Lubricating oil additive composition

Abstract

The invention discloses a lubricating oil additive composition. The lubricating oil additive composition is prepared from the following components in percentage by mass: 10 to 30 weight percent of zinc dialkyl dithiophosphate, 10 to 30 weight percent of succinimide dispersing agent, 15 to 40 weight percent of metal clearing agent and 5 to 10 weight percent of dialkyl dithiophosphate acrylate anti-wear agent, 10-20 wt% of an alkyl biimidazole phosphate ionic liquid, and 5-10 wt% of an alkylated diphenylamine antioxidant. The alkyl bis-imidazole phosphate ionic liquid and the propylene tetrapolymer alkylated diphenylamine are compounded, so that the lubricating oil has excellent oxidation resistance and corrosion inhibition performance in mineral oil and synthetic oil, can reduce the friction coefficient of oil products, and is suitable for vehicle transmission oil, vehicle drive axles or electric transmissions, and the like. And the service condition requirement of long service life of a vehicle transmission system is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of lubricating oil and lubricating oil additives and relates to a lubricating oil additive composition. Background Art

[0002] As vehicle drivetrains evolve toward higher speeds, heavier loads, and higher power, especially given the irreversible trend toward electrification, lubricant operating conditions are becoming increasingly demanding, placing higher demands on lubricant oxidation stability. Traditional lubricants oxidize and form varnish and sludge in vehicle transmissions and drive axles over long periods of use, easily leading to mechanical failure and shortened oil change intervals. The electric drive system is a core component of modern electric vehicles, encompassing key components such as the motor, electronic control unit, and battery. Because the drive motor rotates at very high speeds—typically reaching 20,000 rpm or more—its operating temperature can reach extremely high levels, generating significant heat. Lubricants are required for cooling and lubrication to ensure proper operation of the electric drive system. Therefore, electric drive system lubricants play a crucial role in electric vehicles. Therefore, whether meeting the long-life requirements of traditional vehicles or the operational demands of electric drive lubricants, high-temperature oxidation stability must be considered when formulating lubricant.

[0003] CN111286386A discloses a lubricant additive composition comprising a multifunctional antioxidant whose molecular formula simultaneously contains phenol, amine, and sulfur. This antioxidant not only addresses the high-temperature resistance of phenolic antioxidants but also addresses the deposit formation problem of amine antioxidants, thereby improving the thermal stability and oxidation resistance of the lubricant. The composition is suitable for turbine oils, air compressor oils, high-temperature chain oils, or engine oils. CN111778084A discloses a lubricant antioxidant composition composed of an amine antioxidant and a tetraalkylphosphonium phosphate ionic liquid. This composition significantly increases the oxidation induction period of the base oil and prolongs the service life of the lubricant, making it particularly suitable for high-temperature, demanding lubrication conditions. Imidazole phosphate ionic liquids are excellent antiwear agents. CN101768121A discloses a method for preparing an alkylbisimidazole phosphate salt compound and its excellent antiwear properties in PAO base oils. The use of alkylbisimidazole phosphate ionic liquids as composite antioxidant components in vehicle transmission lubricant formulations has not been reported. Summary of the Invention

[0004] To solve the problems and meet the requirements in the background art, the object of the present invention is to provide a lubricating oil additive composition. The present invention combines an alkyl bisimidazole phosphate ionic liquid and an acrylate tetramer alkylated diphenylamine, which has excellent antioxidant performance and corrosion inhibition performance in both mineral oils and synthetic oils, reduces the formation of deposits, can extend the service life of lubricating oils, and can also reduce the friction coefficient of the oil products. It is applicable to vehicle gearbox oils, vehicle drive axles or electric drive gearboxes, and meets the service condition requirements of long life for vehicle transmission systems.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] By mass percentage, the lubricating oil additive composition includes the following components:

[0007] Component A: Zinc dialkyldithiophosphate 10 - 30 wt%;

[0008] Component B: Succinimide dispersant 10 - 30 wt%;

[0009] Component C: Sulfurized alkylphenol calcium metal detergent 15 - 40 wt%;

[0010] Component D: Dialkyldithiophosphate acrylate antiwear agent 5 - 10 wt%;

[0011] Component E: Alkyl bisimidazole phosphate ionic liquid 10 - 20 wt%;

[0012] Component F: Alkylated diphenylamine antioxidant 5 - 10 wt%;

[0013] The alkylated diphenylamine antioxidant is an acrylate tetramer alkylated diphenylamine.

