Zinc-containing hydraulic fluid composition

Abstract

This invention discloses a zinc-containing hydraulic oil composition, which, by weight percentage, comprises the following components: 0.4-0.8 wt% zinc dialkyl dithiophosphate, 0.2-0.5 wt% bisphenol antioxidant, 0.1-0.25 wt% auxiliary antioxidant, 0.2-0.5 wt% ionic liquid, 0.02-0.05 wt% rust inhibitor, 0.01-0.02 wt% demulsifier, 0.01-0.02 wt% antifoaming agent, 1-5 wt% ester base oil, and the balance being mineral base oil. The zinc-containing hydraulic oil composition disclosed in this invention employs a three-antioxidant system, an azo ethyl sulfate ionic liquid, and a polyester compound system, providing effective corrosion and anti-wear protection for metals. It possesses advantages such as antioxidant properties, low sludge content, and good compatibility with other additives. Through the mutual compatibility of various additives, it exhibits excellent anti-wear properties, rust prevention, demulsification properties, thermal stability, and hydrolytic stability, meeting the stringent operating requirements of high-temperature and high-pressure hydraulic oil systems.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, and specifically relates to zinc-containing hydraulic oil compositions. Background Technology

[0002] The domestic market demands over 1 million tons of hydraulic oil annually, with zinc-containing hydraulic oil accounting for approximately 90%. Especially in critical equipment, current zinc-containing hydraulic oils are insufficient in terms of anti-wear and anti-oxidation properties.

[0003] Chinese Patent No. CN110484332A (Publication Date: November 22, 2019) discloses a hydraulic oil composite additive, its preparation method, and hydraulic oil. This additive improves the thermal stability of the hydraulic oil, offering advantages such as good thermal stability, maintaining appropriate viscosity for a longer period, higher cost-effectiveness, and longer service life. Chinese Patent No. CN1285394A (Publication Date: February 28, 2001) discloses a hydraulic oil composition specifically for loaders, exhibiting excellent oxidation resistance and anti-wear properties.

[0004] The above-mentioned patents and related literature have not been publicly reported to significantly improve wear resistance, compatibility and oxidation resistance simultaneously. Summary of the Invention

[0005] The first objective of this invention is to provide a zinc-containing hydraulic oil composition that simultaneously possesses excellent oxidation resistance, high anti-wear properties, and high compatibility.

[0006] The first technical solution adopted in this invention is: a zinc-containing hydraulic oil composition, which is composed of the following components by weight percentage: 0.4-0.8 wt% zinc dialkyl dithiophosphate, 0.2-0.5 wt% bisphenol antioxidant, 0.1-0.25 wt% auxiliary antioxidant, 0.2-0.5 wt% ionic liquid, 0.02-0.05 wt% rust inhibitor, 0.01-0.02 wt% demulsifier, 0.01-0.02 wt% antifoaming agent, 1-5 wt% ester base oil, and the balance being mineral base oil;

[0007] The ionic liquid is an azo-based ethyl sulfate ionic liquid, and its structure is as follows:

[0008]

[0009] Where n is between 2 and 8.

[0010] The first technical solution adopted in this invention is further characterized by:

[0011] Preferably, the ionic liquid is an azo ethyl sulfate ionic liquid with the following structure:

[0012]

[0013] Where n is 4-8.

[0014] Preferably, the ratio of bisphenol antioxidant to auxiliary antioxidant is 2:1, the auxiliary antioxidant is tris-(2,4-di-tert-butylphenyl) phosphite, and the bisphenol antioxidant is 4,4-methylenebis(2,6-di-tert-butylphenol).

[0015] Preferably, the zinc dialkyl dithiophosphate salt is T203 or T204, and the rust inhibitor is one or a combination of two of the following in any proportion: barium dinonylnaphthalenesulfonate, liquid N-oleoylsarcosine, and liquid alkenyl succinate half ester.

[0016] Preferably, the ester base oil has a kinematic viscosity of 1400-1600 mmHg at 40°C. 2 / s of polyester, the demulsifier is a polyether polymer compound.

