Lubricating composition and manufacturing method of the same and sliding machine

Abstract

To provide a lubricating composition that can improve wear resistance in sliding parts of drive units or the like.SOLUTION: The present invention is a lubricating composition comprising P, wherein an analysis spectrum of 31P-NMR obtained in 1H complete decoupling mode satisfies the following conditions. Specifically, peaks are present in the vicinity of 3.5 ppm where the chemical shift value is 3.1 to 3.7 ppm and in the vicinity of 0 ppm where the chemical shift value is 0 to 0.3 ppm. A first peak area ratio (A2 / A1), which is the ratio of the peak area (A2) in the vicinity of 0 ppm to the peak area (A1) in the vicinity of 3.5 ppm, is 0.18 to 0.8. A peak that may appear in the vicinity of 7 ppm where the chemical shift value is 6.5 to 7.5 ppm has a height of 0.1 times or less relative to the peak in the vicinity of 3.5 ppm.SELECTED DRAWING: Figure 5A

Description

[Technical Field]

[0001] The present invention relates to a lubricating composition. [Background technology]

[0002] Sliding machines, such as drive units (e.g., eAxles) and automatic transmissions used in electric vehicles (hybrid vehicles, electric vehicles, etc.), supply lubricating oil to their sliding parts to ensure low wear and friction, thereby extending their lifespan and reducing losses (improving efficiency). Such sliding characteristics are significantly influenced by the lubricating oil. For this reason, many lubricating oils (lubricating compositions) containing a well-balanced blend of various additives (lubricants) have been proposed. For example, to improve the wear resistance of sliding parts, additives that form adsorption or chemical reaction films on friction surfaces (such as steel surfaces) are blended.

[0003] Incidentally, not only the sliding characteristics but also the improvement of fuel economy and electricity cost of automobiles are becoming important. For this reason, low-viscosity lubricating oils that can reduce mechanical loss associated with stirring resistance are widely used. This trend is particularly noticeable in drive units for electric vehicles. For example, the following Non-Patent Documents 1 and 2 contain descriptions related to such lubricating oils. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] SAE Paper2022-01-1103“Development of TraNsaxle Fluid for Electrified Vehicles: ValidatiNg OptimizedViscosity through Targeted Hardware TestiNg” [Non-patent document 2] SAE Pape2018-01-1756 “Super LowViscosity ATF; AW-2” [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-147521 [Patent Document 2] Patent Publication No. 2023-168653 Summary of the Invention [Problem to be solved by the invention]

[0006] Low viscosity lubricating oils may reduce the oil film thickness in sliding parts and increase wear on the sliding parts, so low viscosity lubricating oils used in drive units and other applications are required to ensure wear resistance over a wide operating range.

[0007] Although Patent Document 1 above describes a lubricating oil composition containing a phosphorus-containing compound, it does not describe anything about an oleylamine-based compound (additive). Patent Document 2 also describes a lubricating composition in which an oleylamine-based compound (bisaminoalkylamine) is added to a hydrocarbon base oil. However, the base oil is for high-viscosity engine oil and does not contain phosphorus.

[0008] The present invention has been made in view of the above circumstances, and has as its object to provide a new lubricating composition etc. that can improve the wear resistance of sliding parts in drive units etc. [Means for solving the problem]

[0009] As a result of intensive research conducted by the present inventors to solve this problem, they discovered that a lubricating composition in which a specific compound is added to a lubricating oil containing P can improve the wear resistance of sliding parts. By expanding on this finding, they have completed the present invention, which will be described below.

[0010] 《Lubricating composition》 The present invention provides a lubricating composition comprising P, 1 H obtained in fully decoupled mode 31The lubricating composition has, in its P-NMR analysis spectrum, peaks at around 3.5 ppm where the chemical shift values ​​are 3.1 to 3.7 ppm and at around 0 ppm where the chemical shift values ​​are 0 to 0.3 ppm, and the first peak area ratio (A2 / A1), which is the ratio of the peak area (A2) at around 0 ppm to the peak area (A1) at around 3.5 ppm, is 0.2 to 0.8, and the height of a peak that may appear at around 7 ppm where the chemical shift values ​​are 6.5 to 7.5 ppm is 0.1 times or less the height of the peak at around 3.5 ppm.

