Lubricating oil composition and its preparation method

Abstract

This invention belongs to the field of lubricating oil, specifically relating to a lubricating oil composition comprising 3-15 parts by weight of a first coal liquefaction synthetic base oil, 75-100 parts by weight of a second coal liquefaction synthetic base oil, and 0.5-10 parts by weight of a functional additive; wherein the first coal liquefaction synthetic base oil has a kinematic viscosity greater than 4 mm at 100°C. 2 / s and less than 8mm 2 / s, the kinematic viscosity of the second coal liquefaction synthetic base oil at 100°C is greater than 9 mm. 2 / s and less than 15mm 2 / s. This invention also relates to a method for preparing the lubricating oil composition. The lubricating oil composition of this invention does not contain viscosity index improvers or antifoaming agents, and has a high viscosity index, high viscosity stability, high viscosity-temperature performance, high low-temperature start-up and low-temperature fluidity, low metal corrosion, strong load-bearing capacity, high wear resistance, excellent antifoaming performance, strong oxidation resistance, significant frictional characteristics, high stability, and long service life.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil, specifically relating to a lubricating oil composition and a method for preparing the lubricating oil composition. Background Technology

[0002] As core transmission components of construction machinery vehicles, the performance of the gearbox and drive axle determines the overall stability and reliability of the machine. Different parts of construction machinery vehicles typically use single-function lubricants, each with different functions, such as gearbox transmission fluid and drive axle gear oil. Market feedback indicates that customers often add or mix different types of single-function lubricants, which can easily lead to incompatibility between the transmission components and the lubricant, causing equipment damage. To reduce the risks associated with improper lubricant use, decrease equipment failure rates and downtime, simplify lubricant management, and improve lubrication efficiency, there is an urgent need to develop a multi-functional lubricant suitable for both gearboxes and drive axles, achieving a unified lubricant for both. Summary of the Invention

[0003] One objective of this invention is to provide a lubricating oil composition that does not contain viscosity index improvers or antifoaming agents, has a high viscosity index, maintains its kinematic viscosity under shear stress without loss, exhibits high viscosity stability, a low pour point, low low-temperature viscosity, high viscosity-temperature performance, high low-temperature start-up and low-temperature fluidity, low metal corrosivity, strong load-bearing capacity, high wear resistance, excellent antifoaming properties, strong oxidation resistance, significant frictional characteristics, high stability, and long service life. Another objective of this invention is to provide a method for preparing the lubricating oil composition.

[0004] To achieve the above objectives, a first aspect of the present invention provides a lubricating oil composition, comprising, by weight:

[0005] First coal liquefaction synthetic base oil 3-15 (e.g., 4, 5, 6, 7, 8, 9, 9.5, 10, 11, 12, 13, 14)

[0006] Secondary coal liquefaction synthetic base oils 75-100 (e.g., 78, 80, 82, 85, 87, 89, 90, 92, 95, 98)

[0007] Functional additives 0.5-10 (e.g., 1, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10);

[0008] The first coal liquefaction synthetic base oil has a kinematic viscosity greater than 4 mm at 100°C. 2 / s and less than 8mm 2 / s (preferably greater than 5mm) 2 / s and less than 7mm 2 / s, for example, 5.5mm 2 / s, 6mm 2 / s, 6.2mm 2 / s, 6.5mm 2 / s, 6.8mm 2 The kinematic viscosity of the second coal liquefaction synthetic base oil at 100°C is greater than 9 mm / s. 2 / s and less than 15mm 2 / s (preferably greater than 9mm) 2 / s and less than 11mm 2 / s, for example, 10mm 2 / s, 10.4mm 2 / s, 10.6mm 2 / s, 10.9mm 2 / s, 12mm 2 / s, 13mm 2 / s, 14mm 2 / s).

[0009] In any embodiment of the first aspect of the present invention, the lubricating oil composition comprises, by weight:

[0010] First Coal Liquefaction Synthetic Base Oil 5-13

[0011] Second coal liquefaction synthetic base oil 80-95

[0012] Functional additives 1.5-8.

[0013] In any embodiment of the first aspect of the present invention, the functional additive is selected from one or more of detergents, dispersants, antioxidants, corrosion and rust inhibitors, extreme pressure anti-wear agents, friction modifiers, demulsifiers, and metal deactivators.

