A lubricating oil composition for improving friction characteristics of gears and a method for producing the same

Abstract

This invention discloses a lubricating oil composition for improving gear friction characteristics and its preparation method. The lubricating oil composition, by weight, comprises the following raw materials: 81-95 parts base oil, 1-4 parts gear oil compounding agent, 1-10 parts viscosity index improver, and 2-5 parts friction-modifying dispersant. This invention introduces a friction-modifying dispersant into gear lubricating oil, solving the problem that conventional friction-modifying dispersants compete with other additives for adsorption on metal surfaces, adversely affecting the oil's friction characteristics. Furthermore, the introduction of this substance can effectively adsorb and disperse deposits such as sludge and varnish in the oil, preventing their aggregation and deposition that cause friction and wear, further improving the oxidation stability and lifespan of vehicle gear oil. The gear lubricating oil composition prepared by this invention has excellent friction characteristics, effectively improving the friction characteristics of transmission fluid and enhancing the friction characteristics and shifting smoothness of automotive transmissions.

Description

Technical Field

[0001] This invention relates to a lubricating oil composition for improving gear friction characteristics and a method for preparing the same. Background Technology

[0002] Efficient shifting in manual transmissions is typically achieved using synchronizers. As a key component of automotive gearboxes, synchronizers ensure that two gears rotating at different speeds undergo a frictional contact process before meshing. This allows the gears to quickly reach and maintain a consistent circumferential speed before engaging, effectively eliminating the impact between gears during shifting. Under high-temperature operating conditions, transmission fluid's highly active additives are prone to oxidation and decomposition, producing large amounts of sludge, varnish, and deposits. As sludge and deposits accumulate, the system temperature further increases, accelerating fluid aging and deterioration, affecting shift smoothness, and corroding the copper alloys in the transmission, ultimately impacting its lifespan.

[0003] Dispersants can adsorb and disperse deposits such as sludge and varnish in oils, preventing their aggregation and deposition that could cause friction and wear, and improving the oxidation stability and lifespan of vehicle gear oils. Therefore, they are widely used in gear oil formulations. Reference patents such as US201862613589, US2016075964A1, US8697617B2, and US201615094478 all use conventional dispersants to improve the dispersibility of oils. However, amines in conventional dispersants have strong reactivity. Highly active amines can compete with other additives for adsorption on metal surfaces, adversely affecting the frictional characteristics of the oil, leading to poorer shifting smoothness of the synchronizer and a shortened service life. Summary of the Invention

[0004] To increase the selection of gear lubricants and at least partially solve the problems of poor shifting smoothness and shortened service life of automotive transmissions, embodiments of the present invention provide a lubricant composition for improving gear friction characteristics and a method for preparing the same.

[0005] As one aspect of the present invention, a lubricating oil composition for improving gear friction characteristics is provided, the lubricating oil composition comprising, by weight, the following components: 81-95 parts base oil, 1-4 parts gear oil compound, 1-10 parts viscosity index improver, and 2-5 parts friction-modifying dispersant.

[0006] In one or more possible embodiments, the base oil is selected from one or more of Group I base oils, Group II base oils, Group III base oils, poly-alpha olefin synthetic oils, ester synthetic oils, or polyether synthetic oils.

[0007] In one or more possible embodiments, the gear oil compound comprises: extreme pressure agent, anti-wear agent, rust inhibitor and metal deactivator;

[0008] The mass ratio of the extreme pressure agent, the anti-wear agent, the rust inhibitor and the metal deactivator is (85-96):(3-15):(0.5-5):(0.5-5).

[0009] In one or more possible embodiments, the extreme pressure agent is selected from isobutylene sulfide, or any mixture of isobutylene sulfide and dialkylpentasulfide, or any mixture of isobutylene sulfide and di-tert-butyl polysulfide.

[0010] In one or more possible embodiments, the anti-wear agent is selected from one or more of ammonium phosphate salts, amine thiophosphate salts, dialkyl phosphite esters, 2,5-dimercaptothiadiazole ammonium salts, benzotriazole ammonium salts, or benzotriazole thiophosphate ammonium salts.

[0011] In one or more possible embodiments, the rust inhibitor is selected from di-n-octyl phosphate oleate amine, dicyclohexyl phosphate oleate amine, octadecyl phosphate oleate amine, C 12 Fatty acid diethanolamide phosphate, C 14 Fatty acid diethanolamide phosphate, C 16 Fatty acid diethanolamide phosphate or C 18 One or more of fatty acid diethanolamide phosphate esters.

[0012] In one or more possible embodiments, the metal deactivator is selected from thiadiazole polysulfides or derivatives of thiadiazole polysulfides.

[0013] In one or more possible embodiments, the viscosity index improver is polymethacrylate and / or ethylene propylene copolymer.

