Gear oil as well as preparation method and application thereof

Abstract

The invention relates to the technical field of lubricating oil, in particular to gear oil as well as a preparation method and application thereof. The gear oil is prepared from 86.75%-93.89% of synthetic base oil, 0.5%-1.5% of an antioxidant, 4.5%-8.5% of an anti-wear reagent at extreme pressure, 1.0%-3.0% of an ashless dispersing agent, 0.05%-0.1% of a metal deactivator, 0.05%-0.1% of an anti-rust agent and 0.01%-0.05% of an anti-foaming agent, the antioxidant comprises 1-(3, 5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazole hexafluorophosphate, 3-(3, 5-di-tert-butyl-4-hydroxyphenyl) alkyl propionate and alkyl diphenylamine, and the anti-foaming agent comprises 1-(3, 5-di-tert-butyl-4-hydroxyphenyl) alkyl propionate and 1-(3, 5-di-tert-butyl-4-hydroxyphenyl) alkyl the anti-wear reagent at extreme pressure comprises a tri-decyl hexadecyl quaternary phosphonium salt docusate ionic liquid, sulfurized olefin and alkyl phosphate amine salt. The gear oil provided by the invention has good thermal oxidation stability and extreme pressure wear resistance, and can be used for lubrication of a vehicle drive axle system with a long oil change mileage requirement.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating oils, and particularly relates to a gear oil and its preparation method and application. Background Art

[0002] Vehicle gear oil is applied to the lubrication of components such as automotive manual transmissions, rear axle final drives, and differentials. The important role of gear oil is to form an oil film or a firm adsorption film and a chemical reaction film on the tooth-to-tooth contact surface of the gears to ensure normal lubrication and prevent scuffing between tooth surfaces, and at the same time has the functions of cooling, rust prevention, and buffering.

[0003] With the development of commercial vehicles towards energy-saving, lightweight, and heavy-duty directions, the operating conditions of their gearboxes and drive axles are becoming increasingly harsh. For example, the heavy-duty of trucks increases the power of the gear drive in the drive axle, while the geometric dimensions of the drive axle gears do not change significantly, resulting in an increase in tooth surface pressure and temperature. In particular, the continuous improvement of the body design of commercial vehicles makes the aerodynamic performance more reasonable, the air resistance during vehicle driving decreases, the air flow passing through the outer surface of the drive axle decreases, and the heat dissipation performance becomes worse. These changes in operating conditions put forward higher requirements for the new generation of vehicle gear oils in terms of thermal oxidation stability, seal adaptability, corrosion resistance, pitting resistance, extreme pressure and anti-wear performance, shear stability, etc.

[0004] In related technologies, vehicle gear oil is prone to premature oxidation and decline under high-temperature long-term operating conditions, or has poor extreme pressure and anti-wear performance, and cannot meet the requirements of long oil change intervals for vehicle gear oil under high-temperature operating conditions. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a gear oil and its preparation method and application. The gear oil provided by the present invention has good thermal oxidation stability and extreme pressure and anti-wear performance, and can be used for the lubrication of vehicle drive axle systems with long oil change interval requirements.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a gear oil, which comprises the following components in terms of weight percentage: synthetic base oil 86.75 - 93.89%, antioxidant 0.5 - 1.5%, extreme pressure and anti-wear agent 4.5 - 8.5%, ashless dispersant 1.0 - 3.0%, metal deactivator 0.05 - 0.1%, rust inhibitor 0.05 - 0.1%, anti-foaming agent 0.01 - 0.05%;

[0008] The synthetic base oil comprises polyalphaolefin synthetic oil and synthetic ester base oil;

[0009] The antioxidant includes 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and alkyl diphenylamine;

[0010] The extreme pressure and antiwear agent includes tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, sulfurized olefin, and alkyl phosphate amine salt;

[0011] The 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate has the structure shown in Formula 1:

[0012]

[0013] The tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid has the structure shown in Formula 2:

[0014]

[0015] Preferably, the mass ratio of the 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and alkyl diphenylamine is (2-5):(1-3):(2-7).

[0016] Preferably, the side-chain alkyl group of the alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is a C7-C9 alkyl group.

[0017] Preferably, the alkyl diphenylamine is butyloctyldiphenylamine or p-2-diisooctyldiphenylamine.

