Wide-temperature-range hydraulic system long-acting low-consumption lubricating medium, and preparation process and application thereof

Abstract

The application belongs to the technical field of lubricating oil, and particularly relates to a long-acting low-consumption lubricating medium for a wide-temperature-range hydraulic system, a preparation process thereof and application. The long-acting low-consumption lubricating medium for the wide-temperature-range hydraulic system comprises, by mass percentage, base oil supplementing a balance to 100%, a viscosity modifier 1-5%, an anti-wear agent 0.5-3%, an antioxidant 0.3-2% and other additives 0.1-1%. The viscosity modifier is obtained by the reaction of a modifier and methyl methacrylate. The modifier is obtained by the reaction of 4-imidazole acrylic acid, dihydroxy epoxide and tetramethyl orthosilicate. The self-made viscosity modifier and antioxidant effectively broaden the working temperature range of the lubricating medium, endow the hydraulic oil with excellent low-temperature performance and prolong the oil change cycle.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, specifically relating to a long-lasting, low-consumption lubricating medium for wide-temperature-range hydraulic systems, its preparation process, and its application. Background Technology

[0002] Hydraulic systems are widely used in engineering machinery, mining equipment, aerospace and other fields. The lubricating medium plays a role in the hydraulic system in transmitting power, lubricating components, cooling and heat dissipation, and preventing corrosion and rust. Therefore, the performance of the lubricating medium directly affects the reliability, energy efficiency and life of the hydraulic system.

[0003] Existing hydraulic oils generally suffer from poor overall environmental adaptability, making it difficult to handle extreme working conditions in both extremely cold and high temperatures. Some hydraulic oils have poor low-temperature fluidity and high pour points, leading to difficulties in starting equipment and increased wear in cold environments. Other hydraulic oils have undesirable viscosity-temperature characteristics, resulting in large viscosity fluctuations over a wide temperature range, which reduces system transmission efficiency and control precision. At the same time, they have insufficient oxidation resistance, are prone to oxidation and degradation at high temperatures, have a rapid increase in acid value, accumulate a lot of sludge, and have short oil change intervals. This has led to a long-term reliance on imported products in high-end applications.

[0004] For example, Chinese patent CN122038018A discloses an anti-wear composite hydraulic oil composition and its preparation method. The composition, by mass percentage, comprises: lubricating base oil (balance), 3.0-5.0% composite anti-wear agent, 1.2-2.5% antioxidant, 2.0-4.5% viscosity index improver, 0.005-0.020% antifoaming agent, 0.8-1.5% demulsifier, and 0.3-0.8% metal passivator. While this technical solution exhibits a high viscosity index and outstanding oxidation stability, its pour point is relatively high, only reaching -35°C.

[0005] Chinese Patent Publication No. CN120988765A discloses a hydraulic oil based on a composite ester and its preparation method. The hydraulic oil components include pentaerythritol synthetic ester, polyethylene sebacic acid ester, a viscosity-temperature modifier, an ashless antioxidant, a bio-based anti-wear agent, and a nano-modifier. The pentaerythritol synthetic ester is a mixed ester obtained by reacting a mixture of 2-ethylhexanoic acid, 3,5-dimethylhexanoic acid, and 4-methyloctanoic acid with pentaerythritol. The viscosity-temperature modifier is a graft copolymer obtained by grafting poly(N-isopropylacrylamide) onto the polyethylene sebacic acid ester molecular chain via transesterification. While this technical solution exhibits a high viscosity index and a low pour point, its oxidative stability is poor, with a rotating oxygen bomb time of only 320 min. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a long-lasting and low-consumption lubricating medium for a wide temperature range hydraulic system. The present invention uses a self-made viscosity modifier and antioxidant to effectively broaden the working temperature range of the lubricating medium, giving the hydraulic oil excellent low-temperature performance while extending the oil change cycle.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The first aspect of this invention provides a long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system, comprising, by mass percentage: base oil to make up to 100%, viscosity improver 1-5%, anti-wear agent 0.5-3%, antioxidant 0.3-2%, and other additives 0.1-1%.

[0009] In some embodiments, the base oil is one or more of hydrogenated base oil, synthetic hydrocarbon oil, and ester oil.

[0010] In some embodiments, the hydrotreated base oil is one or more of Group II and Group III hydrotreated base oils.

[0011] In some embodiments, the synthetic hydrocarbon oil is selected from one or more of polyalphaolefin PAO3, polyalphaolefin PAO4, polyalphaolefin PAO5, and polyalphaolefin PAO6.

