An ultra-low temperature zinc-free hydraulic oil for engineering machinery in cold regions and a preparation method thereof

Abstract

The application discloses an ultralow-temperature zinc-free hydraulic oil for engineering machinery in severe cold regions and a preparation method thereof. The ultralow-temperature zinc-free hydraulic oil comprises the following components in percentage by mass: base oil 80-89%, viscosity index improver 10-19%, anti-wear agent 0.3-1.0%, antioxidant 0.1-1.5%, calcium-based additive 0.01-0.15%, demulsifier 0.005-0.02% and defoaming agent 0.005-0.02%. The ultralow-temperature zinc-free hydraulic oil for engineering machinery in severe cold regions has excellent low-temperature fluidity and viscosity-temperature property; the kinematic viscosity of the oil is less than 1500mm 2 / s at-30 DEG C, the kinematic viscosity is less than 4500mm 2 / s at-40 DEG C, and the oil is suitable for mobile hydraulic systems in some high-latitude regions (the lowest temperature in winter is close to-40 DEG C). The ultralow-temperature zinc-free hydraulic oil for engineering machinery in severe cold regions prepared by the application has excellent high-temperature detergency. The zinc-free hydraulic oil can maintain the state of clear and transparent appearance, stable low acid value and extremely low oil sludge content under high-temperature and long-period operation conditions.

Description

Technical Field

[0001] This invention relates to an ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions and its preparation method. Background Technology

[0002] The coverage of cold and frigid regions both domestically and internationally is extensive, with some areas experiencing winter temperatures dropping to tens of degrees below zero. Conventional cryogenic hydraulic oils can only ensure the smooth start-up of hydraulic systems in construction machinery within the range of -20℃ to -25℃. However, in the temperature range of -30℃ to -40℃, the kinematic viscosity of cryogenic hydraulic oil increases significantly, exceeding the viscosity limit required for hydraulic system startup. This prevents construction machinery from operating smoothly in some high-latitude regions during winter. For outdoor operations in these areas, in addition to excellent anti-wear, anti-oxidation, and anti-corrosion properties, the low-temperature start-up and low-temperature pumpability of the hydraulic oil used in construction machinery are particularly important. In frigid regions, the hydraulic system requirements for construction machinery include: the hydraulic oil must possess excellent low-temperature start-up properties and suitable high-temperature hydraulic efficiency to ensure that the hydraulic oil's kinematic viscosity remains below the startup limit under low-temperature operating conditions. Summary of the Invention

[0003] In order to at least partially solve the technical problems existing in the prior art, the present invention provides an ultra-low temperature zinc-free hydraulic oil for engineering machinery in cold regions and its preparation method, so that when the hydraulic oil is used in engineering machinery in cold regions, it can have excellent low temperature fluidity and viscosity-temperature properties, thereby meeting the oil requirements of mobile hydraulic systems in cold regions.

[0004] As one aspect of the present invention, a low-temperature zinc-free hydraulic oil for engineering machinery in extremely cold regions is disclosed, comprising the following raw materials by mass percentage: 80-89% base oil, 10-19% viscosity index improver, 0.3-1.0% anti-wear agent, 0.1-1.5% antioxidant, 0.01-0.15% calcium-based additive, 0.005-0.02% demulsifier, and 0.005-0.02% defoamer.

[0005] In one or more possible embodiments, the base oil is selected from those with a kinematic viscosity of 2.0–5.0 mm at 100°C. 2 Group II and / or Group III base oils between / s.

[0006] In one or more possible embodiments, the viscosity index improver is a mixture of linear polymethacrylate and comb-shaped polymethacrylate in any ratio with an SSI index less than 40.

[0007] In one or more possible embodiments, the linear polymethacrylate is as shown in formula (I):

[0008]

[0009] In formula (I), the value of m ranges from 200 to 300; the molecular weight of R ranges from 10 to 300.

[0010] In one or more possible embodiments, the comb-shaped polymethacrylate is as shown in formula (II):

[0011]

[0012] In formula (II), the molecular weight of R is in the range of 5000 to 10000.

[0013] In one or more possible embodiments, the anti-wear agent is selected from one or more of dibutyl phosphite, tricresyl phosphate, or triphenyl thiophosphate.

[0014] In one or more possible embodiments, the antioxidant is 2,6-di-tert-butyl-mixed phenols and / or butyloctyl diphenylamine.

[0015] In one or more possible embodiments, the calcium-based additive is selected from one or more of dinonylnaphthalene sulfonate, salicylate, or sulfide alkylphenol salts.

[0016] In one or more possible embodiments, the demulsifier is a polyether-type demulsifier.

[0017] In one or more possible embodiments, the defoamer is a silicone-containing composite antifoamer.

[0018] In one or more possible embodiments, the zinc-free hydraulic oil has a kinematic viscosity of 28.8–31.2 mm at 40°C. 2 / s, viscosity index not less than 250, pour point not exceeding -45℃.