[0018] Preferably, the mass ratio of the tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, sulfurized olefin, and alkyl phosphate amine salt is (1-2):(2.5-4.5):(1-2).

[0019] Preferably, the kinematic viscosity of the polyalphaolefin synthetic oil at 100 °C is 3.0-200 mm 2 / s, and the kinematic viscosity of the synthetic ester base oil at 100 °C is 2.0-15.0 mm 2 / s; the mass ratio of the polyalphaolefin synthetic oil to the synthetic ester base oil is (81.75-88.89):5.

[0020] Preferably, the ashless dispersant is high molecular weight polyisobutylene succinimide, and the relative molecular weight of the high molecular weight polyisobutylene succinimide is greater than 2000.

[0021] Preferably, the metal deactivator is a thiadiazole derivative or a benzotriazole derivative; the rust inhibitor is calcium alkylbenzenesulfonate.

[0022] The present invention provides a method for preparing the gear oil described in the above solution, comprising the following steps: mixing a synthetic base oil, an antioxidant, an extreme pressure and anti-wear agent, an ashless dispersant, a metal deactivator, a rust inhibitor and an anti-foaming agent to obtain the gear oil.

[0023] The present invention provides the application of the gear oil described in the above solution or the gear oil prepared by the preparation method described in the above solution in the lubrication of a vehicle drive axle system.

[0024] The present invention provides a gear oil, which comprises the following components in terms of weight percentage: 86.75-93.89% of a synthetic base oil, 0.5-1.5% of an antioxidant, 4.5-8.5% of an extreme pressure and anti-wear agent, 1.0-3.0% of an ashless dispersant, 0.05-0.1% of a metal deactivator, 0.05-0.1% of a rust inhibitor, and 0.01-0.05% of an anti-foaming agent; the synthetic base oil comprises a polyalphaolefin synthetic oil and a synthetic ester base oil; the antioxidant comprises 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazole hexafluorophosphate, an alkyl ester of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and an alkyl diphenylamine; the extreme pressure and anti-wear agent comprises a tridecylhexadecylphosphonium salt dioctyl sulfosuccinate ionic liquid, a sulfurized olefin and an alkyl phosphate amine salt.

[0025] The present invention uses a polyalphaolefin synthetic oil and a synthetic ester base oil as base oil components, which have good viscosity-temperature performance and tribological performance, and at the same time have very excellent high-temperature performance and oxidation stability performance; the present invention uses 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazole hexafluorophosphate, an alkyl ester of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and an alkyl diphenylamine as antioxidants, and there is a good positive synergistic effect among the components. Compared with the commonly used antioxidants in traditional lubricating oils (such as 2,6-di-tert-butylphenol and zinc dialkyldithiophosphate (ZDDP), etc.), it can greatly improve the oxidation stability performance of the lubricating oil, effectively solve the problem of viscosity increase of the oil product during long-term operation at high temperature, avoid premature oxidation and decline of the lubricating oil, and extend the oil change cycle and service life; the present invention uses a tridecylhexadecylphosphonium salt dioctyl sulfosuccinate ionic liquid, a sulfurized olefin and an alkyl phosphate amine salt as extreme pressure and anti-wear agents, which not only improves the extreme pressure and anti-wear performance, but also reduces the usage amount of active sulfur additives, and solves the contradiction between extreme pressure and corrosion performance. The present invention introduces various functional additives such as antioxidants, extreme pressure and anti-wear agents, ashless dispersants, metal deactivators, rust inhibitors and anti-foaming agents, and there are extremely complex interactions among different additives. By controlling the types and addition amounts of each additive, the lubricating oil composition has outstanding viscosity-temperature performance (viscosity index greater than 145), extreme pressure and anti-wear performance (FZG greater than 12 levels) and oxidation stability performance (DKA oxidation sludge not greater than 2 levels), and has good anti-corrosion performance, low-temperature performance and anti-foaming performance.