[0011] Although the mechanism is not clear, when the lubricating composition of the present invention is used in sliding machinery, it is possible to ensure or improve the wear resistance of sliding parts whose operating conditions (load, sliding speed, etc.) change.

[0012] <<Method for producing lubricating composition>> The present invention can also be understood as a method for producing the above-mentioned lubricating composition. The lubricating composition may be prepared by blending a phosphorus-free base oil with multiple lubricants (additives), or by adding a specific compound (lubricant) to a phosphorus-containing lubricating oil.

[0013] Sliding Machine The present invention can also be understood as a sliding machine in which the above-mentioned lubricating composition is supplied to a sliding surface. Typical examples of sliding machines include automatic transmissions in which a lubricating oil containing P is used, and drive units (electric units such as eAxles) used in electric vehicles (hybrid vehicles, electric vehicles, etc.). Such lubricating compositions usually have lower viscosities (for example, a kinematic viscosity at 100°C of 3.0 to 6.0 mm) than engine oils, transmission oils (including differential oils), etc. 2 / s and kinematic viscosity at 100°C of 1.5 to 3.5 mm 2 / s).

[0014] "others" Unless otherwise specified, "x to y" in this specification includes a lower limit x and an upper limit y. Any numerical value included in the various numerical values ​​or numerical ranges described in this specification may be used as a new lower limit or upper limit to create a new range such as "a to b." Furthermore, "x to y ppm" in this specification means x ppm to y ppm. The same applies to other unit systems. Note that "ppm" means parts per million by mass unless otherwise specified. [Brief explanation of the drawings]

[0015] [Figure 1A] 1 shows the chemical structure of lubricants (samples 11 to 14). [Figure 1B] 1 shows the chemical structure of lubricants (samples 21 and 22). [Figure 2A] The synthesis process of lubricant (sample 11) and its 1H-NMR spectrum. [Figure 2B] The synthesis process of lubricant (sample 12) and its 1H-NMR spectrum. [Figure 2C] The synthesis process of lubricant (sample 13) and its 1H-NMR spectrum. [Figure 2D] The synthesis process of lubricant (sample 22) and its 1H-NMR spectrum. [Figure 3] FIG. 1 is a schematic diagram of a cross-pin wear test. [Figure 4A] This is a bar graph showing the diameter of the wear scar on the pin for each test oil under test conditions of low load and high sliding speed. [Figure 4B] This is a bar graph showing the wear scar diameter on the pin for each test oil under test conditions of low load and low sliding speed. [Figure 4C] This is a bar graph showing the diameter of the wear scar on the pin for each test oil under test conditions of high load and low sliding speed. [Figure 5A] These are the spectra obtained by analyzing the test oils (sample S and samples 11 to 13) using 31P-NMR. [Figure 5B] These are the spectra obtained by analyzing the test oils (samples 21, 22, and sample R) using 31P-NMR. [Figure 6A]1 is an example of a spectrum analysis of sample 11. [Figure 6B] 10 is an example of a spectrum analysis of sample 13. DETAILED DESCRIPTION OF THE INVENTION

[0016] One or more components arbitrarily selected from the present specification may be added to the above-described components of the present invention. The content described in this specification may apply to any of lubricants, lubricating compositions, their manufacturing methods, sliding machines, etc. Components related to manufacturing methods may also be components related to products. Whether any one embodiment is best depends on the target, required performance, etc.

[0017] 《Lubricating composition》 The lubricating composition is a blend of a plurality of lubricants (additives), and contains P as a whole. 31 The spectrum obtained by P-NMR analysis shows a specific form. 31 The P-NMR analytical spectrum (simply referred to as "spectrum" as appropriate) is 1 H was obtained in fully decoupled mode.

[0018] The spectrum of the lubricating composition (test oil) of the present invention has peaks (vertex positions) at chemical shift values ​​of approximately 0 ppm and 3.5 ppm, and may also have a peak at approximately 10 ppm, while the spectrum should preferably have substantially no clear (significant) peak at approximately 7 ppm.

