaced with an oxygen atom bonded to a hydrocarbon group having 1 to 20 carbon atoms, such as a methoxy group, ethoxy group, t-butoxy group, phenoxy group, trimethylsiloxy group, methoxyethoxy group, hydroxymethyl group, methoxymethyl group, ethoxymethyl group, t-butoxymethyl group, or 1-hydroxyethyl group. Examples of the oxygen-containing group include 1-methoxyethyl group, 1-ethoxyethyl group, 2-hydroxyethyl group, 2-methoxyethyl group, 2-ethoxyethyl group, n-2-oxabutylene group, n-2-oxapentylene group, n-3-oxapentylene group, aldehyde group, acetyl group, propionyl group, benzoyl group, trimethylsilylcarbonyl group, carbamoyl group, methylaminocarbonyl group, carboxy group, methoxycarbonyl group, carboxymethyl group, ethoxycarboxymethyl group, carbamoylmethyl group, furanyl group, and pyranyl group. As the oxygen-containing group, a methoxy group is preferred.

[0075] Examples of halogen atoms include group 17 elements such as fluorine, chlorine, bromine, and iodine.

[0076] Examples of halogen-containing groups include trifluoromethyl groups, tribromomethyl groups, pentafluoroethyl groups, and pentafluorophenyl groups, which are groups in which a hydrogen atom in the above-mentioned hydrocarbon groups, silicon-containing groups, nitrogen-containing groups, or oxygen-containing groups having 1 to 20 carbon atoms is substituted with a halogen atom.

[0077] R 13 and R 14 are atoms or substituents selected from the group consisting of hydrogen atoms, hydrocarbon groups having 1 to 20 carbon atoms, aryl groups, substituted aryl groups, silicon-containing groups, nitrogen-containing groups, oxygen-containing groups, halogen atoms and halogen-containing groups, and may be the same or different. 13 and R 14 may be bonded to each other to form a ring, or may not be bonded to each other.

[0078] Details of the hydrocarbon group having 1 to 20 carbon atoms, the silicon-containing group, the nitrogen-containing group, the oxygen-containing group, the halogen atom, and the halogen-containing group are as described above. Examples of the aryl group partially overlap with the examples of the cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms described above, but include substituents derived from aromatic compounds such as a phenyl group, a 1-naphthyl group, a 2-naphthyl group, an anthracenyl group, a phenanthrenyl group, a tetracenyl group, a chrysenyl group, a pyrenyl group, an indenyl group, an azulenyl group, a pyrrolyl group, a pyridyl group, a furanyl group, and a thiophenyl group. As the aryl group, a phenyl group or a 2-naphthyl group is preferred.

[0079] Examples of the aromatic compounds include aromatic hydrocarbons and heterocyclic aromatic compounds such as benzene, naphthalene, anthracene, phenanthrene, tetracene, chrysene, pyrene, indene, azulene, pyrrole, pyridine, furan, and thiophene.

[0080] The substituted aryl group partially overlaps with the examples of the cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms described above, but includes groups in which one or more hydrogen atoms of the aryl group are substituted with at least one substituent selected from the group consisting of hydrocarbon groups having 1 to 20 carbon atoms, aryl groups, silicon-containing groups, nitrogen-containing groups, oxygen-containing groups, halogen atoms, and halogen-containing groups. Specific examples include 3-methylphenyl group (m-tolyl group), 4-methylphenyl group (p-tolyl group), 3-ethylphenyl group, 4-ethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, biphenylyl group, 4-(trimethylsilyl)phenyl group, 4-methylphenyl group (p-tolyl group), 4-methylphenyl group (p-tolyl group), 3-ethylphenyl group, 4-ethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, biphenylyl group, 4-(trimethylsilyl)phenyl group, 4-methyl ... Examples of the alkyl group include a 4-aminophenyl group, a 4-(dimethylamino)phenyl group, a 4-(diethylamino)phenyl group, a 4-morpholinylphenyl group, a 4-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-phenoxyphenyl group, a 3,4-dimethoxyphenyl group, a 3,5-dimethoxyphenyl group, a 3-methyl-4-methoxyphenyl group, a 3,5-dimethyl-4-methoxyphenyl group, a 3-(trifluoromethyl)phenyl group, a 4-(trifluoromethyl)phenyl group, a 3-chlorophenyl group, a 4-chlorophenyl group, a 3-fluorophenyl group, a 4-fluorophenyl group, a 5-methylnaphthyl group, and a 2-(6-methyl)pyridyl group.

[0081] Among them, R 13 and R 14 A bridged metallocene compound (P) in which one or both of the above are independently an aryl group is preferred, and a bridged metallocene compound (P) in which both are independently an aryl group is more preferred.

[0082] In particular, R 13 and R 14and (B) are independently aryl groups, the bridged metallocene compound (P) has high polymerization activity for copolymerization of ethylene and α-olefins. The use of this bridged metallocene compound (P) selectively terminates polymerization by introducing hydrogen into the molecular terminals, resulting in fewer unsaturated bonds in the resulting copolymer (A). Therefore, a copolymer (A) with a high degree of saturation and excellent heat resistance can be obtained simply by a simpler hydrogenation procedure, or even without a hydrogenation procedure, resulting in cost savings. Furthermore, the copolymer (A) obtained from the compound (P) has a controlled molecular weight distribution due to its high random copolymerizability. Therefore, the present composition, which contains a graft-modified copolymer (X) having a main chain portion derived from the copolymer (A) obtained by graft-modifying the following unsaturated monomer (B) onto the copolymer (A) and a graft portion derived from the unsaturated monomer (B), is believed to have excellent, well-balanced defoaming and bleed-out resistance at high levels.

[0083] Q may be the same or different and may be selected from a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an anionic ligand, and a neutral ligand capable of coordinating with a lone electron pair. Details of the halogen atom and the hydrocarbon group having 1 to 20 carbon atoms are as described above. When Q is a halogen atom, it is preferably a chlorine atom. When Q is a hydrocarbon group having 1 to 20 carbon atoms, it is preferable that the hydrocarbon group have 1 to 7 carbon atoms.

[0084] Examples of the anionic ligand include alkoxy groups such as methoxy, t-butoxy, and phenoxy groups, carboxylate groups such as acetate and benzoate, and sulfonate groups such as mesylate and tosylate.

[0085] Examples of neutral ligands capable of coordinating with lone electron pairs include organic phosphorus compounds such as trimethylphosphine, triethylphosphine, triphenylphosphine, and diphenylmethylphosphine, and ether compounds such as tetrahydrofuran, diethyl ether, dioxane, and 1,2-dimethoxyethane.

[0086] n is an integer of 1 to 4, preferably 1 or 2, and more preferably 1. j is an integer of 1 to 4, and preferably 2.

[0087] In the bridged metallocene compound (P) represented by the formula [I], n is preferably 1. Such a bridged metallocene compound (hereinafter also referred to as "bridged metallocene compound (P-1)") is represented by the following general formula [II].

[0088]

[0089] In formula [II], Y, M, R 1 ~R 14 , Q and j are as defined above.

[0090] The bridged metallocene compound (P-1) has an advantage that the production process is simpler and the production cost is reduced compared to the compound in the above formula [I] where n is an integer of 2 to 4, and therefore the use of this bridged metallocene compound (P-1) reduces the production cost of the ethylene-α-olefin copolymer (C).

[0091] In the bridged metallocene compound (P) represented by the general formula [I] above and the bridged metallocene compound (P-1) represented by the general formula [II] above, M is more preferably a zirconium atom. When ethylene and one or more monomers selected from α-olefins having 3 to 20 carbon atoms are copolymerized in the presence of an olefin polymerization catalyst containing the bridged metallocene compound in which M is a zirconium atom, the polymerization activity is higher than when M is a titanium atom or a hafnium atom, and the production cost of the copolymer (B) is advantageously reduced.

