Lubricating oil composition

Abstract

To provide a lubricant composition excellent in wear resistance.MEANS FOR SOLVING THE PROBLEM: A lubricant composition comprises a base oil, wherein the base oil has an aniline point of 120 to 130°C, the lubricant composition has kinematic viscosity of 20 to 60 mm2 / s at 25°C, and the lubricant composition has kinematic viscosity of 3.0 to 6.0 mm2 / s at 100°C.SELECTED DRAWING: None

Description

[Technical Field] 【0001】 In internal combustion engines, wear occurs due to repeated contact between substrates sliding against each other under high load. Lubricating oil compositions applied to internal combustion engines also play a role in preventing such wear. Furthermore, it is common practice to add anti-wear agents to lubricating oil compositions to improve their wear prevention performance. 【0002】 Patent Document 1 proposes a lubricant that contains additives such as zinc dihydrocarbyl dithiophosphate (ZnDTP) and can reduce engine wear. [Prior art documents] [Patent Documents] 【0003】 [Patent Document 1] Japanese Patent Publication No. 2015-227448 [Disclosure of the Invention] [Problems that the invention aims to solve] 【0004】 Lubricating oil compositions are sometimes made with reduced viscosity to improve fuel efficiency and other factors. However, reduced viscosity lubricating oil compositions can increase contact between metals, sometimes leading to a deterioration in wear resistance. Therefore, conventional lubricating oil compositions sometimes could not achieve sufficient wear resistance simply by adding the additives mentioned above. 【0005】 Therefore, the object of the present invention is to provide a lubricating oil composition with excellent wear resistance. [Means for solving the problem] 【0006】 As a result of diligent research, the inventors have found that the above-mentioned problems can be solved by satisfying specific properties in the base oil. That is, the present invention is as follows. 【0007】 The present invention A lubricating oil composition containing a base oil, The aniline point of the base oil is 120-130°C. The kinematic viscosity of the lubricating oil composition at 25°C is 20-60 mm². 2 / s, The kinematic viscosity of the lubricating oil composition at 100°C is 3.0 to 6.0 mm. 2 / s This is a lubricating oil composition characterized by the following: Preferably, the base oil includes a group 3 base oil and / or a group 4 base oil. [Effects of the Invention] 【0008】 This provides a lubricating oil composition with excellent wear resistance. 【0009】 The following describes the components, physical properties, manufacturing method, and uses of the lubricating oil composition according to the present invention. 【0010】 <<<Components of the lubricating oil composition>>> The lubricating oil composition comprises a base oil and other components added according to the desired properties. 【0011】 <<Base oil>> The aniline point of the base oil is 120-130°C, preferably 121-127°C. By setting the aniline point of the base oil within this range and the kinematic viscosity (described later) within a predetermined range, it is possible to efficiently supply the additive to the metal surface (for example, by allowing the additive to precipitate on the metal surface) while sufficiently dissolving the additive in the lubricating oil. Therefore, it is presumed that wear resistance can be improved while maintaining fuel efficiency. 【0012】 The aniline point is adjusted by controlling the polarity caused by the structure of the base oil, such as the paraffin and aromatic components. 【0013】 The aniline point refers to the value measured in accordance with JIS K2256:2013. 【0014】 The base oil is not particularly limited as long as it satisfies the above properties, and mineral oil, synthetic oil, animal and vegetable oil, and mixed oils thereof can be appropriately used. Specific examples include base oils belonging to Group 1, Group 2, Group 3, Group 4, Group 5, etc. in the API (American Petroleum Institute) base oil category, which may be used alone or as a mixture. 【0015】 Examples of Group 1 base oils include paraffinic mineral oils obtained by appropriately combining refining means such as solvent refining, hydrorefining, and dewaxing for the lubricating oil fraction obtained by atmospheric distillation of crude oil. 【0016】 Examples of Group 2 base oils include paraffinic mineral oils obtained by appropriately combining refining means such as hydrocracking and dewaxing for the lubricating oil fraction obtained by atmospheric distillation of crude oil. 