A hydraulic oil composition

Abstract

The application discloses a hydraulic oil composition. The hydraulic oil composition comprises the following components in percentage by mass: 0.5-1.0% of an antioxidant, 0.2-0.5% of an ionic liquid, 0.05-0.10% of a detergent, 0.05-0.10% of a dispersant, 0.03-0.05% of an anti-rust agent, 0.01-0.02% of a light stabilizer and 0.01-0.02% of an anti-foaming agent, and the rest is base oil. The hydraulic oil composition can be used as an anti-wear hydraulic oil for a high-pressure plunger pump, and has excellent anti-wear property, oxidation resistance, filtration property and the like. In addition, the hydraulic oil composition passes the Komatsu HPV35+35 high-pressure plunger pump bench test, and can be applied to a hydraulic system of a harsh high-pressure equipment such as a large excavator.

Description

Technical Field

[0001] This invention relates to a hydraulic oil composition. Background Technology

[0002] Excavators are often referred to as the "barometer" of construction machinery, and their hydraulic systems place great emphasis on the service life and anti-wear performance of hydraulic oil. As a crucial component of the excavator's hydraulic system, the performance and specifications of hydraulic oil are constantly being improved with the upgrading of excavator hydraulic equipment, with working pressures reaching over 40 MPa. Hydraulic oil tanks are also gradually being miniaturized. The reduction in tank size and the increase in working pressure mean that the hydraulic oil circulates at high pressure and high speed in a more compact space, maintaining an operating temperature of 80-100℃ or even higher. This places higher demands on the speed of actuators, system pressure, and the precision of mechanism movements. High temperature is a major factor causing hydraulic oil oxidation and degradation. Increased oil temperature requires better thermal oxidation stability; the oil should also have good defoaming and hydrolytic stability. The introduction of electro-hydraulic servo valves and proportional solenoid alarms into the hydraulic system creates highly sensitive, complex, and tightly fitted components, thus requiring hydraulic oil with high cleanliness and good filtration properties. High load is a major factor causing wear on hydraulic pumps and other components; the oil should provide good load-bearing and anti-wear properties during lubrication. Major international excavator manufacturers offer specialized hydraulic oils designed for their specific products to meet the performance requirements of the equipment. Currently, most domestically produced excavators use hydraulic oils with a recommended oil change interval of less than 3000 hours, lagging behind the specialized oils offered by international excavator manufacturers.

[0003] Due to differences in hydraulic pumps, application equipment, and working environments, there are many types of hydraulic oils, each with varying performance requirements. CN103087807 provides a high-purity hydraulic oil composition that, in addition to possessing the performance of traditional hydraulic oils, maintains the cleanliness of the hydraulic oil system. CN114507554 provides a hydraulic oil composition with excellent low-temperature performance, shear stability, thermal stability, and overall performance, while also exhibiting high biodegradability and low biotoxicity, meeting the operating conditions of hydraulic equipment in environmentally sensitive areas. CN112940829 provides a hydraulic oil composition with a high viscosity index, exhibiting good anti-wear and oxidation stability properties, extending the service life of hydraulic oil and hydraulic components, and improving the working efficiency of hydraulic machinery. CN 112592755 provides a high-efficiency ashless hydraulic oil composite composition, which can be used to blend ashless anti-wear hydraulic oils and possesses good anti-wear and anti-oxidation properties. However, currently, general-purpose HM anti-wear hydraulic oil is used in high-pressure piston pumps for a long time. In the middle and late stages of its life, it often produces a lot of sludge, slow hydraulic system operation, valve jamming, filter blockage, and poor oil filtration after contact with water. Moreover, there are no patents in China that describe anti-wear hydraulic oil compositions developed specifically for the performance characteristics of high-end equipment such as large excavators. Summary of the Invention

[0004] In order to at least partially solve the above-mentioned technical problems existing in the prior art, the present invention provides a hydraulic oil composition with excellent overall performance, which is suitable for the hydraulic system of demanding high-pressure equipment such as large excavators.

[0005] As one aspect of the present invention, a hydraulic oil composition is disclosed, the hydraulic oil composition comprising, by weight percentage: 0.5-1.0% antioxidant, 0.2-0.5% ionic liquid, 0.05-0.10% detergent, 0.05-0.10% dispersant, 0.03-0.05% rust inhibitor, 0.01-0.02% light stabilizer and 0.01-0.02% antifoaming agent, with the balance being base oil;

[0006] The ionic liquid is as shown in formula (Ⅰ):

[0007]

[0008] In equation (Ⅰ), the value of n is in the range of 12≤n≤18, where n is an integer.