[0014] In one or more possible embodiments, the friction-modified dispersant is as shown in formula (I):

[0015]

[0016] In formula (Ⅰ), R is -CH2-, -O- or -SO2-; R1 is -CH2-, -CH2CH2-, -CH(CH3)- or -CH(OH)-; R2, R3, R4, and R5 are each independently selected from mono-linked aliphatic amine type polyisobutylene succinimide B and / or mono-linked polyether amine type polyisobutylene succinimide C.

[0017] In one or more possible embodiments, the mono-linked fatty amine type polyisobutylene succinimide B is as shown in formula (II):

[0018]

[0019] In equation (II), the value of n is 1≤n≤8, and n is an integer.

[0020] In one or more possible embodiments, the mono-linked polyetheramine type polyisobutylene succinimide C is as shown in formula (III):

[0021]

[0022] In equation (Ⅲ), the range of x and z is 1≤(x+z)≤4, and both x and z are integers; the range of y is 1≤y≤9, and y is an integer.

[0023] As another aspect of the present invention, a method for preparing the above-described lubricating oil composition for improving gear friction characteristics is provided, the method comprising the following steps:

[0024] S1, Preparation of Gear Oil Compound

[0025] Under stirring conditions, extreme pressure agent, anti-wear agent, rust inhibitor and metal deactivator are weighed and mixed in the order of mass parts, heated and mixed to obtain gear oil compound;

[0026] S2, Preparation of Lubricating Oil Composition

[0027] Under stirring conditions, base oil, gear oil compound prepared in step S1, viscosity index improver and friction-modifying dispersant are weighed and mixed in the following proportions by mass, and heated and mixed to obtain a lubricating oil composition.

[0028] In one or more possible embodiments, the friction-modified dispersant is a compound prepared by the Mannich reaction of a multifunctional polar crosslinking agent A containing multiple reaction sites, the monopeptide aliphatic amine polyisobutylene succinimide B and / or the monopeptide polyether amine polyisobutylene succinimide C, and paraformaldehyde compound D.

[0029] In one or more possible embodiments, the friction-modified dispersant is a compound prepared by a Mannich reaction of a multifunctional polar crosslinking agent A containing multiple reaction sites, the monopeptidated aliphatic amine polyisobutylene succinimide B, the monopeptidated polyether amine polyisobutylene succinimide C, and paraformaldehyde compound D.

[0030] The molar ratio of the multifunctional polar crosslinking agent A containing multiple reaction sites, the mono-linked aliphatic amine polyisobutylene succinimide B, the mono-linked polyether amine polyisobutylene succinimide C, and the paraformaldehyde compound D is 1:(1-4):(1-4):(3.5-4.2).

[0031] The method for preparing the lubricating oil composition further includes the preparation of a friction-modifying dispersant;

[0032] The preparation method of the friction-modified dispersant includes the following steps:

[0033] Under stirring conditions, the multifunctional polar crosslinking agent A containing multiple reaction sites, the mono-linked aliphatic amine polyisobutylene succinimide B, the mono-linked polyether amine polyisobutylene succinimide C, and the paraformaldehyde compound D are heated and mixed according to the molar ratio. After removing water, the mixture is cooled and filtered to obtain a friction-modified dispersant.

[0034] In one or more possible embodiments, the multifunctional polar crosslinking agent A containing multiple reactive sites is as shown in formula (Ⅳ):

[0035]

[0036] In formula (Ⅳ), R is -CH2-, -O- or -SO2-; R1 is -CH2-, -CH2CH2-, -CH(CH3)- or -CH(OH)-.

[0037] In one or more possible embodiments, the preparation of the multifunctional polar crosslinking agent A containing multiple reactive sites includes the following steps:

[0038] Under stirring conditions, aromatic amine compounds, carboxyl-containing phenolic compounds, and organic solvents are heated and mixed, refluxed under inert gas protection, filtered, and distilled under reduced pressure to obtain the multifunctional polar crosslinking agent A containing multiple reaction sites.

[0039] In one or more possible embodiments, the molar ratio of the aromatic amine compound to the carboxyl-containing phenolic compound is 1:(1.8 to 2.3).

[0040] In one or more possible embodiments, the aromatic amine compound is as shown in formula (V):

[0041]

[0042] In formula (V), R is -CH2-, -O-, or -SO2-.

[0043] In one or more possible embodiments, the carboxyl-containing phenolic compound is selected from one or more of p-hydroxybenzoic acid, p-hydroxyphenylacetic acid, p-hydroxyphenylpropionic acid, 2-(4-hydroxyphenyl)propionic acid, 3-hydroxyphenylethanolic acid, 2-(p-hydroxyphenylazo)benzoic acid, or 2-amino-5-hydroxybenzoic acid.