[0014] In any embodiment of the first aspect of the present invention, the functional additive is a detergent, dispersant, antioxidant, corrosion and rust inhibitor, extreme pressure anti-wear agent, friction modifier, demulsifier, and metal deactivator.

[0015] In any embodiment of the first aspect of the present invention, the lubricating oil composition comprises, by weight:

[0016] First coal liquefaction synthetic base oil 3-15 (e.g., 4, 5, 6, 7, 8, 9, 9.5, 10, 11, 12, 13, 14)

[0017] Secondary coal liquefaction synthetic base oils 75-100 (e.g., 78, 80, 82, 85, 87, 89, 90, 92, 95, 98)

[0018] Cleaning agent 0.5-2 (e.g., 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.5, 1.7, 1.9)

[0019] Dispersant 0.5-2 (e.g., 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.5, 1.7, 1.9)

[0020] Antioxidant 0.3-1 (e.g., 0.4, 0.5, 0.6, 0.7, 0.8, 0.9)

[0021] Corrosion and rust inhibitor, 0.1-0.4 (e.g., 0.2, 0.3)

[0022] Extreme pressure anti-wear agent 0.3-1.5 (e.g. 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.3, 1.4)

[0023] Friction modifier 0.2-0.8 (e.g., 0.3, 0.4, 0.5, 0.6, 0.7)

[0024] Demulsifier 0.01-0.1 (e.g., 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09)

[0025] Metal deactivator 0.01-0.1 (e.g. 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09).

[0026] In any embodiment of the first aspect of the present invention, the lubricating oil composition comprises, by weight:

[0027]

[0028] In any embodiment of the first aspect of the present invention, the lubricating oil composition comprises one or more of the following:

[0029] The detergent is selected from one or more of calcium sulfonate, magnesium sulfonate, alkylphenol salts and alkyl salicylates, such as calcium sulfonate;

[0030] The dispersant is selected from one or both of succinimide and succinate, such as succinimide;

[0031] The antioxidant is selected from one or more of zinc dialkyl dithiophosphate, alkylphenol and dialkyl diphenylamine, such as zinc dialkyl dithiophosphate;

[0032] The corrosion and rust inhibitor is selected from one or more of barium sulfonate, sodium sulfonate, calcium sulfonate, fatty acids and heterocyclic compounds, such as barium sulfonate and sodium sulfonate (optionally mixed in equal weight);

[0033] The extreme pressure anti-wear agent is selected from one or more of zinc dialkyl dithiophosphate, phosphite esters and sulfurized oils, such as zinc dialkyl dithiophosphate and di-n-butyl phosphite (optionally mixed in equal weights);

[0034] The friction modifier is selected from one or more of benzotriazole fatty amine salts, fatty alcohols, esters and amides, such as benzotriazole fatty amine salts;

[0035] The demulsifier is selected from one or more of propylene oxide diamine condensate, high molecular weight polyether, ethylene glycol ester compounds and ethylene glycol ether, such as polyethylene oxide / propylene oxide block polymer;

[0036] The metal deactivator is an organic nitrogen heterocyclic compound, such as pyrrole.

[0037] In this invention, the calcium sulfonate, magnesium sulfonate, alkylphenol salts and alkyl salicylates used are all commonly used lubricating oil detergents, and their chemical formulas and structures are well known to those skilled in the art and can be purchased from the market.

[0038] In this invention, succinimide and succinate are both commonly used lubricating oil dispersants, whose chemical formulas and structures are well known to those skilled in the art and can be purchased from the market.

[0039] In this invention, the zinc dialkyl dithiophosphate, alkylphenol and dialkyl diphenylamine used are all commonly used lubricating oil antioxidants. Their chemical formulas and structures are well known to those skilled in the art and can be purchased from the market.

[0040] In this invention, the barium sulfonate, sodium sulfonate, calcium sulfonate, fatty acids, and heterocyclic compounds used are all commonly used lubricating oil corrosion and rust inhibitors. Their chemical formulas, structures, and properties are well known to those skilled in the art and can be purchased from the market.

[0041] In this invention, the zinc dialkyl dithiophosphate, phosphite (e.g., di-n-butyl phosphite), and sulfurized grease used are all commonly used extreme pressure anti-wear agents for lubricating oils. Their chemical formulas, structures, and properties are well known to those skilled in the art and can be purchased from the market.