[0014] The structural formula of the alkyl bisimidazole phosphate ionic liquid is as follows:

[0015]

[0016] Wherein, R1 and R2 are alkyl groups having 1 - 8 carbon atoms, and R2 is the same as or different from R1.

[0017] The structural formula of the alkyl bisimidazole phosphate ionic liquid is as follows:

[0018]

[0019] Wherein, R1 is ethyl and R2 is ethyl.

[0020] The zinc dialkyldithiophosphate is a mixture composed of T202 and T205, and the mass ratio of T202 to T205 is (0.5 - 1):1.

[0021] The succinimide dispersant is boronated polyisobutylene succinimide or high-molecular-weight polyisobutylene succinimide, or a mixture of both.

[0022] The calcium sulfonate alkylphenol overbased detergent is a highly overbased calcium sulfonate alkylphenol with a base number of 220 KOH / g or more.

[0023] The dialkyldithiophosphate acrylate anti-wear agent is methyl 2-(di-n-butylphosphorodithioylthio)propionate.

[0024] The lubricating oil additive composition is added to a mineral base oil or a synthetic base oil at 5.5 wt% to 7.0 wt%, which improves the antioxidant and anti-corrosion properties of the lubricating oil, reduces the friction coefficient of the oil product, and is suitable for vehicle transmission oil, vehicle drive axle oil or electric drive transmission oil, meeting the service condition requirements of the long service life of the vehicle transmission system.

[0025] Compared with the prior art, the lubricating oil additive composition provided by the present invention has the following beneficial effects:

[0026] 1) The present invention uses a certain proportion of alkyl bisimidazole phosphate ionic liquid and diphenylamine alkylated with propylene tetramer for compounding, which has a high-efficiency synergistic antioxidant effect and excellent corrosion inhibition performance. It can significantly reduce the viscosity increase and acid value increase of the oil product in mineral oil, PAO synthetic oil and ester base oil, can extend the service life of the lubricating oil, and meet the service condition requirements of the long service life of the lubricating oil for the vehicle transmission system. Using the alkyl bisimidazole phosphate ionic liquid alone or the diphenylamine alkylated with propylene tetramer alone cannot achieve this effect.

[0027] 2) Compared with commercially available lubricants, the friction coefficient of the lubricating oil additive composition provided by the present invention is significantly reduced. This is because the alkyl bisimidazole phosphate ionic liquid undergoes a complex chemical reaction with the metal surface to form a more firmly adsorbed protective film, thereby avoiding direct contact between the friction parts, and thus making the friction coefficient significantly reduced and more stable. Detailed Embodiments

[0028] The following detailed description is given to the embodiments of the present invention. The embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The experimental methods without specific conditions noted in the following embodiments are usually carried out under conventional conditions.

[0029] In the following preparation examples, relatively typical zinc dialkyldithiophosphates T202 and T205 are from Wuxi Nanfang Petroleum Additive Co., Ltd., borated polyisobutylene succinimide is from Infineum H637, high molecular weight polyisobutylene succinimide is from RHY162 of CNPC Lubricant Company, alkyl bisimidazole phosphate ionic liquid can be prepared by the method of CN101768121A, propylene tetramer alkylated diphenylamine can be prepared by the method of CN115298290A, and overbased sulfurized alkylphenol calcium is from OLOA 219 sulfurized alkylphenol calcium produced by Chevron. The antioxidant is from Jiangsu Feiya Chemical. The viscosity index improver Viscoplex0-051 and pour point depressant V1-300 are produced by Evonik Industries AG of Germany. API Group I HVIS150BS base oil, API Group III VHVI4, VHVI6 base oils, API Group IV PAO8, PAO40 base oils are from CNPC Lubricant Company. The polyol ester base oil Priolube 3970 is from Croda Chemicals.

[0030] Example 1:

[0031] A lubricant additive composition (I) comprises: 15.0 wt% of T202 and 15.0 wt% of T205 (component A), 10.0 wt% of borated polyisobutylene succinimide (component B), 20.0 wt% of overbased sulfurized alkylphenol calcium with a base number of 245 KOH / g (component C), 10.0 wt% of methyl di-n-butyl dithiophosphate propionate (component D), 20.0 wt% of alkyl bisimidazole phosphate ionic liquid (component E, R1 is ethyl, R2 is ethyl), and 10.0 wt% of propylene tetramer alkylated diphenylamine antioxidant (component F). The sum of the above components is 100 wt%.

[0032] Comparative Example 1: Component (E) is not included, and component (F) is replaced by 30.0 wt% of propylene tetramer alkylated diphenylamine antioxidant, and the rest are the same as composition (I).