[0044] In one or more possible embodiments, the preparation of the mono-linked fatty amine type polyisobutylene succinimide B includes the following steps:

[0045] Under stirring conditions, polyethylene polyamine compounds and base oil are heated and mixed, then polyisobutylene succinic anhydride is added, the mixture is heated to react, water is removed, and then cooled to obtain the mono-aliphatic amine type polyisobutylene succinimide B.

[0046] In one or more possible embodiments, the molar ratio of the polyisobutylene succinic anhydride to the polyethylene polyamine compound is 1:(0.8-1).

[0047] In one or more possible embodiments, the number-average molecular weight of the polyisobutylene succinic anhydride is selected from 1000, 1300, or 2300.

[0048] In one or more possible embodiments, the polyethylene polyamine compound is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, or heavy polyamines.

[0049] In one or more possible embodiments, the base oil has a mass fraction of 50-65% in the mono-coated fatty amine type polyisobutylene succinimide B.

[0050] In one or more possible embodiments, the preparation of the mono-linked polyetheramine type polyisobutylene succinimide C includes the following steps:

[0051] Under stirring conditions, polyetheramine compounds and base oils are heated and mixed, then polyisobutylene succinic anhydride is added, the mixture is heated to react, water is removed, and then cooled to obtain the mono-linked polyetheramine type polyisobutylene succinimide C.

[0052] In one or more possible embodiments, the molar ratio of the polyisobutylene succinic anhydride to the polyetheramine compound is 1:(0.75-1).

[0053] In one or more possible embodiments, the base oil has a mass fraction of 45-55% in the mono-coated polyetheramine type polyisobutylene succinimide C.

[0054] This invention introduces a friction-modified dispersant into gear lubricating oil, solving the problem of conventional dispersants competing with other additives for adsorption on metal surfaces, which adversely affects the oil's frictional properties. Furthermore, the friction-modified dispersant possesses excellent dispersing performance, antioxidant properties, and high-temperature detergency. Its introduction effectively adsorbs and disperses sludge, varnish, and other deposits in the oil, preventing their aggregation and deposition that could cause frictional wear, thereby further improving the oxidation stability and lifespan of vehicle gear oils.

[0055] The gear lubricating oil composition prepared by this invention has excellent frictional properties, which can effectively improve the frictional properties of transmission oil and enhance the frictional properties and shifting smoothness of synchronizers in automobiles.

[0056] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0057] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0058] Figure 1 The graph shows the trend of the friction coefficient of the lubricating oil compositions prepared in Application Examples 1-4 and Comparative Examples 1-2 of the present invention as a function of test time. Detailed Implementation

[0059] The embodiments of the present invention are described in detail below: The embodiments of the present invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The process parameters in the following embodiments that do not specify specific conditions are generally in accordance with conventional conditions.

[0060] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0061] The present invention will be further described below with reference to specific embodiments. The scope of protection of the present invention is not limited by the following embodiments. The main materials involved in the embodiments are all conventional commercially available products.

[0062] The following are preparation examples of the present invention. The preparation examples provide the preparation process and products of the multifunctional polar crosslinking agent A containing multiple reaction sites, the monopeptide aliphatic polyisobutylene succinimide B, and the monopeptide polyetheramine polyisobutylene succinimide C.

[0063] (1) Preparation of multifunctional polar crosslinking agent A containing multiple reaction sites

[0064] Preparation Example 1

[0065] Under stirring conditions, 59.4 g of 4,4'-diaminodiphenylmethane, 91.2 g of p-hydroxyphenylacetic acid and 100 g of xylene were mixed at 130 °C, nitrogen gas was introduced, and the mixture was refluxed for 4 h. After filtration and vacuum distillation, a multifunctional polar crosslinking agent A1 containing multiple reaction sites was obtained.

[0066] The multifunctional polar crosslinking agent A1 containing multiple reaction sites has the following formula:

[0067]

[0068] Preparation Example 2

[0069] Under stirring conditions, 60 g of 3,4'-diaminodiphenyl ether, 82.8 g of p-hydroxybenzoic acid and 100 g of xylene were mixed at 133 °C, nitrogen gas was introduced, and the mixture was refluxed for 3 h. After filtration and vacuum distillation, a multifunctional polar crosslinking agent A2 containing multiple reaction sites was obtained.

[0070] The multifunctional polar crosslinking agent A2 containing multiple reaction sites has the following formula:

[0071]

[0072] Preparation Example 3

[0073] Under stirring conditions, 74.4 g of 4,4'-diaminodiphenyl sulfone, 99.6 g of p-hydroxyphenylpropionic acid and 100 g of xylene were mixed at 138 °C, nitrogen gas was introduced, and the mixture was refluxed for 3 h. After filtration and vacuum distillation, a multifunctional polar crosslinking agent A3 containing multiple reaction sites was obtained.