[0042] In this invention, the benzotriazole fatty amine salt, fatty alcohol, ester and amide compounds used are all commonly used lubricating oil friction modifiers. Their chemical formulas, structures and properties are well known to those skilled in the art and can be purchased from the market.

[0043] In this invention, the propylene oxide diamine condensate, high molecular weight polyether (e.g., polyethylene oxide / propylene oxide block polymer), ethylene glycol ester compounds, and ethylene glycol ethers used are commonly used lubricating oil demulsifiers. Their chemical formulas, structures, molecular weight ranges, and properties are well known to those skilled in the art and can be purchased from the market.

[0044] In this invention, the organic nitrogen heterocyclic compound (e.g., pyrrole) used is a commonly used metal deactivator for lubricating oils. Its chemical formula, structure and properties are well known to those skilled in the art and can be purchased from the market.

[0045] In any embodiment of the first aspect of the present invention, the lubricating oil composition comprises one or more of the following:

[0046] The lubricating oil composition does not contain viscosity index improvers or antifoaming agents;

[0047] The viscosity index of the lubricating oil composition is greater than or equal to 140, preferably 140-160;

[0048] The lubricating oil composition exhibits a kinematic viscosity decrease rate of less than 1% at 100°C, preferably less than 0.8%, less than 0.6%, or 0.4-0.6%.

[0049] The pour point of the lubricating oil composition is less than or equal to -40°C, preferably -50°C to -40°C;

[0050] The viscosity of the lubricating oil composition at -20°C is less than or equal to 4000 mPa·s, preferably less than or equal to 3100 mPa·s or 2000-3100 mPa·s;

[0051] The maximum non-seize load of the lubricating oil composition is greater than or equal to 1100N, preferably greater than or equal to 1150N;

[0052] The kinematic viscosity change rate of the lubricating oil composition at 100°C is less than or equal to 8%.

[0053] The acid value change of the lubricating oil composition is less than or equal to 0.6 mg KOH / g.

[0054] In this invention, the viscosity index of the lubricating oil composition is determined according to Method B in GB / T 1995-1998 "Calculation Method of Viscosity Index of Petroleum Products".

[0055] In this invention, the kinematic viscosity reduction rate of the lubricating oil composition at 100°C is determined according to NB / SH / T 0845-2010 "Determination of Viscosity Shear Stability of Transmission Lubricants - Test Machine Method for Tapered Roller Bearings", and the tapered roller bearing shear test method is used for continuous testing for 20 hours.

[0056] In this invention, the pour point of the lubricating oil composition is determined according to GB / T 3535-2006 "Determination of Pour Point of Petroleum Products".

[0057] In this invention, the viscosity of the lubricating oil composition at -20°C is determined according to Method A in GB / T 11145-2014 "Determination of Low-Temperature Viscosity of Lubricants - Brockfeld Viscometer Method".

[0058] In this invention, the maximum non-seize load of the lubricating oil composition is determined according to GB / T 3142-2019 "Determination of the load-carrying capacity of lubricants - four-ball method".

[0059] In this invention, the kinematic viscosity change rate of the lubricating oil composition at 100°C was determined according to the method in CEC L-48-00, and the test was conducted at 160°C for 192 hours.

[0060] In this invention, the acid value change of the lubricating oil composition is determined according to the method in CEC L-48-00, and tested at 160°C for 192 hours.

[0061] In any embodiment of the first aspect of the present invention, the lubricating oil composition is a transmission fluid and / or a drive axle gear oil.

[0062] A second aspect of the present invention provides a method for preparing the lubricating oil composition of the first aspect of the present invention, comprising the following steps:

[0063] Mix the first coal liquefaction synthetic base oil, the second coal liquefaction synthetic base oil and the functional additives and heat to 50℃-80℃ (e.g., 65℃), and continue mixing for 0.5-4 hours (e.g., 2 hours) while maintaining the temperature.

[0064] Preferably, mixing is always performed under stirring conditions, and more preferably, the stirring speed is 200-800 r / min, for example 400 r / min.