【0017】 Examples of Group 3 base oils and Group 2 Plus base oils include paraffinic mineral oils produced by highly hydrorefining the lubricating oil fraction obtained by atmospheric distillation of crude oil, base oils refined by the ISODEWAX process that converts and dewaxes the wax generated in the dewaxing process into isoparaffin, and GTL (Gas to Liquid) base oils obtained from GTL synthesized by the Fischer-Tropsch method of the natural gas to liquid fuel technology. Compared with mineral oil base oils refined from crude oil, GTL base oils have extremely low sulfur and aromatic contents and extremely high paraffin composition ratios, so they are excellent in oxidation stability and viscosity characteristics at low temperatures. 【0018】 Examples of synthetic oils include polyolefins, diesters of dibasic acids, triesters of trimellitic acid, polyol esters, alkylbenzenes, alkylnaphthalenes, polyoxyalkylene glycols, polyoxyalkylene glycol esters, polyoxyalkylene glycol ethers, polyphenyl ethers, dialkyldiphenyl ethers, fluorinated compounds (perfluoropolyethers, fluorinated polyolefins, etc.), and silicones. The above polyolefins include polymers of various olefins or their hydrogenated products. Any olefin can be used, but examples include ethylene, propylene, butene, and α-olefins with 5 or more carbon atoms. In the production of polyolefins, one of the above olefins may be used alone, or two or more may be used in combination. Polyolefins called poly-α-olefins (PAOs) are Group 4 base oils. 【0019】 The base oil preferably contains Group 3 base oil and / or Group 4 base oil. Furthermore, the base oil preferably contains Group 3 base oil and Group 4 base oil (total) in an amount of 50% by mass or more of the total base oil, and preferably 70% by mass or more. From another perspective, the base oil preferably contains Group 3 base oils, and more preferably contains Group 3 base oils in an amount of 50% by mass or more of the total base oil, and more preferably contains 70% by mass or more. 【0020】 <<Other ingredients>> The lubricating oil composition may contain the known components described above, depending on its intended use. Other components include additives such as friction modifiers (e.g., molybdenum dithiocarbamate), metal-based detergents, anti-wear agents, dispersants, defoamers, pour point depressants, metal deactivators, and antioxidants, as well as viscosity index improvers. 【0021】 The content of other components in the lubricating oil composition is not particularly limited, but based on the whole lubricating oil composition, it can be 1% by mass or more, 2% by mass or more, 3% by mass or more, or 5% by mass or more, etc., and can also be 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, etc. 【0022】 In addition, since the lubricating oil composition can suppress carbonaceous deposits (deposits), it is preferably free of a viscosity index improver. More specifically, the content of the viscosity index improver in the lubricating oil composition can be less than 1% by mass, less than 0.1% by mass, less than 0.01% by mass, or 0% by mass (however, trace amounts are allowed). 【0023】 <<<Physical properties / Properties of the lubricating oil composition>>> <<Kinematic viscosity>> The kinematic viscosity at 25 °C measured in accordance with JIS K 2283 of the lubricating oil composition is preferably 20 to 60 mm 2 / s, more preferably 30 to 60 mm 2 / s, and even more preferably 40 to 60 mm 2 / s. 【0024】 The kinematic viscosity at 40 °C measured in accordance with JIS K 2283 of the lubricating oil composition is preferably 10 to 50 mm 2 / s, more preferably 15 to 45 mm 2 / s, and even more preferably 20 to 40 mm 2 / s. 【0025】 The kinematic viscosity at 100 °C measured in accordance with JIS K 2283 of the lubricating oil composition is preferably 3.0 to 6.0 mm 2 / s, more preferably 4.0 to 6.0 mm 2 / s, and even more preferably 4.5 to 6.0 mm 2 / s. 【0026】 The kinematic viscosity at 25°C, 40°C, and 100°C of the lubricating oil composition can be adjusted by combining base oils with different kinematic viscosities and viscosity indices (for example, base oils with different molecular weights and branched structures), or by combining viscosity index improvers. 【0027】 <<Viscosity Index>> The viscosity index (Viscosity Index; VI) of the lubricating oil composition is preferably 100 or more, more preferably 120 or more, and still more preferably 130 or more. 【0028】 <<Anti-pressure Characteristics>> <WL (Weld Load)> The weld load is preferably 160 N or more, and more preferably 200 N or more. 【0029】 <LWI (Load Wear Index)> The load wear index is preferably 42 N or more, more preferably 45 N or more, and particularly preferably 50 N or more. 