[0019] As another aspect of the present invention, a method for preparing the aforementioned ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions is provided, the method comprising the following steps:

[0020] S1. Under stirring conditions, add base oil, viscosity index improver, anti-wear agent, antioxidant and calcium-based additive in sequence, and heat to mix;

[0021] S2. Under stirring conditions, continue to add demulsifier and defoamer to the mixture obtained in S1 in sequence to obtain ultra-low temperature zinc-free hydraulic oil.

[0022] The ultra-low temperature zinc-free hydraulic oil for construction machinery in frigid regions described in this invention exhibits excellent low-temperature fluidity and viscosity-temperature characteristics. At -30°C, the kinematic viscosity of this oil is less than 1500 mmHg. 2 / s; kinematic viscosity less than 4500 mm³ at -40℃. 2 / s, suitable for the oil needs of mobile hydraulic systems in some high-latitude regions (where the lowest winter temperature is close to -40℃).

[0023] The ultra-low temperature zinc-free hydraulic oil prepared in this invention for engineering machinery in frigid regions exhibits excellent high-temperature detergency. This zinc-free hydraulic oil maintains a clear and transparent appearance, a stable low acid value, and extremely low sludge content even under high temperatures and long-term operating conditions.

[0024] The present invention relates to an ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions. It adopts a compounding method of linear and comb-shaped polymethyl methacrylate viscosity index improver, which can effectively reduce the amount of viscosity index improver (hereinafter referred to as "viscosity index improver") in the oil, thereby improving the shear stability of the hydraulic oil and keeping the shear stability of tapered rollers below 20%. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below: The embodiments of the present invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The process parameters in the following embodiments that do not specify specific conditions are generally in accordance with conventional conditions.

[0026] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0027] The inventors, referring to patents CN111218325A, CN111019743A, CN110484339A, CN109652178A, CN108977260A, and CN102757841A, implemented related technical solutions and found that the ultra-low temperature hydraulic oils prepared by these solutions did not meet their expectations. Therefore, the inventors, through further research and development, created this invention.

[0028] 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 sources of materials involved in the embodiments are shown in Table 1 below. Other materials not specified are all conventional commercially available products.

[0029] Table 1 Material Source Description

[0030] Serial Number materials Model / Specification factory 1 Triphenyl thiophosphate T309 Jinzhou Shengda 2 Trimethyl phosphate T306 Shandong Polymer Chemical 3 dibutyl phosphite T304 Hebei Tuochi 4 2,6-Di-tert-butyl-mixed phenols T502A Jinzhou Runda 5 Butyloctyl diphenylamine L57 Xinxiang Ruifeng 6 Calcium dinonylnaphthalenesulfonate 729 King Company 7 Calcium alkylphenol sulfide 115B Xinxiang Ruifeng 8 Linear polymethacrylate SCR178A Shenyang Great Wall 9 comb-shaped polymethacrylate VPL3-195 Evonik

[0031] The hydraulic oils prepared in the following examples or comparative examples were all prepared by the following steps:

[0032] In a mixing tank, base oil, viscosity index improver, anti-wear agent, antioxidant, and calcium-based additive are added in sequence, and then heated and stirred for 0.5-1 hour. Next, demulsifier is added to the mixture and stirred for 0.5-1 hour. Finally, defoamer is added and stirred for 0.5-1 hour to obtain the hydraulic oil product.

[0033] Example 1

[0034] The raw materials and their contents of the zinc-free hydraulic oil in this embodiment are shown in Table 2:

[0035] Table 2 Material composition and content of Example 1

[0036]

[0037] Example 2

[0038] The raw materials and their contents of the zinc-free hydraulic oil in this embodiment are shown in Table 3:

[0039] Table 3 Material composition and content of Example 2

[0040]

[0041]

[0042] In the course of experimental research, in order to compensate for the disadvantages of hydraulic oil in extremely cold regions as much as possible, the inventors made some modifications to the raw materials of the hydraulic oil. Experimental subjects with mediocre or poor performance were selected as comparative examples of this invention. The following are comparative examples 1 to 3 of this invention.

[0043] Comparative Example 1

[0044] The composition and content of the zinc-free hydraulic oil in this comparative example are shown in Table 4:

[0045] Table 4. Material composition and content of Comparative Example 1

[0046]

[0047]

[0048] Comparative Example 2

[0049] The composition and content of the zinc-free hydraulic oil in this comparative example are shown in Table 5:

[0050] Table 5. Material composition and content of Comparative Example 2

[0051]

[0052] Comparative Example 3

[0053] The composition and content of the zinc-free hydraulic oil in this comparative example are shown in Table 6:

[0054] Table 6. Material composition and content of Comparative Example 3

[0055]

[0056] Comparative Example 4

[0057] The composition and content of the zinc-free hydraulic oil in this comparative example are shown in Table 7:

[0058] Table 7. Material composition and content of Comparative Example 4

[0059]

[0060]

[0061] The inventors conducted the following performance tests on Examples 1-2 and Comparative Examples 1-4, and recorded the performance test results of Examples 1-2 and Comparative Examples 1-4 in Tables 8 and 9 below.