[0019] Here, "around 0 ppm" refers to, for example, 0 to 0.3 ppm or 0.1 to 0.25 ppm. "Around 3.5 ppm" refers to, for example, 3.1 to 3.7 ppm or 3.1 to 3.6 ppm. Note that 2.8 to 3.2 ppm or 2.85 to 3.15 ppm is referred to as "around 3 ppm" as appropriate.

[0020] "Around 7 ppm" is, for example, 6.5 to 7.5 ppm or 6.8 to 7.2 ppm. "Around 10 ppm" is, for example, 10.0 to 10.6 ppm or 10.1 to 10.5 ppm.

[0021] As used herein, a peak generally refers to a portion (site) in a spectrum that protrudes above the baseline (described in detail below), which is the base level of signal intensity. When peaks overlap, the portion protruding from the baseline is included. The peak shape may be sharp or broad. In terms of full width at half maximum (FWHM), it is preferable that the peak be, for example, about 0.01 to 1 ppm, 0.1 to 0.6 ppm, or 0.2 to 0.5 ppm.

[0022] Peak intensity is evaluated, for example, by peak area or peak height. For peaks with significant width, the peak area is determined as the area of ​​the region enclosed by the baseline drawn on the spectrum and the peak waveform. The baseline is defined as a tangent (linear function) obtained by connecting the bottom ends of the slopes on the left and right of the peak of interest in the spectrum, or points in the vicinity where discontinuous inflections are observed that are presumed to be due to the influence of overlapping other peaks (for example, points where shoulders are observed on the peak).

[0023] The peak area is determined by integrating the signal intensity of the peak (multiplying the "minimum resolution of the chemical shift value" by the "peak height") in the region enclosed by the peak of interest and the baseline. The peak height is determined by subtracting the height of the baseline at the peak position (chemical shift value) where the maximum height is obtained from the maximum height of the peak (arranged as the average of three points around the maximum height). Unless otherwise specified, the peak position is the chemical shift value at the position corresponding to the maximum height of the peak.

[0024] The lubricating composition of the present invention has a first peak area ratio (A2 / A1), which is the ratio of the peak area (A2) around 0 ppm to the peak area (A1) around 3.5 ppm, of, for example, 0.18 to 0.8, 0.2 to 0.5, or 0.22 to 0.3. For convenience, the peak area around 3 ppm for comparison will also be referred to as "A1."

[0025] Furthermore, if there is a peak around 10 ppm, the second peak area ratio (A4 / A1), which is the ratio of the peak area (A4) around 10 ppm to the peak area (A1) around 3.5 ppm, is, for example, 0.03 to 0.17, 0.05 to 0.15, or 0.07 to 0.12.

[0026] The spectrum of the lubricating composition of the present invention has substantially no peak around 7 ppm. This can be quantitatively defined as, for example, 0 to 0.1 times or 0.01 to 0.09 times the height of a peak that may appear around 7 ppm relative to the height of a peak that appears around 3.5 ppm.

[0027] Lubricant The lubricating composition is prepared, for example, using a lubricant having two alkylamines (functional groups). The main chain of the lubricant is, for example, a hydrocarbon group (R) having 8 to 24, 12 to 22, or even 16 to 20 carbon atoms. The hydrocarbon group may be a saturated or unsaturated hydrocarbon group. Examples of the hydrocarbon group constituting the main chain include alkyl groups or unsaturated alkyl groups (alkenyl groups) such as oleyl, 2-ethylhexyl, N-octyl, isooctyl, nonyl, decyl, undecyl, dodecyl, lauryl, tridecyl, pentadecyl, hexadecyl, palmitoleyl, heptadecyl, octadecyl, stearyl, linoleyl, nonadecyl, tetradecyl, and arachidyl.

[0028] The alkyl functional groups may have the same or different carbon atoms. Making the carbon atoms the same (m = n) facilitates the synthesis of the lubricant. Examples of such lubricants include N,N-bis(4-aminobutyl)oleylamine and N,N-bis(6-aminohexyl)oleylamine. These lubricants may be used in combination with one or more types.

[0029] The amount of lubricant added can be adjusted as appropriate, and is, for example, 0.001 to 1 mol / kg, 0.02 to 0.5 mol / kg, or 0.03 to 0.1 mol / kg relative to the entire lubricating composition.