[0065] Unless otherwise specified in this invention:

[0066] The term "coal liquefaction synthetic base oil" refers to a lubricating oil base oil produced by first generating syngas from coal, then synthesizing liquid hydrocarbons from the syngas, and finally processing the liquid hydrocarbons. Coal liquefaction synthetic base oil has high purity, with its main component being isoalkanes (content greater than 99.99%), and is essentially free of sulfur, nitrogen, aromatics, and metals. It also has a high viscosity index, low pour point, and low production cost.

[0067] The term "extreme pressure anti-wear agent" refers to a chemical additive that prevents sintering, scratching, and wear on sliding metal surfaces under extreme pressure conditions; it is also known as extreme pressure anti-wear agent for lubricating oils.

[0068] The term "friction improver" refers to an additive that reduces the coefficient of friction of lubricating oil under boundary lubrication conditions. Its main function is to form a protective lubricating film on the metal surface, avoid direct contact between metal peaks, reduce the coefficient of friction under mixed lubrication and boundary lubrication conditions, reduce frictional resistance and wear, and achieve the purpose of saving oil.

[0069] The present invention has achieved at least one of the following beneficial effects:

[0070] The lubricating oil composition of the present invention does not contain viscosity index improvers or antifoaming agents.

[0071] The lubricating oil composition of the present invention has a high viscosity index, no loss of kinematic viscosity under shear stress, high viscosity stability, low pour point, low low temperature viscosity, high viscosity-temperature performance, high low temperature start-up and low temperature fluidity, low metal corrosion, strong load-bearing capacity, high wear resistance, excellent anti-foaming performance, strong oxidation resistance, significant friction characteristics, high stability, and long service life.

[0072] The preparation method of the lubricating oil composition of the present invention is simple to operate and suitable for industrial production. Detailed Implementation

[0073] The embodiments of the present invention will now be clearly and completely described in conjunction with examples. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0074] The materials used in the following examples and comparative examples:

[0075] Low-viscosity coal liquefaction synthetic base oil (kinematic viscosity at 100℃: 6.5 mm) 2 / s): Purchased from Shanxi Lu'an Chemical Co., Ltd., product number: base oil 6# (LMN);

[0076] High-viscosity coal liquefaction synthetic base oil (kinematic viscosity at 100℃: 10.6 mm) 2 / s): Purchased from Shanxi Lu'an Chemical Co., Ltd., product number: base oil 10# (MN);

[0077] Low viscosity coal liquefaction synthetic base oil (kinematic viscosity at 100℃: 3mm) 2 / s) purchased from Shanxi Lu'an Chemical Co., Ltd.;

[0078] High-viscosity coal liquefaction synthetic base oil (kinematic viscosity at 100℃: 20 mm) 2 / s) purchased from Shanxi Lu'an Chemical Co., Ltd.;

[0079] Functional additives: formulated from 0.9% w / w of detergent calcium sulfonate, 0.8% w / w of dispersant succinimide, 0.6% w / w of antioxidant zinc dialkyl dithiophosphate, 0.1% w / w of corrosion and rust inhibitor barium sulfonate, 0.1% w / w of corrosion and rust inhibitor sodium sulfonate, 0.35% w / w of extreme pressure anti-wear agent zinc dialkyl dithiophosphate, 0.35% w / w of extreme pressure anti-wear agent di-n-butyl phosphite, 0.4% w / w of friction modifier benzotriazole fatty amine salt, 0.04% w / w of demulsifier polyethylene oxide / propylene oxide block polymer, and 0.06% w / w of metal deactivator pyrrole. The above weight percentages are calculated based on the total weight of the lubricating oil composition.

[0080] Examples 1 to 3

[0081] According to the formulations in Tables 1 to 3, each component was added simultaneously to a mixing container, heated to 65°C while stirring, and stirred for 2 hours while maintaining the temperature at 65°C. The stirring speed was always kept at 400 r / min to obtain lubricating oil compositions 1 to 3. The kinematic viscosity in Tables 1 to 3 was measured according to the method in item (1) of Test Example 1.

[0082] Table 1 Formulation of Lubricating Oil Composition 1

[0083]

[0084] Table 2 Formulation of Lubricating Oil Composition 2

[0085]

[0086] Table 3 Formulation of Lubricating Oil Composition 3

[0087]

[0088] Comparative Example 1: Existing Transmission Fluid

[0089] The transmission fluid was purchased from Sinopec Lubricating Oil Co., Ltd., product number 8#.

