Gear oil composition

Abstract

The present application provides a gear oil composition comprising an aromatic amine type dispersant, an antioxidant, an antiwear agent, a metal corrosion inhibitor and a lubricating oil base oil, wherein the aromatic amine type dispersant comprises a polyamide compound having the following formula (1): wherein the definitions of the groups are given in the description. The gear oil composition of the present application has very excellent detergency, dispersancy, antiwear and antioxidant properties, while the amount of the antioxidant in the composition can be greatly reduced, and can meet the requirements of GL-5 and above extreme pressure heavy load gear oil products.

Description

Technical Field

[0001] This invention relates to a gear oil composition, and more particularly to a gear oil composition with excellent detergency, dispersancy, anti-wear and anti-oxidation properties. Background Technology

[0002] Vehicle gear oil is used to lubricate gears, bearings, and other parts in mechanical transmissions, drive axles, and steering systems, providing lubrication, cooling, rust prevention, and cushioning. Because automotive gears operate under complex conditions—high contact pressure, high circumferential speed, high sliding speed, and high oil temperature—high performance requirements are placed on gear oils. For example, hypoid gear drives operate under even more demanding conditions. If the correct gear oil is not selected, proper lubrication of the gears cannot be guaranteed, easily leading to premature wear and scratches, and even causing serious vehicle and personal injury accidents.

[0003] With the development of the automotive industry, gearbox volumes are decreasing, loads are increasing, and operating conditions are becoming more severe, leading to higher gear oil temperatures. This necessitates gear oils with higher thermal and oxidation stability, better detergency and dispersancy, and more stringent requirements for deposit control. The goal is to achieve smoother gear rotation, effectively reduce gear wear, extend gearbox life, and minimize unnecessary and expensive maintenance costs. To meet the ever-increasing industrial demands and increasingly demanding operating conditions of automotive gear machinery, the development of vehicle gear oils with excellent deposit dispersibility has become a new research hotspot.

[0004] Unsaturated olefins, aromatics, and trace amounts of sulfur compounds in lubricating oil base oils readily react with oxygen to form gums, which eventually lead to carbon deposits. These carbon deposits impede gearbox gear rotation, increase gear wear, and shorten gearbox life. Existing technology has developed lubricating oil compositions with detergency properties by adding detergent-dispersants to the lubricating oil base oil. Using such detergency-dispersant lubricating oil compositions can effectively reduce coking and carbon deposits, reduce gear corrosion and wear, and extend the safe operating cycle of gears and the service life of spare parts.

[0005] However, gear oil compositions prepared using existing detergent-dispersants can no longer fully meet the requirements of these higher-specification products. Therefore, there is still a need for a gear oil composition that not only meets the increasingly stringent requirements for detergent-dispersing performance of today's higher-specification products, but also possesses excellent antioxidant properties. Summary of the Invention

[0006] This invention proposes a gear oil composition that not only meets the increasingly stringent requirements for detergency and dispersancy in today's higher-specification products, but also significantly reduces the amount of antioxidant required.

[0007] The gear oil composition of the present invention comprises an aromatic amine dispersant, an antioxidant, an anti-wear agent, a metal corrosion inhibitor, and a lubricating oil base oil, wherein the aromatic amine dispersant comprises a polyamide compound having the structure shown in formula (1):

[0008]

[0009] In this context, R1, R2, R3, and R4 may be the same or different from each other, and are independently selected from H, halogen, cyano, and alkyl groups having 1 to 10 carbon atoms; n1 represents the number of R1, n2 represents the number of R2, n3 represents the number of R3, and n4 represents the number of R4; n1, n2, n3, and n4 may be the same or different from each other, and are independently selected from 1, 2, 3, or 4; L is selected from single bonds or alkylene groups having 1 to 5 carbon atoms; PIB represents polyisobutylene.

[0010] According to the present invention, optionally, R1, R2, R3 and R4 are the same and are selected from H, halogen, cyano and alkyl with 1 to 10 carbon atoms; n1, n2 and n3 are the same and are selected from 1, 2, 3 or 4.