【0030】 <<LNL (Maximum Non-seizure Load)>> The LNL (maximum non-seizure load) of the lubricating oil composition is preferably 100 N or more, and more preferably 126 N or more. 【0031】 WL (weld load), LWI (load wear index), and LNL (maximum non-seizure load) are measured in accordance with ASTM D 2783 by the Shell four-ball EP test. (Test Conditions) Rotation speed: 1760 ± 40 rpm Load: Specified step load (6 kgf, 8 kgf, 10 kgf, 13 kgf, 16 kgf, 20 kgf, 2 kgf, 32 kgf, 40 kgf, kgf, 63 kgf, 80 kgf, 100 kgf, 126 kgf, 160 kgf, 200 kgf, 250 kgf, 315 kgf, 400 kgf, 500 kgf, 620 kgf, 800 kgf) Temperature: Room temperature (18.3~35.0°C) Time: Approximately 10 seconds 【0032】 LNL (Maximum Non-Seizure Load) is the maximum test load at which the measured wear mark diameter does not exceed 105% of the compensated wear mark diameter (as specified in the test standard) at that test load. WL (fusion load) is the minimum load at which a single test steel ball fixed to a rotating shaft fuses to a stationary ball. The LWI (Load Wear Index) is an index that indicates the load-bearing capacity of a lubricant within a given load range. It is calculated by applying a specified load to three test steel balls fixed in a sample container, performing 10 tests until fusion occurs, and using the formula shown below. LWI=A / 10 A is the sum of the corrected loads for the test between LNL and WL. The corrected loads can be calculated using the following formula. Correction load=L・Dh / X Here, L is the test load (kgf), Dh is the Hertz diameter (mm), and X is the average wear mark diameter (mm). Dh / X can be calculated using the test load value from Column 4 of TABLE 1 of ASTM D2783. Alternatively, A can be obtained from Table 2 of ASTM D2783 using ISL and WL. 【0033】 <<<<Method for producing lubricating oil composition>>> Lubricating oil compositions can be manufactured according to known methods, and the components can be mixed appropriately without any particular limitations on the mixing order. Additives may be added as a package containing a mixture of multiple types. 【0034】 <<<Applications of Lubricating Oil Compositions>>> The lubricating oil composition according to the present invention can be used for various applications in addition to internal combustion engines, such as hydraulic fluid, industrial gear oil, bearing oil, compressor oil, sliding surface oil, heat transfer fluid, and vacuum pump oil. [Examples] 【0035】 <<<Manufacturing of Lubricating Oil Compositions>>> The following raw materials were blended in the amounts (mass%) shown in the table to produce the lubricating oil compositions for each example and comparative example. 【0036】 <<Base oil>> <Base oil A> 40℃ kinematic viscosity: 9.7mm 2 / s, 100℃ kinematic viscosity: 2.7mm 2 Viscosity index: 112, Aniline point: 113.0°C <Base oil B> 40℃ kinematic viscosity: 18.5mm 2 / s, 100℃ kinematic viscosity: 4.1mm 2 Viscosity index: 126, Aniline point: 122.0°C <Base oil C> 40℃ kinematic viscosity: 44.4mm 2 / s, 100℃ kinematic viscosity: 7.6mm 2 Viscosity index: 138, Aniline point: 133.7°C <Base oil D> 40℃ kinematic viscosity: 19.1mm 2 / s, 100℃ kinematic viscosity: 4.2mm 2 Viscosity index: 124, Aniline point: 116.4°C <Base oil E> 40℃ kinematic viscosity: 46.6mm 2 / s, 100℃ kinematic viscosity: 7.6mm 2 / s, viscosity index: 129, aniline point: 125.7℃ <<Other ingredients>> <Package Additives> A mixture of highly refined mineral oil, succinimide-based dispersant, calcium-based metal detergent, ZnDTP, and amine-based antioxidant. <Friction modifier> Sakuralube 165 (MoDTC (Molybdenum Dithioc arbamate), manufactured by ADEKA Corporation) 【0037】 <<<Physical Properties / Evaluation of Lubricating Oil Compositions>>> Based on the method described above, the kinematic viscosity (25°C, 40°C, 100°C), viscosity index, WL (fusion load), LWI (load wear index), and LNL (maximum non-seizure load) were measured for each lubricating oil composition. The measurement results are shown in the table. 【0038】 [Table 1] 【0039】 [Table 2]

Claims

[Claim 1] A lubricating oil composition containing a base oil, The aniline point of the base oil is 120 to 130°C. The kinematic viscosity of the lubricating oil composition at 25°C is 20 to 60 mm². ２ / s, The kinematic viscosity of the lubricating oil composition at 100°C is 3.0 to 6.0 mm. ２ / s, The viscosity index of the lubricating oil composition is 100 or more and 142 or less. A lubricating oil composition characterized by containing a friction modifier. [Claim 2] The lubricating oil composition according to claim 1, comprising a group 3 base oil and / or a group 4 base oil as the base oil.

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