[0090] Transmission fluids contain low-viscosity mineral base oils, viscosity index improvers, antifoaming agents, and other functional additives.

[0091] Comparative Example 2: Existing Drive Axle Gear Oil

[0092] The drive axle gear oil was purchased from PetroChina Lubricating Oil Co., Ltd., product number GL-5 85W-90.

[0093] Drive axle gear oils contain low-viscosity mineral base oils, heavy-duty high-viscosity bright base oils, antifoaming agents, and other functional additives.

[0094] Comparative Example 3: Lubricating oil composition using only low-viscosity coal liquefaction synthetic base oil

[0095] The high-viscosity coal liquefaction synthetic base oil in Example 1 was replaced with an equal mass of low-viscosity coal liquefaction synthetic base oil (kinematic viscosity at 100°C: 6.5 mm). 2 The composition was obtained by repeating the process described in Example 1.

[0096] Comparative Example 4: Lubricating oil composition using only high-viscosity coal liquefaction synthetic base oil

[0097] The low-viscosity coal liquefaction synthetic base oil in Example 1 was replaced with an equal mass of high-viscosity coal liquefaction synthetic base oil (kinematic viscosity at 100°C: 10.6 mm). 2 The composition was obtained by repeating the process described in Example 1.

[0098] Comparative Example 5 uses a combination of coal liquefaction base oils with excessively low viscosity and those with excessively high viscosity.

[0099] The low-viscosity coal liquefaction synthetic base oil from Example 1 (kinematic viscosity at 100°C: 6.5 mm) 2 Replace / s) with an equal mass of low-viscosity coal liquefaction synthetic base oil (kinematic viscosity at 100℃: 3mm). 2 / s), while simultaneously, high-viscosity coal liquefaction is used to synthesize base oil (kinematic viscosity at 100℃: 10.6mm). 2 Replace / s) with an equal mass of high-viscosity coal liquefaction synthetic base oil (kinematic viscosity at 100℃: 20mm). 2 The composition was obtained by repeating the process described in Example 1.

[0100] Test Example 1

[0101] (1) Kinematic viscosity at 100℃: The kinematic viscosity (mm) at 100℃ was determined according to the method in GB / T 265-1988. 2 / s).

[0102] (2) Viscosity index: determined according to method B in GB / T 1995-1998 "Calculation method of viscosity index of petroleum products".

[0103] (3) Shear stability: According to NB / SH / T 0845-2010 "Determination of viscosity shear stability of transmission lubricant by tapered roller bearing test machine", the tapered roller bearing shear test method was used for 20 hours of continuous testing, and the kinematic viscosity reduction rate (%) at 100℃ was determined.

[0104] (4) Pour point: Determined according to GB / T 3535-2006 "Determination of Pour Point of Petroleum Products".

[0105] (5) Low temperature viscosity: The viscosity at -20℃ was determined according to Method A in GB / T 11145-2014 "Determination of Low Temperature Viscosity of Lubricants by Brockfeld Viscometer Method".

[0106] (6) Copper strip corrosion: The test was conducted at 150°C for 3 hours according to the method in GB / T 5096-2017 "Test Method for Copper Strip Corrosion of Petroleum Products".

[0107] (7) Liquid phase corrosion: According to the method in GB / T 11143-2008 "Test method for rust prevention performance of mineral oil with inhibitor in the presence of water", distilled water was used and the test cycle was 4 hours.

[0108] (8) Load capacity: The maximum non-seize load (N) was determined according to GB / T 3142-2019 "Determination of load capacity of lubricant by four-ball method".

[0109] (9) Wear scar diameter: The diameter was determined under condition B according to NB / SH / T 0189-2017 "Determination of wear resistance of lubricating oil by four-ball method".

[0110] (10) Foam characteristics: The foam volume was determined according to GB / T 12579-2002 "Specific Determination of Foam in Lubricating Oils" at the end of the blowing cycle and the end of the stationary cycle in Procedure I (24℃), Procedure II (93.5℃) and Procedure III (last 24℃). In the results, the data to the left of " / " represents the foam volume at the end of the blowing cycle, and the data to the right of " / " represents the foam volume at the end of the stationary cycle.

[0111] (11) Oxidative stability: The kinematic viscosity change rate, acid value change and test tube rating at 100℃ were determined according to the method in CEC L-48-00, and the test was conducted at 160℃ for 192 hours.

