Grease composition, grease and method for producing and using the same

Abstract

This invention relates to the field of lubricating greases, and discloses a lubricating grease composition, a lubricating grease, its preparation method, and its application. The lubricating grease composition comprises a urea-based thickener, a base oil, an antioxidant, a corrosion inhibitor, a rust inhibitor, a polyol, an organomolybdenum friction modifier, and an extreme pressure anti-wear agent. The mass ratio of the urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organomolybdenum friction modifier, and extreme pressure anti-wear agent is 1:(4.5-15):(0.01-0.09):(0.01-0.07):(0.05-0.45):(0.05-0.9):(0.05-0.7):(0.02-0.45). The lubricating grease composition of this invention has good anti-wear properties, an excellent coefficient of friction, and NVH performance, and can be used for the lubrication of inner ball-cage universal joints in new energy vehicles.

Description

Technical Field

[0001] This invention relates to the field of lubricating greases, and more specifically to a lubricating grease composition, a lubricating grease, a method for preparing the grease, and its applications. Background Technology

[0002] The function of an automotive universal joint is to ensure that the input and output shafts it connects transmit power within a certain range of angular variation. Structurally, they are divided into inner and outer CV joints. Inner CV joints connect the transmission and engine, transmitting engine power from the transmission to the two front wheels, driving the car at high speeds. Outer CV joints are mostly installed on the outside of the driveshaft, close to the wheel hub bearings, and connect the transmission and wheels. Most outer CV joints have a six-ball structure, with six steel balls installed in grooves on the outer and inner wheels. A retainer keeps the centers of each ball on the same plane. Torque is transmitted from the shaft to the inner wheel, then from the inner wheel groove through the steel balls to the outer wheel groove. The steel balls transmit torque while rolling in the grooves. The six-ball structure of the universal joint effectively transmits power and torque.

[0003] In recent years, with the increasing severity of urban pollution and substantial support for the new energy vehicle industry, the sector has experienced rapid development. Significant progress has been made, particularly in the technology of pure electric vehicles and hybrid electric vehicles. Compared to traditional internal combustion engine vehicles, these new energy vehicles offer advantages such as high torque at low speeds, rapid acceleration, and no engine noise. However, when common greases for internal ball-cage universal joints are applied to new energy vehicles, the large-capacity battery packs they carry, which generally make them heavier than traditional gasoline vehicles, lead to poor lubrication. This results in decreased anti-wear performance, increased friction coefficient, and problems such as yaw and wear on the joint grooves. Furthermore, as people's demands for automotive comfort increase, they are paying more attention to NVH (Noise, Vibration, and Harshness) performance (i.e., noise, vibration, and whistling caused by the transmission system). Therefore, the grease required for universal joints in new energy vehicles must possess certain noise reduction properties.

[0004] Therefore, there is an urgent need to provide a special grease for ball joints in new energy vehicles to solve the problems of poor lubrication caused by excessive load in ball joints in new energy vehicles, such as wear, vehicle yaw, and poor NVH performance. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of poor anti-wear performance and high friction coefficient of existing lubricating greases when applied to the inner ball cage type universal joint of new energy vehicles, which leads to vehicle yaw and wear in the grooves, as well as poor NVH performance. This invention provides a lubricating grease composition, lubricating grease, its preparation method and application.

[0006] To achieve the above objectives, the first aspect of the present invention provides a grease composition, wherein the grease composition comprises a urea-based thickener, a base oil, an antioxidant, a corrosion inhibitor, a rust inhibitor, a polyol, an organic molybdenum friction modifier, and an extreme pressure anti-wear agent.

[0007] A second aspect of the present invention provides a method for preparing a lubricating grease, wherein the method includes the following steps:

[0008] (1) In base oil, monoamine and diisocyanate are mixed and saponified to obtain base lipid system;

[0009] (2) The base grease system is expanded, then additives are added and mixed evenly to obtain lubricating grease;

[0010] The additives consist of antioxidants, corrosion inhibitors, rust inhibitors, polyols, organic molybdenum friction modifiers, and extreme pressure anti-wear agents.

[0011] A third aspect of the present invention provides a grease prepared by the method of the present invention.

[0012] Preferably, the average value of the axial derived force at eight points (0°, 2.5°, 5°, 7.5°, 10°, 12.5°, 15°, and 17.5°) measured by the grease at 200 rpm and 400 N is <20 N, and the variance of the axial derived force value is <50.

[0013] The fourth aspect of this invention provides the application of the grease described herein in the ball joint of a new energy vehicle.

[0014] Preferably, the inner ball cage universal joint has a three-pin structure.

[0015] Through the above technical solution, the present invention has achieved the following beneficial technical effects: the grease of the present invention has good anti-wear properties, excellent coefficient of friction and NVH performance, and can be used for lubrication of the inner ball cage type universal joint in new energy vehicles. Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein 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 herein.

