JP5452297B2 - Lubricating oil composition - Google Patents

Description

  The present invention relates to a lubricating oil composition containing an ethylene / α-olefin copolymer.

  Petroleum products generally have a so-called viscosity temperature dependency in which the viscosity changes greatly when the temperature changes. For example, it is preferable that the temperature dependence of the viscosity is small. Therefore, in the lubricating oil, for the purpose of reducing the temperature dependency of the viscosity, a certain polymer that is soluble in the lubricating oil base is used as the viscosity improving agent. In recent years, α-olefin polymers have been widely used as such viscosity improvers, but various improvements have been made to further improve the performance balance of lubricating oils. (Patent Document 1)

Viscosity index improvers such as those mentioned above are generally used to maintain an appropriate viscosity at high temperatures. Recently, as energy saving and resource saving are strongly considered as part of reducing the environmental impact, viscosity at low temperatures is particularly important. There is a need for a viscosity improver that suppresses the rise low (excellent in low temperature characteristics) and has excellent durability. In general lubricating oil applications, in order to obtain excellent low-temperature characteristics, it is effective to keep the polymer concentration as low as possible, and it is also advantageous in terms of economy. However, there is a problem that shear stability deteriorates when the molecular weight is increased. In industrial lubricating oil applications, particularly gear oil for wind power generation, higher-level low-temperature characteristics and shear stability are required, and quality that takes into account the balance between the two performances is required.

International publication WO00 / 34420

  On the other hand, as a lubricant base, mineral oil is classified into three stages of groups (I) to (III) according to API quality classification. Furthermore, poly-α-olefin (PAO) is group (IV) and others are group. Classified in (V). In various lubricating oil applications for automobiles, in order to respond to higher demanded performance and reduced environmental impact, Group (I) mineral oil, Group (II) and (III) mineral oil, The usage rate of synthetic oils such as α-olefins is increasing. On the other hand, in industrial lubricating oil applications, long life and high durability are required, and the group (III) mineral oil or poly-α-olefin is used. In particular, in recent years, gear oil for wind power generation is strongly required to have shear stability as a main parameter for durability. The shear stability required here is difficult to cope with with a conventional high molecular weight type viscosity modifier, and a relatively low molecular weight α-olefin polymer such as polybutene is used. However, depending on the application, there is room for improvement in the viscosity characteristics of polybutene, in particular, sufficient fluidity at low temperatures. In addition, in the gear oil for wind power generation, in addition to the conventional required characteristics, a high micropitting prevention performance is required. Micropitting is a fatigue process caused just before gear damage by cycles of excessive stress in the rolling elastohydrodynamic lubrication (EHL) region under high loads. As a result of intensive studies in such a situation, the present inventors have a specific viscosity, viscosity index, and pour point with an ethylene / α-olefin copolymer having a specific range of ethylene content, viscosity, and molecular weight distribution. The inventors have found that the above problems can be solved by combining more than one kind of synthetic oil and / or mineral oil with a base, and have completed the present invention.

  The problem to be solved by the present invention is to provide an industrial lubricating oil that has an excellent balance between low-temperature viscosity characteristics and shear stability and has high micropitting prevention performance.

30 to 90% by weight of the ethylene / α-olefin copolymer (A) having the following characteristics (A1) to (A3), and the synthetic oil (B) or (C1) having the characteristics (B1) to (B3) 10 to 70% by weight (provided that (A) + (B) + (C) = 100% by weight) of a lubricant base comprising at least one component selected from mineral oils (C) having the characteristics of (C3) Lubricating oil composition characterized by containing;
(A1) The ethylene content is in the range of 30 to 70 mol% (the total of the ethylene content and α-olefin content in the copolymer (A) is 100 mol%)
(A2) Kinematic viscosity at 100 ° C. is in the range of 30 to 350 mm ² / s (A3) Mw / Mn is 2.5 or less

(B1) The kinematic viscosity at 100 ° C. is ² to 20 mm ² / s (B2) The viscosity index is 130 or more (B3) The pour point is −30 ° C. or less.

(C1) The kinematic viscosity at 100 ° C. is ² to 10 mm ² / s (C2) The viscosity index is 120 or more (C3) The pour point is −10 ° C. or less.

  Since the lubricating oil composition of the present invention is excellent in low-temperature viscosity characteristics and shear stability, it is a lubricating oil composition that excels in energy saving and resource saving, and is preferably effective as an industrial lubricating oil, particularly a lubricating oil for wind power generation. It is.