[0026] The lubricating oil composition provided by the present invention can be used for lubricating the vehicle drive axle system with long oil change intervals, has reasonable raw material compatibility, a simple preparation method, and a wide application range. Specific Embodiments

[0027] The present invention provides a gear oil, which comprises the following components in terms of weight percentage: synthetic base oil 86.75 - 93.89%, antioxidant 0.5 - 1.5%, extreme pressure and anti-wear agent 4.5 - 8.5%, ashless dispersant 1.0 - 3.0%, metal deactivator 0.05 - 0.1%, rust inhibitor 0.05 - 0.1%, and anti-foaming agent 0.01 - 0.05%;

[0028] The synthetic base oil comprises polyalphaolefin synthetic oil and synthetic ester base oil;

[0029] The antioxidant comprises 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and alkyl diphenylamine;

[0030] The extreme pressure and anti-wear agent comprises tridecylhexadecylphosphonium salt docusate ionic liquid, sulfurized olefin, and alkyl phosphate amine salt;

[0031] The 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate has the structure shown in Formula 1:

[0032]

[0033] The tridecylhexadecylphosphonium salt docusate ionic liquid has the structure shown in Formula 2:

[0034]

[0035] In the present invention, unless otherwise specified, the raw materials used are all well-known commercially available products in the art.

[0036] In terms of weight percentage, the gear oil provided by the present invention comprises 86.75 - 93.89% of synthetic base oil, which can be 86.75%, 87%, 88%, 89%, 90%, 91%, 92%, 93% or 93.89% in specific embodiments. In the present invention, the synthetic base oil comprises polyalphaolefin synthetic oil and synthetic ester base oil; the mass ratio of the polyalphaolefin synthetic oil to the synthetic ester base oil is preferably (81.75 - 88.89):5, which can be 88.89:5, 81.75:5, 85.82:5, 83:5, 86:5, 87:5 or 88:5 in specific embodiments.

[0037] In the present invention, the kinematic viscosity of the poly-α-olefin synthetic oil at 100 °C is preferably 3.0 to 200 mm 2 / s, more preferably 7.0 to 150 mm 2 / s, and even more preferably 9.0 to 120 mm 2 / s; the poly-α-olefin synthetic oil is preferably base oil SpectraSyn 10 and base oil SpectraSyn 40 。 When the poly-α-olefin synthetic oil is base oil SpectraSyn 10 and base oil SpectraSyn 40, the present invention has no special requirements for the ratio of the two, and it can be adjusted arbitrarily according to the viscosity of the gear oil product.

[0038] In the present invention, the kinematic viscosity of the synthetic ester base oil at 100 °C is preferably 2.0 to 15.0 mm 2 / s, more preferably 3.5 to 10.0 mm 2 / s, and even more preferably 4.5 to 6.0 mm 2 / s; the synthetic ester base oil is preferably EsterexNP451. In the examples of the present invention, the synthetic base oils SpectraSyn 10, SpectraSyn40 and EsterexNP451 are purchased from Mobil Corporation.

[0039] The present invention uses poly-α-olefin synthetic oil and synthetic ester base oil as base oil components, which have good viscosity-temperature performance and tribological performance, and at the same time have very excellent high-temperature performance and oxidation stability performance.

[0040] By weight percentage, the gear oil provided by the present invention includes 0.5 to 1.5% of an antioxidant, which can be 0.5%, 0.7%, 1.0%, 1.2% or 1.5% in specific examples. In the present invention, the antioxidant includes 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazole hexafluorophosphate, alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and alkyl diphenylamine. In the present invention, 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazole hexafluorophosphate has the structure shown in Formula 1; the present invention has no special limitation on the source of 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazole hexafluorophosphate, and it can be prepared by methods well-known to those skilled in the art. In the examples of the present invention, it is specifically prepared by referring to the method in the examples of "CN200910117591.X An antioxidant ionic liquid containing sterically hindered phenol and its preparation method and application".

[0041]

[0042] In the present invention, the alkyl side chain of the 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate is preferably a C7-C9 alkyl group, and the 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate is more preferably IRGANOXL135 from BASF; the alkyl diphenylamine is preferably butyloctyldiphenylamine or p-2-diisooctyldiphenylamine, and the butyloctyldiphenylamine is preferably IRGANOXL57 from BASF. In the present invention, the mass ratio of 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and alkyl diphenylamine is preferably (2-5):(1-3):(2-7), and in specific embodiments, it can be 4:2:4, 5:3:7 or 3:2:5. The present invention uses 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and alkyl diphenylamine as antioxidants, which can greatly improve the oxidation stability of lubricating oil, effectively solve the problem of viscosity increase of oil products during long-term operation at high temperature, avoid premature oxidation and decline of lubricating oil, and extend the oil change cycle and service life.