[0092] Examples of such bridged metallocene compounds (P) include [dimethylmethylene (η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [dimethylmethylene (η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [dimethylmethylene (η 5-cyclopentadienyl) (η 5 -3,6-di-t-butylfluorenyl)]zirconium dichloride, [dimethylmethylene (η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [dimethylmethylene (η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [cyclohexylidene (η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [cyclohexylidene (η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [cyclohexylidene (η 5 -cyclopentadienyl) (η 5 -3,6-di-t-butylfluorenyl)]zirconium dichloride, [cyclohexylidene (η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [cyclohexylidene (η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [diphenylmethylene (η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [diphenylmethylene (η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [diphenylmethylene (η 5 -2-methyl-4-t-butylcyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [diphenylmethylene (η 5 -cyclopentadienyl) (η 5-3,6-di-t-butylfluorenyl)]zirconium dichloride, [diphenylmethylene (η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [diphenylmethylene{η 5 -(2-methyl-4-i-propylcyclopentadienyl)}(η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [diphenylmethylene (η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [methylphenylmethylene (η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [methylphenylmethylene (η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [methylphenylmethylene (η 5 -cyclopentadienyl) (η 5 -3,6-di-t-butylfluorenyl)]zirconium dichloride, [methylphenylmethylene (η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [methylphenylmethylene (η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [methyl(3-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [methyl(3-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [methyl(3-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5-3,6-di-t-butylfluorenyl)]zirconium dichloride, [methyl(3-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [methyl(3-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [methyl(4-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [methyl(4-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [methyl(4-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -3,6-di-t-butylfluorenyl)]zirconium dichloride, [methyl(4-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [methyl(4-methylphenyl)methylene(η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [diphenylsilylene (η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [diphenylsilylene (η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [diphenylsilylene (η 5 -cyclopentadienyl) (η 5 -3,6-di-t-butylfluorenyl)]zirconium dichloride, [diphenylsilylene (η 5 -cyclopentadienyl) (η 5-octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [diphenylsilylene (η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [bis(3-methylphenyl)silylene(η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [bis(3-methylphenyl)silylene(η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [bis(3-methylphenyl)silylene(η 5 -cyclopentadienyl) (η 5 -3,6-di-t-butylfluorenyl)]zirconium dichloride, [bis(3-methylphenyl)silyl(η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [bis(3-methylphenyl)silylene(η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [dicyclohexylsilylene (η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [dicyclohexylsilylene (η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [dicyclohexylsilylene (η 5 -cyclopentadienyl) (η 5 -3,6-di-t-butylfluorenyl)]zirconium dichloride, [dicyclohexylsilylene (η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [dicyclohexylsilylene (η 5 -cyclopentadienyl) (η 5-tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [ethylene (η 5 -cyclopentadienyl) (η 5 -fluorenyl)]zirconium dichloride, [ethylene (η 5 -cyclopentadienyl) (η 5 -2,7-di-t-butylfluorenyl)]zirconium dichloride, [ethylene (η 5 -cyclopentadienyl) (η 5 -3,6-di-t-butylfluorenyl)]zirconium dichloride, [ethylene (η 5 -cyclopentadienyl) (η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [ethylene (η 5 -cyclopentadienyl) (η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, ethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, ethylene [η 5-(3-tert-butyl-5-methylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5-(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5-(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5-(3-tert-butylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-n-butylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-n-butylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-n-butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, diphenylmethylene [η 5-(3-n-butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-n-butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butylcyclopentadienyl)] [η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-tert-butylcyclopentadienyl)] [η5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)](η 5 -fluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-n-butylcyclopentadienyl)](octamethyloctahydrodibenzfluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-n-butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-n-butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-n-butylcyclopentadienyl)](2,7-diphenyl-3,6-di-tert-butylfluorenyl)zirconium dichloride, di(p-tolyl)methylene [η 5 -(3-n-butylcyclopentadienyl)] [η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride.

[0093] Further examples of the bridged metallocene compound (P) include compounds in which the zirconium atom of the above-mentioned compound is replaced with a hafnium atom or a titanium atom, and compounds in which the chloro ligand is replaced with a methyl group.5 -Tetramethyloctahydrodibenzofluorenyl is 4,4,7,7-tetramethyl-(5a,5b,11a,12,12a-η 5 )-1,2,3,4,7,8,9,10-octahydrodibenzo[b,H]fluorenyl group, η 5 -Octamethyloctahydrodibenzofluorenyl is 1,1,4,4,7,7,10,10-octamethyl-(5a,5b,11a,12,12a-η 5 )-1,2,3,4,7,8,9,10-octahydrodibenzo[b,H]fluorenyl group. The bridged metallocene compounds (P) may be used singly or in combination of two or more.

[0094] [Compound (Q)] The compound (Q) according to the present invention is at least one compound selected from the group consisting of organometallic compounds (Q-1), organoaluminum oxy compounds (Q-2), and compounds (Q-3) that react with the bridged metallocene compound (P) to form an ion pair. Specific examples of the organometallic compound (Q-1) that can be used include the following organometallic compounds (Q-1a), (Q-1b), and (Q-1c) of Groups 1 and 2, and Groups 12 and 13 of the Periodic Table:

[0095] (Q-1a) General formula R a m Al (OR b ) n H p X q An organoaluminum compound represented by the formula: a and R b may be the same or different and represent a hydrocarbon group having 1 to 15, preferably 1 to 4, carbon atoms; X represents a halogen atom; m is a number that satisfies 0<m≦3, n is a number that satisfies 0≦n<3, p is a number that satisfies 0≦p<3, and q is a number that satisfies 0≦q<3, and m+n+p+q=3.

[0096] Examples of such compounds include tri-n-alkylaluminums such as trimethylaluminum, triethylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum; tri-branched alkylaluminums such as triisopropylaluminum, triisobutylaluminum, trisec-butylaluminum, tri-t-butylaluminum, tri-2-methylbutylaluminum, tri-3-methylhexylaluminum, and tri-2-ethylhexylaluminum; tricycloalkylaluminums such as tricyclohexylaluminum and tricyclooctylaluminum; triarylaluminums such as triphenylaluminum and tri(4-methylphenyl)aluminum; dialkylaluminum hydrides such as diisopropylaluminum hydride and diisobutylaluminum hydride; and compounds of the general formula (i-CH) x Al y (C5H 10 ) z (wherein x, y, and z are positive numbers, and z≦2x), alkylaluminum alkoxides such as isobutylaluminum methoxide and isobutylaluminum ethoxide, dialkylaluminum alkoxides such as dimethylaluminum methoxide, diethylaluminum ethoxide and dibutylaluminum butoxide, alkylaluminum sesquialkoxides such as ethylaluminum sesquiethoxide and butylaluminum sesquibut ... represented by the general formula R a 2.5 Al (OR b ) 0.5Examples of the alkylaluminum include partially alkoxylated alkylaluminums having an average composition represented by the formula (I) or (II), alkylaluminum aryloxides such as diethylaluminum phenoxide and diethylaluminum (2,6-di-t-butyl-4-methylphenoxide), dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromide and diisobutylaluminum chloride, alkylaluminum sesquihalides such as ethylaluminum sesquichloride, butylaluminum sesquichloride and ethylaluminum sesquibromide, partially halogenated alkylaluminums such as alkylaluminum dihalides such as ethylaluminum dichloride, dialkylaluminum hydrides such as diethylaluminum hydride and dibutylaluminum hydride, alkylaluminum dihydrides such as ethylaluminum dihydride and propylaluminum dihydride, and other partially hydrogenated alkylaluminums, and partially alkoxylated and halogenated alkylaluminums such as ethylaluminum ethoxychloride, butylaluminum butoxychloride and ethylaluminum ethoxybromide. a m Al (OR b ) n H p X q Compounds similar to the compound represented by the formula (1) can also be used, such as organoaluminum compounds in which two or more aluminum compounds are bonded via nitrogen atoms, such as (C2H5)2AlN(C2H5)Al(C2H5)2.

[0097] (Q-1b) General formula M 2 AlR a 4 (wherein M 2 represents Li, Na or K, and R a represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms.) Examples of such compounds include LiAl(C2H5)4, LiAl(C7H15 ) 4 can be given as an example.

[0098] (Q-1c) General formula R a R b M 3 A dialkyl compound of a metal of Group 2 or 12 of the periodic table, represented by the formula: a and R b may be the same or different and represent a hydrocarbon group having 1 to 15, preferably 1 to 4, carbon atoms; M 3 is Mg, Zn or Cd.