Ethylene / α-olefin copolymer (A)
The ethylene / α-olefin copolymer (A) in the present invention comprises an ethylene / α-olefin copolymer having the following characteristics, and can suitably adjust the viscosity of the lubricating oil composition.

  The ethylene content of the ethylene / α-olefin copolymer (A) is usually in the range of 30 to 70 mol%. From the viewpoint of the balance between low temperature characteristics and heat resistance, it is preferably 40 to 70 mol%, more preferably 45 to 65 mol%.

The ethylene content of the ethylene / α-olefin copolymer (A) is measured by ¹³ C-NMR according to the method described in “Polymer Analysis Handbook” (published by Asakura Shoten, P163-170).

Further, as the α-olefin constituting the ethylene / α-olefin copolymer (A), propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, decene-1, unzesen- 1, C3-C20 α-olefins such as 1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1, eicosene-1 It can be illustrated. In the ethylene / α-olefin copolymer (A), one or more of these α-olefins may be contained. Among these α-olefins, 3 to 10 carbon atoms are preferable, and propylene is particularly preferable in terms of imparting good low-temperature viscosity characteristics, shear stability, and heat resistance to the lubricating oil composition.
Such an ethylene / α-olefin copolymer (A) has the following properties (A1), (A2), and (A3).

(A1) Ethylene content The ethylene content of the ethylene / α-olefin copolymer (B) is 30 to 70 mol%, preferably 40 to 70 mol%, more preferably 45 to 65 mol%. It is preferable.

(A2) Kinematic viscosity (100 ° C)
The kinematic viscosity at 100 ° C. of the ethylene / α-olefin copolymer (A) (hereinafter also referred to as “kinematic viscosity (100 ° C.)”) is 30 to 350 mm ² / s, preferably 40 to ²⁰⁰ mm ² / s. Especially preferably, it exists in the range of 50-150 mm < ² > / s.
The lubricating oil composition containing the ethylene / α-olefin copolymer (A) having a kinematic viscosity (100 ° C.) within the above range is excellent in the balance between shear stability, low temperature characteristics and micropitting prevention.

(A3) Molecular weight distribution (Mw / Mn)
In the ethylene / α-olefin copolymer (B), Mw / Mn (Mw: weight average molecular weight, Mn: number average molecular weight), which is an indicator of molecular weight distribution, is 2.5 or less, preferably 2.4 or less. Preferably it is in the range of 2.2. When the molecular weight distribution exceeds 2.5, the shear stability of the lubricating oil viscosity decreases.

For the ethylene / α-olefin copolymer according to the present invention, a catalyst comprising a transition metal compound such as vanadium, zirconium, or titanium, and an organic aluminum compound (organic aluminum oxy compound) and / or an ionized ionic compound can be used. Such an olefin polymerization catalyst is described, for example, in WO00 / 34420.

Lubricating oil base The lubricating oil base used in the present invention is generally used after a refining process such as dewaxing, and there are several grades depending on the refining method, and this grade is an API (American Petroleum Institute) classification. It is prescribed. Table 1 shows the characteristics of the lubricant bases classified into each group.

The poly α-olefin belonging to group (IV) in Table 1 is a hydrocarbon polymer obtained by polymerizing α-olefin having 8 or more carbon atoms as at least a raw material monomer, and is obtained, for example, by polymerizing decene-1. Examples include polydecene. Such an α-olefin oligomer can be produced by cationic polymerization, thermal polymerization, or radical polymerization using a Ziegler catalyst or a Lewis acid as a catalyst.
Examples of the lubricating oil base belonging to group (V) in Table 1 include alkylbenzenes, alkylnaphthalenes, ester oils and the like.
Alkylbenzenes and alkylnaphthalenes are usually mostly dialkylbenzene or dialkylnaphthalene having an alkyl chain length of 6 to 14 carbon atoms. Such alkylbenzenes or alkylnaphthalenes are Friedel of benzene or naphthalene and olefin. Produced by kraft alkylation reaction. The alkylated olefin used in the production of alkylbenzenes or alkylnaphthalenes may be a linear or branched olefin or a combination thereof. These production methods are described, for example, in US Pat. No. 3,909,432.
As ester oils, monoesters produced from monobasic acids and alcohols; diesters produced from dibasic acids and alcohols, or diols and monobasic acids or acid mixtures; diols, triols (eg trimethylolpropane) And polyol ester produced by reacting tetraol (for example, pentaerythritol), hexaol (for example, dipentaerythritol) and the like with a monobasic acid or an acid mixture. Examples of these esters include tridecyl pelargonate, di-2-ethylhexyl adipate, di-2-ethylhexyl azelate, trimethylolpropane triheptanoate, pentaerythritol tetraheptanoate, and the like.

