Hydraulic oil composition as well as preparation method and application thereof

Abstract

The invention provides a hydraulic oil composition as well as a preparation method and application thereof, and belongs to the technical field of industrial oil for an engineering machinery hydraulic system. The hydraulic oil composition comprises base oil, a viscosity index improver, an antioxidant, an anti-wear agent, an anti-rust agent, a metal deactivator, a pour point depressant, an anti-foaming agent and a demulsifier, the base oil is selected from hydrofined base oil; the viscosity index improver is polymethacrylate; the pour point depressant is polymethacrylate. According to the composition disclosed by the invention, the base oil, the viscosity index improver and the pour point depressant are improved, and other additives are matched, so that the prepared hydraulic oil composition has excellent low-temperature fluidity, anti-rust property, wear resistance, high-temperature oxidation resistance and the like, and the oil product can meet all requirements of quality indexes.

Description

Technical Field

[0001] This invention belongs to the technical field of industrial oils for hydraulic systems of engineering machinery, and relates to a hydraulic oil composition, its preparation method and application. Background Technology

[0002] Because ambient temperature has a significant impact on construction machinery, especially at low temperatures where oil viscosity is high, damping force increases, and hydraulic pump efficiency deteriorates; conversely, at higher temperatures, oil viscosity is low, damping force decreases, and oil viscosity further reduces the stability of the hydraulic system. Therefore, oils need a high viscosity index to maintain stable viscosity in environments with wide temperature variations. The smaller the viscosity variation range of the oil in high and low temperature environments, the smaller the damping force variation, resulting in higher efficiency of the hydraulic pump and hydraulic system, thus improving the overall efficiency of the construction machinery. Hydraulic oil circulates in the hydraulic system of construction machinery, coming into contact with steel and copper components, requiring the oil to have certain rust-preventive properties to effectively protect the equipment from corrosion. The hydraulic pump performs work on the hydraulic oil, generating heat and accelerating oil oxidation; therefore, the oil needs excellent oxidation resistance.

[0003] Chinese invention patent CN115992025B discloses a hydraulic oil composition and its preparation method, which has excellent antioxidant properties. It includes an anti-wear agent, a rust inhibitor, a metal deactivator, an antioxidant, a viscosity index improver, a pour point depressant, and the balance being a lubricating base oil. The antioxidant in the composition gives the oil excellent antioxidant properties, which can meet the specifications of HV and HS hydraulic oils in GB11118.1-2011. It is especially suitable for the operating conditions of engineering machinery and equipment that operate at high temperatures for a long time.

[0004] Chinese invention patent CN112940829B provides a thickened hydraulic oil composition and its preparation method. The thickened hydraulic oil composition obtained by using a polymethacrylate viscosity index improver with both viscosity-increasing and pour point-depressing effects combined with an extreme pressure anti-wear agent has good viscosity-temperature properties and low-temperature starting performance, as well as good extreme pressure anti-wear properties. It can extend the service life of hydraulic oil and hydraulic components and improve the working efficiency of hydraulic machinery.

[0005] During operation, hydraulic oil continuously accumulates heat, causing its temperature to remain high and accelerating oxidation. Therefore, there is a need to develop hydraulic oil products with excellent high-temperature oxidation resistance. After years of technological accumulation, domestic deep hydrorefining technology for base oils has matured significantly, and additive performance has also improved substantially, providing the technical conditions for developing hydraulic oils. There is an urgent need to develop high-performance, low-cost hydraulic oil products. Summary of the Invention

[0006] To improve the viscosity-temperature performance, rust prevention, and oxidation resistance of hydraulic oils in existing technologies, this invention provides a hydraulic oil composition to meet the requirements of engineering machinery for stable high and low temperature performance, good anti-wear properties, and excellent oxidation resistance.

[0007] The technical solution of the present invention is as follows:

[0008] This invention provides a hydraulic oil composition comprising: a base oil, a viscosity index improver, an antioxidant, an anti-wear agent, a rust inhibitor, a metal passivator, a pour point depressant, an antifoaming agent, and a demulsifier; wherein the base oil is selected from hydrotreated base oils; the viscosity index improver is polymethyl methacrylate; and the pour point depressant is polymethyl methacrylate.