[0074] The multifunctional polar crosslinking agent A3 containing multiple reaction sites has the following formula:

[0075]

[0076] (2) Preparation of mono-linked fatty amine type polyisobutylene succinimide B

[0077] Preparation Example 4

[0078] Under stirring conditions, 23.2g of polyamine (Hunsmann E100) and 123.2g of base oil Y4 were mixed at 102℃, and then 115g of polyisobutylene succinic anhydride PIBSA-1000 was added. The feeding time was controlled at 1h. After the feeding was completed, the mixture was kept at the temperature for 3h, and then the temperature was increased to 160℃ at a rate of 10℃ / h. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 6h. After cooling, mono-aliphatic amine type polyisobutylene succinimide B1 was obtained.

[0079] Preparation Example 5

[0080] Under stirring conditions, 11.6g of polyethylene polyamine (E100) and 190g of base oil 100SN were mixed at 110℃, and then 115g of polyisobutylene succinic anhydride PIBSA-2300 was added. The feeding time was controlled at 1h. After the feeding was completed, the mixture was kept at the temperature for 2h, and then the temperature was increased to 150℃ at a rate of 8℃ / h. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 4h. After cooling, mono-aliphatic amine type polyisobutylene succinimide B2 was obtained.

[0081] (3) Single-stranded polyetheramine type polyisobutylene succinimide C

[0082] Preparation Example 6

[0083] Under stirring conditions, 60g of polyether diamine ( ED-600 and 160g of base oil Y4 were mixed at 110℃, and then 100g of polyisobutylene succinic anhydride PIBSA-1300 was added. The feeding time was controlled at 30min. After the feeding was completed, the mixture was reacted at 120℃ for 3h, and then the temperature was raised to 160℃. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 6h. After cooling, mono-linked polyetheramine type polyisobutylene succinimide C1 was obtained.

[0084] Preparation Example 7

[0085] Under stirring conditions, 36g of polyether diamine ( ED-900 and 159g of base oil MVI150 were mixed at 120℃, and then 92g of polyisobutylene succinic anhydride PIBSA-2300 were added. The feeding time was controlled at 30min. After the feeding was completed, the mixture was reacted at 130℃ for 2h, and then the temperature was raised to 170℃. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5h. After cooling, mono-linked polyetheramine type polyisobutylene succinimide C2 was obtained.

[0086] The following are embodiments of the present invention.

[0087] Examples 1 to 12 each provide a friction-modified dispersant.

[0088] Example 1

[0089] Under stirring conditions, 46.6 g of the multifunctional polar crosslinking agent A1 containing multiple reaction sites from Preparation Example 1, 492.8 g of the mono-linked aliphatic amine polyisobutylene succinimide B1 from Preparation Example 4, 581.8 g of the mono-linked polyether amine polyisobutylene succinimide C1 from Preparation Example 6, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 7 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 4 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL1.

[0090] Example 2

[0091] Under stirring conditions, 46.6 g of the multifunctional polar crosslinking agent A1 containing multiple reaction sites from Preparation Example 1, 492.8 g of the mono-linked aliphatic amine polyisobutylene succinimide B1 from Preparation Example 4, 1300 g of the mono-linked polyether amine polyisobutylene succinimide C2 from Preparation Example 7, and 36 g of paraformaldehyde were mixed. After 2 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 4 h, the temperature was increased to 160 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 6 h. After cooling to 145 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL2.

[0092] Example 3

[0093] Under stirring conditions, 46.6 g of the multifunctional polar crosslinking agent A1 containing multiple reaction sites from Preparation Example 1, 1266 g of the mono-linked aliphatic amine polyisobutylene succinimide B2 from Preparation Example 5, 581.8 g of the mono-linked polyether amine polyisobutylene succinimide C1 from Preparation Example 6, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL3.

[0094] Example 4

[0095] Under stirring conditions, 46.6 g of the multifunctional polar crosslinking agent A1 containing multiple reaction sites from Preparation Example 1, 1266 g of the mono-linked aliphatic amine polyisobutylene succinimide B2 from Preparation Example 5, 1300 g of the mono-linked polyether amine polyisobutylene succinimide C2 from Preparation Example 7, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL4.

[0096] Example 5

[0097] Under stirring conditions, 46.8 g of the multifunctional polar crosslinking agent A2 containing multiple reaction sites from Preparation Example 2, 492.8 g of the mono-linked aliphatic amine polyisobutylene succinimide B1 from Preparation Example 4, 581.8 g of the mono-linked polyether amine polyisobutylene succinimide C1 from Preparation Example 6, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL5.

[0098] Example 6

[0099] Under stirring conditions, 46.8 g of the multifunctional polar crosslinking agent A2 containing multiple reaction sites from Preparation Example 2, 492.8 g of the mono-linked aliphatic amine polyisobutylene succinimide B1 from Preparation Example 4, 1300 g of the mono-linked polyether amine polyisobutylene succinimide C2 from Preparation Example 7, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL6.