[0099] As the organoaluminum oxy compound (Q-2), a conventionally known aluminoxane can be used as it is. Specific examples include compounds represented by the following general formula [III] and compounds represented by the following general formula [IV].

[0100]

[0101] In formulas [III] and [IV], R represents a hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 2 or more.

[0102] In particular, methylaluminoxanes in which R is a methyl group and n is 3 or more, preferably 10 or more, are used. There is no problem if these aluminoxanes contain a small amount of an organoaluminum compound.

[0103] In the present invention, when copolymerization of ethylene with an α-olefin having 3 or more carbon atoms is carried out at high temperatures, benzene-insoluble organoaluminum oxy compounds such as those exemplified in JP-A No. 2-78687 can also be used. Also suitable are the organoaluminum oxy compounds described in JP-A No. 2-167305 and the aluminoxanes having two or more alkyl groups described in JP-A Nos. 2-24701 and 3-103407. The "benzene-insoluble organoaluminum oxy compounds" that may be used in the present invention are compounds that are insoluble or poorly soluble in benzene, and in which the Al component dissolved in benzene at 60°C is typically 10% or less, preferably 5% or less, and particularly preferably 2% or less, calculated as Al atoms.

[0104] Further, examples of the organoaluminum oxy compound (Q-2) include modified methylaluminoxanes represented by the following general formula [V].

[0105]

[0106] In formula [V], Rx represents a hydrocarbon group having 1 to 10 carbon atoms, and m and n each independently represent an integer of 2 or more.

[0107] Methylaluminoxane, an example of organoaluminum oxy compound (Q-2), is commonly used as an activator in olefin polymerization because it is readily available and has high polymerization activity. However, because methylaluminoxane is difficult to dissolve in saturated hydrocarbons, it has been used as a solution in environmentally undesirable aromatic hydrocarbons such as toluene or benzene. For this reason, flexible methylaluminoxanes represented by formula [V] have recently been developed and used as aluminoxanes dissolved in saturated hydrocarbons. This modified methylaluminoxane represented by formula [V] can be prepared using trimethylaluminum and alkylaluminums other than trimethylaluminum, such as trimethylaluminum and triisobutylaluminum, as described, for example, in U.S. Pat. Nos. 4,960,878 and 5,041,584. Aluminoxanes in which Rx is an isobutyl group are commercially available in the form of saturated hydrocarbon solutions under the trade names MMAO and TMAO (see Tosoh Finechem Corporation, Tosoh Research & Technology Review, Vol. 47, 55 (2003)).

[0108] Further, the organoaluminum oxy compound (Q-2) may also include boron-containing organoaluminum oxy compounds represented by the following general formula [VI]:

[0109]

[0110] In formula [VI], R c represents a hydrocarbon group having 1 to 10 carbon atoms. dmay be the same or different and represent a hydrogen atom, a halogen atom or a hydrocarbon group having 1 to 10 carbon atoms.

[0111] Examples of the compound (Q-3) that reacts with the bridged metallocene compound (P) to form an ion pair (hereinafter, sometimes abbreviated as "ionizing ionic compound (Q-3)") include Lewis acids, ionic compounds, borane compounds, and carborane compounds described in JP-A-1-501950, JP-A-1-502036, JP-A-3-179005, JP-A-3-179006, JP-A-3-207703, JP-A-3-207704, U.S. Pat. No. 5,321,106, and the like. Further examples include heteropoly compounds and isopoly compounds.

[0112] The ionizing ionic compound (Q-3) preferably used in the present invention is a boron compound represented by the following general formula [VII]:

[0113]

[0114] In formula [VII], R e+ As for H + , carbenium cation, oxonium cation, ammonium cation, phosphonium cation, cycloheptyltrienyl cation, ferrocenium cation having a transition metal, etc. f ~R i may be the same or different and are substituents selected from a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, a nitrogen-containing group, an oxygen-containing group, a halogen atom, and a halogen-containing group, and are preferably substituted aryl groups.

[0115] Specific examples of the carbenium cation include trisubstituted carbenium cations such as triphenylcarbenium cation, tris(4-methylphenyl)carbenium cation, and tris(3,5-dimethylphenyl)carbenium cation.

[0116] Specific examples of the ammonium cation include trialkyl-substituted ammonium cations such as trimethylammonium cation, triethylammonium cation, tri(n-propyl)ammonium cation, triisopropylammonium cation, tri(n-butyl)ammonium cation, and triisobutylammonium cation; N,N-dialkylanilinium cations such as N,N-dimethylanilinium cation, N,N-diethylanilinium cation, and N,N-2,4,6-pentamethylanilinium cation; and dialkylammonium cations such as diisopropylammonium cation and dicyclohexylammonium cation.

[0117] Specific examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tris(4-methylphenyl)phosphonium cation, and tris(3,5-dimethylphenyl)phosphonium cation.

[0118] R e+ Of the above specific examples, carbenium cations and ammonium cations are preferred, with triphenylcarbenium cation, N,N-dimethylanilinium cation and N,N-diethylanilinium cation being particularly preferred.

[0119] Among the ionizable ionic compounds (Q-3) preferably used in the present invention, examples of compounds containing a carbenium cation include triphenylcarbenium tetraphenylborate, triphenylcarbenium tetrakis(pentafluorophenyl)borate, triphenylcarbenium tetrakis{3,5-di-(trifluoromethyl)phenyl}borate, tris(4-methylphenyl)carbenium tetrakis(pentafluorophenyl)borate, and tris(3,5-dimethylphenyl)carbenium tetrakis(pentafluorophenyl)borate.

[0120] Among the ionizing ionic compounds (Q-3) preferably used in the present invention, compounds containing a trialkyl-substituted ammonium cation include triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, trimethylammonium tetrakis(4-methylphenyl)borate, trimethylammonium tetrakis(2-methylphenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(2,4-dimethylphenyl)borate, tri(n-butyl)ammonium tetrakis(3,5-dimethylphenyl)borate, and tri(n-butyl)ammonium tetrakis{4-(trifluoromethyl)phenyl}borate. , tri(n-butyl)ammonium tetrakis{3,5-di(trifluoromethyl)phenyl}borate, tri(n-butyl)ammonium tetrakis(2-methylphenyl)borate, dioctadecylmethylammonium tetraphenylborate, dioctadecylmethylammonium tetrakis(4-methylphenyl)borate, dioctadecylmethylammonium tetrakis(4-methylphenyl)borate, dioctadecylmethylammonium tetrakis(pentafluorophenyl)borate, dioctadecylmethylammonium tetrakis(2,4-dimethylphenyl)borate, dioctadecylmethylammonium tetrakis(3,5-dimethylphenyl)borate, dioctadecylmethylammonium tetrakis{4-(trifluoromethyl)phenyl}borate, dioctadecylmethylammonium tetrakis{3,5-di(trifluoromethyl)phenyl}borate, dioctadecylmethylammonium and the like can be exemplified.

[0121] Among the ionized ionic compounds (Q-3) preferably used in the present invention, examples of compounds containing an N,N-dialkylanilinium cation include N,N-dimethylanilinium tetraphenylborate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis{3,5-di(trifluoromethyl)phenyl}borate, N,N-diethylanilinium tetraphenylborate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diethylanilinium tetrakis{3,5-di(trifluoromethyl)phenyl}borate, N,N-2,4,6-pentamethylanilinium tetraphenylborate, and N,N-2,4,6-pentamethylanilinium tetrakis(pentafluorophenyl)borate.

[0122] Among the ionized ionic compounds (Q-3) preferably used in the present invention, examples of compounds containing a dialkylammonium cation include di-n-propylammonium tetrakis(pentafluorophenyl)borate and dicyclohexylammonium tetraphenylborate.

[0123] In addition, the ionizing ionic compounds exemplified in JP-A-2004-51676 can also be used without limitation. The ionizing ionic compound (Q-3) may be used alone or in combination of two or more.