[0017] The first aspect of the present invention provides a grease composition, wherein the composition comprises a urea-based thickener, a base oil, an antioxidant, a corrosion inhibitor, a rust inhibitor, a polyol, an organomolybdenum friction modifier, and an extreme pressure anti-wear agent.

[0018] According to some embodiments of the present invention, the mass ratio of the urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organomolybdenum friction modifier and extreme pressure anti-wear agent is 1:(4.5-15):(0.01-0.09):(0.01-0.07):(0.05-0.45):(0.05-0.9):(0.05-0.7):(0.02-0.45).

[0019] Preferably, the mass ratio of the urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organic molybdenum friction modifier, and extreme pressure anti-wear agent is 1:(4.5-13):(0.02-0.05):(0.02-0.05):(0.2-0.3):(0.2-0.3):(0.2-0.3):(0.05-0.2).

[0020] In this invention, when the mass ratio of the urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organic molybdenum friction modifier, and extreme pressure anti-wear agent meets the above-defined range, the grease composition has good anti-wear properties, excellent coefficient of friction, and NVH performance.

[0021] According to some embodiments of the present invention, the base oil is a hydrocarbon oil or an ester oil.

[0022] Preferably, the kinematic viscosity of the base oil at 40°C is 100-150 mmHg. 2 / s. In this invention, the kinematic viscosity of the base oil at 40°C can be 100 mm. 2 / s, 110mm 2 / s, 120mm 2 / s, 130mm 2 / s, 140mm 2 / s, 150mm 2 Any value within a range formed by any two values ​​in / s.

[0023] Preferably, the hydrocarbon oil content is 80-95 wt% based on the total mass of the base oil. In this invention, the hydrocarbon oil content can be any value within a range consisting of any two values ​​from 80 wt%, 85 wt%, 90 wt%, and 95 wt% of the total mass of the base oil.

[0024] Preferably, the content of the ester oil is 5-20 wt% based on the total mass of the base oil. In this invention, the content of the ester oil can be any value within a range consisting of any two values ​​from 5 wt%, 10 wt%, 15 wt%, and 20 wt% of the total mass of the base oil.

[0025] In this invention, adjusting the content of hydrocarbon oils and ester oils in the base oil can improve the solubility of the base oil and additives, thereby improving the lubricating performance of the grease composition.

[0026] According to some embodiments of the present invention, the hydrocarbon oil is selected from at least one of alkane mineral oils, cycloalkane mineral oils, and polyalphaolefins.

[0027] Preferably, the kinematic viscosity of the hydrocarbon oil at 40°C is 120-200 mmHg. 2 / s. In this invention, the kinematic viscosity of the hydrocarbon oil at 40°C can be 120 mm. 2 / s, 140mm 2 / s, 160mm 2 / s, 180mm 2 / s, 200mm 2 Any value within a range formed by any two values ​​in / s.

[0028] According to some embodiments of the present invention, the ester oil is selected from at least one of diisooctyl sebacate, pentaerythritol sebacate, trimellitate, and trihydroxy ester.

[0029] Preferably, the kinematic viscosity of the ester oil at 40°C is 10-80 mmHg. 2 / s. In this invention, the kinematic viscosity of the ester oil at 40°C can be 10 mm. 2 / s, 30mm 2 / s, 40mm 2 / s, 50mm 2 / s, 60mm 2 / s, 70mm 2 / s, 80mm 2 Any value within a range formed by any two values ​​in / s.

[0030] In this invention, the type of hydrocarbon oil affects the low-temperature performance of the grease composition. Using the hydrocarbon oil described in this invention can improve the low-temperature performance of the grease composition. The type of ester oil affects the solubility of the base oil and additives. Using the ester oil described in this invention improves the solubility of the base oil and additives, thereby improving the low-temperature performance of the grease composition.

[0031] In addition, the kinematic viscosity of hydrocarbon oils and ester oils affects the low-temperature operating performance and transmission efficiency of the grease composition. Limiting the kinematic viscosity of hydrocarbon oils and ester oils to the above-mentioned range can improve the low-temperature operating performance and transmission efficiency of the grease composition.

[0032] According to some embodiments of the present invention, the urea-based thickener is selected from tetraurea thickeners or diurea-based thickeners, preferably diurea-based thickeners.

[0033] Preferably, the bisurea-based thickener is prepared by reacting a monoamine with a diisocyanate.

[0034] In this invention, the diurea-based thickener is obtained in-house. The specific preparation method is as follows: add monoamine and diisocyanate to an organic solvent and saponify at 50-80°C for 0.5-1 h to generate the diurea-based thickener.