[0100] Example 7

[0101] Under stirring conditions, 46.8 g of the multifunctional polar crosslinking agent A2 containing multiple reaction sites from Preparation Example 2, 1266 g of the mono-linked aliphatic amine polyisobutylene succinimide B2 from Preparation Example 5, 581.8 g of the mono-linked polyether amine polyisobutylene succinimide C1 from Preparation Example 6, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL7.

[0102] Example 8

[0103] Under stirring conditions, 46.8 g of the multifunctional polar crosslinking agent A2 containing multiple reaction sites from Preparation Example 2, 1266 g of the mono-linked aliphatic amine polyisobutylene succinimide B2 from Preparation Example 5, 1300 g of the mono-linked polyether amine polyisobutylene succinimide C2 from Preparation Example 7, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL8.

[0104] Example 9

[0105] Under stirring conditions, 51.6 g of the multifunctional polar crosslinking agent A3 containing multiple reactive sites from Preparation Example 3, 492.8 g of the mono-linked aliphatic amine polyisobutylene succinimide B1 from Preparation Example 4, 581.8 g of the mono-linked polyether amine polyisobutylene succinimide C1 from Preparation Example 6, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth as a filter aid to obtain the friction-modified dispersant SSL9.

[0106] Example 10

[0107] Under stirring conditions, 51.6 g of the multifunctional polar crosslinking agent A3 containing multiple reaction sites from Preparation Example 3, 492.8 g of the mono-linked aliphatic amine polyisobutylene succinimide B1 from Preparation Example 4, 1300 g of the mono-linked polyether amine polyisobutylene succinimide C2 from Preparation Example 7, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL10.

[0108] Example 11

[0109] Under stirring conditions, 51.6 g of the multifunctional polar crosslinking agent A3 containing multiple reaction sites from Preparation Example 3, 1266 g of the mono-linked aliphatic amine polyisobutylene succinimide B2 from Preparation Example 5, 581.8 g of the mono-linked polyether amine polyisobutylene succinimide C1 from Preparation Example 6, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL11.

[0110] Example 12

[0111] Under stirring conditions, 51.6 g of the multifunctional polar crosslinking agent A3 containing multiple reaction sites from Preparation Example 3, 1266 g of the mono-linked aliphatic amine polyisobutylene succinimide B2 from Preparation Example 5, 1300 g of the mono-linked polyether amine polyisobutylene succinimide C2 from Preparation Example 7, and 36 g of paraformaldehyde were mixed. After 1 h, the temperature was increased to 110 °C at a rate of 10 °C / h. After 3 h, the temperature was increased to 150 °C. Nitrogen gas was introduced into the system, and water was removed by gas stripping for 5 h. After cooling to 130 °C, the mixture was filtered using diatomaceous earth filter aid to obtain the friction-modified dispersant SSL12.

[0112] Examples 13-16 each provide a gear oil compound.

[0113] Example 13

[0114] The composition and mass fraction of gear oil compound SSL13 in this embodiment are shown in Table 1 below:

[0115] Table 1 Composition and mass of gear oil compound

[0116] type Components mass fraction / % Extreme pressure agent Isobutylene sulfide 87 anti-wear agent Hexammonium dodecyl phosphate 8 Rust inhibitor Dicyclohexyl phosphate oleic acid ammonium 3.6 Metal deactivating agents Methylbenzotriazole 1.4

[0117] Example 14

[0118] The composition and mass of the gear oil compound SSL14 in this embodiment are shown in Table 2 below:

[0119] Table 2 Composition and Quality of Gear Oil Compound

[0120]

[0121]

[0122] Example 15

[0123] The composition and mass of the gear oil compound SSL15 in this embodiment are shown in Table 3 below:

[0124] Table 3 Composition and Quality of Gear Oil Compound

[0125] type Components mass / g Extreme pressure agent High-pressure sulfurized isobutylene 87 Anti-wear agent 1 Hexammonium dodecyl phosphate 4 Anti-wear agent 2 2,5-Dimercaptothiadiazole ammonium salt 2 Anti-wear agent 3 Benzotriazole ammonium salt 2 Rust inhibitor Dicyclohexyl phosphate oleic acid ammonium 3.6 Metal deactivating agents Methylbenzotriazole 1.4

[0126] Example 16

[0127] The composition and mass of the gear oil compound SSL16 in this embodiment are shown in Table 4 below:

[0128] Table 4 Composition and Quality of Gear Oil Compound

[0129] type Components mass / g Extreme pressure agent Isobutylene sulfide 87 Anti-wear agent 1 Hexammonium dodecyl phosphate 5 Anti-wear agent 2 2,5-Dimercaptothiadiazole ammonium salt 1.5 Anti-wear agent 3 Benzotriazole ammonium salt 1.5 Rust inhibitor Dicyclohexyl phosphate oleic acid ammonium 3.5 Metal deactivators Methylbenzotriazole 1.5

[0130] The following are application examples of the present invention, each providing a lubricating oil composition for improving gear friction characteristics. In the following application examples, the lubricating oil composition for improving gear friction characteristics is prepared through the following steps:

[0131] S1, Preparation of Gear Oil Compound

[0132] First, the required weight parts of extreme pressure agent, anti-wear agent, rust inhibitor and metal deactivator are weighed separately using a weighing device, and then poured into a mixing and stirring device in sequence. The mixture is stirred at 30-35℃ for 1 to 2 hours until it is evenly mixed, thus obtaining the gear oil compound.