  The synthetic oil (B) according to the present invention is a lubricant base belonging to the group (IV) or (V) of the API quality classification having the following characteristics (B1) to (B3), among which the group (IV) Poly α-olefins belonging to No. 5 are preferred, but may have a similar kinematic viscosity at a ratio of 20% by weight or less, and may contain synthetic oils such as polyol esters and diesters belonging to Group (V).

(B1) The kinematic viscosity at 100 ° C. is ² to 20 mm ² / s, preferably 4 to 10 mm ² / s (B2) The viscosity index is 120 or more, preferably 130 or more (B3) The pour point is − 30 ° C or lower, preferably -40 ° C or lower

The mineral oil (C) is a lubricant base having the following characteristics (C1) to (C3), and is a lubricant base classified in the API quality classification group (III).
Lubricating oil bases classified into the group (III) are lubricating oil bases having a high degree of purification by a hydrocracking method or the like and a high viscosity index.
(C1) The kinematic viscosity at 100 ° C. is ² to 10 mm ² / s, preferably 4 to 8 mm ² / s (C2) The viscosity index is 120 or more, preferably 125 or more (C3) The pour point is − 10 ° C or less, preferably -15 ° C or less

The lubricating oil base in the present invention comprises one or more components selected from synthetic oil (B) or mineral oil (C), and only one or two or more synthetic oils (B) may be used. However, only one or two or more mineral oils (C) may be used, and one or two or more synthetic oils (B) may be mixed with one or more mineral oils (C). Also good.
Moreover, each characteristic in the above is measured by the following method.
(B1, C1): Measured according to ASTM D445 (JIS K2283) (B2, C2): Measured according to ASTM D2270 (JIS K2283) (B3, C3): Measured according to ASTM D97 (JIS K2269)

Lubricating oil composition The lubricating oil composition of the present invention comprises 10 to 70% by weight of a lubricating oil base consisting of one or more components selected from the synthetic oil (B) or the mineral oil (C), and the ethylene. The α-olefin copolymer (A) is a composition containing 30 to 90% by weight (provided that (A) + (B) + (C) = 100% by weight). Preferably, the ethylene / α-olefin copolymer (A) is a composition containing 40 to 80% by weight, more preferably 40 to 70% by weight.
Such a lubricating oil composition has excellent shear stability and is excellent in that it contains a synthetic oil such as polyalphaolefin and / or a highly refined high viscosity index mineral oil as a lubricating oil base. It is characterized by low temperature characteristics and shear stability.
The lubricating oil composition of the present invention may contain additives such as pour point depressants, extreme pressure agents, friction modifiers, oiliness agents, antioxidants, antifoaming agents, rust inhibitors, and corrosion inhibitors as necessary. (A) + (B) + (C) = Generally 20 parts by weight or less can be blended with respect to 100 parts by weight. Among these additives, it is preferable to add an extreme pressure agent and a pour point depressant (particularly when the mineral oil (C) is contained in an amount of 20% by weight or more). It is more preferable to add 10 parts by weight or less with respect to (A) + (B) + (C) = 100 parts by weight.
Here, the additive used together as needed is demonstrated.

Pour point depressant Pour point depressant includes alkyl methacrylate polymer or copolymer, alkyl acrylate polymer or copolymer, alkyl fumarate polymer or copolymer, alkyl maleate polymer Or a copolymer, an alkyl aromatic compound, etc. can be mentioned. Among these, a polymethacrylate pour point depressant which is a pour point depressant containing a polymer or copolymer of an alkyl methacrylate is particularly preferable, and the alkyl group of the alkyl methacrylate preferably has 12 to 20 carbon atoms. The amount is preferably 0.05 to 2 parts by weight with respect to (A) + (B) + (C) = 100 parts by weight. These can obtain what is marketed as a pour point depressant. For example, commercially available brand names include 146, Include 136 manufactured by Sanyo Kasei Co., Ltd., LeBlanc 141 LeBlanc 171 manufactured by Toho Chemical Co., Ltd., and the like.