[0043] In terms of mass percentage, the gear oil provided by the present invention contains 4.5-8.5% of extreme pressure and anti-wear agent, and in specific embodiments, it can be 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0% or 8.5%. In the present invention, the extreme pressure and anti-wear agent includes tridecylhexadecylphosphonium salt docusate ionic liquid, sulfurized olefin and alkyl phosphate amine salt. The tridecylhexadecylphosphonium salt docusate ionic liquid has the structure shown in Formula 2; the present invention has no special limitation on the source of the tridecylhexadecylphosphonium salt docusate ionic liquid, and it can be prepared by using methods well-known to those skilled in the art. In specific embodiments, it is prepared with reference to the literature "Fan Mingjin, Yang Desuo, Wang Xiaoling, et al. DOSS-Based QAILs: As Both Neat Lubricants and Lubricant Additives with Excellent Tribological Properties and Good Detergency. Industrial & Engineering Chemistry Research, 2014, 53(46): 17952-17960".

[0044]

[0045] In the present invention, the sulfurized olefin is preferably sulfurized isobutene, and the sulfurized isobutene is preferably T321 of Ningxia Tianhe Fine Chemical Co., Ltd.; the alkyl phosphate amine salt is preferably NA-LUBEAW 6110 of King Industries.

[0046] In the present invention, the mass ratio of the tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, sulfurized olefin and alkyl phosphate amine salt is preferably (1-2):(2.5-4.5):(1-2), more preferably 1:(2-3):1, and in specific embodiments, it can be 1:2.5:1, 2:4.5:2 or 1:2:1.

[0047] The present invention uses a tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, sulfurized olefin and alkyl phosphate amine salt as extreme pressure and anti-wear agents. Each component has a good positive synergistic effect with each other. Compared with the traditional gear oil formulation that uses sulfurized isobutene alone as the main agent, it not only improves the extreme pressure and anti-wear performance, but also reduces the usage amount of active sulfur, and solves the contradiction between extreme pressure and corrosion performance.

[0048] Based on weight percentage, the gear oil provided by the present invention includes 1.0-3.0% of ashless dispersant, and in specific embodiments, it can be 1.0%, 1.5%, 2.0%, 2.5% or 3.0%. In the present invention, the ashless dispersant is preferably high molecular weight polyisobutylene succinimide, and the relative molecular weight of the high molecular weight polyisobutylene succinimide is preferably greater than 2000. In the present invention, the high molecular weight polyisobutylene succinimide is preferably RF 1161 of Xinxiang Ruifeng New Materials Co., Ltd. The present invention preferably uses high molecular weight polyisobutylene succinimide as the ashless dispersant, which can solubilize sludge and deposits generated during long-term operation of the oil at high temperature.

[0049] The gear oil provided by the present invention comprises 0.05 - 0.1% of a metal deactivator by weight percentage. In specific embodiments, it can be 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%. In the present invention, the metal deactivator is preferably a thiadiazole derivative or a benzotriazole derivative, more preferably a thiadiazole derivative; the thiadiazole derivative is preferably 2,5 - bis(tert - dodecyl dithio)-1,3,4 - thiadiazole; the benzotriazole derivative is preferably N,N - dibutylaminomethylenebenzotriazole and / or N,N - dioctylaminomethylenebenzotriazole. In the present invention, the 2,5 - bis(tert - dodecyl dithio)-1,3,4 - thiadiazole is preferably DMTD - 12 of Chuzhou Kanghua Electronic Materials Co., Ltd. The present invention preferably uses a thiadiazole derivative as the metal deactivator, which can have a good synergistic effect with the extreme pressure and anti - wear agent in the present invention, avoiding the contradiction of competitive adsorption. It can not only prevent the corrosion of the vehicle drive axle system by the active sulfur additive, but also provide good extreme pressure performance.