[0133] S2, Formulation of friction-modified dispersants

[0134] The preparation method of this substance is as described in Examples 1-12.

[0135] S3, Preparation of Lubricating Oil Composition

[0136] First, the required weight parts of base oil, gear oil compound prepared in step S1, viscosity index improver and friction-modifying dispersant are weighed separately using a weighing device, and then poured into a mixing and stirring device in sequence. The mixture is stirred at 60-70℃ for 2-3 hours until homogeneous, thus obtaining the lubricating oil composition.

[0137] Application Example 1

[0138] The lubricating oil composition for improving gear friction characteristics prepared in this application example includes the constituent raw materials and mass fractions shown in Table 5 below;

[0139] Table 5. Composition of Lubricating Oil Composition and its Mass Fraction

[0140]

[0141]

[0142] Application Example 2

[0143] The lubricating oil composition for improving gear friction characteristics prepared in this application example includes the constituent raw materials and their quantities shown in Table 6 below;

[0144] Table 6. Composition of Lubricating Oil Compositions and Their Mass Fractions

[0145]

[0146] Application Example 3

[0147] The lubricating oil composition for improving gear friction characteristics prepared in this application example includes the constituent raw materials and their quantities shown in Table 7 below;

[0148] Table 7. Composition of Lubricating Oil Compositions and Their Mass Fractions

[0149]

[0150]

[0151] Application Example 4

[0152] The lubricating oil composition for improving gear friction characteristics prepared in this application example includes the constituent raw materials and their quantities shown in Table 8 below;

[0153] Table 8. Composition of Lubricating Oil Compositions and Their Mass Fractions

[0154]

[0155] Application Comparative Example 1

[0156] The difference from Application Example 1 is that the friction-modified dispersant is a commercially available anti-wear ashless dispersant T151PB.

[0157] Application Comparative Example 2

[0158] The difference from Application Example 2 is that the friction-modified dispersant is the commercially available high molecular weight ashless dispersant T161.

[0159] The performance of the above application examples 1 to 4 and application comparison examples 1 to 2 was evaluated as follows, and the evaluation results are recorded in the table below.

[0160] Test 1 Antioxidant Performance Evaluation

[0161] The high-temperature oxidation resistance of gear lubricant compositions is evaluated using the DKA oxidation test method (CEC L-48-A-00). The DKA oxidation test simulates test conditions of 150–170°C in contact with air. The oxidation resistance of the gear oil is measured by evaluating changes in viscosity, acid value, and sludge score. Smaller changes in viscosity and acid value, and lower sludge grades, indicate better oxidation resistance. The specific steps are as follows:

[0162] A 100ml oil sample was collected and placed in a glass tube, which was then immersed in a 120℃ oil bath. A condenser was connected to the top of the glass tube, and a measured amount of air was bubbled into the lubricating oil. The test lasted for 192 hours. The test results are recorded in Table 9 below.

[0163] Table 9 Results of DKA oxidation experiments

[0164]

[0165] The test results show that when the friction-modified dispersant provided by this invention is applied to gear lubricating oil, the oil maintains a low viscosity increase and acid value increase, and the sludge grade is low, indicating that it can effectively inhibit the oxidative degradation of the oil and give the oil good antioxidant properties.

[0166] Analysis of Friction Characteristics in Test 2

[0167] (1) Four-ball friction test

[0168] The maximum non-seize load (PB value) was determined according to the relevant methods in GB / T 3142-1982 "Determination of Lubricant Load Capacity (Four-Ball Method)".

[0169] Among them, during the four-ball friction test, the trend of the oil friction coefficient with test time is as follows: Figure 1 As shown.

[0170] (2) SRV friction and wear test

[0171] The wear scar diameter of the oil test specimens was determined using an SRV4 high-frequency reciprocating linear vibration testing machine manufactured by OPTIMOL GmbH, Germany, according to the relevant methods described in the industry standard NB / SH / T 0847 "Extreme Pressure Lubricating Oil Friction and Wear Determination SRV Testing Machine Method". Using a copper disc with surface-to-surface contact between the upper and lower test specimens, the wear scar diameter, maximum friction coefficient, minimum friction coefficient, and friction coefficient at different time points were measured under constant conditions to evaluate the wear and friction performance of the manual transmission fluid. The test conditions were: load 250 N, frequency 50 Hz, time 2 h, temperature 80 ℃, and stroke 1 mm.