Examples of extreme pressure agents include sulfurized oils and fats, sulfurized olefins, sulfides, phosphate esters, phosphite esters, phosphate ester amine salts, and phosphite amine salts.

Examples of the friction modifier include organometallic friction modifiers represented by organic molybdenum compounds such as molybdenum dithiophosphate and molybdenum dithiocarbamate.
Moreover, as an oil-based agent, the fatty acid, fatty acid ester, higher alcohol, etc. which have a C8-C22 alkyl group are mentioned.

Specifically as antioxidants antioxidant, 2,6-di -t- butyl-4 phenolic antioxidants such as methylphenol; an amine type antioxidants such as dioctyl diphenylamine. Examples of the antifoaming agent include silicon-based antifoaming agents such as dimethylsiloxane and silica gel dispersion; alcohols and ester-based antifoaming agents.

Examples of the rust inhibitor include carboxylic acid, carboxylate, ester, and phosphoric acid. Examples of the corrosion inhibitor include benzotriazole and derivatives thereof, and thiazole compounds.
Examples of the corrosion inhibitor include benzotriazole, thiadiazole, and imidazole compounds.

    Since the lubricating oil composition of the present invention is particularly excellent in shear stability and low-temperature viscosity characteristics, it is effective as an industrial lubricating oil. Industrial lubricants include those having a viscosity range of ISO 220 to ISO 680, and are particularly effective as gear oils for wind power generation.

    EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, the various physical properties in an Example were measured as follows.

-Ethylene content Using a JEOL LA500 nuclear magnetic resonance apparatus, 120 in a mixed solvent of orthodichlorobenzene and benzene-d6 (orthodichlorobenzene / benzene-d6 = 3/1 to 4/1 (volume ratio)) The measurement was performed at 0 ° C., a pulse width of 45 ° pulse, and a pulse repetition time of 5.5 seconds.

・Kinematic viscosity (40 ℃, 100 ℃)
Measurements were made based on ASTM D 445. In this example, the viscosity of the blended oil was adjusted as follows based on each ISO classification.
ISO 220: Formulated and prepared so that the kinematic viscosity (40 ° C.) was 220 ± 22 mm 2 / s.
ISO 320: The composition was prepared so that the kinematic viscosity (40 ° C.) was 320 ± 32 mm 2 / s.
ISO 460: Formulated so that the kinematic viscosity (40 ° C.) was 460 ± 46 mm 2 / s.
・

・Molecular weight distribution (Mw / Mn)
GPC (gel permeation chromatography) was used and measured at 140 ° C. with an orthodichlorobenzene solvent.

・Low temperature viscosity (-30 ℃, -40 ℃)
Measurements were made based on ASTM D341 using a BF (Brookfield) viscometer.

・Shear stability (Viscosity reduction rate%)
A test was carried out using a KRL shear tester based on CEC-L-45 (CEC: a management mechanism for European automotive fuel and lubricant test methods) to evaluate the rate of decrease in viscosity at 40 ° C.
Shear stability is a measure of kinematic viscosity loss due to the copolymer component in the lubricating oil being sheared at the metal sliding portion and the molecular chain being broken.

-Micropitting failure load stage FVA-54 micropitting tester based on the standard of Fender is used to increase the load stepwise from stage 5 to 10, and the percentage of micropitting generation on the gear tooth surface for each load stage. The weight loss of the entire gear is also measured. (Rotation speed: 1500rpm, temperature: 90 ° C)
(Polymerization example 1)

Ethyl aluminum sesquichloride (Al (C2H5) 1.5 · Cl1.5) hexane adjusted to 96 mmol / L by adding 1 liter of dehydrated and purified hexane to a continuous polymerization reactor with a stirring blade with a capacity of 2 liters sufficiently purged with nitrogen After the solution was continuously supplied in an amount of 500 ml / h for 1 hour, a hexane solution of VO (OC2H5) Cl2 adjusted to 16 mmol / l as a catalyst was added in an amount of 500 ml / h and hexane in an amount of 500 ml / h. Continuously fed. On the other hand, from the upper part of the polymerization vessel, the polymerization solution was continuously extracted so that the polymerization solution in the polymerization vessel was always 1 liter. Next, ethylene gas was supplied in an amount of 27 L / h, propylene gas was supplied in an amount of 26 L / h, and hydrogen gas was supplied in an amount of 100 L / h using a bubbling tube. The copolymerization reaction was carried out at 35 ° C. by circulating a refrigerant through a jacket attached to the outside of the polymerization vessel.
When the reaction was performed under the above conditions, a polymerization solution containing an ethylene / propylene copolymer was obtained. The obtained polymerization solution was deashed with hydrochloric acid, poured into a large amount of methanol to precipitate an ethylene / propylene copolymer, and then dried under reduced pressure at 130 ° C. for 24 hours. Table 1 shows the properties of the obtained polymer.
(Polymerization example 2)

