Ultralow-temperature zinc-free hydraulic oil for engineering machinery

Abstract

The invention discloses ultralow-temperature zinc-free hydraulic oil for engineering machinery, which is prepared from the following raw material components in percentage by mass: 57 to 85 percent of II-type base oil, 5 to 30 percent of III-type base oil, 9 to 18 percent of viscosity index improver and 0.4 to 2.7 percent of other additives, and the sum of the contents of the raw materials is 100 percent. The kinematic viscosity of the zinc-free hydraulic oil at 40 DEG C is 41.4-50.6 mm < 2 > / s, the viscosity index is higher than 200, the pour point is lower than-45 DEG C, and the zinc-free hydraulic oil can provide excellent startability, high-temperature detergency, wear resistance and winter-summer universality for an engineering machinery hydraulic system in a low-temperature environment in winter.

Description

Technical Field

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

[0002] In winter, the hydraulic system of construction machinery has high requirements for the viscosity-temperature property, low-temperature fluidity and hydraulic efficiency of hydraulic oil. If the kinematic viscosity of hydraulic oil exceeds the starting limit of hydraulic system at low temperature, it will easily cause difficulty in starting the construction machinery. Conventional 46 ultra-low temperature hydraulic oil can only ensure the excellent starting performance of hydraulic system at temperatures above -18℃. In the range of -18℃ to -30℃, the kinematic viscosity of conventional 46 ultra-low temperature hydraulic oil increases significantly as the temperature decreases, which cannot ensure the smooth starting of the hydraulic system of construction machinery.

[0003] Chinese patent CN111218325A, published on June 2, 2020, discloses an ultra-low temperature ashless anti-wear hydraulic oil and a preparation method thereof. The ultra-low temperature hydraulic oil is blended with Hitec543, PAO4 and PAO10. The product has a low pour point and excellent anti-wear properties, but the raw material cost of the product is high, which significantly increases the maintenance cost of engineering machinery end customers. Chinese patent CN111019743A, published on April 17, 2020, discloses a coal-based fully synthetic low-temperature hydraulic oil and a preparation method thereof. The ultra-low temperature hydraulic oil is blended with coal-based Class III + base oil and coal-based PAO40. The product has a low pour point, but the viscosity-temperature property in the wide temperature range of -30°C to 60°C is lower than that of existing ultra-low temperature hydraulic oil products. The Chinese patent CN108977260A, published on December 11, 2018, discloses an ultra-low temperature hydraulic oil, which is prepared by blending a Class II base oil, a composite additive and a viscosity index improver, wherein the kinematic viscosity of the Class II base oil at 40°C is distributed in the range of 9 to 11 mm 2 / s, 30~32mm 2 / s and 58~60mm 2 / s, and the additives include anti-wear agent, rust inhibitor and antioxidant. This formula uses Class II base oil, which reduces the cost of raw materials, but the additives are only anti-wear agent, rust inhibitor and antioxidant. Under high temperature conditions of engineering machinery hydraulic system, the oil is easily over-oxidized due to high temperature, the oil color deepens, and the sludge content increases, affecting the stable operation of the precision system. Summary of the invention

[0004] The purpose of the present 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 by the present invention is that the ultra-low temperature zinc-free hydraulic oil for engineering machinery is composed of the following raw material components according to mass percentage: 57% to 85% of Class II base oil, 5% to 30% of Class III base oil, 9% to 18% of viscosity index improver, and 0.4% to 2.7% of other additives, and the total content of the above raw materials is 100%.

[0006] The present invention is also characterized in that:

[0007] The kinematic viscosity of Group II and Group III base oils at 100°C is between 3 and 8 mm 2 / s.

[0008] The viscosity index improver is a mixture of linear polymethacrylate and comb-shaped polymethacrylate whose SSI index in a tapered roller shear test is less than 40.

[0009] The mass percentages of the two viscosity index improvers are: 6% to 10% of the linear polymethacrylate viscosity index improver and 3% to 8% of the comb-shaped polymethacrylate viscosity index improver.

[0010] 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%, defoamer 0.005% to 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 butyl octyl diphenylamine.

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

[0014] The demulsifier is a polyether demulsifier.

[0015] The defoaming agent is methyl silane defoaming agent.

[0016] The beneficial effects of the present invention are:

[0017] The hydraulic oil of the present invention uses polymethacrylate, zinc-free additives and hydrogenated base oil as main raw materials, adopts a scheme of compounding a novel comb-shaped polymethacrylate viscosity modifier with a traditional linear polymethacrylate viscosity modifier, can significantly reduce the overall amount of the viscosity modifier, improve shear stability, and introduces a calcium-based additive to improve the high-temperature detergency of the oil product, and prevents the oil product from discoloring, oxidizing and increasing the acid value when the hydraulic system of the engineering machinery is running at a high temperature.

[0018] The 40°C kinematic viscosity of the zinc-free hydraulic oil of the present invention is 41.4-50.6 mm 2 / s, the viscosity index is higher than 200, and the pour point is lower than -45℃. It can provide excellent starting performance, high temperature cleanliness, wear resistance and winter and summer versatility for the hydraulic system of construction machinery in the low temperature environment in winter, and meet the annual oil demand of the hydraulic system of construction machinery in Heilongjiang and Inner Mongolia and other regions. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with specific implementation modes.