[0030] Phosphorus (P) may come from any source (additive) as long as it is contained in the entire lubricating composition. The P content is, for example, 100 to 2000 ppm, 200 to 1000 ppm, or 300 to 500 ppm.

[0031] The desired spectrum ( 31 The form of the lubricant and P in the lubricating composition is not important as long as P-NMR can be obtained. For example, a new phosphorus-containing compound may be produced by a chemical reaction between the additive (lubricant) and P in the lubricating composition, or P may simply be coordinated to the additive (compound). [Example]

[0032] The present invention will be explained in more detail with reference to specific examples of lubricating compositions (lubricating oils).

[0033] Lubricant The lubricants shown in Figures 1A and 1B (collectively referred to as "Figure 1") were prepared. Samples 11, 12, 13, and 22 were synthesized as follows. Sample 14: Oleylamine (Sigma-Aldrich / Technical Grade 70%) and Sample 21: N,N-bis(2-hydroxyethyl)oleylamine (Lion Corporation, Liponol 0 / 12) were commercially available products and used as is.

[0034] (1) Sample 11: N,N-bis(4-aminobutyl)oleylamine As shown in Figure 2A, oleylamine (C 18 H 37 N) as the starting material, and lubricant (C 26 H 55 N3 / R=C 18 H 35 , m=N=4) was synthesized. The details are as follows.

[0035] A reaction vessel (300 mL) was charged with 11.38 g (42.5 mmol) of oleylamine, 114 mL of N,N-dimethylformamide (anhydrous), 24.00 g (85.1 mmol) of N-(4-bromobutyl)phthalimide, and 7.15 g (85.1 mmol) of sodium bicarbonate, and the mixture was stirred to form a suspension, which was then heated to 100°C and stirred overnight.

[0036] The next day, the reaction mixture was allowed to cool to room temperature and diluted with 1 L of tap water and 1 L of ethyl acetate. The aqueous layer was removed by separation, and the resulting organic layer was washed with 0.5 L of saturated brine. Sodium sulfate was added to this organic layer to dry it. The drying agent was filtered off, and the filtrate was concentrated to obtain 24.0 g of a crude product. This was purified using a column (SiO2: 480 g, toluene / acetone = 4 / 1) to obtain 14.2 g of a bisphthalimide product as a pale yellow oil.

[0037] 13.77 g (20.6 mmol) of this bisphthalimide compound was placed in a reaction vessel (1 L), and 275 mL of tetrahydrofuran and 275 mL of ethanol were added. The mixture was stirred under an argon gas atmosphere to form a homogeneous solution. 10.29 g (205.5 mmol) of hydrazine hydrate was added to the mixture, and the mixture was stirred overnight under reflux. The next day, thin-layer chromatography analysis of the reaction solution confirmed the disappearance of the bisphthalimide compound, and the reaction was considered complete.

[0038] The reaction mixture was allowed to cool to room temperature, and the precipitated solid was filtered off. The filtrate was concentrated to give 11.6 g of a crude product. This was purified by column chromatography (SiO: 50 g, methanol only → ammonia-methanol solution: 8 M) to give 6.54 g of a nearly colorless oily product.

[0039] The compound 1 H-NMR analysis was performed. The spectrum obtained is shown in Figure 2A. Characteristic peaks were detected around 2.44 ppm ("a" in the figure) and 2.64 ppm ("b" in the figure), confirming that the synthesized product was N,N-bis(4-aminobutyl)oleylamine.

[0040] (2) Sample 12: N,N-bis(6-aminohexyl)oleylamine As shown in Figure 2B, oleylamine (C 18 H 37 N) as the starting material, and the lubricant of sample 12 (C 30 H 63 N3 / R=C 18 H 35 , m=N=6) was synthesized. The details are as follows.

[0041] A 500 mL reaction vessel was charged with 15.95 g (59.6 mmol) of oleylamine, 160 mL of N,N-dimethylformamide (anhydrous), 36.99 g (119.3 mmol) of N-(4-bromobutyl)phthalimide, and 10.02 g (119.3 mmol) of sodium bicarbonate, and the mixture was stirred to form a suspension, which was then heated to 100°C and stirred overnight.