[0011] According to the present invention, optionally, R1, R2, R3 and R4 are each H and L is a single bond.

[0012] According to the present invention, optionally, the polyamide compound has the structure shown in formula (1-1):

[0013]

[0014] According to the present invention, the method for preparing the aromatic amine dispersant includes:

[0015] (A) The first reactant and the second reactant are brought into contact and reacted in the first solvent to obtain an intermediate product;

[0016] (B) The intermediate product and polyisobutylene maleic anhydride are brought into contact and reacted in a second solvent;

[0017] The first reactant has the structure shown in formula (2), and the second reactant has the structure shown in formula (3) or formula (4):

[0018]

[0019] R5 is selected from alkyl groups having 1 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and substituted or unsubstituted aryl groups having 6 to 15 carbon atoms. The substituents of the substituted aryl and substituted cycloalkyl groups are each independently selected from one or more of deuterium, halogens, and alkyl groups having 1 to 5 carbon atoms.

[0020] According to the present invention, optionally, the second reactant is selected from one of indocyanine anhydride, 6-methylindocyanine, and 6,8-dibromoindocyanine anhydride; or, the second reactant is selected from one of pentane p-aminobenzoate, ethyl 2-aminobenzoate, menthol o-aminobenzoate, and benzyl p-aminobenzoate; preferably, the second reactant is indocyanine anhydride.

[0021] According to the present invention, optionally, in step (A), the molar ratio of the first reactant to the second reactant is 1:(3-3.5), preferably 1:(3-3.2); the reaction conditions include: a reaction temperature of 80-100°C and a reaction time of 8-12 h; preferably, the reaction temperature is 85-95°C and the reaction time is 9-10 h.

[0022] According to the present invention, optionally, in step (B), the molar ratio of the intermediate product to the polyisobutylene maleic anhydride is 1:(3-3.5), preferably 1:(3-3.2); the reaction conditions include: a reaction temperature of 140-160°C and a reaction time of 4-8 h; preferably, the reaction temperature is 145-155°C and the reaction time is 5-7 h.

[0023] According to the present invention, optionally, the number average molecular weight of the polyisobutylene maleic anhydride is 800-2500, preferably 1000-2300; in step (A), the first solvent is toluene, benzene or xylene, preferably toluene; in step (B), the second solvent is a base oil, preferably 150SN or white oil, more preferably 150SN.

[0024] According to a preferred embodiment of the present invention, the reactions in steps (A) and (B) are carried out under the protection of an inert gas, which is nitrogen, helium or argon, preferably nitrogen.

[0025] According to the present invention, the aromatic amine dispersant comprises a polyamide compound with a centrosymmetric structure. The structure is centered on an N atom and contains multiple symmetrically positioned amide functional groups and multiple benzene rings. This compound exhibits high overall structural symmetry and a suitable molecular weight, making it more compatible with the polycyclic aromatic hydrocarbon structure of soot and resulting in better dispersibility. It not only effectively disperses soot but also inhibits viscosity growth in oils during use, thereby effectively solving the soot dispersion problem. The preparation method is simple and has high synthesis efficiency.

[0026] The aromatic amine dispersant of the present invention mainly comprises the polyamide compound shown in formula (1) above, for example, comprising 50% or more by weight, 60% or more by weight, 70% or more by weight, 80% or more by weight, or 90% or more by weight. Preferably, the aromatic amine dispersant is composed of a polyamide compound. The polyamide compound has multiple electron-donating amide groups and contains numerous large conjugated systems, exhibits good structural symmetry, and possesses excellent dispersing performance.

[0027] In this invention, when n1 is greater than 1, R1 is the same or different; when n2 is greater than 1, R2 is the same or different; when n3 is greater than 1, R3 is the same or different; when n4 is greater than 1, R4 is the same or different.

[0028] In this invention, a single bond refers to a situation where the portion represented by L does not contain any other atoms. For example, when L in chemical formula (1) is a single bond, N can be directly attached to the benzene ring.