[0035] Preferably, the mass ratio of the monoamine to the diisocyanate is (0.8-2):1. In this invention, the mass ratio of the monoamine to the diisocyanate can be any value within the range of any two values ​​from 0.8:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, and 2:1.

[0036] Preferably, the monoamine is selected from at least one of octadecylamine, hexadecylamine, dodecylamine, octylamine, aniline, naphthylamine, p-toluidine, and cyclohexylamine, more preferably a mixture of cyclohexylamine and octylamine, and more preferably, the mass ratio of cyclohexane to octylamine is (0.5-2):1. In this invention, the mass ratio of cyclohexane to octylamine can be any value within the range of any two values ​​from 0.5:1, 1:1, 1.5:1, to 2:1.

[0037] Preferably, the diisocyanate is selected from at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, methane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate, and more preferably toluene diisocyanate.

[0038] In this invention, the composition of monoamine and diisocyanate and the amount of each substance meet the above-mentioned limits, which can improve the ability of the grease composition to resist shearing and improve mechanical stability.

[0039] According to some embodiments of the present invention, the antioxidant is selected from amine-type antioxidants.

[0040] Preferably, the amine antioxidant is selected from at least one of diisooctyl diphenylamine, alkylated diphenylamine, and N-phenyl-β-naphthylamine.

[0041] According to some embodiments of the present invention, the preservative is selected from benzotriazole and / or methylbenzotriazole.

[0042] According to some embodiments of the present invention, the rust inhibitor is an organic sulfonate.

[0043] Preferably, the organic sulfonate has an alkalinity of 300-400 mg KOH / g.

[0044] Preferably, the organic sulfonate is selected from calcium organic sulfonate and / or barium organic sulfonate.

[0045] More preferably, the organic calcium sulfonate is selected from calcium dodecylbenzene sulfonate and / or calcium dodecylnaphthalene sulfonate, with calcium dodecylnaphthalene sulfonate being the most preferred.

[0046] More preferably, the barium organic sulfonate is selected from at least one of barium dodecyl sulfonate, barium hexadecyl sulfonate, and barium octadecyl sulfonate.

[0047] In this invention, the type of rust inhibitor can improve the rust prevention performance of the grease composition; in addition, the rust inhibitor (organic sulfonate) interacts with the extreme pressure anti-wear agent (sulfur-phosphorus-zinc salt) to generate tiny molybdenum disulfide crystals on the surface of the friction pair, reducing the coefficient of friction of the grease composition, further improving the anti-wear performance of the grease composition and reducing the NVH characteristics of the universal joint.

[0048] According to some embodiments of the present invention, the polyol is selected from at least one of ethylene glycol, 1,2-propanediol, 1,4-butanediol, glycerol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, and pentaerythritol, preferably at least one of ethylene glycol, glycerol, trimethylolpropane, and pentaerythritol.

[0049] In this invention, polyols can promote the formation of a friction protective film during the friction process, maintain a smaller fluctuation in the coefficient of friction of the grease composition, make the coefficient of friction curve more stable, ensure a smoother ride for the vehicle, and also improve the extreme pressure anti-wear performance of the grease composition.

[0050] According to some embodiments of the present invention, the organic molybdenum friction modifier is selected from at least one of sodium molybdenum naphthalene sulfonate, calcium molybdenum naphthalene sulfonate, ammonium molybdenum naphthalene sulfonate, dibutyl dithiodiol molybdenum, diisobutyl dithiodiol molybdenum, dioctyl dithiodiol molybdenum, dioctyl dithiophosphate molybdenum, and dioctyl dithiophosphate molybdenum, preferably at least one of dioctyl dithiodiol molybdenum, ammonium molybdenum naphthalene sulfonate, and dibutyl dithiodiol molybdenum.

[0051] According to some embodiments of the present invention, the extreme pressure anti-wear agent is a sulfur-phosphorus-zinc salt.

[0052] Preferably, the zinc thiophosphate salt is selected from at least one of octyl butyl zinc thiophosphate salt, tetradecyl zinc thiophosphate salt, and hexadecyl zinc thiophosphate salt.

[0053] For three-pin constant velocity joints in automobiles, NVH performance is generally evaluated using a constant velocity drive shaft assembly axial derivative force test bench to test the axial derivative force at different angles. Generally, the smaller the axial derivative force, the smaller the range of angle changes, and the better the vehicle's NVH performance. A grease composition with a low coefficient of friction can effectively reduce axial derivative forces and improve NVH performance. This invention adds a polyol to the grease composition, effectively generating a more active Fe-H film on the friction pair surface. In the presence of this film, the stability of the film formed by the extreme pressure anti-wear agent and the organic molybdenum friction modifier can be effectively improved, thereby achieving friction stability. This results in a grease composition with good anti-wear properties, a low coefficient of friction, and significantly improved NVH characteristics of the transmission system in new energy vehicles.

