Ultra-low temperature zinc-free hydraulic oil for construction machinery

Abstract

The application discloses an ultra-low temperature zinc-free hydraulic oil for engineering machinery, which is composed of the following components by mass percentage: 57-85% of type II base oil, 5-30% of type III base oil, 9-18% of viscosity index improver and 0.4-2.7% of other additives, and the total of the content of the above raw materials is 100%. 2 The zinc-free hydraulic oil has a 40 DEG C kinetic viscosity of 41.4-50.6 mm / s, a viscosity index higher than 200 and a pour point lower than -45 DEG C, and can provide excellent startability, high-temperature detergency, wear resistance and winter-summer versatility for the hydraulic system of the engineering machinery in winter low-temperature environment.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic oil technology and relates to an ultra-low temperature zinc-free hydraulic oil for engineering machinery. Background Technology

[0002] In winter, the hydraulic systems of construction machinery place high demands on the viscosity-temperature characteristics, low-temperature fluidity, and hydraulic efficiency of the hydraulic oil. If the kinematic viscosity of the hydraulic oil exceeds the starting limit of the hydraulic system at low temperatures, it can easily cause difficulties in starting the construction machinery. Conventional No. 46 cryogenic hydraulic oil can only guarantee excellent starting performance of the hydraulic system at temperatures above -18℃. Within the range of -18℃ to -30℃, the kinematic viscosity of conventional No. 46 cryogenic hydraulic oil increases significantly as the temperature decreases, making it impossible to guarantee a smooth start-up of the construction machinery's hydraulic system.

[0003] Chinese patent CN111218325A, published on June 2, 2020, discloses an ultra-low temperature ashless anti-wear hydraulic oil and its preparation method. It uses Hitec 543, PAO4, and PAO10 to blend the ultra-low temperature hydraulic oil. This product has a low pour point and excellent anti-wear properties; however, the raw material cost is high, significantly increasing the maintenance costs for end-users of construction machinery. Chinese patent CN111019743A, published on April 17, 2020, discloses a coal-based fully synthetic low-temperature hydraulic oil and its preparation method. It uses coal-based Group III+ base oil and coal-based PAO40 to blend the ultra-low temperature hydraulic oil. This product has a low pour point, but its viscosity-temperature characteristics over a wide temperature range of -30℃ to 60℃ are lower than existing ultra-low temperature hydraulic oil products. Chinese patent CN108977260A, published on December 11, 2018, discloses an ultra-low temperature hydraulic oil. This oil is formulated using Group II base oil, composite additives, and a viscosity index improver. The Group II base oil has a kinematic viscosity distribution of 9–11 mm at 40°C. 2 / s, 30~32mm 2 / s and 58~60mm 2 The additives include anti-wear agents, rust inhibitors, and antioxidants. This formulation uses Group II base oils, reducing raw material costs. However, with only anti-wear agents, rust inhibitors, and antioxidants as additives, the oil is prone to excessive oxidation, darkening in color, and increasing sludge content under high-temperature conditions in hydraulic systems of engineering machinery, affecting the stable operation of precision systems. Summary of the Invention

[0004] The purpose of this invention is to provide an ultra-low temperature zinc-free hydraulic oil for engineering machinery, which has excellent viscosity-temperature properties, low-temperature fluidity, and high-temperature detergency.

[0005] The technical solution adopted in this invention is an ultra-low temperature zinc-free hydraulic oil for engineering machinery, which is composed of the following raw material components by mass percentage: 57% to 85% of Group II base oil, 5% to 30% of Group III base oil, 9% to 18% of viscosity index improver, and 0.4% to 2.7% of other additives, with the total content of the above raw materials being 100%.

[0006] The invention is further characterized by:

[0007] Group II and Group III base oils have a kinematic viscosity of 3–8 mm at 100°C. 2 Between / s.

[0008] The viscosity index improver is a mixture of linear polymethyl methacrylate and comb-shaped polymethyl methacrylate with a tapered roller shear index (SSI) of less than 40.

[0009] The mass percentages of the two viscosity index improvers are as follows: linear polymethyl methacrylate viscosity index improver 6%–10%, and comb-shaped polymethyl methacrylate viscosity index improver 3%–8%.

[0010] Other additives include: anti-wear agent 0.3%–1%, antioxidant 0.1%–1.5%, calcium-based additive 0.01%–0.15%, demulsifier 0.005%–0.02%, and defoamer 0.005%–0.02%.

[0011] The anti-wear agent is at least one of dibutyl phosphite, tricresyl phosphate, and triphenyl thiophosphate.