[0172] The test results of the two tests mentioned above are recorded in Table 10 below.

[0173] Table 10 Friction Characteristics Analysis

[0174]

[0175] The test results show that, on the one hand, the friction coefficient of the lubricating oil composition provided by the present invention does not change significantly with the test time, indicating that it has good retention and stability and good friction characteristics; on the other hand, the lubricating oil composition provided by the present invention has a high maximum non-seize load and a small average wear scar diameter, indicating that it has good extreme pressure anti-wear performance.

[0176] In summary, the lubricating oil composition provided by the present invention has excellent antioxidant properties, extreme pressure anti-wear properties, and friction characteristics.

[0177] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All modifications or applications made in accordance with the above embodiments are within the scope of protection of this technical solution.

[0178] Although specific embodiments of the invention have been described in detail, those skilled in the art will understand that various modifications and substitutions can be made to those details based on all the teachings disclosed, and all such changes are within the scope of protection of this invention. The full scope of this invention is given by the appended claims and any equivalents thereof.

Claims

1. A lubricating oil composition for improving gear friction characteristics, characterized in that, The lubricating oil composition, by weight, consists of the following raw materials: 81-95 parts base oil, 1-4 parts gear oil compound, 1-10 parts viscosity index improver, and 2-5 parts friction-modifying dispersant; The gear oil compound is a mixture of extreme pressure agent, anti-wear agent, rust inhibitor and metal deactivator; The rust inhibitor is selected from di-n-octyl phosphate oleate amine, dicyclohexyl phosphate oleate amine, octadecyl phosphate oleate amine, and C. 12 Fatty acid diethanolamide phosphate, C 14 Fatty acid diethanolamide phosphate, C 16 Fatty acid diethanolamide phosphate or C 18 One or more of the following: fatty acid diethanolamide phosphate esters; The friction-modified dispersant is as shown in formula (I): （Ⅰ）， In formula (I), R is -CH2-, -O-, or -SO2-; R1 is -CH2-, -CH2CH2-, -CH(CH3)-, or -CH(OH)-; R2, R3, R4, and R5 are each independently selected from a monopeptide aliphatic amine type polyisobutylene succinimide B group or a monopeptide polyether amine type polyisobutylene succinimide C group; and formula (I) contains both a monopeptide aliphatic amine type polyisobutylene succinimide B group and a monopeptide polyether amine type polyisobutylene succinimide C group.

2. The lubricating oil composition for improving gear friction characteristics according to claim 1, characterized in that, The base oil is selected from one or more of Group I base oil, Group II base oil, Group III base oil, poly-alpha olefin synthetic oil, ester synthetic oil, or polyether synthetic oil.

3. The lubricating oil composition for improving gear friction characteristics according to claim 1, characterized in that, The mass ratio of the extreme pressure agent, the anti-wear agent, the rust inhibitor and the metal deactivator is (85~96):(3~15):(0.5~5):(0.5~5).

4. The lubricating oil composition for improving gear friction characteristics according to claim 3, characterized in that, The extreme pressure agent is selected from isobutylene sulfide, or any mixture of isobutylene sulfide and dialkylpentasulfide in any ratio, or any mixture of isobutylene sulfide and di-tert-butyl polysulfide in any ratio.

5. The lubricating oil composition for improving gear friction characteristics according to claim 3, characterized in that, The anti-wear agent is selected from one or more of the following: ammonium phosphate salt, amine thiophosphate salt, dialkyl phosphite ammonium salt, 2,5-dimercaptothiadiazole ammonium salt, benzotriazole ammonium salt, or benzotriazole thiophosphate ammonium salt.

6. The lubricating oil composition for improving gear friction characteristics according to claim 3, characterized in that, The metal deactivator is selected from thiadiazole polysulfides or derivatives of thiadiazole polysulfides.

7. The lubricating oil composition for improving gear friction characteristics according to claim 1, characterized in that, The viscosity index improver is a polymethacrylate and / or ethylene propylene copolymer.

8. The lubricating oil composition for improving gear friction characteristics according to claim 1, characterized in that, The monopeptide fatty amine type polyisobutylene succinimide B is as shown in formula (II): （Ⅱ）； In equation (II), the value of n is 1≤n≤8, and n is an integer.

9. The lubricating oil composition for improving gear friction characteristics according to claim 1, characterized in that, The mono-linked polyetheramine type polyisobutylene succinimide C is as shown in formula (III): （Ⅲ）； In equation (Ⅲ), the range of x and z is 1≤(x+z)≤4, and both x and z are integers; the range of y is 1≤y≤9, and y is an integer.