[0050] The gear oil provided by the present invention comprises 0.05 - 0.1% of a rust inhibitor by weight percentage. In specific embodiments, it can be 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%. In the present invention, the rust inhibitor is preferably calcium alkylbenzene sulfonate, and the calcium alkylbenzene sulfonate is preferably a low - base - number long - chain linear calcium alkylbenzene sulfonate with an alkyl carbon number of C20 - C24. In the present invention, the low - base - number long - chain linear calcium alkylbenzene sulfonate is preferably RF 1104 of Xinxiang Ruifeng New Materials Co., Ltd. In the present invention, the low base number means that the alkylbenzene sulfonic acid is only neutralized to a calcium salt, and its micelles do not contain basic components such as calcium carbonate, and the base number below 60 is considered a low base number. The present invention preferably uses a low - base - number long - chain linear calcium alkylbenzene sulfonate as the rust inhibitor, which not only has good rust prevention performance, but also has a certain auxiliary extreme pressure and anti - wear effect, and has good compatibility with other additives.

[0051] In terms of weight percentage, the gear oil provided by the present invention includes 0.01-0.05% of an anti-foaming agent, which can be 0.01%, 0.02%, 0.03%, 0.04% or 0.05% in specific embodiments. In the present invention, the anti-foaming agent is preferably a silicon-type anti-foaming agent and a non-silicon-type anti-foaming agent; the silicon-type anti-foaming agent is preferably polymethylsilicone oil; the non-silicon-type anti-foaming agent is preferably polyacrylate. In the present invention, the mass ratio of the silicon-type anti-foaming agent to the non-silicon-type anti-foaming agent is preferably (1-2):(1-2), more preferably 1:1. In the present invention, the polymethylsilicone oil is preferably T901 from Shanghai Shenpu Fine Chemical Factory, and the polyacrylate is preferably T912 from Shanghai Shenpu Fine Chemical Factory. The present invention limits the dosage of the anti-foaming agent within the above range, which can maintain certain foam characteristics and avoid the occurrence of dry friction phenomena caused by the destruction of the oil film due to bubbles during use.

[0052] The present invention provides a preparation method of the gear oil described in the above solution, including the following steps: mixing a synthetic base oil, an antioxidant, an extreme pressure anti-wear agent, an ashless dispersant, a metal deactivator, a rust inhibitor and an anti-foaming agent to obtain the gear oil.

[0053] The present invention preferably adds the antioxidant, extreme pressure anti-wear agent, ashless dispersant, metal deactivator, rust inhibitor and anti-foaming agent to the synthetic base oil at 60-80°C under stirring conditions. After the addition is completed, continue to stir at 60-80°C for 3-5 hours until the obtained mixed material is uniform and transparent, and the gear oil is obtained after cooling. In the embodiments of the present invention, the mixing is preferably carried out in a stainless steel blending kettle with a stirrer.

[0054] The present invention provides an application of the gear oil described in the above solution or the gear oil prepared by the preparation method described in the above solution in the lubrication of a vehicle drive axle system.

[0055] The following examples are used to illustrate in detail the gear oil provided by the present invention, its preparation method and application, but they should not be construed as limiting the protection scope of the present invention.

[0056] The sources of some preparation raw materials involved in the following examples and comparative examples include:

[0057] The poly-α-olefin synthetic oil SpectraSyn 10 is purchased from Mobil, and the kinematic viscosity at 100°C is 10.61 mm 2 / s; the poly-α-olefin synthetic oil SpectraSyn40 is purchased from Mobil, and the kinematic viscosity at 100°C is 41.55 mm 2 / s; the synthetic ester base oil is preferably EsterexNP451 purchased from Mobil, and the kinematic viscosity at 100°C is 4.97 mm 2 / s;

[0058] The alkyl ester of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid is IRGANOX L135 from BASF;

[0059] Butyloctyldiphenylamine is IRGANOX L57 from BASF;

[0060] Isobutylene sulfide is T321 from Ningxia Tianhe Fine Chemical Co., Ltd.;

[0061] The amine salt of alkyl phosphate ester is NA-LUBE AW 6110 from King Industries;

[0062] The high molecular weight polyisobutylene succinimide is preferably RF 1161 from Xinxiang Ruifeng New Materials Co., Ltd.;

[0063] 2,5-Bis(tert-dodecyl dithio)-1,3,4-thiadiazole is preferably DMTD-12 from Chuzhou Kanghua Electronic Materials Co., Ltd.;

[0064] The calcium salt of low-base value long-chain linear alkylbenzene sulfonic acid is RF 1104 from Xinxiang Ruifeng New Materials Co., Ltd.;

[0065] The silicone-type antifoaming agent polymethylsilicone oil is T901 from Shanghai Shenpu Fine Chemical Factory;

[0066] The non-silicone-type antifoaming agent polyacrylate is T912 from Shanghai Shenpu Fine Chemical Factory.