[0029] In one embodiment of the present invention, R1, R2, R3, and R4 are identical and selected from H, halogen, cyano, and alkyl groups having 1 to 10 carbon atoms; n1, n2, and n3 are identical and selected from 1, 2, 3, or 4. Specifically, R1, R2, R3, and R4 can simultaneously be H, halogen, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, etc., but are not limited thereto. More preferably, the substitution positions of R1, R2, R3 and R4 on their respective benzene rings can be the same, that is, the connection positions of R1, R2, R3 and R4 on their respective benzene rings have the same relative positional relationship with the amide group. For example, R1, R2, R3 and R4 are respectively ortho to the amide group on their respective benzene rings, or R1, R2, R3 and R4 are respectively meta to the amide group on their respective benzene rings.

[0030] In one embodiment of the present invention, R1, R2, R3 and R4 are each H, and L is a single bond.

[0031] According to the present invention, the antioxidant may be selected from one or more of phenolic ester antioxidants, phenolic antioxidants and amine antioxidants, preferably phenolic ester antioxidants, such as 2,6-di-tert-butyl-4-hydroxyphenyl acrylate, 2,6-di-tert-butyl-p-cresol, 4,4-methylenebis(2,6-di-tert-butylphenol), 2,6-di-tert-butyl-α-dimethylamino-p-cresol and N-phenyl-α-naphthylamine, and common commercial brands include T512, Irganox L135, T501, T511, T521, T531, etc.

[0032] According to the present invention, the anti-wear agent may be selected from one or more of phosphate esters, sulfurized olefins, dialkyl dithiocarbamates and dialkyl dithiophosphates, preferably phosphate esters, such as one or more of di-n-butyl acid phosphite, tricresyl phosphate, dialkyl dithiophosphate and butyl triphenyl thiophosphate, and common commercial brands include T304, T306, T309, etc.

[0033] According to the present invention, the metal corrosion inhibitor may be selected from one or more of benzotriazole derivatives, thiazole derivatives, and thiadiazole derivatives, preferably benzotriazole derivatives, such as benzotriazole, benzothiazole, toluenetriazole, octyltriazole, 2-mercaptobenzothiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbon-substituted-1,3,4-thiadiazole, 2-dimercapto-5-dithio-1,3,4-thiadiazole, N,N-dihexylaminomethylenebenzyltriazole, and 2-mercaptobenzothiazole. Common commercial brands include T706, T551, Irgamet 39, Irgamet 42, etc.

[0034] According to the present invention, the lubricating oil base oil can be selected from one or more of API Group I, II, III, IV, and V lubricating oil base oils, such as mineral lubricating oil base oils and / or synthetic lubricating oil base oils. Common commercial brands of the mineral lubricating oil base oils include Group I 150SN, 600SN, 150BS, etc., and Group II 100N, 150N, etc. Common commercial brands of the synthetic lubricating oil base oils include PAO4, PAO6, PAO8, PAO10, etc. The viscosity index of the lubricating oil base oil is generally greater than 80, the mass fraction of saturated hydrocarbons is greater than 90%, and the mass fraction of sulfur is less than 0.03%.

[0035] According to the present invention, the aromatic amine dispersant accounts for 0.1% to 20% of the total mass of the gear oil composition, preferably 0.2% to 16%; the antioxidant accounts for 0.02% to 5% of the total mass of the gear oil composition, preferably 0.1% to 3%; the anti-wear agent accounts for 0.1% to 10% of the total mass of the gear oil composition, preferably 0.2% to 8%; the metal corrosion inhibitor accounts for 0.01% to 5% of the total mass of the gear oil composition, preferably 0.02% to 3%; and the lubricating oil base oil constitutes the main component of the gear oil composition.

[0036] The method for preparing the gear oil composition of the present invention includes the step of mixing the components of the aforementioned gear oil composition.

[0037] The gear oil composition of the present invention has excellent detergency and dispersancy properties, and can significantly reduce the amount of antioxidant added in the composition, thus meeting the requirements of GL-5 and above extreme pressure heavy-duty gear oil products. Detailed Implementation

[0038] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto.

[0039] Unless otherwise specified, all raw materials used in the following embodiments are commercially available products.