Polymerization was carried out in the same manner as in Polymerization Example 1 except that the amount of ethylene gas was 35 L / h, the amount of propylene gas was 35 L / h, and the amount of hydrogen gas charged was changed to 80 L / h. Table 1 shows the properties of the obtained polymer.
(Polymerization Example 3)

The same procedure as in Polymerization Example 1 was conducted except that the ethylene gas amount was 45 L / h, the poropylene gas amount was 45 L / h, and the hydrogen gas charge was changed to 80 L / h. Table 1 shows the properties of the obtained polymer.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 1 was 79.0% by weight, and the lubricant base was 100 ° C. kinematic viscosity classified as API group (IV). 10.7% by weight of poly-α-olefin (NESTBASE 2006 made by NESTE OIL) with a weight of 5.825mm2 / s, 10.3% by weight fatty acid ester DIDA (made by Daihachi Chemical Co., Ltd.) classified as API group (V) %, 280 parts by weight of extreme pressure agent HITEC307 (manufactured by AFTON) (with the total amount of ethylene / propylene copolymer (A) and lubricating oil base as 100 parts by weight) was adjusted to ISO 220 equivalent viscosity. Table 3 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 2 (instead of 79.0% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) is 55. The composition was adjusted in the same manner as in Example 1 except that 14.6% by weight of a poly-α-olefin (NEXBASE 2006) was used as a lubricating oil base (instead of 10.7% by weight). Table 3 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 3 (instead of 79.0% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was 47. The composition was adjusted in the same manner as in Example 1 except that 22.5% by weight of poly.alpha olefin (NEXBASE 2006) was used as a lubricant base (42.5% by weight) (instead of 10.7% by weight). Table 3 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 2 (instead of 79.0% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was obtained in 64. 7% by weight, as a lubricant base, blended in the same manner as in Example 1 except that 25.0% by weight (instead of 10.7% by weight) of poly-α-olefin (NEXBASE 2006) was used to achieve an ISO 320 equivalent viscosity. It was adjusted. Table 3 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 3 (instead of 79.0% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) is 55. The composition was adjusted in the same manner as in Example 3 except that 5% by weight of a poly-α-olefin (NEXBASE 2006) was used as a lubricating oil base, 34.2% by weight (instead of 10.7% by weight). Table 3 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 2 (in place of 79.0% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) is 75. 7% by weight, and as a lubricant base, blended in the same manner as in Example 1 except that 14.0% by weight (instead of 10.7% by weight) of poly-α-olefin (NEXBASE 2006) was used to achieve an ISO 460 equivalent viscosity. It was adjusted. Table 3 shows the lubricating oil physical properties of the blended oil.

As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 3 (instead of 79.0% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was used. 9% by weight, blended in the same manner as in Example 1 except that 24.8% by weight (instead of 10.7% by weight) of poly-α-olefin (NEXBASE 2006) was used as the lubricating oil base to achieve an ISO 460 equivalent viscosity. It was adjusted. Table 3 shows the lubricating oil physical properties of the blended oil.

（比較例１）

(Comparative Example 1)

76.0% by weight of commercially available liquid polybutene 15R, as a lubricant base, 15.7% by weight of poly-α-olefin (NEXBASE 2006) classified as API group (IV), classified as API group (V) The viscosity was adjusted to an ISO 220 equivalent viscosity by using 10.3% by weight of fatty acid ester DIDA (diisodecyl adipate) and 2.8 parts by weight of extreme pressure agent HITEC 307 (the total amount thereof being 100 parts by weight). Table 4 shows the lubricating oil physical properties of the blended oil.
(Comparative Example 2)

Except for using 61.9% by weight of commercially available liquid polybutene 35R (instead of 76.0% by weight of polybutene 15R) and 27.8% by weight of poly-α-olefin (NEXBASE 2006) (instead of 13.7% by weight). The formulation was adjusted in the same manner as in Comparative Example 1. Table 4 shows the lubricating oil physical properties of the blended oil.
(Comparative Example 3)