[0067] Example 1

[0068] Weigh 9258 g of poly-α-olefin SpectraSyn 10, 8520 g of poly-α-olefin SpectraSyn 40 and 1000 g of synthetic ester Esterex NP451, heat up to 70 ± 5 °C and stir, then add 40 g of 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, 20 g of the alkyl ester of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 40 g of butyloctyldiphenylamine, 200 g of tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, 500 g of isobutylene sulfide, 200 g of the amine salt of alkyl phosphate ester, 200 g of the high molecular weight polyisobutylene succinimide, 10 g of 2,5-bis(tert-dodecyl dithio)-1,3,4-thiadiazole, 10 g of the calcium salt of low-base value long-chain linear alkylbenzene sulfonic acid, 1 g of the antifoaming agent polymethylsilicone oil and 1 g of the antifoaming agent polyacrylate, stir at 70 ± 5 °C for 3 h, and cool to room temperature (25 °C) to obtain the vehicle gear oil.

[0069] Example 2

[0070] Weigh 8100 g of polyalphaolefin SpectraSyn 10, 8250 g of polyalphaolefin SpectraSyn 40, and 1000 g of synthetic ester Esterex NP451. Heat the mixture to 70 ± 5 °C and stir. Then add 100 g of 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, 60 g of alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 140 g of butyloctyldiphenylamine, 400 g of tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, 900 g of sulfurized isobutene, 400 g of alkyl phosphate amine salt, 600 g of high molecular weight polyisobutylene succinimide, 20 g of 2,5-bis(tert-dodecyl dithio)-1,3,4-thiadiazole, 20 g of calcium long-chain linear alkylbenzene sulfonate with low base number, 6.6 g of antifoaming agent polymethylsilicone oil, and 3.4 g of antifoaming agent polyacrylate. Stir the mixture at 70 ± 5 °C for 3 h, and then cool it to room temperature (25 °C) to obtain the vehicle gear oil.

[0071] Example 3

[0072] Weigh 8582 g of polyalphaolefin SpectraSyn 10, 8582 g of polyalphaolefin SpectraSyn 40, and 1000 g of synthetic ester Esterex NP451. Heat the mixture to 70 ± 5 °C and stir. Then add 60 g of 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, 40 g of alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 100 g of butyloctyldiphenylamine, 300 g of tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, 600 g of sulfurized isobutene, 300 g of alkyl phosphate amine salt, 400 g of high molecular weight polyisobutylene succinimide, 14 g of 2,5-bis(tert-dodecyl dithio)-1,3,4-thiadiazole, 16 g of calcium long-chain linear alkylbenzene sulfonate with low base number, 4 g of antifoaming agent polymethylsilicone oil, and 2 g of antifoaming agent polyacrylate. Stir the mixture at 70 ± 5 °C for 3 h, and then cool it to room temperature (25 °C) to obtain the vehicle gear oil.

[0073] Comparative Example 1

[0074] Prepare the long-life vehicle gear oil according to Example 3, except that 60 g of 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazolium hexafluorophosphate, 40 g of alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 100 g of butyloctyldiphenylamine are replaced with 70 g of alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 130 g of butyloctyldiphenylamine.

[0075] Comparative Example 2

[0076] A long-life vehicle gear oil was prepared according to Example 3, except that 300 g of tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, 600 g of isobutene sulfide and 300 g of alkyl phosphate amine salt were replaced with 750 g of isobutene sulfide and 450 g of alkyl phosphate amine salt.

[0077] Performance tests were carried out on the vehicle gear oils prepared in the examples and comparative examples, and the results are shown in Table 1.