[0042] The next day, the reaction mixture was allowed to cool to room temperature and diluted with 1.5 L of tap water and 1.5 L of ethyl acetate. The aqueous layer was removed by separation, and the resulting organic layer was washed with 0.5 L of tap water and 0.5 L of saturated brine. Sodium sulfate was added to this organic layer to dry it. The drying agent was filtered off, and the filtrate was concentrated to obtain 38 g of a crude product. This was purified by column purification (SiO2: 650 g, toluene / acetone = 10 / 1 → 1 / 1) to obtain 28.5 g of a pale yellow oily bisphthalimide product.

[0043] 28.5 g (39.3 mmol) of this bisphthalimide compound was placed in a 2 L reaction vessel, and 570 mL of tetrahydrofuran and 570 mL of ethanol were added. The mixture was stirred under an argon gas atmosphere to form a homogeneous solution. 19.7 g (392.5 mmol) of hydrazine hydrate was added to the mixture, and the mixture was stirred overnight under reflux. The next day, thin-layer chromatography analysis of the reaction solution confirmed the disappearance of the bisphthalimide compound, and the reaction was deemed complete.

[0044] The reaction mixture was allowed to cool to room temperature, and the precipitated solid was filtered off. The filtrate was concentrated and purified by column chromatography (SiO2: 100 g, methanol only → ammonia-methanol solution: 7 M) to obtain 15.05 g of a very pale yellow oily product.

[0045] The compound 1 H-NMR analysis was performed. The spectrum obtained is shown in Figure 2B. Characteristic peaks were detected around 2.44 ppm ("a" in the figure) and 2.64 ppm ("b" in the figure), confirming that the synthesized product was N,N-bis(6-aminohexyl)oleylamine.

[0046] (3) Sample 13: N,N-bis(2-aminoethyl)oleylamine As shown in Figure 2C, oleylamine (C 18 H 37 N) as the starting material, and the lubricant of sample 13 (C 22 H 43 N3 / R=C 18 H 35 , m=N=2) was synthesized. The details are as follows.

[0047] 20.0 g (74.7 mmol) of oleylamine, 400 mL of anhydrous acetonitrile, 43.6 g (171 mmol) of N-(2-bromoethyl)phthalimide, and 30.9 g (224 mmol) of potassium carbonate were placed in a 1.0 L reaction vessel and stirred to form a suspension, which was then heated under reflux (100°C) and stirred overnight.

[0048] The next day, the reaction mixture was allowed to cool to room temperature and diluted with 1 L of tap water and 1 L of ethyl acetate. The aqueous layer was removed by separation, and the resulting organic layer was washed with 0.5 L of saturated brine. Sodium sulfate was added to this organic layer to dry it. The drying agent was filtered off, and the filtrate was concentrated to obtain 55.0 g of a crude product. This was purified using a column (SiO2: 480 g, toluene / acetone = 20 / 1) to obtain 18.9 g of a pale yellow oily bisphthalimide product. This synthesis was performed twice.

[0049] 19.0 g (31.0 mmol) of this bisphthalimide compound was placed in a reaction vessel (1 L), and 380 mL of tetrahydrofuran and 380 mL of ethanol were added. The mixture was stirred under an argon gas atmosphere to form a homogeneous solution. 15.5 g (310.8 mmol) of hydrazine hydrate was added to the mixture, and the mixture was stirred overnight under reflux. The next day, thin-layer chromatography analysis of the reaction solution confirmed the disappearance of the bisphthalimide compound, and the reaction was deemed complete.

[0050] The reaction mixture was allowed to cool to room temperature, and the precipitated solid was filtered off. The filtrate was concentrated without drying to obtain 21.6 g of a crude product. This was purified by column chromatography (SiO2: 210 g, methanol only → ammonia-methanol solution: 4 M → ammonia-methanol solution: 8 M) to obtain 10.1 g of a mixture of pale yellow oil and white solid.

[0051] The compound 1 H-NMR analysis was performed. The spectrum obtained is shown in Figure 2C. Characteristic peaks were detected around 2.53 ppm ("a1" in the figure), 2.45 ppm ("a2" in the figure), and 2.68 ppm ("b" in the figure), confirming that the synthesized product was N,N-bis(2-aminoethyl)oleylamine.