[0124] Examples of the catalyst system include the following [1] to [4]: ​​[1] Comprising a bridged metallocene compound (P) and a compound (Q-2): [2] Comprising a bridged metallocene compound (P), a compound (Q-1), and a compound (Q-2): [3] Comprising a bridged metallocene compound (P), a compound (Q-1), and a compound (Q-3): [4] Comprising a bridged metallocene compound (P), a compound (Q-2), and a compound (Q-3): The bridged metallocene compound (P) and the compounds (Q-1) to (Q-3) may be introduced into the reaction system in any order.

[0125] [Support (R)] In the present invention, a support (R) may be used as a constituent component of the olefin polymerization catalyst, if necessary. The support (R) that may be used in the present invention is an inorganic or organic compound, and is a granular or fine particle solid. Among these, the inorganic compound is preferably a porous oxide, an inorganic chloride, a clay, a clay mineral, or an ion-exchangeable layered compound.

[0126] Specific examples of porous oxides that can be used include SiO2, Al2O3, MgO, ZrO, TiO2, BO3, CaO, ZnO, BaO, and ThO2, as well as composites or mixtures containing these, such as natural or synthetic zeolites, SiO2-MgO, SiO2-Al2O3, SiO2-TiO2, SiO2-VO5, SiO2-Cr2O3, and SiO2-TiO2-MgO. Of these, those containing SiO2 and / or Al2O3 as the main component are preferred. While the properties of such porous oxides vary depending on the type and production method, the carriers preferably used in the present invention have a particle size of 0.5 to 300 μm, preferably 1.0 to 200 μm, and a specific surface area of ​​50 to 1,000 m. 2 / g, preferably 100 to 700 m 2 / g, and the pore volume is in the range of 0.3 to 3.0 cm 3 Such a support is calcined at 100 to 1000°C, preferably 150 to 700°C, if necessary, before use.

[0127] Examples of inorganic chlorides that can be used include MgCl, MgBr, MnCl, and MnBr. The inorganic chlorides may be used as they are or may be pulverized using a ball mill or a vibration mill. Alternatively, the inorganic chlorides may be dissolved in a solvent such as alcohol and then precipitated into fine particles using a precipitating agent.

[0128] Clay is usually composed mainly of clay minerals. Ion-exchangeable layered compounds are compounds with a crystalline structure in which the constituent planes are stacked parallel to each other with weak bonding forces due to ionic bonds or the like, and the ions contained therein are exchangeable. Most clay minerals are ion-exchangeable layered compounds. These clays, clay minerals, and ion-exchangeable layered compounds are not limited to natural products, and artificial synthetic products can also be used. Examples of clays, clay minerals, and ion-exchangeable layered compounds include clays, clay minerals, and ionic crystalline compounds having layered crystalline structures such as hexagonal close packing type, antimony type, CdCl type, and CdI type. Examples of such clays and clay minerals include kaolin, bentonite, kibushi clay, gairome clay, allophane, hisingerite, pyrophyllite, ummo group, montmorillonite group, vermiculite, ryokudeite group, palygorskite, kaolinite, nacrite, dickite, and halloysite. Examples of ion-exchange layered compounds include crystalline acid salts of polyvalent metals such as α-Zr(HAsO)H0, α-Zr(HPO), α-Zr(KPO3H0, α-Ti(HPO), α-Ti(HAsO)H0, α-Sn(HPO), H0, γ-Zr(HPO), γ-Ti(HPO), and γ-Ti(NHPO). It is also preferable to subject the clay and clay minerals used in the present invention to chemical treatment. Examples of chemical treatment include surface treatment to remove impurities adhering to the surface and treatment to affect the crystalline structure of the clay. Specific examples of chemical treatment include acid treatment, alkali treatment, salt treatment, and organic treatment.

[0129] The ion-exchangeable layered compound may be a layered compound in which the interlayer spacing is expanded by utilizing the ion exchange property and exchanging the exchangeable ions between the layers with other large, bulky ions. Such bulky ions act as supports supporting the layered structure and are usually called pillars. The introduction of another substance (guest compound) between the layers of a layered compound is called intercalation. Examples of guest compounds include cationic inorganic compounds such as TiCl4 and ZrCl4, metal alkoxides such as Ti(OR)4, Zr(OR)4, PO(OR)3, and B(OR)3 (where R is a hydrocarbon group, etc.), and [Al 13 O4 (OH) 24 ] 7+ , [Zr(OH) 14 ] 2+ , [Fe3O(OCOCH3)6] + Examples of the metal hydroxide ions include those mentioned above. These compounds can be used singly or in combination of two or more. When intercalating these compounds, polymers obtained by hydrolysis and polycondensation of metal alkoxides (R is a hydrocarbon group, for example) such as Si(OR)4, Al(OR)3, and Ge(OR)4, colloidal inorganic compounds such as SiO2, and the like can also be present. Examples of the pillars include oxides produced by intercalating the metal hydroxide ions between layers and then dehydrating them with heat.

[0130] Among these, clay or clay minerals are preferred, and montmorillonite, vermiculite, pectolite, taeniolite, and synthetic mica are particularly preferred. Examples of organic compounds usable as the carrier (R) include granular or particulate solids with particle sizes ranging from 0.5 to 300 μm. Specific examples include (co)polymers primarily composed of α-olefins having 2 to 14 carbon atoms, such as ethylene, propylene, 1-butene, and 4-methyl-1-pentene, or (co)polymers primarily composed of vinylcyclohexane and styrene, as well as modified products thereof.

[0131] The method of use and order of addition of each component of the polymerization catalyst can be selected arbitrarily. At least two or more of the components in the catalyst may be contacted in advance. The bridged metallocene compound (P) (hereinafter also referred to as "component (P)") is usually used in an amount of 1 x 10 per liter of reaction volume. -9 ~1 x 10 -1 mol, preferably 1×10 -8 ~1 x 10 -2 It is used in an amount that will give a mol.

[0132] The organometallic compound (Q-1) (hereinafter also referred to as "component (Q-1)") is used in an amount such that the molar ratio of component (Q-1) to the transition metal atom (M) in component (P) [(Q-1) / M] is generally 0.01 to 50,000, preferably 0.05 to 10,000.

[0133] The organoaluminum oxy compound (Q-2) (hereinafter also referred to as "component (Q-2)") is used in an amount such that the molar ratio of aluminum atoms in component (Q-2) to transition metal atoms (M) in component (P) [(Q-2) / M] is generally 10 to 5,000, preferably 20 to 2,000.

[0134] The ionizing ionic compound (Q-3) (hereinafter also referred to as "component (Q-3)") is used in an amount such that the molar ratio of component (Q-3) to the transition metal atom (M) in component (P) [(Q-3) / M] is generally 1 to 10,000, preferably 1 to 5,000.

[0135] The polymerization temperature is usually -50 to 300°C, preferably 30 to 250°C, more preferably 100 to 250°C, and even more preferably 130 to 200°C. Within this polymerization temperature range, as the temperature increases, the solution viscosity during polymerization decreases and the heat of polymerization is easily removed. The polymerization pressure is usually atmospheric pressure to 10 MPa gauge pressure (MPa-G), preferably atmospheric pressure to 8 MPa-G.

[0136] The polymerization reaction can be carried out in any of batch, semi-continuous, and continuous modes. Furthermore, the polymerization can be carried out continuously in two or more polymerization vessels with different reaction conditions. The molecular weight of the resulting copolymer can be adjusted by changing the hydrogen concentration in the polymerization system or the polymerization temperature. Furthermore, it can also be adjusted by the amount of component (Q) used. When hydrogen is added, the amount is suitably about 0.001 to 5,000 NL per kg of the copolymer produced.

[0137] The polymerization solvent used in the liquid-phase polymerization method is usually an inert hydrocarbon solvent, preferably a saturated hydrocarbon having a boiling point of 50 to 200°C under normal pressure. Specific examples of the polymerization solvent include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene, and alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane, with hexane, heptane, octane, decane, and cyclohexane being particularly preferred. The α-olefin to be polymerized itself can also be used as the polymerization solvent. Aromatic hydrocarbons such as benzene, toluene, and xylene, and halogenated hydrocarbons such as ethylene chloride, chlorobenzene, and dichloromethane can also be used as the polymerization solvent, but their use is not preferred from the standpoint of reducing the burden on the environment and minimizing the impact on human health.