10. A method for preparing a lubricating oil composition for improving gear friction characteristics as described in any one of claims 1 to 9, characterized in that, The method includes the following steps: S1, Preparation of Gear Oil Compound Under stirring conditions, extreme pressure agent, anti-wear agent, rust inhibitor and metal deactivator are weighed and mixed in the order of mass parts, heated and mixed to obtain gear oil compound; S2, Preparation of Lubricating Oil Composition Under stirring conditions, base oil, gear oil compound prepared in step S1, viscosity index improver and friction-modifying dispersant are weighed and mixed in the following proportions by mass, and heated and mixed to obtain a lubricating oil composition.

11. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 10, characterized in that, The friction-modified dispersant is a compound prepared by the Mannich reaction of a multifunctional polar crosslinking agent A containing multiple reaction sites, a monopeptide aliphatic amine polyisobutylene succinimide B, a monopeptide polyether amine polyisobutylene succinimide C, and a paraformaldehyde compound D.

12. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 11, characterized in that, The friction-modified dispersant is a compound prepared by the Mannich reaction of a multifunctional polar crosslinking agent A containing multiple reaction sites, a monopeptide aliphatic amine polyisobutylene succinimide B, a monopeptide polyether amine polyisobutylene succinimide C, and a paraformaldehyde compound D. The molar ratio of the multifunctional polar crosslinking agent A containing multiple reaction sites, the mono-linked fatty amine type polyisobutylene succinimide B, the mono-linked polyether amine type polyisobutylene succinimide C, and the paraformaldehyde compound D is 1:(1~4):(1~4):(3.5~4.2).

13. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 12, characterized in that, The method for preparing the lubricating oil composition further includes the preparation of a friction-modifying dispersant; The preparation method of the friction-modified dispersant includes the following steps: Under stirring conditions, the multifunctional polar crosslinking agent A containing multiple reaction sites, the mono-linked aliphatic amine polyisobutylene succinimide B, the mono-linked polyether amine polyisobutylene succinimide C, and the paraformaldehyde compound D are heated and mixed according to the molar ratio. After removing water, the mixture is cooled and filtered to obtain a friction-modified dispersant.

14. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 13, characterized in that, The multifunctional polar crosslinking agent A containing multiple reaction sites is shown in formula (Ⅳ): （Ⅳ）； In formula (Ⅳ), R is -CH2-, -O- or -SO2-; R1 is -CH2-, -CH2CH2-, -CH(CH3)- or -CH(OH)-.

15. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 14, characterized in that, The preparation of the multifunctional polar crosslinking agent A containing multiple reaction sites includes the following steps: Under stirring conditions, aromatic amine compounds, carboxyl-containing phenolic compounds, and organic solvents are heated and mixed, refluxed under inert gas protection, filtered, and distilled under reduced pressure to obtain the multifunctional polar crosslinking agent A containing multiple reaction sites.

16. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 15, characterized in that, The molar ratio of the aromatic amine compound to the carboxyl-containing phenolic compound is 1:(1.8~2.3).

17. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 16, characterized in that, The aromatic amine compounds are shown in formula (V): （Ⅴ）； In formula (V), R is -CH2-, -O-, or -SO2-.

18. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 16, characterized in that, The carboxyl-containing phenolic compound is selected from one or more of p-hydroxybenzoic acid, p-hydroxyphenylacetic acid, p-hydroxyphenylpropionic acid, 2-(4-hydroxyphenyl)propionic acid, 3-hydroxyphenylethanolic acid, 2-(p-hydroxyphenylazo)benzoic acid or 2-amino-5-hydroxybenzoic acid.

19. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 13, characterized in that, The preparation of the mono-linked fatty amine type polyisobutylene succinimide B includes the following steps: Under stirring conditions, polyethylene polyamine compounds and base oil are heated and mixed, then polyisobutylene succinic anhydride is added, the mixture is heated to react, water is removed, and then cooled to obtain the mono-linked fatty amine type polyisobutylene succinimide B. The molar ratio of the polyisobutylene succinic anhydride to the polyethylene polyamine compound is 1:(0.8~1). The number-average molecular weight of the polyisobutylene succinic anhydride is selected from 1000, 1300 or 2300. The polyethylene polyamine compound is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, or polyamines; The base oil has a mass fraction of 50-65% in the mono-coated fatty amine type polyisobutylene succinimide B.

20. The method for preparing the lubricating oil composition for improving gear friction characteristics according to claim 13, characterized in that, The preparation of the mono-linked polyetheramine type polyisobutylene succinimide C includes the following steps: Under stirring conditions, polyetheramine compounds and base oils are heated and mixed, then polyisobutylene succinic anhydride is added, the mixture is heated to react, water is removed, and then cooled to obtain the mono-linked polyetheramine type polyisobutylene succinimide C. The molar ratio of the polyisobutylene succinic anhydride to the polyetheramine compound is 1:(0.75~1). The base oil has a mass fraction of 45-55% in the mono-coated polyetheramine type polyisobutylene succinimide C.

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