[0033] Comparative Example 2: Component (F) is not included, and component (E) is replaced by 30.0 wt% of alkyl bisimidazole phosphate ionic liquid, and the rest are the same as composition (I).

[0034] Comparative Example 3: Components (A), (B), (C), (D), (E), and (F) are not included, and a commercially available Infineum transmission oil compound Hitec 3080 is used.

[0035] The oxidation induction period of the oil product was tested by using the SH / T 0719 oxidation induction period determination method (high-pressure differential scanning calorimetry PDSC). The test conditions were as follows: the protective gas was nitrogen, the pressure was 3.5 Mpa, and the time for the catalytic oxidation reaction was tested under the condition of 220 °C with an oxygen flow rate of 100 mL / min. The larger the result, the better the antioxidant performance of the oil product. The improved Cincinnati thermal oxidation stability test (the temperature was increased by 40 °C) was adopted. The test conditions were as follows: iron rods and copper rod catalysts were added to 200 ml of the oil sample, the oil temperature was maintained at 165 °C, air was passed through for 168 h, and after cooling, the sludge was collected through a 5-micron filter and weighed.

[0036] The SRV testing machine simulation evaluation method was used to simulate the thermal stability of the oil product. The test conditions were as follows: 135 °C, 168 h, steel rods and copper rod catalysts, air was passed through, and after oxidation, the weight loss of the copper rod mg / 200 ml and the total sediment mg / 200 ml were mainly evaluated.

[0037] The compositions of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were all added to the 75W / 80 mineral-type transmission lubricating oil base oil at 7.0% (mass fraction) for evaluation. The properties of the 75W / 80 mineral-type base oil are shown in Table 1, and the evaluation results are shown in Table 2.

[0038] Table 1 Composition of the base oil of 75W / 80 mineral-type transmission lubricating oil

[0039]

[0040]

[0041] Table 2 Test results of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3

[0042]

[0043] The results in Table 2 show that the viscosity increase, acid value increase, and sludge amount of the oil product are significantly lower than those when adding alkyl bisimidazole phosphate ionic liquid or propylene tetramer alkylated diphenylamine antioxidant alone, indicating that the compounded oil product has excellent antioxidant performance and thermal oxidation stability, and can reduce the viscosity increase and acid value increase of the oil product. The compounding of alkyl bisimidazole phosphate ionic liquid and propylene tetramer alkylated diphenylamine has more efficient antioxidant performance than using diphenylamine antioxidants alone. There is a highly efficient synergistic effect between the two, which can significantly extend the service life of mineral lubricants and meet the service conditions requirements of long life for vehicle drive systems.

[0044] Example 2:

[0045] A lubricating oil additive composition (II) comprises: 5.0 wt% of T202 and 5.0 wt% of T205 (Component A), 25.0 wt% of high molecular weight polyisobutylene succinimide (Component B), 40.0 wt% of overbased calcium sulfonated alkylphenate with a base number of 245 KOH / g (Component C), 5.0 wt% of methyl dithiophosphate propionate (Component D), 10.0 wt% of alkyl bisimidazole phosphate ionic liquid (Component E, R1 is ethyl, R2 is ethyl), and 10.0 wt% of propylene tetramer alkylated diphenylamine antioxidant (Component F). The sum of the above components is 100 wt%.

[0046] Comparative Example 4: Component (E) was replaced by 5.0 wt% of alkyl bisimidazole phosphate ionic liquid, and Component (F) was replaced by 15.0 wt% of propylene tetramer alkylated diphenylamine antioxidant, and the rest was the same as Composition (II).

[0047] Comparative Example 5: Component (E) was not included, and Component (F) was replaced by 20.0 wt% of propylene tetramer alkylated diphenylamine antioxidant, and the rest was the same as Composition (II).

[0048] The compositions of Example 2, Comparative Example 4, and Comparative Example 5 were all evaluated by adding them to a 75W / 90 synthetic drive axle lubricating oil base oil at 5.6% (mass fraction). The properties of the 75W / 90 synthetic drive axle lubricating oil base oil are shown in Table 3, and the evaluation results are shown in Table 4.