[0138] The kinematic viscosity at 100°C of the ethylene-α-olefin copolymer (C) depends on the molecular weight of the polymer. That is, a high molecular weight results in a high viscosity, and a low molecular weight results in a low viscosity, and therefore the kinematic viscosity at 100°C is adjusted by adjusting the molecular weight as described above. In addition, the molecular weight distribution (Mw / Mn) of the obtained polymer can be adjusted by removing low molecular weight components from the obtained polymer by a conventionally known method such as vacuum distillation. Furthermore, the obtained polymer may be subjected to hydrogenation (hereinafter also referred to as hydrogenation) by a conventionally known method. If the double bonds of the obtained polymer are reduced by hydrogenation, the oxidation stability and heat resistance are improved.

[0139] The obtained ethylene-α-olefin copolymer (C) may be used alone, or two or more types having different molecular weights or different monomer compositions may be used in combination. When two or more types are used in combination, a mixing step for homogenization is usually added, which tends to deteriorate productivity, so it is preferable to use one type alone.

[0140] <Lubricating Oil Composition> The lubricating oil composition according to the present invention contains a lubricating base oil comprising the mineral oil (A) and / or synthetic oil (B) and the ethylene-α-olefin copolymer (C).

[0141] The lubricating oil composition according to the present invention contains 0.1 mass% or more but less than 30 mass% of an ethylene-α-olefin copolymer (C). The content of the ethylene-α-olefin copolymer (C) relative to 100 mass% of the lubricating oil composition is preferably 0.2 to 25 mass%, more preferably 0.25 to 20 mass%, and even more preferably 0.3 to 15 mass%. If the content of the ethylene-α-olefin copolymer (C) is less than 3 mass%, sufficient viscosity index improving ability cannot be obtained. If the content of the ethylene-α-olefin copolymer (C) is 30 mass% or more, fuel economy performance deteriorates.

[0142] From the viewpoint of providing excellent low-temperature properties, the lubricating oil composition according to the present invention preferably has a CCS viscosity (Cold Cranking Simulator viscosity) at −35° C. of not more than 4500, more preferably not more than 4000. If the CCS viscosity of the lubricating oil composition at −35° C. exceeds 4500, the lubricating oil composition will have poor low-temperature properties, which undesirably deteriorates engine startability and long-term component integrity.

[0143] In the lubricating oil composition of the present invention, the blending ratio of the lubricating base oil comprising the mineral oil (A) and / or synthetic oil (B) to the ethylene-α-olefin copolymer (C) is not particularly limited as long as the required properties for the intended application are satisfied, but typically, the mass ratio of the lubricating base oil to the ethylene-α-olefin copolymer (C) (mass of lubricating base oil / mass of copolymer (C)) is 99.7 / 0.3 to 50 / 50. In the low-viscosity lubricating oil composition (X), the preferred range of the mass ratio of the lubricating base oil to the ethylene-α-olefin copolymer (C) (mass of lubricating base oil / mass of copolymer (C)) is the same as the range described above in one preferred embodiment. In the ultra-low viscosity lubricating oil composition (Y), the mass ratio of the lubricating base oil to the ethylene-α-olefin copolymer (C) (mass of lubricating base oil / mass of copolymer (C)) is 99 / 1 to 50 / 50 in one preferred embodiment.

[0144] Furthermore, the lubricating oil composition of the present invention may contain additives such as detergent-dispersants, viscosity index improvers, antioxidants, corrosion inhibitors, anti-wear agents, friction modifiers, pour point depressants, rust inhibitors and anti-foaming agents, as needed, within the scope of the present invention.

[0145] Examples of additives that can be used in the lubricating oil composition of the present invention include the following, which can be used alone or in combination of two or more. Examples of detergent-dispersants include metal sulfonates, metal phenates, metal phosphanates, and succinimides. Alkali metal and alkaline earth metal salicylates, phenates, and sulfonate detergents are preferred in the lubricating oil composition of the present invention. Specific examples include calcium or magnesium sulfonates, phenates, salicylates, succinimides, and benzylamines. Detergent-dispersants can be used in an amount of 0 to 15 mass% based on 100 mass% of the lubricating oil composition, as needed. There are no particular restrictions on the base number of the detergent-dispersant, but it is preferable that it be less than 350 mgKOH / g.

[0146] As the viscosity index improver, in addition to the ethylene-α-olefin copolymer (excluding the ethylene-α-olefin copolymer (C)), known viscosity index improvers such as olefin copolymers, methacrylate copolymers, and liquid polybutene, each having a molecular weight of more than 50,000, can be used in combination. The viscosity index improver is used in the range of 0 to 50% by mass relative to 100% by mass of the lubricating oil composition, as needed.

[0147] Examples of antioxidants include phenolic compounds such as 2,6-di-t-butyl-4-methylphenol and amine compounds. The antioxidant is used in an amount of 0 to 3 mass % based on 100 mass % of the lubricating oil composition, as needed.

[0148] Examples of the corrosion inhibitor include compounds such as benzotriazole, benzimidazole, thiadiazole, etc. The corrosion inhibitor is used in an amount of 0 to 3 mass % based on 100 mass % of the lubricating oil composition, as required.

[0149] Examples of anti-wear agents include inorganic or organic molybdenum compounds such as molybdenum disulfide, graphite, antimony sulfide, polytetrafluoroethylene, etc. The anti-wear agent is used in an amount of 0 to 3 mass % based on 100 mass % of the lubricating oil composition, as needed.

[0150] Examples of friction modifiers include amine compounds, imide compounds, fatty acid esters, fatty acid amides, and fatty acid metal salts, each of which has at least one alkyl or alkenyl group having 6 to 30 carbon atoms, particularly at least one linear alkyl or alkenyl group having 6 to 30 carbon atoms, in the molecule.

[0151] Examples of amine compounds include linear or branched, preferably linear, aliphatic monoamines having 6 to 30 carbon atoms, linear or branched, preferably linear aliphatic polyamines, and alkylene oxide adducts of these aliphatic amines. Examples of imide compounds include succinimides having linear or branched alkyl or alkenyl groups having 6 to 30 carbon atoms and / or compounds thereof modified with carboxylic acid, boric acid, phosphoric acid, sulfuric acid, etc. Examples of fatty acid esters include esters of linear or branched, preferably linear, fatty acids having 7 to 31 carbon atoms and aliphatic monohydric alcohols or aliphatic polyhydric alcohols. Examples of fatty acid amides include amides of linear or branched, preferably linear, fatty acids having 7 to 31 carbon atoms and aliphatic monoamines or aliphatic polyamines. Examples of fatty acid metal salts include alkaline earth metal salts (magnesium salts, calcium salts, etc.) and zinc salts of straight-chain or branched, preferably straight-chain, fatty acids having 7 to 31 carbon atoms.

[0152] The friction modifier is used in an amount of 0 to 5.0 mass % based on 100 mass % of the lubricating oil composition, as needed. Various known pour point depressants can be used as the pour point depressant. Specifically, a polymer compound containing an organic acid ester group is used, and a vinyl polymer containing an organic acid ester group is particularly preferred. Examples of vinyl polymers containing an organic acid ester group include alkyl methacrylate (co)polymers, alkyl acrylate (co)polymers, alkyl fumarate (co)polymers, alkyl maleate (co)polymers, and alkylated naphthalene.

[0153] Such pour point depressants have a melting point of -13°C or lower, preferably -15°C or lower, and more preferably -17°C or lower. The melting point of the pour point depressant is measured using a differential scanning calorimeter (DSC). Specifically, about 5 mg of a sample is placed in an aluminum pan, heated to 200°C, held at 200°C for 5 minutes, cooled to -40°C at 10°C / min, held at -40°C for 5 minutes, and then heated at 10°C / min. The melting point is determined from the endothermic curve obtained when the temperature is increased at 10°C / min.

[0154] The pour point depressant further has a weight average molecular weight (Mw) in the range of 20,000 to 400,000, preferably 30,000 to 300,000, more preferably 40,000 to 200,000, as determined by gel permeation chromatography (GPC) in terms of polystyrene standards.

[0155] The pour point depressant is used as needed in an amount of 0 to 2 mass % relative to 100 mass % of the lubricating oil composition.

