An ashless hydraulic fluid lubricating oil composition

Abstract

The application discloses a kind of ashless hydraulic oil lubricating oil compositions, according to mass percentage includes the following components: ashless antiwear agent 0.2-0.4wt%, bisphenol antioxidant 0.2-0.5wt%, auxiliary antioxidant 0.1-0.25%, ionic liquid 0.2-0.5wt%, rust inhibitor 0.02-0.04wt%, passivator 0.02-0.05%, demulsifier 0.01-0.02wt%, anti-foaming agent is 0.01-0.02wt%, ester base oil 1-5wt%, the rest is base oil.The hydraulic oil lubricating oil composition of the application has oxidation resistance, low sludge, hydrolytic stability, passes through high-pressure plunger Komatsu HPV35+35 bench test, meets the harsh operating condition requirements of high-temperature high-pressure hydraulic system, and can be applied to various hydraulic systems.

Description

Technical Field

[0001] This invention belongs to the technical field of lubricating oil and lubricating oil additives, and specifically relates to an ashless hydraulic oil lubricating oil composition. Background Technology

[0002] Hydraulic oil product lines from various domestic and international brands all use ashless anti-wear hydraulic oil in their high-end products. This overcomes the problems of zinc-containing anti-wear agents having excessive hydrolytic stability and poor copper protection. It has better application effects in systems containing copper, silver and other components. At the same time, OEMs, mainly Japanese construction machinery manufacturers, advocate the use of ashless hydraulic oil.

[0003] In its ashless hydraulic oil solutions, international additive companies add amine antioxidants such as diphenylamine and naphthylamine to enhance antioxidant effects. These antioxidants can significantly improve performance such as rotating bomb life and Tost life. However, amine antioxidants can lead to an increase in sludge during the production process, which in turn reduces the anti-wear performance of the lubricating oil and greatly affects the user experience. Summary of the Invention

[0004] The purpose of this invention is to provide an ashless hydraulic oil lubricating oil composition that solves the problems of poor anti-wear performance and excessive oxidized sludge in traditional ashless hydraulic oils.

[0005] Research on the production of ashless hydraulic oil using auxiliary antioxidants, ionic liquids, and polyesters is limited. The technical solution adopted in this invention is an ashless hydraulic oil lubricating oil composition, comprising the following components by mass percentage: 0.2-0.4 wt% ashless anti-wear agent, 0.2-0.5 wt% bisphenol antioxidant, 0.1-0.25% auxiliary antioxidant, 0.2-0.5 wt% ionic liquid, 0.02-0.04 wt% rust inhibitor, 0.02-0.05% passivator, 0.01-0.02 wt% demulsifier, 0.01-0.02 wt% antifoaming agent, 1-5 wt% ester base oil, and the remainder being base oil.

[0006] The invention is further characterized in that,

[0007] The ashless anti-wear agent can preferably be T232 or T309; among them, trialkyl thiophosphate T232 or its derivative T309 can form a protective film of iron phosphate compounds on the metal surface, reducing wear and providing excellent anti-wear performance. It also has good thermal stability and wet filterability. Furthermore, T232 or T309 has excellent synergistic effects with hindered bisphenol antioxidants, auxiliary antioxidants, and passivators, which can extend the service life of the oil. It also has excellent compatibility with rust inhibitors and ionic liquids, synergistically adsorbing onto the metal surface to improve rust prevention. The mass percentage of the ashless anti-wear agent in the composition is 0.2-0.4%. If the mass percentage of the ashless anti-wear agent is less than 0.2%, there is a possibility of insufficient anti-wear ability; if the mass percentage of the ashless anti-wear agent is greater than 0.4%, there is a possibility of excessive sludge and decreased rust prevention effect.

[0008] To ensure the antioxidant properties of the oil, hindered bisphenol antioxidants are preferred. Hindered bisphenol antioxidants have excellent antioxidant properties, and 4,4'-methylenebis or 2,6-di-tert-butylphenol are preferred, with a purity of 99% or higher meeting the requirements.