[0017] Preferably, the antifoaming agent is one or two of T921 and T922 in any proportion, and the mineral base oil is a Group II hydrotreated base oil.

[0018] The second technical solution adopted in this invention is: a zinc-containing hydraulic oil composition, which is composed of the following components by weight percentage: 0.4-0.8 wt% zinc dialkyl dithiophosphate, 0.2-0.5 wt% bisphenol antioxidant, 0.2-0.5 wt% ionic liquid, 0.02-0.05 wt% rust inhibitor, 0.01-0.02 wt% demulsifier, 0.01-0.02 wt% antifoaming agent, 1-5 wt% ester base oil, and the balance being mineral base oil;

[0019] The ionic liquid is an azo-based ethyl sulfate ionic liquid, and its structure is as follows:

[0020]

[0021] Where n is between 2 and 8.

[0022] The second technical solution adopted in this invention is further characterized by:

[0023] Preferably, the ionic liquid is an azo ethyl sulfate ionic liquid with the following structure:

[0024]

[0025] Where n is 4-8.

[0026] Preferably, the zinc dialkyl dithiophosphate salt is T203 or T204, the bisphenol antioxidant is 4,4-methylenebis(2,6-di-tert-butylphenol), and the rust inhibitor is one or two of barium dinonylnaphthalenesulfonate, liquid N-oleoylsarcosine, and liquid alkenyl succinate half ester in any proportion.

[0027] Preferably, the ester base oil has a kinematic viscosity of 1400-1600 mmHg at 40°C. 2 / s of polyester, the demulsifier is a polyether polymer compound, the antifoaming agent is one or two of T921 and T922 in any proportion, and the mineral base oil is a Group II hydrogenated base oil.

[0028] The beneficial effects of this invention are as follows: The zinc-containing hydraulic oil composition of this invention adopts a compound system of three antioxidants, azo ethyl sulfate ionic liquid, polyester, etc., which provides effective corrosion protection and anti-wear protection for metals. Through strict screening of additives, this composition has the advantages of antioxidant properties, low sludge, and good compatibility with other additives. Through the mutual compatibility of various additives, it has excellent anti-wear properties, rust prevention, demulsification properties, thermal stability and hydrolytic stability, meeting the harsh working conditions of high temperature and high pressure hydraulic oil systems. It has passed the FZG and T6H20C dual pump test bench and is suitable for various hydraulic systems such as piston pumps, vane pumps, and gear pumps. Detailed Implementation

[0029] The present invention will be further described below through specific embodiments.

[0030] This invention discloses a zinc-containing hydraulic oil composition, employing a three-antioxidant system, an azo ethyl sulfate ionic liquid, and a polyester compound system to provide effective corrosion and anti-wear protection for metals. The molecular structure of the azo ethyl sulfate ionic liquid shows that it is a nitrogen-nitrogen double bond compound and an imidazole compound, which can passivate metal activity and inhibit the catalytic effect of metals and their compounds on oil oxidation. Combined with bisphenol antioxidants, auxiliary antioxidants, and T204, it extends oil life and improves anti-wear properties. Simultaneously, the ionic liquid itself has excellent solubility, improving compatibility during oil switching.

[0031] Composed of the following components by weight percentage: 0.4-0.8 wt% zinc dialkyl dithiophosphate, 0.2-0.5 wt% bisphenol antioxidant, 0.1-0.25 wt% auxiliary antioxidant, 0.2-0.5 wt% ionic liquid, 0.02-0.05 wt% rust inhibitor, 0.01-0.02 wt% demulsifier, 0.01-0.02 wt% antifoaming agent, 1-5 wt% ester base oil, and the balance being mineral base oil;

[0032] The ionic liquid is an azo-based ethyl sulfate ionic liquid, and its structure is as follows:

[0033]

[0034] Where n is between 2 and 8.