[0052] (4) Sample 22: N,N-bis(2-methylacetate)oleylamine As shown in Figure 2D, oleylamine chloride (C 18 H 35 Cl) as the starting material, and the lubricant of sample 22 (C 24 H 45 O4N / R=C 18 H 35 The details are as follows:

[0053] A 500 mL reaction vessel was charged with 19.37 g (67.5 mmol) of oleyl chloride (I), 15.98 g (81.0 mmol) of dimethyl iminodiacetate hydrochloride (II), and 180 mL of dehydrated acetonitrile and stirred under an argon atmosphere. To this was added 21.63 g (216.0 mmol) of potassium bicarbonate and 1.12 g (6.75 mmol) of potassium iodide, and the mixture was heated to reflux for 48 hours. After cooling to room temperature, approximately 13 mL of acetic acid was added to neutralize the reaction mixture. After diluting with 200 mL of tap water, the mixture was extracted with ethyl acetate (200 mL x 2). The resulting organic layer was dried over anhydrous sodium sulfate, the desiccant was filtered off, and the filtrate was concentrated using an evaporator to obtain 28.9 g of crude product. This was purified by column chromatography (SiO2: 50 g, toluene / acetone = 20 / 1 to 10 / 1) to obtain 13.79 g of a nearly colorless oily synthetic product.

[0054] The compound 1 H-NMR analysis was performed. The spectrum obtained is shown in Figure 2D. Characteristic peaks were detected around 3.55 ppm ("a1" in the figure) and 3.71 ppm ("b" in the figure), confirming that the synthesized product was the dimethyl ester of oleylamine (N,N-bis(2-methylacetate)oleylamine).

[0055] Preparation of test oil Next, test oils (samples 11 to 22) were prepared by blending each lubricant (additive) shown in Figure 1 with a commercially available fluid (a P-containing lubricant). The commercially available fluid used was an electric vehicle transaxle fluid (e-Transaxle Fluid TE, also known as "eTAF," manufactured by Toyota Motor Corporation). A lubricant consisting solely of this eTAF (sample S) was also used as a test oil to serve as the evaluation standard.

[0056] The test oils were prepared by adding each lubricant to the fluid at a ratio of 0.04 mol / kg and heating and stirring at 60°C. The test oils were named with the same sample names as the lubricants they were blended with.

[0057] The eTAF (sample S) itself was analyzed using the SOAP (Spectrometric Oil Analysis Program) metal element analysis (see: https: / / www.tokyo-oilana.com / request / ibutsu / soap-rd) method, and found to contain P: 440 ppm, Ca: 170 ppm, B: 50 ppm, and Si: 10 ppm. The contents of Zn, Na, and Mo were less than 1 ppm. Although quantitative analysis was not performed, the eTAF also contained N and S.

[0058] <Abrasion test> (1) Test conditions A cross-pin wear test, shown in Figure 3, was conducted using each test oil. The wear test was performed by pressing a fixed pin perpendicular to a rotating pin. The wear resistance of the test oil was evaluated based on the diameter of the wear scar that appeared on the fixed pin, which slid in a pure sliding state under point contact.

[0059] Both pins were cylindrical (φ20 mm) made of steel (SCM420) with carburized surfaces. Their surface hardness (Vickers hardness) was 720-850 Hv. The pins were 150 mm long, with the central section (10 mm long) used for analysis being split (replaceable).

[0060] Wear tests were conducted under low and high loads, as shown in Figure 3. Two levels of sliding speed were used under low loads. The test oil was heated to the oil temperature shown in Figure 3 and supplied to the sliding parts of both pins (near the friction surfaces). In order to simulate actual operating conditions, low temperatures were used under low loads and high temperatures under high loads.

[0061] The test oil supply rate was approximately 5 mL / min, and the test time was 45 minutes. To confirm reproducibility, the test was repeated three times for each sample, and the wear resistance was evaluated using the arithmetic mean value of the wear scar diameter (maximum width). The results are summarized in Figures 4A to 4C (collectively referred to as "Figure 4"). In each figure, the variation in test results due to repetition is indicated by error bars. The wear test results when only eTAF (sample S) was used are also shown in Figure 4 as an evaluation standard.