[0009] The mass percentage of bisphenol antioxidant in the composition is 0.2-0.5%, preferably 0.3-0.4%. If the mass percentage of bisphenol antioxidant is less than 0.2%, there may be insufficient antioxidant capacity; if the mass percentage of bisphenol antioxidant is greater than 0.5%, there may be excessive formation of oil sludge.

[0010] The auxiliary antioxidant is a phosphite, preferably tri-(2,4-di-tert-butylphenyl) phosphite; when combined with bisphenol antioxidants, it can significantly improve oil life and inhibit sludge production. The mass percentage of the auxiliary antioxidant in the composition is 0.1-0.25%, preferably 0.15-0.2%. If the mass percentage of the auxiliary antioxidant is less than 0.1%, the antioxidant effect may be poor; if the mass percentage of the auxiliary antioxidant is greater than 0.25%, the solubility may reach its limit at low temperatures, leading to precipitation.

[0011] The ionic liquid is an azo-based ethyl sulfate ionic liquid, and its structure is as follows:

[0012]

[0013] Where n is 2-8.

[0014] Furthermore, the ionic liquid is an azo ethyl sulfate, and its preferred structure is:

[0015]

[0016] Where n is 4-8.

[0017] As can be seen from the molecular structure of azo ethyl sulfate ionic liquids, ionic liquids are azo compounds and heterocyclic compounds, which can reduce the corrosion rate of metals and effectively protect the metal surface. The azo structure has a strong systemic effect with ethyl sulfate, forming a protective film on the surface of metals such as copper. At the same time, it has good compatibility and excellent metal passivation, rust prevention, wear resistance, and light stability, and is also low in toxicity and non-irritating.

[0018] The mass percentage of the ionic liquid is 0.2-0.5%, preferably 0.3-0.4%. If the mass percentage of the ionic liquid is less than 0.2%, the effects of metal passivation, rust prevention, and light stability may be poor; if the mass percentage of the ionic liquid is greater than 0.5%, the competitive adsorption on the metal surface may lead to a decrease in wear resistance.

[0019] The preferred rust inhibitor is a liquid imidazoline derivative, which inhibits the contact between water and oxygen through chemical adsorption, making the metal less prone to corrosion. The content of the rust inhibitor in the composition is not particularly limited, but is typically 0.02-0.04% by mass. If the mass percentage of the rust inhibitor in the composition is less than 0.02%, the oil may have poor metal protection and be more prone to rusting; if the mass percentage of the rust inhibitor in the composition is greater than 0.04%, it may increase the acid value of the oil.

[0020] The passivating agent is a benzotriazole derivative. There is no particular limitation on the content of the passivating agent in the composition, which is usually 0.02-0.05% by mass. If the mass percentage of the passivating agent in the composition is less than 0.02%, there is a possibility of poor metal protection of the oil and low rotating oxygen bomb. If the mass percentage of the passivating agent in the composition is greater than 0.05%, there is a possibility of excessive sludge and increased cost.

[0021] Demulsifiers are high-molecular-weight compounds with hydrophilic ether linkages, exhibiting good dispersibility and film-forming properties, enabling rapid separation of hydraulic oil from water. Their good oil solubility ensures the demulsifier remains within the oil, resulting in excellent water retention in the blended oil. The preferred component in the composition is a polyether polymer, with a typical demulsifier content of 0.01-0.02%. If the demulsifier mass percentage in the composition is less than 0.01%, the oil may emulsify easily; if the demulsifier mass percentage is greater than 0.02%, there is a possibility of excessive demulsifier without poor emulsification performance of the oil, and increased costs.

[0022] The antifoaming agent is preferably one or a combination of T921 and T922 in any proportion. This antifoaming agent balances the advantages and disadvantages of silicone / non-silicone antifoaming agents, ensuring excellent antifoaming performance while overcoming the impact on air release. In this invention, the content of the antifoaming agent is typically 0.01-0.02% by mass. If the mass percentage of the antifoaming agent in the composition is less than 0.01%, the oil may have poor antifoaming performance; if the mass 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.

[0023] Ester base oils are polyesters, possessing the dual properties of synthetic esters and PAOs, along with high lubricity and good compatibility. They can comprehensively improve the high and low temperature performance, lubricity, and hydrolytic stability of oils, enhance the solubility of additives, and reduce sludge formation. In this invention, there is no particular limitation on the polyester content in the composition, typically 1-5% by mass. If the polyester content in the composition is less than 1% by mass, the improvement effect on the oil is not significant; if the polyester content in the composition is greater than 5% by mass, excessive polyester leads to faster oil degradation after contact with water and increases costs.