[0035] The present invention also discloses a second zinc-containing hydraulic oil composition, which comprises the following components by weight percentage: 0.4-0.8 wt% zinc dialkyl dithiophosphate, 0.2-0.5 wt% bisphenol antioxidant, 0.2-0.5 wt% ionic liquid, 0.02-0.05 wt% rust inhibitor, 0.01-0.02 wt% demulsifier, 0.01-0.02 wt% antifoaming agent, 1-5 wt% ester base oil, and the balance being mineral base oil;

[0036] The ionic liquid is an azo-based ethyl sulfate ionic liquid, and its structure is as follows:

[0037]

[0038] Where n is between 2 and 8.

[0039] In the two compositions, the preferred ionic liquid is an azo ethyl sulfate ionic liquid with the following structure:

[0040]

[0041] Among them, n is preferably 4-8.

[0042] Preferably, the zinc dialkyl dithiophosphate salt is T203 or T204. As an anti-wear agent, zinc dialkyl dithiophosphate salt, preferably T204, has good extreme pressure anti-wear properties, high temperature oxidation resistance, and hydrolytic stability. It can form a better protective film on the metal surface and reduce wear. At the same time, T204 has a very good synergistic effect with phenolic antioxidants and auxiliary antioxidants, which can extend the service life of oil. T204 also has the function of decomposing peroxides and improving the antioxidant capacity.

[0043] Preferably, the bisphenol antioxidant is 4,4'-methylenebis(2,6-di-tert-butylphenol), and the antioxidant is preferably a hindered bisphenol. This invention does not have a particular limitation on the bisphenol antioxidant 4,4'-methylenebis(2,6-di-tert-butylphenol), as long as its purity is above 99%. It has excellent antioxidant properties, and the bisphenol has low volatility and good synergistic effect. The weight percentage of the bisphenol antioxidant is 0.2-0.5%, preferably 0.3-0.4%. If the weight percentage of the bisphenol antioxidant is less than 0.2%, there is a possibility of insufficient antioxidant capacity; if the weight percentage of the bisphenol antioxidant is greater than 0.5%, there is a possibility of excessive sludge formation in the oil.

[0044] Preferably, the auxiliary antioxidant is tris-(2,4-di-tert-butylphenyl) phosphite. Phosphite, when combined with zinc dialkyl dithiophosphate and bisphenol, significantly improves oil life and inhibits sludge production. This invention does not impose any particular limitation on the auxiliary antioxidant tris-(2,4-di-tert-butylphenyl) phosphite; a purity of 99% or higher is sufficient. The weight percentage of the auxiliary antioxidant is 0.1-0.25%, preferably 0.15-0.2%. If the weight percentage of the auxiliary antioxidant is less than 0.1%, the antioxidant effect may be poor; if the weight percentage of the auxiliary antioxidant is greater than 0.25%, the solubility may reach its limit at low temperatures, leading to precipitation.

[0045] Preferably, the rust inhibitor is one or two of barium dinonylnaphthalenesulfonate, liquid N-oleoylsarcosine, and liquid alkenyl succinate half ester in any proportion. The present invention does not particularly limit the alkyl group of the polyether polymer demulsifier. Typically, DL32, a high-molecular-weight compound with an ether bond as its hydrophilic structure, has good dispersibility and film-forming properties, enabling rapid separation of hydraulic oil and water; good oil solubility ensures that the demulsifier remains in the oil, and the blended oil has excellent water retention properties.

[0046] Preferably, the ester base oil has a kinematic viscosity of 1400-1600 mmHg at 40°C. 2 The polyester in this composition possesses the dual properties of synthetic esters and PAO, along with high lubricity and good compatibility. It can comprehensively improve the high and low temperature performance, lubricity, and hydrolytic stability of oils, enhance the solubility of additives, and reduce sludge formation. This invention does not impose a particular limitation on the polyester content in the composition, typically ranging from 1-5% by weight. If the polyester weight percentage in the composition is less than 1%, the improvement effect on the oil is not significant; if the polyester weight percentage in the composition is greater than 5%, excessive polyester leads to faster oil degradation after contact with water and increases costs.