[0040] The main raw materials used are as follows:

[0041] Polyisobutylene succinimide (PIB number-average molecular weight 1000), Yangzi Petrochemical;

[0042] Polyisobutylene maleic anhydride (PIB number-average molecular weight 1000), Yangzi Petrochemical;

[0043] Indocyanine anhydride, Ark Pharmaceuticals;

[0044] Tris(4-aminophenyl)amine, Shanghai Adamas Reagent Co., Ltd.;

[0045] Ashless dispersant, T161, Yangzi Petrochemical;

[0046] Phenolic ester antioxidant, T512, Beijing Xingpu Company;

[0047] Anti-wear agent, phosphate ester, Shandong Zibo Huihua Chemical Co., Ltd., di-n-butyl phosphite, T304;

[0048] Metal corrosion inhibitor, benzotriazole, Jinzhou Kangtai Lubricating Oil Additives Co., Ltd., T706;

[0049] 100SN, Maoming Petrochemical Company;

[0050] 150BS, Jinan Refining & Chemical Company.

[0051] Example 1

[0052] (A) Add 2.9g of tris(4-aminophenyl)amine and 4.89g of indomethacin anhydride to a 500ml reactor, then add 160ml of toluene, purge with nitrogen, turn on the reflux condenser, set the heating temperature to 90℃, and heat for 10 hours. Stop the reaction, distill off the toluene, and obtain intermediate product A1.

[0053] (B) Dissolve 33g of polyisobutylene maleic anhydride (number average molecular weight of 1000) in 100ml of 150SN, then add it to a reaction vessel containing intermediate product A1, purge with nitrogen, turn on the cooling water, heat to 150°C, heat for 6 hours, stop the reaction, and obtain the ashless dispersant F1 of this embodiment.

[0054] The final product and intermediate product A1 were separated and purified, and then characterized by infrared spectroscopy. The infrared characterization results show that the structure of the final product is as shown in equation (5), and the structure of the intermediate product A1 is as shown in equation (6).

[0055] Example 2

[0056] The method of Example 1 was used, with the only difference being that in step (A), the heating temperature was set to 80°C and the heating time was 12 hours; in step (B), the heating temperature was set to 160°C and the heating time was 5 hours. Ashless dispersant F2 of this example was obtained.

[0057] Example 3

[0058] The method of Example 1 was used, with the only difference being that in step (A), the heating temperature was set to 100°C and the heating time was 8 hours; in step (B), the heating temperature was set to 140°C and the heating time was 8 hours. Ashless dispersant F3 of this example was obtained.

[0059] Comparative Example 1

[0060] The method of Example 1 was used, except that indomethacin anhydride was not added. Tris(4-aminophenyl)amine and polyisobutylene maleic anhydride were reacted at a molar ratio of 1:3. The reaction conditions were as follows: 33g of polyisobutylene maleic anhydride (number average molecular weight of 1000) was dissolved in 100ml of 150SN solution and added to the reaction vessel. Then 2.9g of tris(4-aminophenyl)amine was added, nitrogen gas was introduced, cooling water was turned on, the temperature was raised to 150°C, and the heating time was 6 hours. The reaction was then stopped. Ashless dispersant DF1 of this comparative example was obtained.

[0061] Comparative Example 2

[0062] The method of Example 1 was used, except that tris(4-aminophenyl)amine was replaced with an equimolar amount of diaminodiphenylmethane. This yielded the ashless dispersant DF2 of this comparative example.

[0063] Comparative Example 3

[0064] The method of Example 1 was used, except that only polyisobutylene maleimide was used to synthesize the polyisobutylene maleimide-type ashless dispersant, wherein the number average molecular weight of the polyisobutylene maleimide was 1000. The ashless dispersant DF3 of this comparative example was obtained.