Comparison except that commercial liquid polybutene 15R was used (instead of 76.0% by weight) 83.6% by weight and poly-alpha olefin (NEXBASE 2006) (instead of 13.7% by weight) 6.1% by weight. It mix | blended like Example 1 and adjusted to the viscosity equivalent to ISO320. Table 4 shows the lubricating oil physical properties of the blended oil.
(Comparative Example 4)

Other than using commercially available liquid polybutene 35R (instead of polybutene 15R76.0 wt%) 68.3 wt% and poly-alpha olefin (NEXBASE 2006) (instead of 13.7 wt%) 21.4 wt% It mixed and adjusted like the comparative example 3. Table 4 shows the lubricating oil physical properties of the blended oil.
(Comparative Example 5)

Commercial olefin copolymer viscosity modifier M-1010 (instead of polybutene 15R76.0% by weight) 28.3% by weight, poly alpha olefin (NEXBASE 2006) (instead of 13.7% by weight) 61. The formulation was adjusted in the same manner as in Comparative Example 3 except that 4% by weight was used. Table 4 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), 69.6% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1, and as a lubricating oil base, a mineral oil YUBASE- classified as an API group (III). 6 is 30.4% by weight, (the total amount of the ethylene / propylene copolymer (A) and the lubricating oil base is 100 parts by weight) 2.8 parts by weight of the extreme pressure agent HITEC307 (the ethylene / propylene copolymer ( The total amount of A) and the lubricant base was 100 parts by weight) and the blending was adjusted to ISO 220 equivalent viscosity using 0.5 parts by weight of the pour point depressant include 146 Table 5 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 2 (instead of 69.6% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was 48 The composition was adjusted in the same manner as in Example 8 except that 51.4% by weight (instead of 30.4% by weight) of mineral oil YUBASE-6 was used as a lubricant base. Table 5 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 3 (instead of 69.6% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was used. The composition was adjusted in the same manner as in Example 8 except that 58.5% by weight (instead of 30.4% by weight) of mineral oil YUBASE-6 was used as a lubricant base. Table 5 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 2 (instead of 69.6% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was 59. .5 wt% As a lubricant base, mineral oil YUBASE-6 was blended in the same manner as in Example 8 except that 40.5 wt% (instead of 30.4 wt%) was used, and adjusted to an ISO 320 equivalent viscosity. . Table 5 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), 50% of the ethylene / propylene copolymer obtained in Polymerization Example 3 (instead of 69.6% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was used. The composition was adjusted in the same manner as in Example 8 except that 49.4% by weight (instead of 30.4% by weight) of mineral oil YUBASE-6 was used as a lubricant base. Table 5 shows the lubricating oil physical properties of the blended oil.

  As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 2 (instead of 69.6% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was 68. .8 wt% As a lubricating oil base, the mineral oil YUBASE-6 was blended in the same manner as in Example 8 except that 31.2 wt% (instead of 30.4 wt%) was used, and adjusted to an ISO 460 equivalent viscosity. . Table 5 shows the lubricating oil physical properties of the blended oil.

As the ethylene / propylene copolymer (A), the ethylene / propylene copolymer obtained in Polymerization Example 3 (instead of 69.6% by weight of the ethylene / propylene copolymer obtained in Polymerization Example 1) was 58 The composition was adjusted in the same manner as in Example 8, except that 41.3% by weight (instead of 30.4% by weight) of mineral oil YUBASE-6 was used as a lubricant base. Table 5 shows the lubricating oil physical properties of the blended oil.

（比較例６）

(Comparative Example 6)

Commercial liquid polybutene 15R 68.1% by weight, lubricant base, mineral oil YUBASE-6 classified as API group (III) 31.9% by weight, (total amount of these as 100 parts by weight) extreme pressure The viscosity was adjusted to an ISO 220 equivalent viscosity using 2.8 parts by weight of the agent HITEC307 and 0.5 parts by weight of the pour point depressant include 146 (assuming the total amount of these was 100 parts by weight). Table 6 shows the properties of the lubricating oil.
(Comparative Example 7)