[0009] By adopting the above technical solution, the ionic liquid of the present invention is further preferably a diimidazole cation and a diphosphate anion. Using the ionic liquid to prepare lubricating oil additives can improve the metal passivation activity and rust prevention performance of the lubricating oil additives, and improve the protective ability of lubricating oil to metals. It has excellent solubility, and the C12-18 alkyl chain increases the solubility. It has excellent compatibility and ensures that it dissolves in oil under high and low temperature conditions.

[0010] In one or more possible embodiments, the antioxidant includes: phenolic antioxidants, auxiliary antioxidants, and zinc dialkyl dithiophosphate;

[0011] The mass ratio of the phenolic antioxidant to the auxiliary antioxidant is 5:1.

[0012] By adopting the above technical solution, an antioxidant compounded with phenolic antioxidants and auxiliary antioxidants not only has excellent antioxidant performance, but can also effectively complex metal ions and has a metal passivation effect, thereby greatly reducing the generation of sludge. In addition, the antioxidant has low volatility, which can further reduce the volatilization of antioxidants at high temperatures.

[0013] In one or more possible embodiments, the phenolic antioxidant is as shown in formula (II):

[0014]

[0015] In equation (II), the value of n is in the range of 12≤n≤18, where n is an integer;

[0016] The auxiliary antioxidant is a mixture of pentaerythritol bis(diphosphite) and pentaerythritol tetra(3-lauryl thiopropionate) in any ratio, wherein the pentaerythritol bis(diphosphite) is as shown in formula (III):

[0017]

[0018] By adopting the above technical solution, pentaerythritol bis(diphosphite) and pentaerythritol tetra(3-lauryl thiopropionate) are selected as auxiliary antioxidants. Compared with traditional thioester antioxidants, their comprehensive performance is superior. When used in combination with hindered phenolic primary antioxidants and zinc dialkyl dithiophosphate, the thermal stability of hydraulic oil can be significantly improved.

[0019] In one or more possible embodiments, the mass ratio of the pentaerythritol bis(diphosphite) to the pentaerythritol tetra(3-lauryl thiopropionate) is 1:1.

[0020] In one or more possible embodiments, the detergent can be any commercially available material, and the present invention preferably uses calcium salicylate T109B with an alkalinity of 280-300.

[0021] By adopting the above technical solution, the detergent of the present invention can better dissolve and disperse oil sludge, while reducing the particle size of the coated oil sludge, so that the oil sludge is reasonably distributed. Large particles are discharged after passing through the filter, while small particles of oil sludge are suspended in the oil and will not be deposited on the valve, resulting in good permeability of the final oil product. In addition, calcium salicylate T109B with an alkalinity of 280-300 has excellent detergent properties, high temperature stability, strong neutralization ability, and excellent compounding performance with calcium salts of aromatic sulfonic acids.

[0022] In one or more possible embodiments, the dispersant can be any commercially available material. To further enhance the dispersing effect of hydraulic oil on sludge, polyisobutylene succinimide is preferred in this invention.

[0023] In one or more possible embodiments, the rust inhibitor can be any commercially available material, but the present invention preferably uses a calcium salt of an aromatic sulfonic acid.

[0024] By adopting the above technical solution, the preferred rust inhibitor of the present invention can form an adsorbent protective film on the metal surface, thereby inhibiting the contact between water and oxygen and preventing the metal from rusting.

[0025] In one or more possible embodiments, the antifoaming agent is methyl silicone oil T903.

[0026] By adopting the above technical solution, the preferred antifoaming agent of the present invention overcomes the shortcomings of low solubility, poor air release and poor stability of silicone oil, and has excellent foam suppression and solubility.

[0027] In one or more possible embodiments, the light stabilizer can be any commercially available material, with dimethyl sebacate being preferred in this invention.

[0028] By adopting the above technical solution, the light stabilizer preferred by the present invention has good compatibility with lubricating oil, effectively improving thermal stability and weather resistance, and reducing the discoloration trend of hydraulic oil.

[0029] In one or more possible embodiments, the base oil can be any commercially available material, and the base oil of the present invention is preferably a mixture of PCL150N and PCL500N.

[0030] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of this application include at least the following:

[0031] The hydraulic oil composition of the present invention can be used as an anti-wear hydraulic oil for high-pressure plunger pumps. It has excellent anti-wear, anti-oxidation, and filterability properties. It has passed the bench test of Komatsu HPV35+35 high-pressure plunger pump and can be used in the hydraulic systems of demanding high-pressure equipment such as large excavators.

[0032] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0033] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0034] Figure 1 The image shows the appearance of the hydraulic pump after the hydraulic oil composition of Example 1 of the present invention has been tested on an HPV35+35 bench.