[0012] In some embodiments, the ester oil is selected from one or more of pentaerythritol ester, trimethylolpropane ester, neopentyl glycol ester, di-n-octyl adipate, 1,6-hexanediol di-n-octyl ester, di-n-octyl 3-methyl adipate, and di(2-ethylhexyl) sebacate.

[0013] In some embodiments, the base oil is a mixture of Group II hydrotreated base oil and pentaerythritol ester in a mass ratio of 6-8:2-4.

[0014] In some embodiments, the Group II hydrotreated base oil is one or more of 150N Group II hydrotreated base oil, 220N Group II hydrotreated base oil, and 250N Group II hydrotreated base oil.

[0015] In some embodiments, the pentaerythritol ester has a viscosity index of 130-140 and a pour point of -50 to -60°C.

[0016] In some embodiments, the viscosity improver is obtained by reacting a modifier with methyl methacrylate.

[0017] In some embodiments, the modifier is obtained by reacting 4-imidazolium acrylic acid, dihydroxyepoxide, and methyl orthosilicate.

[0018] In some embodiments, the modifier is prepared by mixing 4-imidazolium acrylic acid, dihydroxyepoxide and ethyl acetate, adding tetramethylammonium chloride and hydroquinone, stirring at 100-120°C until the acid value is less than 5 mg KOH, cooling to 70-90°C, adding methyl orthosilicate and dibutyltin dilaurate, and continuing to stir under nitrogen protection for 3-6 hours to obtain the modifier.

[0019] In some embodiments, the dihydroxyepoxide is selected from one or more of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and butylene glycol diglycidyl ether.

[0020] In some embodiments, the molar ratio of the 4-imidazolium acrylic acid, the dihydroxyepoxide, and the methyl orthosilicate is 2-2.2:1:2-2.2.

[0021] In some embodiments, the amount of ethyl acetate added is 0.5-1.5 times that of the dihydroxyepoxide compound.

[0022] In some embodiments, the amount of tetramethylammonium chloride added is 0.2-1% of the dihydroxyepoxide compound.

[0023] In some embodiments, the amount of hydroquinone added is 0.1-1% of the dihydroxyepoxide compound.

[0024] In some embodiments, the amount of dibutyltin dilaurate added is 1-2% of methyl orthosilicate.

[0025] In some embodiments, the viscosity improver is prepared by mixing the improver and methyl methacrylate, adding azobisisobutyronitrile, reacting at 50-70°C for 2-5 hours, and then reacting at 90-110°C for 2-5 hours to obtain the product.

[0026] In some embodiments, the mass ratio of methyl methacrylate to modifier is 70-80:20-30.

[0027] In some embodiments, the amount of azobisisobutyronitrile added is 0.1-0.5% of the total mass of methyl methacrylate and the modifier.

[0028] In some embodiments, the anti-wear agent is selected from one or more of zinc dialkyl dithiophosphate, dibutyl phosphite, tricresyl phosphate, and triphenyl thiophosphate.

[0029] In some embodiments, the antioxidant is obtained by reacting an imino-containing cyclic borate ester and a diisocyanate with 4-(2H-benzotriazol-2-yl)-1,3-benzenediol.

[0030] In some embodiments, the imino-containing cyclic borate ester is obtained by reacting p-carboxyphenylboronic acid and diethanolamine.

[0031] In some embodiments, the preparation method of the imino-containing cyclic borate ester is as follows: under nitrogen protection, p-carboxyphenylboronic acid, diethanolamine and DMF (N,N-dimethylformamide) are mixed and stirred at 40-60°C for 1-3 hours. After the reaction is completed, the mixture is recrystallized with petroleum ether, filtered, and washed to obtain the product.

[0032] In some embodiments, the mass ratio of p-carboxyphenylboronic acid, diethanolamine, and DMF is 1.2-1.5:1:80-100.

[0033] In some embodiments, the antioxidant is prepared by mixing an imino-containing cyclic borate ester and xylene, adding diisocyanate dropwise, stirring and reacting at 75-85°C for 3-5 hours, adding 4-(2H-benzotriazol-2-yl)-1,3-benzenediol, continuing to stir and react for 3-5 hours, and removing xylene by rotary evaporation after the reaction is completed.