[0156] Examples of the rust inhibitor include various amine compounds, metal carboxylates, polyhydric alcohol esters, phosphorus compounds, sulfonates, etc. The rust inhibitor is used in an amount of 0 to 3 mass % based on 100 mass % of the lubricating oil composition, as needed.

[0157] Examples of antifoaming agents include silicone compounds such as dimethylsiloxane and silica gel dispersions, alcohol-based or ester-based compounds, etc. The antifoaming agent is used in an amount of 0 to 0.2% by mass relative to 100% by mass of the lubricating oil composition, as needed.

[0158] In addition to the above additives, demulsifiers, colorants, oiliness agents (oiliness improvers), etc. may be used as needed. For low viscosity lubricating oils or ultra-low viscosity lubricating oils, so-called DI packages are industrially supplied in which various necessary additives are blended for this purpose and concentrated and dissolved in lubricating oils such as mineral oils or synthetic hydrocarbon oils, and such DI packages can also be applied to the lubricating oil composition of the present invention.

[0159] <Uses> The lubricating oil composition of the present invention can be suitably used as an automobile engine oil, automobile gear oil, automobile transmission oil, industrial lubricant, hydraulic oil, etc., and because it has a low viscosity but a high viscosity index and high shear stability, it can be suitably used over a long period of time as a fuel-saving lubricant.

[0160] The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples in any way.

[0161] [Evaluation Methods] In the following examples and comparative examples, the physical properties of the ethylene-α-olefin copolymers and lubricating oil compositions were measured by the following methods.

[0162] <Ethylene content (mol %)> Using a Fourier transform infrared spectrophotometer FT / IR-610 or FT / IR-6100 manufactured by JASCO Corporation, the 721 cm -1 Absorption near 1155 cm due to skeletal vibration of propylene -1 The absorbance ratio (D1155 cm -1 / D721cm -1 The ethylene content (% by mass) was calculated from the calculated ethylene content (% by mass) and the ethylene content (% by mass) was calculated from a calibration curve prepared in advance (prepared using a standard sample according to ASTM D3900). Next, the ethylene content (% by mass) was calculated according to the following formula using the obtained ethylene content (% by mass).

[0163]

[0164] Using o-dichlorobenzene / benzene-d6 (4 / 1 [vol / vol%]) as the measurement solvent, the measurement was performed under the following conditions (100 MHz, JEOL ECX400P): measurement temperature 120°C, spectral width 250 ppm, pulse repetition time 5.5 seconds, and pulse width 4.7 μs (45° pulse); or under the following conditions (125 MHz, Bruker BioSpin AVANCEIII Cryo-500): measurement temperature 120°C, spectral width 250 ppm, pulse repetition time 5.5 seconds, and pulse width 5.0 μs (45° pulse). 13 The C-NMR spectrum was measured, and the B value was calculated based on the following formula [1].

[0165]

[0166] In formula [1], P E indicates the ethylene content (mol%), and P O indicates the α-olefin content (mol%), and P OE indicates the content (mol %) of ethylene-α-olefin chains in all dyad chains.

[0167] <Molecular Weight Distribution> The molecular weight distribution was measured using a Tosoh Corporation HLC-8320 GPC as follows. Four TSKgel SuperMultipore HZ-M columns were used as separation columns, the column temperature was 40°C, tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the mobile phase, the development rate was 0.35 ml / min, the sample concentration was 5.5 g / L, the sample injection volume was 20 μL, and a differential refractometer was used as the detector. Standard polystyrenes used were those manufactured by Tosoh Corporation (PStQuickMP-M). According to the general-purpose calibration procedure, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were calculated in terms of polystyrene molecular weight, and the molecular weight distribution (Mw / Mn) was calculated from these values.

[0168] <Amount of unsaturated bonds> Using o-dichlorobenzene-d4 as a measurement solvent, the measurement was carried out under the following measurement conditions: measurement temperature 120°C, spectrum width 20 ppm, pulse repetition time 7.0 seconds, and pulse width 6.15 μsec (45° pulse). 1 H-NMR spectra (400 MHz, JEOL ECX400P) were measured. The solvent peak (ortho-dichlorobenzene, 7.1 ppm) was used as the chemical shift reference, and the number of unsaturated bonds per 1000 carbon atoms (unsaturated bonds / 1000) was calculated from the ratio of the integrals of the main peak observed between 0 and 3 ppm and the peaks attributable to vinyl, vinylidene, disubstituted olefins, and trisubstituted olefins observed between 4 and 6 ppm.

[0169] <Melting Point (Tm)> Using a Seiko Instruments X-DSC-7000, approximately 8 mg of ethylene-α-olefin copolymer was placed in a sealable aluminum sample pan and placed in a DSC cell. The DSC cell was heated from room temperature to 150°C at a rate of 10°C / min under a nitrogen atmosphere, then held at 150°C for 5 minutes, and then cooled at a rate of 10°C / min to -100°C (cooling down process). The sample was then held at 100°C for 5 minutes and then heated at a rate of 10°C / min. The temperature at which the enthalpy curve obtained during the heating process showed a maximum was taken as the melting point (Tm), and the sum of the endotherms associated with melting was taken as the heat of fusion (ΔH). If no peak was observed or the heat of fusion (ΔH) was 1 J / g or less, the melting point (Tm) was deemed not to be observed. The melting point (Tm) and heat of fusion (ΔH) were determined in accordance with JIS K7121.

[0170] <Amount of Chlorine Contained> Using Thermo Fisher Scientific ICS-1600, an ethylene-α-olefin copolymer was placed in a sample boat and subjected to combustion decomposition in an Ar / O gas flow at a combustion furnace set temperature of 900° C. The gas generated at this time was absorbed in an absorption liquid and quantified by ion chromatography.

[0171] <Viscosity characteristics> Kinematic viscosity at 100°C (KV 100 ), kinematic viscosity at 40°C (KV 40 ) and viscosity index (VI) were measured and calculated according to the method described in JIS K2283.

[0172] <Cold Cranking Simulator (CCS) Viscosity> The CCS viscosity at -35°C was measured based on ASTM D2602. The CCS viscosity is used to evaluate the sliding properties (startability) of a crankshaft at low temperatures. The smaller the value, the better the low-temperature viscosity (low-temperature properties) of the lubricating oil.

[0173] <Shear Stability Index (SSI)> SSI was measured and calculated according to the method described in JPI-5S-29-88.

[0174] The ethylene-α-olefin copolymer (C) used in the examples and comparative examples was obtained by the following production example (production method).

[0175] [Production Example 1] Ethylene-α-olefin copolymer (C-1) 250 mL of heptane was charged into a 1 L glass polymerization vessel that had been thoroughly purged with nitrogen, and the temperature inside the system was raised to 50°C. After that, ethylene was continuously fed into the polymerization vessel at flow rates of 25 L / h, propylene at 75 L / h, and hydrogen at 100 L / h, and the mixture was stirred at a rotation speed of 600 rpm. Next, 0.2 mmol of triisobutylaluminum was charged into the polymerization vessel, followed by 0.688 mmol of MMAO and [diphenylmethylene (η 5 -cyclopentadienyl) (η 5 Polymerization was initiated by charging a mixture of 0.00230 mmol of ethylenediaminetetraacetic acid (2,7-di-t-butylfluorenyl)zirconium dichloride and 0.00230 mmol of ethylenediaminetetraacetic acid (2,7-di-t-butylfluorenyl)zirconium dichloride in toluene for at least 15 minutes into a polymerization vessel. Subsequently, continuous supply of ethylene, propylene, and hydrogen was continued, and polymerization was carried out for 15 minutes at 50°C. Polymerization was terminated by adding a small amount of isobutyl alcohol to the system, and then unreacted ethylene, propylene, and hydrogen were purged. The resulting polymerization solution was washed three times with 1000 mL of 0.2 mol / L hydrochloric acid and then three times with 1000 mL of distilled water. After drying over magnesium sulfate, the solvent was removed by distillation under reduced pressure to obtain a crude ethylene-propylene copolymer.