[0062] (2) Evaluation As can be seen from FIG. 4A, all of the samples except for Sample 22 exhibited better wear resistance than Sample S at a low load and a high sliding velocity (1.2 m / s).

[0063] As can be seen from FIG. 4B, all of the samples except for Samples 14 and 22 exhibited better wear resistance than Sample S when subjected to a low load and a low sliding velocity (0.5 m / s).

[0064] As can be seen from FIG. 4C, when the load was high and the sliding velocity was low (0.63 m / s), all of the samples except for Samples 11 and 12 exhibited significantly worse wear resistance than Sample S.

[0065] As can be seen from Figure 4, the only test oils that were able to improve wear resistance under low loads while maintaining wear resistance under high loads were Samples 11 and 12. In particular, Sample 11 had almost the same wear resistance under high loads as Sample S (eTAF), demonstrating excellent sliding properties.

[0066] (3) Discussion The lubricants added to eTAF are all organic compounds, commonly known as oily agents. These oily agents form an adsorbed film on the friction surface, suppressing wear under low loads.

[0067] On the other hand, lubricating oils used in drive units such as eTAF generally contain phosphorus-based additives known as extreme pressure agents, which form an inorganic reactive film on friction surfaces under high pressure to protect the surfaces from wear.

[0068] The state and form of the lubricant blended and added to eTAF are not clear. However, it is believed that the wear resistance shown in Figure 4 is reflected as a result of the interaction (reaction, alteration, competitive adsorption, etc.) between the above-mentioned lubricant and the additives (especially P-based compounds) originally contained in eTAF. In particular, the lubricants of Samples 11 and 12 are thought to have further improved wear resistance under low loads without inhibiting the action and effect of the extreme pressure agent contained in eTAF.

[0069] <Analysis of test oil> (1) Method 31 The test oils were analyzed for phosphorus (e.g., organic phosphorus compounds) using P-NMR (nuclear magnetic resonance spectroscopy). For comparison, a commercially available lubricating oil (sample R) made from automatic transmission fluid (Autofluid WS, manufactured by Toyota Motor Corporation, also known as "ATF") was also analyzed in the same way.

[0070] 31 P-NMR analysis was performed at UBE Scientific Analysis Center, Inc. using an ECA400 manufactured by JEOL Ltd. 1 The H complete decoupling method was used. At this time, no solvent was used, and the observation frequency was 158.60 MHz, the observation width was 138888.39 Hz, the number of accumulations was 12,800, the pulse width was 4.2 μs, and the external reference substance was 85% phosphoric acid (0 ppm).

[0071] The results are shown in Figures 5A and 5B (collectively referred to as "Figure 5"). The dashed lines in the figures indicate the approximate positions of the peaks of interest (chemical shift positions: 0 ppm, 3 ppm, 7 ppm, and 10 ppm).

[0072] (2) Spectral peak shape For each test oil, 31 The spectra (peak shapes) obtained by P-NMR were different. Specifically, they were as follows:

[0073] First, in the spectrum of the reference sample S(eTAF), a sharp, strong peak was observed around 7 ppm. Also, a slightly broad peak was observed around 3 ppm. Conversely, no clear peaks were observed elsewhere (for example, around 10 ppm). If anything, an unclear, weak, broad peak was observed around 0 ppm.

[0074] Next, a slightly broad but significantly strong peak was observed around 3.5 ppm in the spectra of Samples 11 and 12, which had excellent wear resistance. The chemical shift value of this peak was slightly larger than that of Sample S (i.e., it was slightly shifted).

[0075] A slightly broad peak was also clearly observed near 0 ppm. Such a clear peak was not observed in sample S. Conversely, the peak near 7 ppm observed in sample S was not observed or disappeared in samples 11 and 12. Furthermore, a sharp peak was observed near 10 ppm in sample 11.

[0076] As such, there are clear differences in the spectra between Sample S and Sample 11 or Sample 12, indicating that the chemical structures of the phosphorus-based substances in the test oils are different.

[0077] Sample 13 showed a spectrum with the same tendency as Sample 11, but the peaks near 0 ppm and 3.5 ppm were broader and weaker than those of Sample 11.