[0062] Table 8 Performance test results of Examples 1-2

[0063]

[0064] Table 9 Performance test results for comparative examples 1-4

[0065]

[0066] Based on Examples 1-2 and Comparative Examples 1-4, and in conjunction with the performance test results in Tables 8 and 9, we can see that:

[0067] Comparing Example 1 and Comparative Example 1, it can be seen that when blending cryogenic hydraulic oils with the same kinematic viscosity and viscosity index at 40°C, the shear stability of the traditional linear viscosity index enhancer scheme is 38%, significantly higher than the shear stability value (24%) of the linear and comb-like composite scheme. This indicates that the beneficial effect of combining linear and comb-like viscosity index enhancers is a significant improvement in the shear stability of the oil. Similarly, comparing Example 2 and Comparative Example 2, it can be seen that when blending cryogenic hydraulic oils with the same kinematic viscosity at 40°C, the scheme using only the comb-like viscosity index enhancer has a kinematic viscosity of 21.35 at 40°C, significantly lower than the kinematic viscosity of 31.65 at 40°C for the linear and comb-like composite scheme. This indicates that the beneficial effect of combining linear and comb-like viscosity index enhancers ensures that the oil possesses both excellent low-temperature fluidity and viscosity-temperature characteristics, improving the oil's adaptability to all seasons.

[0068] Furthermore, through Examples 1-2 and Comparative Examples 1-2, we can also find that the effects of using linear polymethyl methacrylate viscosity indexers or comb-shaped polymethyl methacrylate viscosity indexers alone or without using them are weaker than the performance effects of using a combination of the two viscosity indexers in terms of viscosity-temperature properties, low-temperature fluidity, and shear stability of the prepared oils.

[0069] In summary, the ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions prepared by this invention has excellent low-temperature start-up performance, excellent viscosity-temperature performance, water separation, air release, anti-foaming properties, shear stability, and high-temperature detergency properties, which can meet the requirements of cold start-up and no oil change in all seasons for engineering machinery in high-latitude cold regions.

[0070] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All modifications or applications made in accordance with the above embodiments are within the scope of protection of this technical solution.

[0071] Although specific embodiments of the invention have been described in detail, those skilled in the art will understand that various modifications and substitutions can be made to those details based on all the teachings disclosed, and all such changes are within the scope of protection of this invention. The full scope of this invention is given by the appended claims and any equivalents thereof.

Claims

1. A low-temperature zinc-free hydraulic oil for engineering machinery in frigid regions, characterized in that, By weight percentage, it consists of the following raw materials: base oil 80-89%, viscosity index improver 10-19%, anti-wear agent 0.3-1.0%, antioxidant 0.1-1.5%, calcium-based additive 0.01-0.15%, demulsifier 0.005-0.02%, and defoamer 0.005-0.02%; the sum of the weight percentages of the above raw materials is 100%. The base oil is selected from oils with a kinematic viscosity of 2.0–5.0 mm at 100°C. 2 Group II and / or Group III base oils between / s; The viscosity index improver is a mixture of linear polymethacrylate SCR178A and comb-shaped polymethacrylate VISCOPLEX3-195 with a viscosity index less than 40; by mass percentage, the linear polymethacrylate comprises 9 wt% and the comb-shaped polymethacrylate comprises 3 wt%; or, the linear polymethacrylate comprises 6 wt% and the comb-shaped polymethacrylate comprises 5 wt%. The zinc-free hydraulic oil has a kinematic viscosity of 28.8~31.2 mm at 40°C. 2 / s, viscosity index not less than 250, pour point not exceeding -45℃.

2. The ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions according to claim 1, characterized in that, The anti-wear agent is selected from one or more of dibutyl phosphite, tricresyl phosphate, or triphenyl thiophosphate.

3. The ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions according to claim 1, characterized in that, The antioxidant is 2,6-di-tert-butyl-mixed phenol and / or butyloctyl diphenylamine.

4. The ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions according to claim 1, characterized in that, The calcium-based additive is selected from one or more of dinonylnaphthalene sulfonate, salicylate, or sulfide alkylphenol salt.

5. The ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions according to claim 1, characterized in that, The demulsifier is a polyether-type demulsifier.

6. The ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions according to claim 1, characterized in that, The defoamer is a silicone-containing composite antifoaming agent.

7. A method for preparing ultra-low temperature zinc-free hydraulic oil for engineering machinery in frigid regions as described in any one of claims 1 to 6, characterized in that, The method includes the following steps: S1. Under stirring conditions, add base oil, viscosity index improver, anti-wear agent, antioxidant and calcium-based additive in sequence, and heat to mix; S2. Under stirring conditions, continue to add demulsifier and defoamer to the mixture obtained in S1 in sequence to obtain ultra-low temperature zinc-free hydraulic oil.

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