[0112] (12) Friction characteristics: The dynamic friction coefficient and static-dynamic ratio were determined according to the method in JASO M348.

[0113] The results for the above parameters are shown in Table 4.

[0114]

[0115]

[0116] As shown in Table 4:

[0117] Compared with the existing transmission fluid in Comparative Example 1, the lubricating oil composition of the present invention does not contain viscosity index improvers or antifoaming agents. Furthermore, the lubricating oil composition of the present invention has a higher viscosity index, a lower rate of decrease in kinematic viscosity under shear stress, a lower pour point, lower low-temperature viscosity, better viscosity-temperature performance, better low-temperature start-up and low-temperature fluidity, lower metal corrosivity, stronger load-bearing capacity, better wear resistance, better antifoaming performance, stronger oxidation resistance, more significant friction characteristics, shortens equipment shifting time, and improves equipment shifting smoothness.

[0118] Compared with the existing drive axle gear oil in Comparative Example 2, the lubricating oil composition of the present invention does not contain an antifoaming agent. Furthermore, the lubricating oil composition of the present invention has a higher viscosity index, a lower rate of decrease in kinematic viscosity under shear stress, a lower pour point, lower low-temperature viscosity, better viscosity-temperature performance, better low-temperature start-up and low-temperature fluidity, lower metal corrosion, stronger load-bearing capacity, better wear resistance, stronger antifoaming performance, and stronger oxidation resistance.

[0119] Compared with the lubricating oil composition of Comparative Example 3, which only uses low-viscosity coal liquefaction synthetic base oil, the lubricating oil composition of the present invention has a higher viscosity index, a lower rate of decrease in kinematic viscosity under shear stress, higher viscosity-temperature performance, stronger load-bearing capacity, and higher wear resistance.

[0120] Compared with the lubricating oil composition of Comparative Example 4, which only uses high-viscosity coal liquefaction synthetic base oil, the lubricating oil composition of the present invention has a higher viscosity index, a lower rate of decrease in kinematic viscosity under shear stress, a lower pour point, lower low-temperature viscosity, better viscosity-temperature performance, better low-temperature start-up and low-temperature fluidity, stronger load-bearing capacity, better wear resistance, stronger oxidation resistance, more significant friction characteristics, shorter equipment shifting time, and improved equipment shifting smoothness.

[0121] Compared with Comparative Example 5, which uses a combination of low-viscosity coal liquefaction synthetic base oil with excessively low viscosity and high-viscosity coal liquefaction synthetic base oil with excessively high viscosity, the lubricating oil composition of the present invention has a higher viscosity index, a lower rate of decrease in kinematic viscosity under shear stress, a lower pour point, lower low-temperature viscosity, better viscosity-temperature performance, better low-temperature start-up and low-temperature fluidity, better anti-wear performance, stronger oxidation resistance, more significant friction characteristics, shortened equipment shifting time, and improved equipment shifting smoothness.

[0122] Therefore, the lubricating oil composition of this invention does not require the addition of viscosity index improvers and antifoaming agents, and the base oil used is essentially free of sulfur, nitrogen, aromatics, and metals. The lubricating oil composition of this invention has a high viscosity index, maintains its kinematic viscosity under shear stress without loss, exhibits high viscosity stability, a low pour point, low low-temperature viscosity, high viscosity-temperature performance, high low-temperature start-up and low-temperature fluidity, low metal corrosivity, strong load-bearing capacity, high wear resistance, excellent antifoaming properties, strong oxidation resistance, and significant frictional characteristics. This shortens equipment shifting time, improves the smoothness of equipment shifting, and reduces noise.

[0123] Test Example 2

[0124] The lubricating oil compositions of Examples 1-3 were actually installed on the loader's gearbox and drive axle and operated for 1000 hours. Observations showed that the loader's gearbox and drive axle using the lubricating oil compositions of Examples 1-3 did not experience any abnormal malfunctions during operation, the equipment operated well, and the oil sample test results were all normal, indicating that the lubricating oil compositions of Examples 1-3 are suitable for both gearboxes and drive axles.

[0125] The kinematic viscosity of the lubricating oil compositions of Examples 1-3 at 100°C was determined according to the method in GB / T 265-1988 before and after operation of the gearbox and drive axle, and the rate of change of kinematic viscosity was calculated.