[0078] In the spectrum of sample 21, a strong peak was observed around 1.5 ppm, which was not observed in samples S or 11 to 13. Unlike samples 11 to 13, the spectrum also retained the sharp peak around 7 ppm observed in sample S.

[0079] Sample 22 showed a spectrum with the same tendency as sample S. That is, the sharp peak around 7 ppm observed in sample S remained, while the peak around 0 ppm and the peak shift to around 3.5 ppm observed in samples 11 to 13 were not observed.

[0080] Sample R was clearly different from the other samples, with only a broad peak observed around 1-2 ppm. Both eTAF and ATF are lubricants used in drivetrains, but their spectra are completely different, reflecting the differences in the structure (characteristics) of the P-based substances (phosphorus compounds) they contain. 31Based on the spectrum (peak shape) obtained by P-NMR, it is possible to identify lubricating compositions containing P, and it can be said that it is sufficiently possible to distinguish the lubricating composition of the present invention from conventional lubricating compositions.

[0081] (3) Quantitative analysis of spectra The quantitative analysis results of the spectra (peak morphology) for Sample S and Samples 11 to 13 are summarized in Table 1. The analytical method used is illustrated in Figure 6A (Sample 11) and Figure 6B (Sample 13). As shown in these figures, baseline correction (linear function) was first performed for each peak. The area enclosed by the baseline and peak waveform was taken as the area of ​​each peak. Baseline correction and peak area calculations were performed using spreadsheet software (Microsoft Excel) from the spectral point cloud data.

[0082] The ratios (A2 / A1, A4 / A1) of the peak area near 0 ppm (A2) and the peak area near 10 ppm (A4) to the peak area near 3.5 ppm or 3 ppm (A1) were also calculated using the peak areas. The results are shown in Table 1.

[0083] As can be seen from Table 1, Samples 11 and 12, which exhibited excellent abrasion resistance, had a first peak area ratio (A2 / A1) of 0.2 or more. Conversely, their second peak area ratios (A4 / A1) were 0.15 or less.

[0084] There was no peak near 7 ppm in the spectra of Sample 11 or Sample 12. In other words, the peak height near 7 ppm was 0.1 times or less the peak height near 3.5 ppm. The peak height is the maximum peak height minus the baseline height at the peak position (chemical shift value) where the value was read, and is calculated using the software described above.

[0085] From the above, 31It has been confirmed that the use of the lubricating composition (lubricating oil) of the present invention, whose spectrum obtained by P-NMR exhibits unique characteristics, can ensure or improve the wear resistance of sliding parts.

[0086] [Table 1]

Claims

1. A lubricating composition comprising P, １ H fully decoupled mode ３１ In the P-NMR analysis spectrum, There are peaks at around 3.5 ppm where the chemical shift value is 3.1 to 3.7 ppm and at around 0 ppm where the chemical shift value is 0 to 0.3 ppm. The peak area (A １ ) relative to the peak area (A ２ ) the first peak area ratio (A ２ / A １ ) is 0.18 to 0.8, The lubricating composition has a chemical shift value of 6.5 to 7.5 ppm, and a peak that may appear around 7 ppm has a height that is 0.1 times or less of the peak that appears around 3.5 ppm.

2. 2. The lubricating composition according to claim 1, further comprising a peak at around 10 ppm in the range of said chemical shift value from 10.0 to 10.6 ppm.

3. The peak area (A １ ) relative to the peak area (A ４ ) the second peak area ratio (A ４ / A １ 3. The lubricating composition according to claim 2, wherein σ is 0.03 to 0.

17.

4. The lubricating composition according to any one of claims 1 to 3, which is used in an automatic transmission or a drive unit for an electric vehicle.

5. A method for producing the lubricating composition according to any one of claims 1 to 3, which comprises adding a lubricant to a lubricating oil containing P.

6. 6. The method for producing a lubricating composition according to claim 5, wherein the lubricant is N,N-bis(4-aminobutyl)oleylamine and / or N,N-bis(6-aminohexyl)oleylamine.

7. A sliding machine, wherein the lubricating composition according to any one of claims 1 to 3 is supplied to a sliding surface.

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