[0078] Table 1 Performance test results of vehicle gear oils prepared in examples and comparative examples

[0079]

[0080]

[0081] As can be seen from Table 1, the vehicle gear oil provided by the present invention has outstanding viscosity-temperature performance (viscosity index greater than 145), extreme pressure and anti-wear performance (FZG greater than 12 levels) and oxidation stability performance (DKA oxidation sludge not greater than 2 levels), and has good corrosion resistance, low-temperature performance and anti-foaming performance. At the same time, compared with Comparative Example 1, the long-life vehicle gear oil prepared in Example 3 has excellent antioxidant performance, indicating that the use of 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butylimidazole hexafluorophosphate, alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and butyloctyldiphenylamine in the present invention produces a good positive synergistic effect, which is beneficial to improving the oxidation stability performance of the lubricating oil, effectively preventing the viscosity increase of the oil during long-term operation at high temperature, and avoiding premature oxidation and deterioration of the lubricating oil; compared with Comparative Example 2, the long-life vehicle gear oil prepared in Example 3 has excellent extreme pressure and anti-wear performance, indicating that the compounding of tridecylhexadecylphosphonium salt dioctylsulfosuccinate ionic liquid, sulfurized olefin and alkyl phosphate amine salt in the present invention can produce a good synergistic effect, which can not only improve the extreme pressure performance of the lubricating oil, but also avoid the corrosion problem caused by the use of excessive active sulfur additives.

[0082] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A gear oil, characterized in that: The composition comprises the following components in percentage by weight: 86.75-93.89% of synthetic base oil, 0.5-1.5% of antioxidant, 4.5-8.5% of extreme pressure anti-wear agent, 1.0-3.0% of ashless dispersant, 0.05-0.1% of metal passivator, 0.05-0.1% of rust inhibitor, and 0.01-0.05% of anti-foaming agent; The synthetic base oil includes poly-alpha-olefin synthetic oil and synthetic ester base oil; The antioxidant includes 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butyl imidazole hexafluorophosphate, 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and alkyl diphenylamine; The extreme pressure anti-wear agent comprises tri-decyl hexadecyl quaternary phosphonium salt docusate ionic liquid, sulfided olefin and alkyl phosphate amine salt; The 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butyl imidazole hexafluorophosphate has a structure shown in Formula 1: The tri-decyl hexadecyl quaternary phosphonium salt docusate ionic liquid has a structure shown in Formula 2:

2. The gear oil according to claim 1, characterized in that The mass ratio of the 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-butyl imidazole hexafluorophosphate, 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid alkyl ester and alkyl diphenylamine is (2-5):(1-3):(2-7).

3. The gear oil according to claim 1 or 2, characterized in that: The side chain alkyl group of the 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid alkyl ester is a C7-C9 alkyl group.

4. The gear oil according to claim 1 or 2, characterized in that: The alkyl diphenylamine is butyl octyl diphenylamine or p-2-diisooctyl diphenylamine.

5. The gear oil according to claim 1, characterized in that The mass ratio of the tri-decyl hexadecyl quaternary phosphonium salt docusate ionic liquid, sulfided olefin and alkyl phosphate amine salt is (1-2): (2.5-4.5): (1-2).

6. The gear oil according to claim 1, characterized in that The kinematic viscosity of the poly-α-olefin synthetic oil at 100° C. is 3.0 to 200 mm 2 / s, the kinematic viscosity of the synthetic ester base oil at 100°C is 2.0-15.0 mm 2 / s; the mass ratio of the poly-α-olefin synthetic oil to the synthetic ester base oil is (81.75-88.89):

5.

7. The gear oil according to claim 1, characterized in that The ashless dispersant is high molecular weight polyisobutylene succinimide, and the relative molecular weight of the high molecular weight polyisobutylene succinimide is greater than 2000.

8. The gear oil according to claim 1, characterized in that The metal passivator is a thiadiazole derivative or a benzotriazole derivative; and the rust inhibitor is calcium alkylbenzene sulfonate.

9. The method for preparing the gear oil according to any one of claims 1 to 8, comprising the following steps: The gear oil is obtained by mixing synthetic base oil, antioxidant, extreme pressure anti-wear agent, ashless dispersant, metal passivator, rust inhibitor and anti-foaming agent.

10. Use of the gear oil according to any one of claims 1 to 8 or the gear oil prepared by the preparation method according to claim 9 in lubrication of a vehicle drive axle system.

Images