Comparison except that 55.2% by weight of commercially available liquid polybutene 35R (instead of 68.1% by weight of polybutene 15R) and 44.8% by weight of mineral oil YUBASE-6 (instead of 31.9% by weight) were used. The formulation was adjusted in the same manner as in Example 6. Table 6 shows the properties of the lubricating oil.
(Comparative Example 8)

Comparative Example 6 with the exception that 75.0% by weight of commercially available liquid polybutene 15R (instead of 68.1% by weight) and 25.0% by weight of mineral oil YUBASE-6 (instead of 31.9% by weight) were used. In the same manner, the viscosity was adjusted to an ISO 320 equivalent viscosity. Table 6 shows the properties of the lubricating oil.
(Comparative Example 9)

Comparison except that commercially available liquid polybutene 35R was used (60.3% by weight of polybutene 15R instead of 68.1% by weight) and 39.7% by weight of mineral oil YUBASE-6 (instead of 31.9% by weight). Blended and adjusted as in Example 3. Table 6 shows the properties of the lubricating oil.
(Comparative Example 10)

  Comparative Example 6 with the exception that 89.8% by weight of commercial liquid polybutene 15R (instead of 68.1% by weight) and 10.2% by weight of mineral oil YUBASE-6 (instead of 31.9% by weight) were used. It mixed and adjusted similarly. Table 6 shows the properties of the lubricating oil.

(Comparative Example 11)

  Comparison except that 72.7% by weight of commercially available liquid polybutene 35R (instead of 68.1% by weight of polybutene 15R) and 27.3% by weight of mineral oil YUBASE-6 (instead of 31.9% by weight) were used. It was blended and adjusted in the same manner as in Example 6. Table 6 shows the properties of the lubricating oil.

As shown in Tables 3 to 6, the lubricating oil composition of the present invention containing a specific ethylene / α-olefin copolymer and a specific lubricating oil base is a lubricating oil as a similar hydrocarbon polymer. Compared to polybutene used in applications, it is overwhelmingly superior in terms of low-temperature characteristics. Furthermore, compared with a high molecular weight type viscosity modifier such as an olefin copolymer system widely used in various lubricating oil applications, it is particularly excellent in terms of shear stability.
For this reason, the lubricating oil composition of the present invention is particularly suitable for use in gear oil for wind power generation in which a balance between low-temperature viscosity characteristics and shear stability is particularly required, among industrial lubricating oil applications. In this application, the lubricating oil composition of the present invention can achieve both energy saving and durability.

Since the lubricating oil composition of the present invention is excellent in low-temperature viscosity characteristics and shear stability, it is a lubricating oil composition that is excellent in energy saving and resource saving, and is preferably effective as an industrial lubricating oil, especially a lubricating oil for wind power generation. It is.

Claims (6)

30 to 90% by weight of the ethylene / α-olefin copolymer (A) having the following characteristics (A1) to (A3), and the synthetic oil (B) or (C1) having the characteristics (B1) to (B3) 10 to 70% by weight of a lubricant base composed of one or more components selected from mineral oil (C) having the characteristics of (C3) (provided that (A) + (B) + (C) = 100% A lubricating oil composition characterized by comprising:
(A1) The ethylene content is in the range of 30 to 70 mol% (the total of the ethylene content and α-olefin content in the copolymer (A) is 100 mol%)
(A2) Kinematic viscosity at 100 ° C is in the range of 30 to 350 mm2 / s. (A3) Mw / Mn is 2.5 or less.

(B1) The kinematic viscosity at 100 ° C. is ² to 20 mm ² / s (B2) The viscosity index is 130 or more (B3) The pour point is −30 ° C. or less.

(C1) The kinematic viscosity at 100 ° C. is ² to 10 mm ² / s (C2) The viscosity index is 120 or more (C3) The pour point is −10 ° C. or less.
    The lubricating oil composition according to claim 1, wherein the copolymer (A) is a copolymer composed of ethylene and an α-olefin having 3 to 10 carbon atoms.     The lubricating oil composition according to claim 1, wherein the synthetic oil (B) is a lubricating oil base selected from poly-α-olefin (PAO) or ester oil.     The lubricating oil composition according to any one of claims 1 to 3, further comprising a pour point depressant in the lubricating oil composition. The lubricating oil composition according to any one of claims 1 to 4, wherein the lubricating oil composition has a viscosity at 40 ° C in a range of 190 to 750 mm ² / s. The industrial lubricating oil composition according to any one of claims 1 to 5, wherein the lubricating oil composition is a gear oil composition for wind power generation.