[0034] In some embodiments, the diisocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

[0035] In some embodiments, the mass ratio of the imino-containing cyclic borate ester, diisocyanate, and 4-(2H-benzotriazol-2-yl)-1,3-benzenediol is 1-1.5:1:1-1.5.

[0036] In some embodiments, the amount of xylene added is 3-5 times the mass of the imino-containing cyclic borate ester.

[0037] In some embodiments, the other additives include one or more of rust inhibitors, defoamers, and metal passivators.

[0038] In some embodiments, the rust inhibitor accounts for 0.1-1% of the total mass of the long-lasting, low-consumption lubricating medium in the wide-temperature-range hydraulic system.

[0039] In some embodiments, the rust inhibitor is selected from one or more of sulfonates, alkenyl succinic acid, alkenyl succinic anhydride, and alkenyl succinate.

[0040] In some embodiments, the defoamer accounts for 0.005-0.02% of the total mass of the long-lasting, low-consumption lubricating medium in a wide-temperature-range hydraulic system.

[0041] In some embodiments, the defoamer is dimethyl silicone oil.

[0042] In some embodiments, the metal passivating agent accounts for 0.02-1% of the total mass of the long-lasting, low-consumption lubricating medium in the wide-temperature-range hydraulic system.

[0043] In some embodiments, the metal passivating agent is selected from benzotriazole derivatives and / or thiadiazole derivatives.

[0044] The second aspect of this invention provides a preparation process for a long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system, comprising the following steps: heating the base oil to 50-70°C and stirring to remove water; sequentially adding anti-wear agent, viscosity modifier, antioxidant, and other additives, stirring for 10-30 minutes after each addition; continuing to stir for 1-3 hours until the system is uniform and transparent; filtering through a filter element, and dispensing after passing the test.

[0045] The third aspect of this invention provides an application of a long-lasting, low-consumption lubricating medium for wide-temperature-range hydraulic systems in hydraulic systems of engineering machinery, mining equipment, or aerospace.

[0046] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0047] 1. Factors that can improve viscosity index and low-temperature performance mainly include base oil and viscosity modifiers. Ester oils generally have low pour points and excellent viscosity-temperature properties; however, they are expensive and have poor oxidation resistance. This invention uses a compound of Group II hydrotreated base oil and pentaerythritol ester as the base oil to optimize its low-temperature performance, viscosity index, and cost. Based on the compound of Group II hydrotreated base oil and pentaerythritol ester as the base oil, this invention prepares a viscosity modifier, which is obtained by reacting a modifier with methyl methacrylate. The modifier is obtained by first reacting 4-imidazolium acrylic acid with a dihydroxyepoxide compound in a ring-opening reaction, and then with methyl orthosilicate in a condensation reaction. That is, a branched chain with an imidazolium ring and alkoxysilane is introduced into polymethyl methacrylate. This viscosity modifier can significantly reduce the low-temperature kinematic viscosity and pour point of the lubricating medium, and improve the viscosity index. At the same time, it has excellent thermal oxidation stability, thus also improving the oxidation resistance and rotating bomb life of the lubricating medium.

[0048] 2. The improvement of the anti-oxidation performance of lubricating media is mainly achieved by adding antioxidants. The antioxidant provided by this invention is obtained by reacting imino-containing cyclic borate esters and diisocyanates with 4-(2H-benzotriazole-2-yl)-1,3-benzenediol, thus obtaining an antioxidant containing cyclic borate esters and benzotriazole structures. This antioxidant can significantly improve the anti-oxidation performance and rotating bomb life of lubricating media. Attached Figure Description

[0049] Figure 1 This is a physical image of the long-lasting, low-consumption lubricating medium for the wide-temperature-range hydraulic system in Example 1. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Preparation Example 1 Modifier A

[0052] Mix 4-imidazolium acrylic acid, dihydroxyepoxide (ethylene glycol diglycidyl ether), and ethyl acetate, add tetramethylammonium chloride and hydroquinone, stir at 110°C until the acid value is less than 5 mg KOH, cool to 80°C, add methyl orthosilicate and dibutyltin dilaurate, and continue stirring for 5 hours under nitrogen protection to obtain the final product.

[0053] The molar ratio of 4-imidazolium acrylic acid, dihydroxyepoxide and methyl orthosilicate is 2.2:1:2.2.

[0054] The amount of ethyl acetate added is 1 times that of the dihydroxyepoxide compound.

[0055] The amount of tetramethylammonium chloride added is 0.8% of the dihydroxyepoxide compound.