[0035] Figure 2 The image shows the plunger appearance after the hydraulic oil composition of Example 1 of the present invention was tested on an HPV35+35 bench. Detailed Implementation

[0036] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. These are exemplary embodiments of the present disclosure; however, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0039] In the description of this invention, it should be noted that the terms "comprising", "including", "having", "containing", etc., are all open-ended terms, meaning that they include but are not limited to.

[0040] The present invention will be further described below with reference to specific embodiments. The scope of protection of the present invention is not limited by the following embodiments. The main materials involved in the embodiments are all conventional commercially available products.

[0041] Example 1

[0042] The constituent raw materials and their mass percentages of the hydraulic oil composition in this embodiment are shown in Table 1 below:

[0043] Table 1. Composition of the hydraulic oil composition in Example 1 and its mass percentage.

[0044]

[0045] Example 2

[0046] The constituent raw materials and their mass percentages of the hydraulic oil composition in this embodiment are shown in Table 2 below:

[0047] Table 2. Composition of the hydraulic oil composition in Example 2 and its mass percentage.

[0048]

[0049]

[0050] Example 3

[0051] The constituent raw materials and their mass percentages of the hydraulic oil composition in this embodiment are shown in Table 3 below:

[0052] Table 3. Composition of the hydraulic oil composition in Example 3 and its mass percentage.

[0053]

[0054]

[0055] Using the above embodiments as examples, the inventors conducted key performance tests such as thermal stability, filtration performance, and oxidative stability, as well as a Komatsu HPV35+35 bench test. The results are shown in Table 4 below:

[0056] Table 4 Performance Test Data

[0057]

[0058]

[0059] The performance test data in Table 4 show that the hydraulic oil composition prepared in this invention exhibits excellent anti-wear properties, oxidation resistance, storage stability, anti-foaming properties, and friction characteristics. The total sediment weight for thermal stability is less than 10 mg, and the anti-wear performance was tested on a Komatsu HPV35+35 bench. Figure 1 and Figure 2 As can be seen, the hydraulic oil composition prepared in Example 1 has a smooth and flat appearance after HPV35+35 bench testing, with no obvious wear, further demonstrating that the hydraulic oil composition prepared in this invention has excellent anti-wear properties.

[0060] Furthermore, based on the performance test data in Table 4, it can be seen that the static friction coefficient of the hydraulic oil composition of the present invention meets the requirements, and it also has excellent filterability, antifoaming properties, etc., and its key performance meets the stringent requirements of the high-pressure plunger pump hydraulic system.

[0061] Although the invention has been described in considerable detail and particularly with regard to several of the described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment, thereby effectively covering the intended scope of the invention. Furthermore, the invention has been described above with respect to embodiments foreseeable by the inventors in order to provide a useful description, and non-substantial modifications to the invention that have not yet been foreseen may still represent equivalent modifications.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A hydraulic oil composition, characterized in that, By weight percentage, it comprises the following raw materials: antioxidant 0.5-1.0%, ionic liquid 0.2-0.5%, detergent 0.05-0.10%, dispersant 0.05-0.10%, rust inhibitor 0.03-0.05%, light stabilizer 0.01-0.02%, and antifoaming agent 0.01-0.02%, with the balance being base oil; The ionic liquid is as shown in formula (Ⅰ): （Ⅰ）， In equation (Ⅰ), the value of n is in the range of 12≤n≤18, where n is an integer; The antioxidants are: phenolic antioxidants, auxiliary antioxidants, and zinc dialkyl dithiophosphate; The mass ratio of the phenolic antioxidant to the auxiliary antioxidant is 5:1; The phenolic antioxidant is as shown in formula (II): （Ⅱ）， In equation (II), the value of n is in the range of 12≤n≤18, where n is an integer; The auxiliary antioxidant is a mixture of pentaerythritol bis(diphosphite) and pentaerythritol tetra(3-lauryl thiopropionate) in any ratio, wherein the pentaerythritol bis(diphosphite) is as shown in formula (III): （Ⅲ）； The detergent is selected from calcium salicylate T109B with an alkalinity of 280-300; the dispersant is polyisobutylene succinimide; the rust inhibitor is a calcium salt of aromatic sulfonic acid; the light stabilizer is dimethyl sebacate; and the base oil is a mixture of PCL150N and PCL500N.

2. The hydraulic oil composition according to claim 1, characterized in that, The mass ratio of the pentaerythritol bis(diphosphite) to the pentaerythritol tetra(3-lauryl thiopropionate) is 1:

1.

3. The hydraulic oil composition according to claim 1, characterized in that, The antifoaming agent is methyl silicone oil T903.

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