[0176] A 1 L stainless steel autoclave was charged with 100 mL of a hexane solution of 0.5 mass % Pd / alumina catalyst and 500 mL of a 30 mass % hexane solution of the obtained crude ethylene-α-olefin copolymer, and the autoclave was sealed and then purged with nitrogen. The temperature was then raised to 140°C with stirring, and the system was purged with hydrogen. The pressure was then increased to 1.5 MPa with hydrogen, and a hydrogenation reaction was carried out for 15 minutes. The reaction solution was filtered to remove the hydrogenation catalyst, and the solvent was distilled off under reduced pressure. The mixture was then dried under reduced pressure at 80°C for 24 hours to obtain ethylene-α-olefin copolymer (C-1), which is an ethylene-propylene copolymer.

[0177] The resulting ethylene-α-olefin copolymer (C-1) had a weight average molecular weight (Mw): 13,000, a molecular weight distribution (Mw / Mn): 2.0, and a kinematic viscosity (KV 100 ): 2,100 mm 2 / s, ethylene content: 53 mol %, B value: 1.2, unsaturated bond amount: less than 0.1 per 1000 carbon atoms, and no melting point was observed.

[0178] [Production Example 2] Ethylene-α-olefin copolymer (C-2) 250 mL of heptane was charged into a 1 L glass polymerization vessel that had been thoroughly purged with nitrogen, and the temperature inside the system was raised to 50°C. After that, ethylene was continuously fed into the polymerization vessel at flow rates of 25 L / h, propylene at 75 L / h, and hydrogen at 100 L / h, and the mixture was stirred at a rotation speed of 600 rpm. Next, 0.2 mmol of triisobutylaluminum was charged into the polymerization vessel, followed by 0.688 mmol of MMAO and [methylphenylmethylene (η 5 -cyclopentadienyl) (η 5 Polymerization was initiated by charging a mixture of 0.00230 mmol of ethylenediaminetetraacetic acid (2,7-di-t-butylfluorenyl)zirconium dichloride and 0.00230 mmol of ethylenediaminetetraacetic acid (2,7-di-t-butylfluorenyl)zirconium dichloride in toluene for at least 15 minutes into a polymerization vessel. Subsequently, continuous supply of ethylene, propylene, and hydrogen was continued, and polymerization was carried out for 15 minutes at 50°C. Polymerization was terminated by adding a small amount of isobutyl alcohol to the system, and then unreacted ethylene, propylene, and hydrogen were purged. The resulting polymerization solution was washed three times with 1000 mL of 0.2 mol / L hydrochloric acid and then three times with 1000 mL of distilled water. After drying over magnesium sulfate, the solvent was removed by distillation under reduced pressure to obtain a crude ethylene-propylene copolymer.

[0179] A 1 L stainless steel autoclave was charged with 100 mL of a 0.5 mass % Pd / alumina catalyst hexane solution and 500 mL of a 30 mass % hexane solution of the obtained crude ethylene-α-olefin copolymer, and the autoclave was sealed and then purged with nitrogen. The temperature was then raised to 140°C with stirring, and the system was purged with hydrogen. The pressure was then increased to 1.5 MPa with hydrogen, and a hydrogenation reaction was carried out for 15 minutes. The reaction solution was filtered to remove the hydrogenation catalyst, and the solvent was distilled off under reduced pressure. The mixture was then dried under reduced pressure at 80°C for 24 hours to obtain ethylene-α-olefin copolymer (C-2), which is an ethylene-propylene copolymer.

[0180] The resulting ethylene-α-olefin copolymer (C-2) had a weight average molecular weight (Mw): 12,600, a molecular weight distribution (Mw / Mn): 1.9, and a kinematic viscosity (KV 100 ): 2,000 mm 2 / s, ethylene content: 53 mol %, B value: 1.3, unsaturated bond amount: 0.3 per 1000 carbon atoms, and no melting point was observed.

[0181] [Production Example 3] Ethylene-α-olefin copolymer (C-3) 910 mL of heptane and 45 g of propylene were charged into a 2 L stainless steel autoclave that had been thoroughly purged with nitrogen, and the temperature inside the system was raised to 130°C. After that, 2.24 MPa of hydrogen and 0.09 MPa of ethylene were fed to adjust the total pressure to 3 MPaG. Next, 0.4 mmol of triisobutylaluminum, [diphenylmethylene (η 5 -cyclopentadienyl) (η 5 0.0006 mmol of N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate (2,7-di-t-butylfluorenyl)zirconium dichloride and 0.006 mmol of N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate were injected with nitrogen, and polymerization was initiated by increasing the stirring speed to 400 rpm. Subsequently, the total pressure was maintained at 3 MPaG by continuously supplying only ethylene, and polymerization was carried out for 5 minutes at 130°C. After terminating the polymerization by adding a small amount of ethanol to the system, unreacted ethylene, propylene, and hydrogen were purged. The resulting polymerization solution was washed three times with 1000 mL of 0.2 mol / L hydrochloric acid and then three times with 1000 mL of distilled water. After drying over magnesium sulfate, the solvent was removed by distillation under reduced pressure to obtain a crude ethylene-propylene copolymer.

[0182] Into a 1 L stainless steel autoclave, 100 mL of a hexane solution of 0.5 mass% Pd / alumina catalyst (hydrogenation catalyst) and 500 mL of a 30 mass% hexane solution of the obtained crude ethylene-propylene copolymer were added, and the autoclave was sealed and then purged with nitrogen. Next, the temperature was raised to 140 ° C with stirring, and the system was purged with hydrogen, and then the pressure was raised to 1.5 MPa with hydrogen and a hydrogenation reaction was carried out for 15 minutes. After filtering the reaction solution to remove the hydrogenation catalyst, the solvent was distilled off under reduced pressure and dried at 80 ° C under reduced pressure for 24 hours. Furthermore, using a Kobe Steel Pantec 2-03 thin film distillation apparatus, the degree of vacuum was maintained at 400 Pa, and thin film distillation was carried out at a set temperature of 180 ° C and a flow rate of 3.1 mL / min to obtain an ethylene-α-olefin copolymer (C-3).

[0183] The resulting ethylene-α-olefin copolymer (C-3) had a weight average molecular weight (Mw): 2,700, a molecular weight distribution (Mw / Mn): 1.5, and a kinematic viscosity (KV 100 ): 40mm 2 / s, ethylene content: 51 mol %, B value: 1.2, unsaturated bond amount: less than 0.1 per 1000 carbon atoms, and no melting point was observed.

[0184] [Production Example 4] Ethylene-α-olefin copolymer (C-4) 910 mL of heptane and 45 g of propylene were charged into a 2 L stainless steel autoclave that had been thoroughly purged with nitrogen, and the temperature inside the system was raised to 130°C. After that, 2.24 MPa of hydrogen and 0.09 MPa of ethylene were fed to adjust the total pressure to 3 MPaG. Next, 0.4 mmol of triisobutylaluminum, [methylphenylmethylene (η 5 -cyclopentadienyl) (η 50.0006 mmol of N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate (2,7-di-t-butylfluorenyl)zirconium dichloride and 0.006 mmol of N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate were injected with nitrogen, and polymerization was initiated by increasing the stirring speed to 400 rpm. Subsequently, the total pressure was maintained at 3 MPaG by continuously supplying only ethylene, and polymerization was carried out for 5 minutes at 130°C. After terminating the polymerization by adding a small amount of ethanol to the system, unreacted ethylene, propylene, and hydrogen were purged. The resulting polymerization solution was washed three times with 1000 mL of 0.2 mol / L hydrochloric acid and then three times with 1000 mL of distilled water. After drying over magnesium sulfate, the solvent was removed by distillation under reduced pressure to obtain a crude ethylene-propylene copolymer.

[0185] Into a 1 L stainless steel autoclave, 100 mL of a hexane solution of 0.5 mass% Pd / alumina catalyst (hydrogenation catalyst) and 500 mL of a 30 mass% hexane solution of the obtained crude ethylene-propylene copolymer were added, and the autoclave was sealed and then nitrogen substitution was performed. Next, the temperature was raised to 140 ° C with stirring, and the system was purged with hydrogen, and then the pressure was increased to 1.5 MPa with hydrogen and a hydrogenation reaction was carried out for 15 minutes. After filtering the reaction solution to remove the hydrogenation catalyst, the solvent was distilled off under reduced pressure and dried at 80 ° C under reduced pressure for 24 hours. Furthermore, using a Kobe Steel Pantec 2-03 thin film distillation apparatus, the degree of vacuum was maintained at 400 Pa, and thin film distillation was performed at a set temperature of 180 ° C and a flow rate of 3.1 mL / min to obtain an ethylene-α-olefin copolymer (C-4).