[0056] The amount of hydroquinone added is 0.5% of the dihydroxyepoxide compound.

[0057] The amount of dibutyltin dilaurate added is 1% of methyl orthosilicate.

[0058] Preparation Example 2 Modifier B

[0059] Acrylic acid, dihydroxyepoxide (ethylene glycol diglycidyl ether), and ethyl acetate were mixed, and tetramethylammonium chloride and hydroquinone were added. The mixture was stirred at 110°C until the acid value was less than 5 mg KOH. The mixture was then cooled to 80°C, and methyl orthosilicate and dibutyltin dilaurate were added. The mixture was stirred for another 5 hours under nitrogen protection to obtain the final product.

[0060] The molar ratio of acrylic acid, dihydroxyepoxide and methyl orthosilicate is 2.2:1:2.2.

[0061] The amount of ethyl acetate added is 1 times that of the dihydroxyepoxide compound.

[0062] The amount of tetramethylammonium chloride added is 0.8% of the dihydroxyepoxide compound.

[0063] The amount of hydroquinone added is 0.5% of the dihydroxyepoxide compound.

[0064] The amount of dibutyltin dilaurate added is 1% of methyl orthosilicate.

[0065] Preparation Example 3 Modifier C

[0066] The mixture of 4-imidazolium acrylic acid, dihydroxyepoxide (ethylene glycol diglycidyl ether), and ethyl acetate, along with tetramethylammonium chloride and hydroquinone, is stirred at 110°C until the acid value is less than 5 mg KOH.

[0067] The molar ratio of the 4-imidazolium acrylic acid and the dihydroxyepoxide is 2.2:1.

[0068] The amount of ethyl acetate added is 1 times that of the dihydroxyepoxide compound.

[0069] The amount of tetramethylammonium chloride added is 0.8% of the dihydroxyepoxide compound.

[0070] The amount of hydroquinone added is 0.5% of the dihydroxyepoxide compound.

[0071] Preparation Example 4: Imine-containing cyclic borate esters

[0072] Under nitrogen protection, p-carboxyphenylboronic acid, diethanolamine and DMF were mixed and stirred at 50°C for 3 hours. After the reaction was completed, the mixture was recrystallized with petroleum ether, filtered and washed to obtain the final product.

[0073] The mass ratio of p-carboxyphenylboronic acid, diethanolamine, and DMF is 1.3:1:90.

[0074] Example 1: A long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system, comprising the following components by mass percentage: viscosity modifier 4%, anti-wear agent 2%, antioxidant 1%, rust inhibitor 0.2%, metal passivator 0.2%, defoamer 0.01%, and base oil to make up to 100%.

[0075] Viscosity improver: Mix modifier A and methyl methacrylate at a mass ratio of 25:75, add azobisisobutyronitrile (0.4% of the total mass of methyl methacrylate and modifier), react at 60℃ for 4 hours, and then react at 110℃ for 5 hours to obtain the product.

[0076] Anti-wear agent: Tricresol phosphate.

[0077] Antioxidant: Mix imino-containing cyclic borate ester and xylene at a mass ratio of 1:4, add diisocyanate (hexamethylene diisocyanate) dropwise, stir and react at 80℃ for 3h, add 4-(2H-benzotriazol-2-yl)-1,3-benzenediol, continue stirring and react for 3h, and remove xylene by rotary evaporation after the reaction is completed to obtain the product.

[0078] The mass ratio of the imino-containing cyclic borate ester, diisocyanate, and 4-(2H-benzotriazol-2-yl)-1,3-benzenediol is 1.4:1:1.3.

[0079] Rust inhibitor: Dodecenyl succinic acid, Jinzhou Chenghua New Materials Co., Ltd., T746.

[0080] Metal passivating agent: benzotriazole derivative, Jinzhou Chenghua New Materials Co., Ltd., T551.

[0081] Defoamer: Dimethyl silicone oil.

[0082] Base oil: A mixture of Group II hydrotreated base oil and pentaerythritol ester in a mass ratio of 8:2.

[0083] The Group II hydrotreated base oil is 150N Group II hydrotreated base oil, manufactured by Suzhou Sepahan Special Oils Co., Ltd.

[0084] The pentaerythritol ester has a viscosity index of 136 and a pour point of -58℃. It is manufactured by Yingkou Xinghuo Chemical Co., Ltd., and is classified as PE343.