[0009] In this invention, the selection of base oil provides suitable viscosity and oxidation resistance. Polymethyl methacrylate (PMMA), as a viscosity index improver and pour point depressant, is an oil-soluble chain polymer compound. At high temperatures, the polymer molecules extend, increasing their hydrodynamic volume and leading to increased internal friction, i.e., increased viscosity. At low temperatures, the polymer molecules contract and curl up, reducing their hydrodynamic volume and internal friction, thus decreasing the viscosity of the oil.

[0010] Further, by weight percentage, it includes: 88.7-98.75% base oil, 1-5% viscosity index improver, 0.01-1% antioxidant, 0.01-2% anti-wear agent, 0.1-2% rust inhibitor, 0.01-0.1% metal passivator, 0.1-1% pour point depressant, 0.01-0.1% antifoaming agent, and 0.01-0.1% demulsifier.

[0011] Preferably, the composition comprises, by weight percentage: 93.9-98.75% base oil, 3-5% viscosity index improver, 0.5-1% antioxidant, 1-2% anti-wear agent, 1-2% rust inhibitor, 0.01-0.03% metal passivator, 0.5-1% pour point depressant, 0.05-0.1% antifoaming agent, and 0.05-0.1% demulsifier.

[0012] More preferably, by weight percentage, it comprises: 93.95% base oil, 5% viscosity index improver, 1% antioxidant, 2% anti-wear agent, 2% rust inhibitor, 0.03% metal passivator, 1% pour point depressant, 0.1% antifoaming agent, and 0.1% demulsifier.

[0013] Furthermore, the antioxidant is 2,6-di-tert-butyl-4-methylphenol and / or sulfurized bisphenol; the anti-wear agent is tricresyl phosphate; the rust inhibitor is dodecenylsuccinic acid and / or barium dinonylnaphthalenesulfonate; the metal passivator is a benzotriazole derivative; the antifoaming agent is selected from organosilicon antifoaming agents; and the demulsifier is selected from surfactants.

[0014] In this invention, 2,6-di-tert-butyl-4-methylphenol exhibits excellent antioxidant properties. Under high-temperature conditions, it protects the base oil from oxidation through its own oxidation, while the intermediate group can terminate the oxidation reaction, thus improving the oil's antioxidant properties. Tricresol phosphate, as an anti-wear agent, has good anti-wear properties and low corrosiveness. Under load on the metal surface, the anti-wear agent reacts with the metal surface to form a metal protective film with low shear strength, thereby preventing metal wear. Benzotriazole derivatives, as metal passivators, form stable metal films and chelates through film formation and chelation, exhibiting a certain synergistic effect with antioxidants, effectively reducing metal corrosion and oil oxidation. Dodecenylsuccinic acid compounds have excellent rust-preventive properties. During the use of lubricating oil, they can chemically react with metals to form a metal oxide film, effectively protecting the metal and preventing corrosion. Methyl silicone oil-type antifoaming agents have good defoaming properties and air release properties, ensuring the continuity of antifoaming during use. Surfactants can adhere to the surface of base oil and other additive molecules, enabling the oil to separate rapidly upon contact with water.

[0015] Furthermore, the hydrotreated base oil is selected from 150N base oil; wherein, the kinematic viscosity at 40°C is not less than 30 mmHg. 2 / s, open flash point not lower than 180℃, pour point not lower than -18℃.

[0016] Furthermore, the viscosity index improver, polymethyl methacrylate, has a molecular weight of 200,000-300,000 and a side chain carbon atom count of 15-30. Based on the characteristics of the base oil used in this invention, a polymethyl methacrylate with a molecular weight of 200,000-300,000 is preferred, and when its mass percentage is 5%, it can ensure that the kinematic viscosity of the oil at -18°C is ≤1500 mmHg. 2 / s.

[0017] Furthermore, the pour point depressant polymethacrylate has a molecular weight of 80,000-120,000 and a side chain carbon atom count of 10-20.