[0126] The acid values ​​of the lubricating oil compositions of Examples 1-3 were determined according to the method in GB / T 7304-2014 before and after operation of the gearbox and drive axle, and the changes in acid values ​​were calculated.

[0127] The wear iron content in the lubricating oil compositions of Examples 1-3 was determined according to the method in ASTM D5185-2018 before and after operation of the gearbox and drive axle, and the change in iron content was calculated.

[0128] The results are shown in Table 5.

[0129] Table 5. Parameter results of the lubricating oil composition before and after 1000 hours of equipment operation.

[0130]

[0131] As shown in Table 5, before and after operation of the gearbox and drive axle, the kinematic viscosity change rate at 100°C, acid value change rate, and wear iron content change rate of the lubricating oil composition of the present invention are all low and within a reasonable range in this field. This indicates that the lubricating oil composition of the present invention has high stability, long service life, and good metal protection performance. Moreover, the kinematic viscosity change rate at 100°C, acid value change rate, and wear iron content change rate of the lubricating oil composition of Example 1 of the present invention are further reduced, its stability is further improved, and its service life is further extended.

[0132] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A lubricating oil composition, which is a transmission fluid and / or a drive axle gear oil; The lubricating oil composition comprises, by weight, the following components: First coal liquefaction synthetic base oil 7-9.5; Second coal liquefaction synthetic base oil 85-90; Cleaning agent 0.9; Dispersant 0.8; Antioxidant 0.6; Corrosion and rust inhibitor 0.2; Extreme pressure anti-wear agent 0.7; Friction modifier 0.4; Demulsifier 0.04; Metal deactivator 0.06; The lubricating oil composition does not contain viscosity index improvers or antifoaming agents; The first coal liquefaction synthetic base oil has a kinematic viscosity of 6.0 mm at 100°C. 2 / s-6.5 mm 2 / s, the kinematic viscosity of the second coal liquefaction synthetic base oil at 100°C is 10 mm. 2 / s-10.9 mm 2 / s; the antioxidant is zinc dialkyl dithiophosphate; the extreme pressure anti-wear agent is selected from zinc dialkyl dithiophosphate and di-n-butyl phosphite.

2. The lubricating oil composition according to claim 1, characterized in that... One or more of the following: The detergent is selected from one or more of calcium sulfonate, magnesium sulfonate, alkylphenol salts and alkyl salicylates; The dispersant is selected from one or both of succinimide and succinate; The corrosion and rust inhibitor is selected from one or more of barium sulfonate, sodium sulfonate, calcium sulfonate, fatty acids, and heterocyclic compounds; The friction modifier is selected from one or more compounds chosen from benzotriazole fatty amine salts, fatty alcohols, esters, and amides. The demulsifier is selected from one or more of propylene oxide diamine condensate, high molecular weight polyether, ethylene glycol ester compounds and ethylene glycol ether; The metal deactivator is an organic nitrogen heterocyclic compound.

3. The lubricating oil composition according to claim 1 or 2, characterized in that... One or more of the following: The viscosity index of the lubricating oil composition is greater than or equal to 140; The lubricating oil composition exhibits a kinematic viscosity decrease rate of less than 1% at 100°C. The pour point of the lubricating oil composition is less than or equal to -40°C; The viscosity of the lubricating oil composition at -20°C is less than or equal to 3100 mPa•s; The maximum non-seize load of the lubricating oil composition is greater than or equal to 1150 N; The kinematic viscosity change rate of the lubricating oil composition at 100°C is less than or equal to 8%; The acid value change of the lubricating oil composition is less than or equal to 0.6 mgKOH / g.

4. A method for preparing the lubricating oil composition according to any one of claims 1 to 3, comprising the following steps: Mix the first coal liquefaction synthetic base oil, the second coal liquefaction synthetic base oil with detergents, dispersants, antioxidants, corrosion and rust inhibitors, extreme pressure anti-wear agents, friction modifiers, demulsifiers and metal deactivators, and heat to 50 ℃-80 ℃. Maintain the temperature and continue mixing for 0.5-4 hours.

5. The method according to claim 4, wherein, Mixing is always done under stirring conditions.

6. The method according to claim 5, wherein, The stirring speed is 200-800 r / min.

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