[0047] Preferably, the demulsifier is a polyether polymer compound. A polyether polymer demulsifier effectively reduces surface tension and facilitates rapid water separation. This invention does not specifically limit the alkyl group of the polyether polymer demulsifier; DL32 is commonly used. DL32 is a high-molecular-weight compound with a hydrophilic ether structure, exhibiting good dispersibility and film-forming properties, enabling rapid separation of hydraulic oil and water. Its good oil solubility ensures the demulsifier remains in the oil, resulting in excellent water retention in the blended oil. This invention does not specifically limit the content of the demulsifier in the composition; it is typically 0.01-0.02% by weight. If the weight percentage of the demulsifier in the composition is less than 0.01%, the oil may easily emulsify. If the weight percentage of the demulsifier in the composition is greater than 0.02%, there is a possibility that excessive demulsifier may result in poor oil emulsification performance, and it also increases costs.

[0048] Preferably, the antifoaming agent is one or two of T921 and T922 in any proportion. This antifoaming agent balances the advantages and disadvantages of silicone-based and non-silicone-based antifoaming agents, ensuring excellent antifoaming performance while overcoming the impact on air release. This invention does not particularly limit the content of the antifoaming agent in the composition, typically 0.01-0.02% by weight. If the weight percentage of the antifoaming agent in the composition is less than 0.01%, the oil may have poor antifoaming performance; if the weight percentage of the antifoaming agent in the composition is greater than 0.02%, there is a possibility that there is too much antifoaming agent but the oil's antifoaming performance is still poor, and costs are increased.

[0049] Preferably, the mineral base oil is a Group II hydrotreated base oil, with low viscosity being HVIP5 / 6 and high viscosity being HVIH10. The high and low viscosity can be blended to meet different oil product requirements, such as ISOVG32 / 46 / 68 viscosity grades.

[0050] Example 1

[0051] This embodiment provides a zinc-containing hydraulic oil composition, and the specific component ratios are shown in Table 1.

[0052] Table 1

[0053] name Dosage (wt%) T203 0.5 4,4-Methylenebis(2,6-di-tert-butylphenol) 0.4 Tris-(2,4-di-tert-butylphenyl)phosphite 0.2 Ionic liquids 0.4 Barium dinonylnaphthalenesulfonate 0.03 DL32 0.01 T921 0.01 Polyester 3 HVIP6 60 HVI H10 35.45

[0054] Example 2

[0055] This embodiment provides a zinc-containing hydraulic oil composition, and the specific component ratios are shown in Table 2.

[0056] Table 2

[0057] name Dosage (wt%) T204 0.4 4,4-Methylenebis(2,6-di-tert-butylphenol) 0.5 Tris-(2,4-di-tert-butylphenyl)phosphite 0.25 Ionic liquids 0.3 Liquid N-oleic sarcosine 0.02 DL32 0.02 T921 0.01 Polyester 5 HVI H6 57 HVI H10 36.5

[0058] Example 3

[0059] This embodiment provides a zinc-containing hydraulic oil composition, and the specific component ratios are shown in Table 3.

[0060] Table 3

[0061]

[0062]

[0063] Example 4

[0064] This embodiment provides a zinc-containing hydraulic oil composition, and the specific component ratios are shown in Table 4.

[0065] Table 4

[0066] name Dosage (wt%) T204 0.6 4,4-Methylenebis(2,6-di-tert-butylphenol) 0.3 Tris-(2,4-di-tert-butylphenyl)phosphite 0.15 Ionic liquids 0.2 Liquid alkenyl succinate half ester 0.05 DL32 0.015 T921 0.015 Polyester 1 HVI P6 60 HVI H10 37.67

[0067] Example 5

[0068] This embodiment provides a zinc-containing hydraulic oil composition, and the specific component ratios are shown in Table 5.