[0085] The preparation process of the above-mentioned long-lasting and low-consumption lubricating medium for wide-temperature-range hydraulic systems includes the following steps: heating the base oil to 60°C and stirring to remove water; adding anti-wear agent, viscosity modifier, antioxidant and other additives in sequence, stirring for 20 minutes after each addition; continuing to stir for 3 hours until the system is uniform and transparent; filtering through a filter element, and dispensing after passing the test.

[0086] Example 2 is a long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system. The only difference from Example 1 is that its composition is as follows: by mass percentage, the raw materials include: viscosity improver 2%, anti-wear agent 1.5%, antioxidant 1.5%, rust inhibitor 0.1%, metal passivator 0.3%, defoamer 0.01%, and base oil to make up to 100%; the rest are the same.

[0087] Example 3 is a long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system. The only difference from Example 1 is that its composition is as follows: by mass percentage, the raw materials include: viscosity improver 3%, anti-wear agent 1.8%, antioxidant 1.2%, rust inhibitor 0.3%, metal passivator 0.1%, defoamer 0.01%, and base oil to make up to 100%; the rest are the same.

[0088] Comparative Example 1

[0089] The difference between this comparative example and Example 1 is that modifier A was replaced with modifier B in the viscosity improver preparation process; all other aspects are the same.

[0090] Comparative Example 2

[0091] The difference between this comparative example and Example 1 is that modifier A was replaced with modifier C in the preparation of the viscosity improver; all other aspects are the same.

[0092] Comparative Example 3

[0093] The difference between this comparative example and Example 1 is that in the preparation of the viscosity improver, modifier A was replaced with commercially available PMA viscosity improver, Shanxi Huaxin New Material Co., Ltd., T630; all other aspects are the same.

[0094] Comparative Example 4

[0095] The difference between this comparative example and Example 1 is as follows: Antioxidant: Imino-containing cyclic borate ester and xylene are mixed at a mass ratio of 1:4, diisocyanate (hexamethylene diisocyanate) is added dropwise, and the mixture is stirred at 80°C for 3 hours. 4-Bromophenol is added, and the mixture is stirred for another 3 hours. After the reaction is completed, xylene is removed by rotary evaporation.

[0096] The mass ratio of the imino-containing cyclic borate ester, diisocyanate, and 4-bromophenol is 1.4:1:1.3; all other components are the same.

[0097] Comparative Example 5

[0098] The difference between this comparative example and Example 1 is as follows: Antioxidant: commercially available 2,6-di-tert-butylphenol mixture, Jinzhou Chenghua New Material Co., Ltd., T502A; all other aspects are the same.

[0099] Comparative Example 6

[0100] The difference between this comparative example and Example 1 is as follows: Antioxidant: commercially available liquid butyl / octyl diphenylamine, Jinzhou Chenghua New Materials Co., Ltd., T5057; all other aspects are the same.

[0101] Comparative Example 7

[0102] The difference between this comparative example and Example 1 is as follows: Antioxidant: commercially available 2,6-di-tert-butylphenol mixture (Jinzhou Chenghua New Materials Co., Ltd., T502A) and commercially available liquid butyl / octyl diphenylamine (Jinzhou Chenghua New Materials Co., Ltd., T5057) in a mass ratio of 1:1; all other aspects are the same.

[0103] Performance testing:

[0104] The following performance tests were conducted on the long-lasting, low-consumption lubricating media for the wide-temperature-range hydraulic systems prepared in the above embodiments and comparative examples:

[0105] 1. Kinematic viscosity (40℃, 100℃, -24℃ and -40℃): GB / T 265;

[0106] 2. Viscosity index: GB / T 1995;

[0107] 3. Pour point: GB / T 3535;

[0108] 4. Rotating oxygen bomb life: SH / T 0193, measured under conditions of 150℃ and 0.6MPa oxygen pressure;

[0109] 5. Thermal oxidation stability: SH / T 0209.

[0110] Performance test results:

[0111] Table 1

[0112]

[0113] Table 2

[0114]

[0115] As can be seen from Tables 1 and 2, the long-lasting and low-consumption lubricating medium of the wide-temperature-range hydraulic system provided by the present invention has excellent low-temperature fluidity (low viscosity at -24℃ and -40℃), wide-temperature-range viscosity stability (slow viscosity change in the range of -40℃ to 100℃), excellent oxidation resistance and long service life (rotating oxygen bomb service life greater than 600 min, and slow acid value increase).