[0018] The present invention also provides a method for preparing any of the above-mentioned hydraulic oil compositions, namely, mixing a viscosity index improver, an antioxidant, an anti-wear agent, a rust inhibitor, a metal passivator, a pour point depressant, an antifoaming agent, a demulsifier, and a base oil, heating the mixture to 55-65°C, and stirring it thoroughly for 1-2 hours to complete the blending preparation.

[0019] The present invention also provides the application of the hydraulic oil composition described above or the hydraulic oil composition prepared by any of the preparation methods described above in the hydraulic system of engineering machinery.

[0020] The hydraulic system of the engineering machinery includes any one of gear pumps, piston pumps, vane pumps, and screw pumps.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The hydraulic oil composition of this invention is made of hydrorefined base oil combined with specific types of viscosity index improvers and pour point depressants. With the help of additives such as antioxidants, anti-wear agents, and rust inhibitors, it has excellent low-temperature fluidity, rust prevention, and anti-wear properties, especially excellent high-temperature oxidation resistance. At the same time, by limiting the dosage of each component and basic parameters such as viscosity index improvers, its fluidity, rust prevention, and anti-wear properties are further improved, which can ensure the smooth operation of the hydraulic system of engineering machinery in harsh outdoor environments. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified, specific conditions were applied in the examples. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0024] Examples 1-3

[0025] Add 150N base oil (model: 150N; kinematic viscosity at 40℃: 30 mmHg) according to the proportions in Table 1. 2 / s, flash point is 220℃, pour point is -24℃), polymethyl methacrylate (model: 7-310; molecular weight 250,000, side chain carbon number 30), 2,6-di-tert-butyl-4-methylphenol (model: T501; kinematic viscosity 27 mm). 2 / s), Tricresol phosphate (model: T306), Dodecenylsuccinic acid (model: T746; total acid value 307 mg KOH / g, pH value 4.6), Benzotriazole derivative (kinematic viscosity 89.3 mm). 2 / s), polymethyl methacrylate (model VISCOPLEX 1-156, molecular weight 120,000, side chain carbon number 20), methyl silicone oil (1# composite antifoaming agent, model: H2030), polyether polymer (model: DL32; kinematic viscosity 107.4mm). 2 Mix the hydraulic oil composition by stirring at 60±5℃ for 1-2 hours to complete the blending.

[0026] Table 1. Composition and Dosage of Hydraulic Oil Composition

[0027]

[0028] The performance test results of the hydraulic oil compositions prepared in the above embodiments are shown in Table 2.

[0029] Table 2. Performance test results of the hydraulic oil compositions prepared by blending in the examples.

[0030]

[0031] The hydraulic oil compositions of Examples 1-3 have a kinematic viscosity of 1470 mmHg at -18°C. 2 The wear scar diameter is between 0.4 and 0.5 mm / s, indicating that the hydraulic oil has good low-temperature fluidity and anti-wear properties, which can effectively ensure the smooth operation of the hydraulic system of engineering machinery in harsh environments.

[0032] Comparative Example 1

[0033] The only difference between this comparative example and Example 1 is the viscosity index improver. The viscosity index improver in this comparative example is T612 (ethylene propylene copolymer), and the blending method is the same as in Example 1.

[0034] Comparative Example 2

[0035] The only difference between this comparative example and Example 1 is the pour point depressant. The pour point depressant in this comparative example is T803 (poly-α-olefin), and the mixing method is the same as in Example 1.

[0036] Comparative Example 3

[0037] The only difference between this comparative example and Example 1 is the kinematic viscosity of the base oil. The kinematic viscosity of the base oil in this comparative example is 28 mm. 2 / s, the mixing method is the same as in Example 1.

[0038] Comparative Example 4

[0039] The only difference between this comparative example and Example 1 is the base oil. The base oil in this comparative example is CTL6 base oil, and the blending method is the same as in Example 1.

[0040] Comparative Example 5

[0041] The only difference between this comparative example and Example 1 is the amount of viscosity index improver used. In this comparative example, the amount of viscosity index improver used is 6%, the amount of base oil used is 92.9%, and the blending method is the same as in Example 1.