[0069] Table 5

[0070] name Dosage (wt%) T204 0.8 4,4-Methylenebis(2,6-di-tert-butylphenol) 0.2 Ionic liquids 0.5 Liquid alkenyl succinate half ester 0.03 DL32 0.01 T921 0.02 Polyester 4 HVI H6 58 HVI H10 36.44

[0071] Example 6

[0072] This embodiment provides a zinc-containing hydraulic oil composition, and the specific component ratios are shown in Table 6.

[0073] Table 6

[0074] name Dosage (wt%) T204 0.6 4,4-Methylenebis(2,6-di-tert-butylphenol) 0.3 Ionic liquids 0.2 Liquid alkenyl succinate half ester 0.02 DL32 0.015 T921 0.015 Polyester 1 HVI P6 60 HVI H10 37.85

[0075] Example 7

[0076] This embodiment provides a zinc-containing hydraulic oil composition, and the specific component ratios are shown in Table 7.

[0077] Table 7

[0078] name Dosage (wt%) T204 0.4 4,4-Methylenebis(2,6-di-tert-butylphenol) 0.5 Ionic liquids 0.3 Liquid alkenyl succinate half ester 0.05 DL32 0.02 T921 0.01 Polyester 5 HVI P6 60 HVI H10 33.72

[0079] The beneficial effects of the present invention are experimentally verified below with reference to the embodiments.

[0080] Taking Example 1 as an example, and comparing it with the existing Denison HF0, the test results of the oil are shown in Table 8 below:

[0081] Table 8 Performance Data for Example 1

[0082]

[0083]

[0084] As shown in Table 1, the zinc-containing hydraulic oil composition of the present invention possesses anti-wear properties, extreme pressure properties, antioxidant properties, demulsibility, and hydrolytic stability. The rotating oxygen bomb test result is 455 min, and the total thermal stability sediment is 4.2 mg, demonstrating excellent antioxidant properties. The air release test result is 3.7 min, and the demulsibility test result is 5 min, indicating good compatibility of the composition. The T6H20C anti-wear test bench results after 608 hours show that the total weight loss of the blades and pins is 2.8 mg, and the wear resistance of the plunger pump is only 60.6 mg, demonstrating extremely excellent anti-wear properties.

Claims

1. A zinc-containing hydraulic oil composition, characterized in that, Composed of the following components by weight percentage: zinc dialkyl dithiophosphate T204 0.4-0.8wt%, bisphenol antioxidant 0.2-0.5wt%, auxiliary antioxidant 0.1-0.25wt%, ionic liquid 0.2-0.5wt%, rust inhibitor 0.02-0.05wt%, demulsifier 0.01-0.02wt%, antifoaming agent 0.01-0.02wt%, polyester 1-5wt%, balance mineral base oil; The ionic liquid is an azo-based ethyl sulfate ionic liquid, and its structure is as follows: Where n is 2-8; The ratio of bisphenol antioxidant to auxiliary antioxidant is 2:1, the auxiliary antioxidant is tris-(2,4-di-tert-butylphenyl) phosphite, and the bisphenol antioxidant is 4,4-methylenebis(2,6-di-tert-butylphenol). The kinematic viscosity of the polyester at 40°C is 1400-1600 mmHg. 2 / s.

2. The zinc-containing hydraulic oil composition according to claim 1, characterized in that, The ionic liquid is an azo-based ethyl sulfate ionic liquid, and its structure is as follows: Where n is 4-8.

3. The zinc-containing hydraulic oil composition according to claim 1, characterized in that, The rust inhibitor is one or a combination of two of the following in any proportion: barium dinonylnaphthalenesulfonate, liquid N-oleoylsarcosine, and liquid alkenyl succinate half ester.

4. The zinc-containing hydraulic oil composition according to claim 1, characterized in that, The demulsifier is a polyether polymer compound.

5. The zinc-containing hydraulic oil composition according to claim 1, characterized in that, The antifoaming agent is one or two of T921 and T922 in any proportion, and the mineral base oil is a Group II hydrotreated base oil.

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