[0116] The changes in viscosity modifiers in Comparative Examples 1-3 resulted in increased viscosity, higher pour point, and decreased viscosity index of the obtained lubricating media at -24℃ and -40℃, while also affecting oxidation resistance and the life of rotating bomb.

[0117] The changes in antioxidants in Comparative Examples 4-7 resulted in a significant decrease in the antioxidant properties of the obtained lubricating media and the life of the rotating oxidizer.

[0118] Comparative Examples 1-7 show that the present invention effectively broadens the working temperature range of the lubricating medium by using specific viscosity modifiers and antioxidants, giving the hydraulic oil excellent low-temperature performance while extending the oil change cycle.

[0119] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system, characterized in that, By weight percentage, the raw materials include: base oil to make up the balance to 100%, viscosity improver 1-5%, anti-wear agent 0.5-3%, antioxidant 0.3-2%, and other additives 0.1-1%; The viscosity improver is obtained by reacting a modifier with methyl methacrylate; The modifier is obtained by reacting 4-imidazolium acrylic acid, dihydroxyepoxide and methyl orthosilicate.

2. The long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system according to claim 1, characterized in that, The base oil is one or more of the following: hydrotreated base oil, synthetic hydrocarbon oil, and ester oil; the hydrotreated base oil is one or more of the following: Group II hydrotreated base oil and Group III hydrotreated base oil; the synthetic hydrocarbon oil is selected from one or more of the following: polyalphaolefin PAO3, polyalphaolefin PAO4, polyalphaolefin PAO5, and polyalphaolefin PAO6; the ester oil is selected from one or more of the following: pentaerythritol ester, trimethylolpropane ester, neopentyl glycol ester, di-n-octyl adipate, 1,6-hexanediol di-n-octyl ester, di-n-octyl 3-methyladipate, and di(2-ethylhexyl) sebacate.

3. The long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system according to claim 2, characterized in that, The base oil is a mixture of Group II hydrotreated base oil and pentaerythritol ester in a mass ratio of 6-8:2-4.

4. The long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system according to any one of claims 1-3, characterized in that, The modifier is prepared by mixing 4-imidazolium acrylic acid, dihydroxyepoxide and ethyl acetate, adding tetramethylammonium chloride and hydroquinone, stirring at 100-120℃ until the acid value is less than 5 mg KOH, cooling to 70-90℃, adding methyl orthosilicate and dibutyltin dilaurate, and continuing to stir under nitrogen protection for 3-6 hours to obtain the modifier.

5. The long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system according to claim 4, characterized in that, The viscosity improver is prepared by mixing the improver and methyl methacrylate, adding azobisisobutyronitrile, reacting at 50-70℃ for 2-5 hours, and then reacting at 90-110℃ for 2-5 hours to obtain the product.

6. The long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system according to claim 4 or 5, characterized in that, The antioxidant is obtained by reacting an imino-containing cyclic borate ester and a diisocyanate with 4-(2H-benzotriazol-2-yl)-1,3-benzenediol; the imino-containing cyclic borate ester is obtained by reacting p-carboxyphenylboronic acid with diethanolamine.

7. The long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system according to claim 6, characterized in that, The method for preparing the imino-containing cyclic borate ester is as follows: under nitrogen protection, p-carboxyphenylboronic acid, diethanolamine and DMF are mixed and stirred at 40-60℃ for 1-3 hours. After the reaction is completed, the mixture is recrystallized with petroleum ether, filtered and washed to obtain the product.

8. The long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system according to claim 7, characterized in that, The antioxidant is prepared by mixing an imino-containing cyclic borate ester and xylene, adding diisocyanate dropwise, stirring and reacting at 75-85℃ for 3-5 hours, adding 4-(2H-benzotriazol-2-yl)-1,3-benzenediol, continuing to stir and react for 3-5 hours, and removing xylene by rotary evaporation after the reaction is completed.

9. The preparation process of the long-lasting, low-consumption lubricating medium for a wide-temperature-range hydraulic system according to any one of claims 1-8, characterized in that, The process includes the following steps: heating the base oil to 50-70℃ and stirring to remove water; adding anti-wear agent, viscosity improver, antioxidant and other additives in sequence, stirring for 10-30 minutes after each addition; continuing to stir for 1-3 hours until the system is uniform and transparent; filtering through a filter element, and dispensing after passing the test.

10. The application of the long-lasting, low-consumption lubricating medium of the wide-temperature-range hydraulic system according to any one of claims 1-8 in hydraulic systems of engineering machinery, mining equipment, or aerospace.

Images