[0049] Table 3 Composition and Properties of the Base Oil of 75W / 90 Synthetic Drive Axle Lubricating Oil

[0050]

[0051] Table 4 Test Results of Example 2, Comparative Example 4, and Comparative Example 5

[0052]

[0053] The results in Table 4 show that when alkyl bisimidazole phosphate ionic liquid and propylene tetramer alkylated diphenylamine are compounded and added to the PAO synthetic base oil, they exhibit excellent antioxidant performance and rust prevention effect, indicating that the alkyl bisimidazole phosphate ionic liquid compounding system has excellent antioxidant performance and good corrosion inhibition performance at the same time; Comparative Example 4 shows that when the usage ratio of alkyl bisimidazole phosphate ionic liquid decreases, the antioxidant performance of the composition decreases to a large extent and the corrosion prevention performance also decreases accordingly, indicating that the compounding ratio of the ionic liquid and the antioxidant will affect the antioxidant effect and corrosion prevention effect of the oil product; Comparative Example 5 shows that the composition without using alkyl bisimidazole phosphate ionic liquid has a direct adverse effect on the corrosion prevention performance of the oil product, meaning that the addition of alkyl bisimidazole phosphate ionic liquid in the composition has a good corrosion prevention effect on the oil product.

[0054] Example 3:

[0055] A lubricating oil additive composition (Ⅲ) comprises: 9.0 wt% of T202 and 18.0 wt% of T205 (Component A), 28.0 wt% of high molecular weight polyisobutylene succinimide (Component B), 15.0 wt% of overbased calcium sulfonated alkylphenate with a base number of 245 KOH / g (Component C), 7.5 wt% of methyl di-n-butyl dithiophosphate propionate (Component D), 17.5 wt% of alkyl bisimidazole phosphate ionic liquid ((Component E, R1 is ethyl, R2 is ethyl)), 5.0 wt% of propylene tetramer alkylated diphenylamine antioxidant (Component F). The sum of the above components is 100 wt%.

[0056] Comparative Example 6: Component (F) was replaced by 5.0 wt% of nonyl diphenylamine, and the rest was the same as Composition (Ⅲ).

[0057] Comparative Example 7: Component (F) was replaced by 5.0 wt% of dioctyl diphenylamine, and the rest was the same as Composition (Ⅲ).

[0058] Comparative Example 8: It did not contain Component (A), Component (B), Component (C), Component (D), Component (E) and Component (F), and a commercially available Afton electric drive transmission oil compound Hitec 35701 was used.

[0059] The corrosion inhibition of the composition was measured by FED-STD-791D Method 5308, and the test conditions were 204 °C, an air flow rate of 5 L / h, and a time of 72 hours. After the test, the sludge amount of the lubricating oil, the viscosity change at 40 °C, the increase in acid value, and the mass changes of metal sheets of steel, copper, aluminum, magnesium, and silver were measured.

[0060] The friction reduction performance of the composition was measured by the SRV method. The test method was NB / SH / T0847, and the test conditions were: temperature 80 °C, load 300 N, stroke 1 mm, test time 1 hour, and frequency 50 Hz.

[0061] The compositions of Example 3, Comparative Example 6, Comparative Example 7 and Comparative Example 8 were all added to the polyol ester base oil Priolube 3970 at 5.5% (mass fraction) for evaluation, and the evaluation results are shown in Table 5.

[0062] Table 5 Test results of Example 3 and Comparative Examples 6, 7 and 8

[0063]

[0064]

[0065] The results in Table 5 show that: (1) Compared with Comparative Examples 6, 7, and 8, Composition III has a lower friction coefficient, a smaller increase in oil viscosity, a lower change in acid value, and better corrosion inhibition performance, indicating that the additive composition of the present invention has better antioxidant performance, corrosion inhibition performance, and antifriction performance in ester-based base oils. (2) When comparing Composition III with Comparative Examples 6 and 7, with other components such as alkyl bisimidazole phosphate ionic liquids in the composition remaining unchanged, the change in the structure of the antioxidant has an obvious effect on the antioxidant performance of the composition. Compared with diphenylamine alkylated with propylene trimer, such as nonyl diphenylamine and dioctyl diphenylamine, diphenylamine alkylated with propylene tetramer has more excellent antioxidant stability, and the compounding of bisimidazole phosphate ionic liquid and diphenylamine alkylated with propylene tetramer has a more efficient antioxidant synergistic effect. (3) When comparing Comparative Examples 6, 7, and 8, the corrosion inhibition performance has been improved. This is because alkyl bisimidazole phosphate ionic liquid is added to the formulation. Ionic liquids with imidazole as the cation have excellent corrosion inhibition performance and do not produce acidic substances during use, will not cause corrosion to the friction pair, help reduce the acid value after oil oxidation, and reduce the corrosion effect on the friction pair. (4) When comparing Composition III of the present invention with the commercial product Comparative Example 8, the friction coefficient is significantly reduced. This is because the alkyl bisimidazole phosphate ionic liquid undergoes complex chemical reactions with the metal surface to form a more firmly adsorbed protective film, thereby avoiding direct contact between the friction parts, and thus significantly reducing the friction coefficient more stably.