[0186] The resulting ethylene-α-olefin copolymer (C-4) had a weight average molecular weight (Mw): 2,800, a molecular weight distribution (Mw / Mn): 1.6, and a kinematic viscosity (KV 100 ): 40mm 2 / s, ethylene content: 52 mol %, B value: 1.3, unsaturated bond amount: 0.3 per 1000 carbon atoms, and no melting point was observed.

[0187] Production Example 5 Ethylene-α-olefin copolymer (C-5) 500 ml of xylene was placed in a 1.0 L glass reactor that had been thoroughly purged with nitrogen. The temperature was then raised to 90°C, and while stirring the inside of the polymerization reactor at 600 rpm, ethylene and propylene were continuously fed at rates of 99 L / hour and 36.0 L / hour, respectively, until the liquid phase and gas phase were saturated. While ethylene and propylene were continuously supplied, 6.0 mL (6.0 mmol) of a toluene solution of triisobutylaluminum (1.0 mol / L), 3.0 mL (0.030 mmol) of a toluene solution of dimethylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride (0.010 mol / L), and then 12.0 mL (0.120 mmol) of a toluene solution of triphenylcarbenium tetrakis(pentafluorophenyl)borate (0.010 mol / L) were added, and polymerization was carried out at normal pressure and 90°C for 40 minutes. The polymerization was terminated by adding a small amount of isobutanol. The resulting polymerization reaction solution was washed with dilute hydrochloric acid, and the organic layer obtained after separation was poured into a large amount of methanol to precipitate an ethylene-propylene copolymer. The precipitate was filtered and then dried under reduced pressure at 130°C for 10 hours to obtain an ethylene-propylene copolymer, ethylene-α-olefin copolymer (C-5).

[0188] The resulting ethylene-α-olefin copolymer (C-5) had a weight average molecular weight (Mw): 14,300, a molecular weight distribution (Mw / Mn): 2.1, an ethylene content: 55 mol%, a B value: 1.1, and an unsaturated bond content: 0.1 per 1000 carbon atoms, and no melting point was observed. 100 ) was measured according to the above method, but the viscosity was too high to be measured.

[0189]

[0190] [Preparation of Lubricating Oil Compositions] The components other than the ethylene-α-olefin copolymer (C) used in the preparation of the following lubricating oil compositions are as follows: Lubricating base oil: The following lubricating base oil was used as the synthetic oil (B). Synthetic oil (B-1): kinematic viscosity (KV 100 ) is 4.0 mm 2 / s, kinematic viscosity (KV 40 ) is 17.6 mm 2 / s, a viscosity index (VI) of 125, and a pour point of -60°C or less: Synthetic poly-α-olefin oil (Synfluid PAO4 manufactured by Chevron Phillips Chemical Company) Synthetic oil (B-2): kinematic viscosity (KV 100 ) is 5.9 mm 2 / s, kinematic viscosity (KV 40 ) is 30.9 mm 2 / s, a viscosity index (VI) of 136, and a pour point of -60°C or less: Synthetic poly-α-olefin oil (Synfluid PAO6 manufactured by Chevron Phillips Chemical Company) Synthetic oil (B-3): kinematic viscosity (KV 100 ) is 1.8 mm 2 / s, kinematic viscosity (KV 40 ) is 5.0 mm 2 / s, a synthetic poly-α-olefin oil with a pour point of -60°C or less (Synfluid PAO2 manufactured by Chevron Phillips Chemical Company) Additives (DI package): conventional engine oil additives for GF-5 including Ca and Mg overbased detergents, ashless dispersants, aminic and phenolic antioxidants, zinc dialkyldithiophosphates, friction modifiers, and antifoaming agents

[0191] <Lubricant composition> [Example X1] A lubricant composition was prepared by mixing synthetic oil (B-1), which is the synthetic oil (B), as the lubricant base oil and copolymer (C-1), which is the ethylene-α-olefin copolymer (C) obtained in Production Example 1, with a DI package in a conventional manner. The amounts of each component added and the physical properties of the resulting lubricant composition are shown in Table 3.

[0192] [Examples X2 to X8, Comparative Examples X1 to X3, Reference Example X1] Lubricating oil compositions were formulated and prepared in the same manner as in Example X1, except that the types and amounts of components were changed as shown in Table 3. The physical properties of the obtained lubricating oil compositions are as shown in Table 3.

[0193]

[0194] [Examples Y1 to Y4, Comparative Examples Y1 to Y2] Lubricating oil compositions were formulated and prepared in the same manner as in Example X1, except that the types and amounts of components were changed as shown in Table 4. The physical properties of the obtained lubricating oil compositions are as shown in Table 4.

[0195]

[0196] As shown in Tables 3 and 4, when Examples are compared with Comparative Examples, Examples have a high viscosity index and a low shear stability index. Furthermore, Examples are also excellent in low temperature properties.

Claims

1. A lubricating oil composition comprising a lubricating base oil and an ethylene-α-olefin copolymer (C) having the following characteristics (C1) to (C3), wherein the content of the ethylene-α-olefin copolymer (C) is 0.1 mass% or more but less than 30 mass% based on 100 mass% of the lubricating oil composition, and the kinematic viscosity of the lubricating oil composition at 100°C is 2.0 mm 2 / s or more 6.9 mm 2 / s, and the lubricating base oil is a mineral oil (A) having the following characteristics (A1) to (A3) and / or a synthetic oil (B) having the following characteristics (B1) to (B3). (A1) A lubricating oil composition having a kinematic viscosity at 100°C of 2 to 7 mm 2 (A2) The viscosity index is 95 or more. (A3) The pour point is -10°C or less. (B1) The kinematic viscosity at 100°C is 1 to 7 mm 2 (B2) The kinematic viscosity at 40°C is 4 to 40 mm 2 (B3) The pour point is -30°C or lower. (C1) The content of structural units (i) derived from ethylene is 30 to 80 mol%, and the content of structural units (ii) derived from an α-olefin having 3 to 20 carbon atoms is 70 to 20 mol% (provided that the total content of structural units (i) and (ii) is 100 mol%). (C2) The kinematic viscosity at 100°C is 10 to 5,000 mm 2 (C3) The number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 500 to 10,000, and the molecular weight distribution (Mw / Mn, Mw is the weight average molecular weight) is 2.5 or less.

2. The kinematic viscosity of the lubricating oil composition at 100°C is 4.0 mm 2 / s or more 6.9 mm 2 2. The lubricating oil composition of claim 1, wherein the .lambda. / s is less than 1.

0.

3. The kinematic viscosity of the lubricating oil composition at 100°C is 2.0 mm 2 / s or more 4.0mm 2 2. The lubricating oil composition of claim 1, wherein the .lambda. / s is less than 1.

0.

4. The lubricating oil composition according to claim 1, wherein the viscosity index of said mineral oil (A) is 105 or higher.

5. The lubricating oil composition according to claim 1, wherein the content of the structural units (i) derived from ethylene in the ethylene-α-olefin copolymer (C) is in the range of 40 to 70 mol %.

6. The ethylene-α-olefin copolymer (C) has a kinematic viscosity at 100°C of 15 to 2,500 mm 2 2. The lubricating oil composition of claim 1, wherein the % by weight of the lubricating oil is in the range of 1 / 2.

7. The lubricating oil composition according to claim 1, wherein the α-olefin of the ethylene-α-olefin copolymer (C) is propylene.

8. An automobile engine oil comprising the lubricating oil composition according to any one of claims 1 to 7.

9. An automotive gear oil comprising the lubricating oil composition of any one of claims 1 to 7.

10. An automobile transmission oil comprising the lubricating oil composition according to any one of claims 1 to 7.

11. An industrial lubricant comprising the lubricating oil composition according to any one of claims 1 to 7.

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