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

[0021] Among them, the 100℃ kinematic viscosity of Class II and Class III base oils is between 3 and 8 mm 2 / s.

[0022] The viscosity index improver is a mixture of linear polymethacrylate and comb-shaped polymethacrylate with a tapered roller shear test SSI index less than 40, and the mass percentages of the two are: 6% to 10% of linear polymethacrylate viscosity index improver and 3% to 8% of comb-shaped polymethacrylate viscosity index improver. The structure of the linear polymethacrylate viscosity index improver is:

[0023]

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

[0025]

[0026] 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%, defoamer 0.005% to 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 butyl octyl diphenylamine.

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

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

[0031] Example 1

[0032] The components and contents 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%) Tricresyl phosphate 0.3 2,6-Di-tert-butyl mixed phenol 0.1 Butyl octyl diphenylamine 0.4 Calcium dinonylnaphthalenesulfonate 0.06 Calcium alkyl phenol sulfide 0.01 Linear polymethacrylate 7 Comb polymethacrylate 3 Polyether demulsifier 0.005 Methylsilane defoamer 0.005 Group II base oil 59.12 Group III base oil 30 total 100％

[0035] Example 2

[0036] The components and contents 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 components and contents 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 components and contents 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%) Tricresyl phosphate 1 2,6-Di-tert-butyl mixed phenol 1 Butyl octyl diphenylamine 0.2 Calcium dinonylnaphthalenesulfonate 0.1 Calcium Salicylate 0.05 Linear polymethacrylate 6 Comb polymethacrylate 4 Polyether demulsifier 0.02 Methylsilane defoamer 0.02 Group II base oil 82.61 Group III base oil 5 total 100％

[0049] Comparative Example 1

[0050] This comparative example is compared with Example 1. The viscosity index improver only uses linear polymethacrylate, and no comb-shaped polymethacrylate is used. The contents of the remaining components are the same as those 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 contents of hydraulic oil in comparative example 1

[0052] name Dosage (wt%) Tricresyl phosphate 0.3 2,6-Di-tert-butyl mixed phenol 0.1 Butyl octyl diphenylamine 0.4 Calcium dinonylnaphthalenesulfonate 0.06 Calcium alkyl phenol sulfide 0.01 Linear polymethacrylate 10 Polyether demulsifier 0.005 Methylsilane defoamer 0.005 Group II base oil 59.12 Group III base oil 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] From the test results of Examples 1 and 4 in Table 6, it can be seen that the ultra-low temperature zinc-free hydraulic oil for engineering machinery of the present invention has excellent low temperature fluidity (-30°C kinematic viscosity is not more than 4500mm 2 / s), viscosity-temperature resistance (viscosity index greater than 200) and high-temperature detergency (thermal stability total sediment weight less than 100 mg) and other properties, which can meet the requirements of winter cold start and winter and summer general use of construction machinery.

[0058] By comparing the test results of Example 1 and Comparative Example 1, it can be seen that the biggest advantage of the combined solution of comb-like viscosity modifier and linear viscosity modifier compared with the single linear viscosity modifier solution is that the No. 46 ultra-low temperature hydraulic oil blended in Class II and Class III base oils has better low-temperature fluidity.

Claims

1. Ultra-low temperature zinc-free hydraulic oil for construction machinery, characterized in that: The composition is composed of the following raw material components according to mass percentage: 57% to 85% of Class II base oil, 5% to 30% of Class III base oil, 9% to 18% of viscosity index improver, and 0.4% to 2.7% of other additives. The total content of the above raw materials is 100%.

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

3. The ultra-low temperature zinc-free hydraulic oil for construction machinery according to claim 1, characterized in that: The viscosity index improver is a mixture of linear polymethacrylate and comb-shaped polymethacrylate with a SSI index of less than 40 in a tapered roller shear test.

4. The ultra-low temperature zinc-free hydraulic oil for construction machinery according to claim 3, characterized in that: The mass percentages of the two viscosity index improvers are: 6% to 10% of the linear polymethacrylate viscosity index improver and 3% to 8% of the comb-shaped polymethacrylate viscosity index improver.

5. The ultra-low temperature zinc-free hydraulic oil for construction 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%.

6. The ultra-low temperature zinc-free hydraulic oil for construction machinery according to claim 5, characterized in that: The anti-wear agent is at least one of dibutyl phosphite, tricresyl phosphate and triphenyl thiophosphate.

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

8. The ultra-low temperature zinc-free hydraulic oil for construction machinery according to claim 5, characterized in that: The calcium-based additive is at least one of calcium dinonylnaphthalene sulfonate, calcium sulfide alkylphenol, and calcium salicylate.

9. The ultra-low temperature zinc-free hydraulic oil for construction machinery according to claim 5, characterized in that: The demulsifier is a polyether demulsifier.

10. The ultra-low temperature zinc-free hydraulic oil for construction machinery according to claim 5, characterized in that: The defoamer is a methylsilane defoamer.

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