[0012] The antioxidant is at least one of 2,6-di-tert-butyl-mixed phenol and butyloctyl diphenylamine.

[0013] The calcium-based additive is at least one of dinonylnaphthalenesulfonate calcium, sulfide alkylphenol calcium, and calcium salicylate.

[0014] The demulsifier is a polyether demulsifier.

[0015] The defoamer is a methylsilane defoamer.

[0016] The beneficial effects of this invention are:

[0017] The hydraulic oil of this invention uses polymethyl methacrylate, zinc-free additives, and hydrogenated base oil as the main raw materials. It adopts a scheme of using a novel comb-shaped polymethyl methacrylate viscosity indexer in combination with a traditional linear polymethyl methacrylate viscosity indexer, which can significantly reduce the total amount of viscosity indexer used, improve shear stability, and introduce calcium-based additives to improve the high-temperature detergency of the oil. This prevents the oil from discoloration, oxidation, and increased acid value under the high-temperature operation of hydraulic systems in engineering machinery.

[0018] The zinc-free hydraulic oil of this invention has a kinematic viscosity of 41.4–50.6 mm at 40°C. 2 With a viscosity index above 200 and a pour point below -45℃, it can provide excellent startability, high-temperature detergency, wear resistance, and winter and summer versatility for hydraulic systems of construction machinery in low-temperature winter environments, meeting the year-round oil demand of hydraulic systems of construction machinery in regions such as Heilongjiang and Inner Mongolia. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments.

[0020] This invention discloses an ultra-low temperature zinc-free hydraulic oil for engineering machinery, which is composed of the following raw material components by mass percentage: 57% to 85% Group II base oil, 5% to 30% Group III base oil, 9% to 18% viscosity index improver, and 0.4% to 2.7% other additives, with the total content of the above raw materials being 100%.

[0021] Among them, the kinematic viscosity at 100°C for Group II and Group III base oils is 3–8 mm. 2 Between / s.

[0022] The viscosity index improver is a mixture of linear polymethyl methacrylate and comb-shaped polymethyl methacrylate with a tapered roller shear index (SSI) of less than 40. The mass percentages of the two are: 6%–10% for linear polymethyl methacrylate and 3%–8% for comb-shaped polymethyl methacrylate. The structure of the linear polymethyl methacrylate viscosity index improver is as follows:

[0023]

[0024] The structure of the comb-shaped polymethacrylate viscosity index improver is as follows:

[0025]

[0026] Other additives include: anti-wear agent 0.3%–1%, antioxidant 0.1%–1.5%, calcium-based additive 0.01%–0.15%, demulsifier 0.005%–0.02%, and defoamer 0.005%–0.02%.

[0027] The anti-wear agent is at least one of dibutyl phosphite, tricresyl phosphate, and triphenyl thiophosphate.

[0028] The antioxidant is at least one of 2,6-di-tert-butyl-mixed phenol and butyloctyl diphenylamine.

[0029] The calcium-based additive is at least one of dinonylnaphthalenesulfonate calcium, sulfide alkylphenol calcium, and calcium salicylate.

[0030] The demulsifier is a polyether demulsifier, and the defoamer is a methylsilane defoamer.

[0031] Example 1

[0032] The composition and content of the hydraulic oil in this embodiment are shown in Table 1:

[0033] Table 1. Composition and content of hydraulic oil in Example 1

[0034] name Dosage (wt%) Trimethyl phosphate 0.3 2,6-Di-tert-butyl-mixed phenols 0.1 Butyloctyl diphenylamine 0.4 Calcium dinonylnaphthalenesulfonate 0.06 Calcium alkylphenol sulfide 0.01 Linear polymethacrylate 7 comb-shaped polymethacrylate 3 Polyether demulsifier 0.005 Methylsilane defoamer 0.005 Group II base oils 59.12 Group III base oils 30 total 100％

[0035] Example 2

[0036] The composition and content of the hydraulic oil in this embodiment are shown in Table 2:

[0037] Table 2. Composition and content of hydraulic oil in Example 2

[0038]

[0039]

[0040] Example 3

[0041] The composition and content of the hydraulic oil in this embodiment are shown in Table 3:

[0042] Table 3. Composition and content of hydraulic oil in Example 3

[0043]

[0044]

[0045] Example 4

[0046] The composition and content of the hydraulic oil in this embodiment are shown in Table 4:

[0047] Table 4. Composition and content of hydraulic oil in Example 4

[0048] name Dosage (wt%) Trimethyl phosphate 1 2,6-Di-tert-butyl-mixed phenols 1 Butyloctyl diphenylamine 0.2 Calcium dinonylnaphthalenesulfonate 0.1 Calcium salicylate 0.05 Linear polymethacrylate 6 comb-shaped polymethacrylate 4 Polyether demulsifier 0.02 Methylsilane defoamer 0.02 Group II base oils 82.61 Group III base oils 5 total 100％

[0049] Comparative Example 1

[0050] This comparative example is compared with Example 1. The viscosity index improver used only linear polymethyl methacrylate and not comb-shaped polymethyl methacrylate. The contents of the other components are the same as in Example 1. The components and contents of the hydraulic oil in this comparative example are shown in Table 5.