[0024] Ester base oils have a kinematic viscosity of 1400-1600 mmHg at 40°C. 2 / s.

[0025] The base oil is usually a Group II hydrotreated base oil, with low viscosity being HVI P5 / 6 and high viscosity being HVI H10. High and low viscosity can be blended to meet different oil product requirements, such as ISO VG32 / 46 / 68 viscosity grades.

[0026] The beneficial effects of this invention are:

[0027] This invention discloses an ashless hydraulic oil lubricating oil composition comprising an ashless anti-wear agent, a hindered bisphenol antioxidant, and an auxiliary antioxidant system. 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, excellent hydrolytic stability, and filterability. It has passed the Komatsu HPV35+35 bench test in Japan, meeting the stringent operating requirements of high-temperature and high-pressure hydraulic oil systems, and is applicable to various hydraulic systems. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] Example 1:

[0030] The ashless hydraulic oil lubricating oil composition of the present invention has the following specific proportions of each raw material as shown in Table 1:

[0031]

[0032] Example 2:

[0033] The ashless hydraulic oil lubricating oil composition of the present invention has the following specific proportions of each raw material as shown in Table 2:

[0034]

[0035]

[0036] Example 3:

[0037] The ashless hydraulic oil lubricating oil composition of the present invention has the following specific proportions of each raw material as shown in Table 3:

[0038]

[0039] Example 4:

[0040] The ashless hydraulic oil lubricating oil composition of the present invention has the following specific proportions of each raw material as shown in Table 4:

[0041]

[0042] Taking Example 1 as an example, the test results of the hydraulic lubricating oil product formulated in this invention are compared with the performance of Komatsu HO46-HM on the market, as shown in Table 5 below:

[0043] Table 5 Comparison of main performance requirements of Komatsu-specific hydraulic oil with performance data of Example 1 of this invention.

[0044]

[0045] As can be seen from Table 5, the ashless hydraulic oil composition of the present invention has good anti-wear properties, extreme pressure properties, anti-oxidation properties, demulsification properties, and hydrolytic stability; in particular, it has passed the Komatsu HPV35+35 bench test with high-pressure dual plungers, demonstrating extremely excellent anti-wear properties.

[0046] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. Components and structures not described in detail in this embodiment are well-known components and common structures or common means in the industry, and will not be described in detail here.

Claims

1. A ashless hydraulic lubricating oil composition, characterized in that, The composition by weight percentage includes the following components: 0.2-0.4 wt% ashless anti-wear agent, 0.2-0.5 wt% bisphenol antioxidant, 0.1-0.25 wt% auxiliary antioxidant, 0.2-0.5 wt% ionic liquid, 0.02-0.04 wt% rust inhibitor, 0.02-0.05 wt% passivator, 0.01-0.02 wt% demulsifier, 0.01-0.02 wt% antifoaming agent, 1-5 wt% ester base oil, and the remainder being base oil; The bisphenol antioxidant is 4,4'-methylenebis(2,6-di-tert-butylphenol). The auxiliary antioxidant is tris-(2,4-di-tert-butylphenyl) phosphite; The ionic liquid is an azo ethyl sulfate, and its structure is as follows: Where n is 2-8; The ashless anti-wear agent is at least one of trialkyl thiophosphate T309 and trialkyl thiophosphate derivative T232; The ester base oil has a kinematic viscosity of 1400-1600 mmHg at 40°C. 2 / s.

2. The ashless hydraulic oil lubricating oil composition according to claim 1, characterized in that, The antifoaming agent is any one or a combination of two of T921 and T922 in any proportion.

3. The ashless hydraulic oil lubricating oil composition according to claim 1, characterized in that, The base oil is a Group II hydrotreated base oil.

4. The ashless hydraulic oil lubricating oil composition according to claim 1, characterized in that, The rust inhibitor is a liquid imidazoline derivative; the demulsifier is a polyether polymer compound.

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