[0065] Examples 4-6 and Comparative Examples 4-8 of Gear Oil Compositions

[0066] The formulations of the gear oil compositions in Examples 4-6 and Comparative Examples 4-8 are shown in Table 1. Each component was added to a mixing container in the specified proportions, and the mixture was heated and stirred at 60°C for 2 hours to obtain the gear oil compositions in the examples and comparative examples. Aromatic amine dispersants F1, F2, and F3 were used in Examples 4-6; dispersants DF1, DF2, DF-3, and commercially available dispersant T161 were used in Comparative Examples 4-7, respectively. Compared to Comparative Example 7, Comparative Example 8 increased the amount of antioxidant. The dispersibility of the prepared gear oil compositions was evaluated using the sludge dispersion method. 2g of oil and 2g of sludge were mixed and ultrasonically dispersed. After aging in an oven at 100°C for 2 hours, the sludge suspension was dropped onto filter paper. After 24 hours, the percentage ratio of the sludge diffusion ring diameter to the oil ring was measured. A higher ratio indicates better dispersibility of the gear oil.

[0067] The wear resistance tests of the compositions in the examples and comparative examples were conducted using a high-frequency reciprocating friction testing machine. The test conditions were: load 400g, frequency 20Hz, temperature 60℃, and test time 60min. The smaller the wear scar diameter, the stronger the wear resistance of the composition.

[0068] The antioxidant properties of the compositions of the examples and comparative examples were tested using high-pressure differential scanning calorimetry (PDSC) at a temperature of 170°C. A longer oxidation induction period indicates a stronger antioxidant capacity of the composition.

[0069] Table 1

[0070]

[0071] Comparing Examples 4-6 and Comparative Examples 4-7 in Table 1, it can be seen that the gear oil composition of the present invention has excellent detergency and dispersancy, anti-wear properties, and antioxidant properties. Comparing Examples 4-6 and Comparative Examples 7-8, it can be seen that the gear oil composition of the present invention has excellent antioxidant properties, which can significantly reduce the amount of antioxidant required.

Claims

1. A gear oil composition comprising an aromatic amine dispersant, an antioxidant, an anti-wear agent, a metal corrosion inhibitor, and a lubricating oil base oil, wherein the aromatic amine dispersant comprises a polyamide compound having a structure as shown in formula (1): Equation (1) PIB stands for polyisobutylene group; The antioxidant is selected from one or more of phenolic ester antioxidants, phenolic antioxidants, and amine antioxidants; the anti-wear agent is selected from one or more of phosphate esters, sulfurized olefins, dialkyl dithiocarbamates, and dialkyl dithiophosphates; the metal corrosion inhibitor is selected from one or more of benzotriazole derivatives, thiazole derivatives, and thiadiazole derivatives; and the lubricating oil base oil is selected from one or more of API Group I, II, III, IV, and V lubricating oil base oils.

2. The gear oil composition according to claim 1, characterized in that, The preparation method of the aromatic amine dispersant includes: (A) The first reactant and the second reactant are brought into contact and reacted in the first solvent to obtain an intermediate product; (B) The intermediate product and polyisobutylene maleic anhydride are brought into contact and reacted in a second solvent; The first reactant is selected from tris(4-aminophenyl)amine, and the second reactant is selected from indomethacin anhydride.

3. The gear oil composition according to claim 2, characterized in that, In step (A), the molar ratio of the first reactant to the second reactant is 1:(3~3.5); the reaction conditions include: a reaction temperature of 80-100℃ and a reaction time of 8-12h.

4. The gear oil composition according to claim 2, characterized in that, In step (B), the molar ratio of the intermediate product to the polyisobutylene maleic anhydride is 1:(3~3.5); the reaction conditions include: a reaction temperature of 140-160℃ and a reaction time of 4-8h.

5. The gear oil composition according to claim 2, characterized in that, The polyisobutylene maleic anhydride has a number average molecular weight of 800-2500; in step (A), the first solvent is toluene, benzene or xylene; in step (B), the second solvent is a base oil.

6. The gear oil composition according to any one of claims 1 to 5, characterized in that, The aromatic amine dispersant accounts for 0.1% to 20% of the total mass of the gear oil composition; the antioxidant accounts for 0.02% to 5% of the total mass of the gear oil composition; the anti-wear agent accounts for 0.1% to 10% of the total mass of the gear oil composition; the metal corrosion inhibitor accounts for 0.01% to 5% of the total mass of the gear oil composition; and the lubricating oil base oil constitutes the main component of the gear oil composition.

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