[0066] Example 4:

[0067] A lubricating oil additive composition (IV) includes: 15.0 wt% of T202 and 15.0 wt% of T205 (Component A), 30.0 wt% of high molecular weight polyisobutylene succinimide (Component B), 20.0 wt% of overbased sulfurized alkylphenol calcium with a base number of 245 KOH / g (Component C), 5.0 wt% of methyl dithiophosphonopropionate (Component D), 10.0 wt% of alkyl bisimidazole phosphate ionic liquid (Component E, R1 is ethyl, R2 is ethyl), and 5.0 wt% of diphenylamine antioxidant alkylated with propylene tetramer (Component F). The sum of the above components is 100 wt%.

[0068] Comparative Example 9: Component (E) is replaced by 10.0 wt% of alkyl bisimidazole phosphate ionic liquid (R1 is hexyl, R2 is hexyl), and the rest is the same as Composition (IV).

[0069] Comparative Example 10: Component (E) is replaced by 10.0 wt% of alkyl bisimidazole phosphate ionic liquid (R1 is decyl, R2 is decyl), and the rest is the same as Composition (IV).

[0070] The compositions of Example 4, Comparative Example 9, and Comparative Example 10 were each added to a vehicle gearbox oil at 6.8% (mass fraction) for evaluation. The properties of the 75W / 85 vehicle gearbox oil are shown in Table 6, and the evaluation results are shown in Table 7.

[0071] Table 6 Base oil composition and properties of 75W / 85 vehicle gearbox oil

[0072]

[0073] Table 7 Test results of Example 4, Comparative Example 9, and Comparative Example 10

[0074]

[0075] The results in Table 7 show that alkyl bisimidazole phosphate ionic liquids with different structures in the formulation have a significant impact on the antioxidant performance of the oil, and ethyl bisimidazole phosphate ionic liquid exhibits better antioxidant performance.

[0076] Of course, the present invention may have many other embodiments. Those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the claims of the present invention.

Claims

1. A lubricating oil additive composition, characterized in that, By mass percentage, the lubricating oil additive composition comprises the following components: Component A: zinc dialkyldithiophosphate 10-30 wt%; Component B: succinimide dispersant 10-30 wt%; Component C: sulfurized alkylphenol calcium metal detergent 15-40 wt%; Component D: dialkyldithiophosphate acrylate antiwear agent 5-10 wt%; Component E: alkyl bisimidazole phosphate ionic liquid 10-20 wt%; Component F: alkylated diphenylamine antioxidant 5-10 wt%; The alkylated diphenylamine antioxidant is diphenylamine alkylated with propylene tetramer.

2. The lubricating oil additive composition according to claim 1, characterized in that, The structural formula of the alkyl bisimidazole phosphate ionic liquid is as follows: Wherein, R1 and R2 are alkyl groups having 1-8 carbon atoms.

3. A lubricating oil additive composition according to claim 1, characterized in that, The structural formula of the alkyl bisimidazole phosphate ionic liquid is as follows: Wherein, R1 is ethyl and R2 is ethyl.

4. A lubricating oil additive composition according to claim 1, characterized in that, The zinc dialkyldithiophosphate is a mixture composed of T202 and T205, and the mass ratio of T202 to T205 is (0.5-1):

1.

5. A lubricating oil additive composition according to claim 1, wherein The succinimide dispersant is boronated polyisobutylene succinimide or high molecular weight polyisobutylene succinimide, or a mixture of the two.

6. The lubricating oil additive composition according to claim 1, characterized in that, The sulfurized alkylphenol calcium metal detergent is a high-base sulfurized alkylphenol calcium with a base number of more than 220 KOH / g.

7. A lubricating oil additive composition according to claim 1, characterized in that, The dialkyldithiophosphate acrylate antiwear agent is methyl dipropionate phosphate.

8. Use of a lubricating oil additive composition according to claim 1, characterized in that, The lubricating oil additive composition is added to mineral base oil or synthetic base oil at 5.5 wt% to 7.0 wt% to improve the antioxidant and anti-corrosion properties of the lubricating oil, reduce the friction coefficient of the oil product, and is suitable for vehicle gearbox oil, vehicle drive axle oil or electric drive gearbox oil, meeting the service condition requirements of the long life of the vehicle transmission system.

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