[0042] Comparative Example 6

[0043] The only difference between this comparative example and Example 1 is the number of carbon atoms in the viscosity index improver. The viscosity index improver in this comparative example has 40 carbon atoms, and the mixing method is the same as in Example 1.

[0044] The hydraulic oil compositions prepared by blending the above comparative proportions and the commercially available product (Great Wall HM32) were tested using the same test methods as in Examples 1-3, and the results are shown in Table 3.

[0045] Table 3. Performance test results of hydraulic oil compositions prepared by comparative blending

[0046]

[0047] The performance data of the hydraulic oil composition by comparison show that the present invention, through the selection of base oil, viscosity index improver and pour point depressant, enables the hydraulic oil composition to have excellent low temperature fluidity, rust prevention, wear resistance and oxidation resistance, especially excellent thermal stability, and the oil can meet all quality requirements.

[0048] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A hydraulic oil composition, characterized in that, The hydraulic oil composition comprises: base oil, viscosity index improver, antioxidant, anti-wear agent, rust inhibitor, metal passivator, pour point depressant, antifoaming agent, and demulsifier; the base oil is selected from hydrotreated base oil; the viscosity index improver is polymethyl methacrylate; and the pour point depressant is polymethyl methacrylate.

2. The hydraulic oil composition according to claim 1, characterized in that, By weight percentage, it includes: base oil 88.7-98.75%, viscosity index improver 1-5%, antioxidant 0.01-1%, anti-wear agent 0.01-2%, rust inhibitor 0.1-2%, metal passivator 0.01-0.1%, pour point depressant 0.1-1%, antifoaming agent 0.01-0.1%, and demulsifier 0.01-0.1%.

3. The hydraulic oil composition according to claim 2, characterized in that, By weight percentage, it includes: base oil 93.9-98.75%, viscosity index improver 3-5%, antioxidant 0.5-1%, anti-wear agent 1-2%, rust inhibitor 1-2%, metal passivator 0.01-0.03%, pour point depressant 0.5-1%, antifoaming agent 0.05-0.1%, and demulsifier 0.05-0.1%.

4. The hydraulic oil composition according to claim 3, characterized in that, By weight percentage, it includes: 93.95% base oil, 5% viscosity index improver, 1% antioxidant, 2% anti-wear agent, 2% rust inhibitor, 0.03% metal passivator, 1% pour point depressant, 0.1% antifoaming agent, and 0.1% demulsifier.

5. The hydraulic oil composition according to any one of claims 1-4, characterized in that, The antioxidant is 2,6-di-tert-butyl-4-methylphenol and / or sulfurized bisphenol; the anti-wear agent is tricresyl phosphate; the rust inhibitor is dodecenylsuccinic acid and / or barium dinonylnaphthalenesulfonate; the metal passivator is a benzotriazole derivative; the antifoaming agent is selected from organosilicon antifoaming agents; and the demulsifier is selected from surfactants.

6. The hydraulic oil composition according to claim 1, characterized in that, The hydrotreated base oil is selected from 150N base oil; wherein, the kinematic viscosity at 40°C is not less than 30 mmHg. 2 / s, open flash point not lower than 180℃, pour point not lower than -18℃.

7. The hydraulic oil composition according to claim 1, characterized in that, The viscosity index improver, polymethyl methacrylate, has a molecular weight of 200,000-300,000 and a side chain carbon atom count of 15-30.

8. The hydraulic oil composition according to claim 7, characterized in that, The pour point depressant, polymethyl methacrylate, has a molecular weight of 80,000-120,000 and a side chain carbon atom count of 10-20.

9. The method for preparing the hydraulic oil composition according to any one of claims 1-8, characterized in that, Mix viscosity index improver, antioxidant, anti-wear agent, rust inhibitor, metal passivator, pour point depressant, antifoaming agent, demulsifier and base oil, heat to 55-65℃, mix and stir thoroughly for 1-2 hours to complete the blending preparation.

10. The application of the hydraulic oil composition according to any one of claims 1-8 or the hydraulic oil composition prepared by the preparation method according to claim 9 in the hydraulic system of engineering machinery, characterized in that, The hydraulic system of the engineering machinery includes any one of gear pumps, piston pumps, vane pumps, and screw pumps.

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