[0051] Table 5. Components and content of hydraulic oil in Comparative Example 1

[0052] name Dosage (wt%) Trimethyl phosphate 0.3 2,6-Di-tert-butyl-mixed phenols 0.1 Butyloctyl diphenylamine 0.4 Calcium dinonylnaphthalenesulfonate 0.06 Calcium alkylphenol sulfide 0.01 Linear polymethacrylate 10 Polyether demulsifier 0.005 Methylsilane defoamer 0.005 Group II base oils 59.12 Group III base oils 30 total 100％

[0053] The performance of the hydraulic oils obtained in Example 1, Example 4, and Comparative Example 1 was tested, and the results are shown in Table 6:

[0054] Table 6 Performance Test Results

[0055]

[0056]

[0057] As can be seen from the test results of Examples 1 and 4 in Table 6, the ultra-low temperature zinc-free hydraulic oil for engineering machinery of the present invention has excellent low-temperature fluidity (kinematic viscosity at -30℃ not greater than 4500 mm). 2 With properties such as viscosity index (greater than 200) and high-temperature cleaning properties (total sludge weight less than 100mg), it can meet the requirements of cold start in winter and general use in winter and summer for construction machinery.

[0058] Comparing the test results of Example 1 and Comparative Example 1, it can be seen that the biggest advantage of the combination of comb-shaped and linear viscosity index agents compared with the linear viscosity index agent alone is that the No. 46 cryogenic hydraulic oil blended in Group II and Group III base oils has better low-temperature fluidity.

Claims

1. A low-temperature zinc-free hydraulic oil for construction machinery, characterized in that, It is composed of the following raw material components by mass percentage: Group II base oil 57%–85%, Group III base oil 5%–30%, viscosity index improver 9%–18%, and other additives 0.4%–2.7%, with the total content of the above raw materials being 100%; The viscosity index improver is a mixture of linear polymethyl methacrylate and comb-shaped polymethyl methacrylate with a tapered roller shear index (SSI) of less than 40, and the mass percentages of the two viscosity index improvers are as follows: 6%–10% for linear polymethyl methacrylate and 3%–8% for comb-shaped polymethyl methacrylate. The zinc-free hydraulic oil has a kinematic viscosity of 41.4–50.6 mm at 40°C. 2 Between / s, viscosity index above 200, pour point below -45℃, kinematic viscosity not greater than 4500 mmHg at -30℃. 2 / s.

2. The ultra-low temperature zinc-free hydraulic oil for engineering machinery according to claim 1, characterized in that, The kinematic viscosity at 100°C of the Group II and Group III base oils is 3–8 mm. 2 Between / s.

3. The ultra-low temperature zinc-free hydraulic oil for engineering machinery according to claim 1, characterized in that, The other additives are: anti-wear agent 0.3% to 1%, antioxidant 0.1% to 1.5%, calcium-based additive 0.01% to 0.15%, demulsifier 0.005% to 0.02%, and defoamer 0.005% to 0.02%.

4. The ultra-low temperature zinc-free hydraulic oil for engineering machinery according to claim 3, characterized in that, The anti-wear agent is at least one of dibutyl phosphite, tricresyl phosphate, and triphenyl thiophosphate.

5. The ultra-low temperature zinc-free hydraulic oil for engineering machinery according to claim 3, characterized in that, The antioxidant is at least one of 2,6-di-tert-butyl-mixed phenol and butyloctyl diphenylamine.

6. The ultra-low temperature zinc-free hydraulic oil for engineering machinery according to claim 3, characterized in that, The calcium-based additive is at least one of dinonylnaphthalenesulfonate calcium, sulfide alkylphenol calcium, and calcium salicylate.

7. The ultra-low temperature zinc-free hydraulic oil for engineering machinery according to claim 3, characterized in that, The demulsifier is a polyether demulsifier.

8. The ultra-low temperature zinc-free hydraulic oil for engineering machinery according to claim 3, characterized in that, The defoamer is a methylsilane defoamer.

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