[0054] A second aspect of the present invention provides a method for preparing a lubricating grease, wherein the method includes the following steps:

[0055] (1) In base oil, monoamine and diisocyanate are mixed and saponified to obtain base lipid system;

[0056] (2) The base grease system is expanded, then additives are added and mixed evenly to obtain lubricating grease;

[0057] The additives consist of antioxidants, corrosion inhibitors, rust inhibitors, polyols, organic molybdenum friction modifiers, and extreme pressure anti-wear agents.

[0058] According to some embodiments of the present invention, the mass ratio of the monoamine to the diisocyanate is (0.8-2):1. In the present invention, the mass ratio of the monoamine to the diisocyanate can be any value within a range consisting of any two values ​​from 0.8:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, and 2:1.

[0059] Preferably, the monoamine is selected from at least one of octadecylamine, hexadecylamine, dodecylamine, octylamine, aniline, naphthylamine, p-toluidine and cyclohexylamine, more preferably a mixture of cyclohexylamine and octylamine, and even more preferably, the mass ratio of cyclohexane to octylamine is (0.5-2):1.

[0060] In this invention, the mass ratio of cyclohexane to octylamine can be any value within the range of any two values ​​from 0.5:1, 1:1, 1.5:1, to 2:1.

[0061] Preferably, the diisocyanate is selected from at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, methane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate, and more preferably toluene diisocyanate.

[0062] According to some embodiments of the present invention, the total mass ratio of the monoamine and diisocyanate to the mass ratio of the base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organomolybdenum friction modifier, and extreme pressure anti-wear agent is 1:(4.5-15):(0.01-0.09):(0.01-0.07):(0.05-0.45):(0.05-0.9):(0.05-0.7):(0.02-0.45).

[0063] According to some embodiments of the present invention, the conditions for the saponification reaction include: a temperature of 50-80°C and a time of 0.5-1 h. In the present invention, the temperature of the saponification reaction can be any value within the range of any two values ​​formed by 50°C, 60°C, 70°C, and 80°C; the time of the saponification reaction can be any value within the range of any two values ​​formed by 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, and 1 h.

[0064] According to some embodiments of the present invention, the conditions for the puffing treatment include: a temperature of 150-180°C and a time of 1-3 hours. In the present invention, the temperature of the puffing reaction can be any value within the range of any two values ​​formed by 150°C, 160°C, 170°C, and 180°C; the time of the saponification reaction can be any value within the range of any two values ​​formed by 1 hour, 1.5 hours, 2 hours, 2.5 hours, and 3 hours.

[0065] According to some embodiments of the present invention, the mixing conditions include a temperature of 70-90°C and a time of 1-2 hours. In this invention, the mixing temperature of the base lipid system and the additive can be any value within the range of any two values ​​chosen from 70°C, 75°C, 80°C, 85°C, and 90°C; the mixing time of the base lipid system and the additive can be any value within the range of any two values ​​chosen from 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, and 2 hours.

[0066] In this invention, after the base lipid system undergoes expansion treatment and before the additives are added, a cooling treatment is also performed to prevent the antioxidants and preservatives from decomposing due to high temperatures. Preferably, the cooling treatment method includes controlling the temperature of the base lipid system to 70-120°C. In this invention, the cooling treatment conditions ensure that the temperature of the base lipid system is controlled within any value within the range of any two values ​​from 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, and 120°C.

[0067] In this invention, after the base lipid system and additives are mixed evenly, a grinding process is also included. There are no particular limitations on the grinding method; for example, a three-wheel mill can be used.

[0068] In this invention, the bisurea-based thickener is generated during the preparation of the grease. Specifically, monoamine and diisocyanate are added to the base oil. Under certain conditions, the monoamine and diisocyanate undergo a saponification reaction to generate the urea-based thickener. The mixture is then heated to 150-180°C and held at that temperature for 1-2 hours for expansion treatment to obtain the grease. After cooling the grease to 70-90°C, additives are added and stirred until homogenized. The mixture is then homogenized using a three-wheel mill or homogenizer to obtain a high-performance automotive constant velocity universal joint grease. The bisurea-based thickener prepared by the above method, unlike metal soap-based thickeners, does not contain metal ions. This avoids the catalytic oxidation of the base oil in the grease by metal ions in soap-based thickeners, thereby improving the high-temperature resistance of the grease.

[0069] A third aspect of the present invention provides a lubricating grease prepared by the method described herein.

[0070] Preferably, the average value of the axial derived force at eight points (0°, 2.5°, 5°, 7.5°, 10°, 12.5°, 15°, and 17.5°) measured by the grease at 200 rpm and 400 N is <20 N, and the variance of the axial derived force value is <50.

[0071] In this invention, the NVH performance of the lubricating grease is measured using an axial derived force test bench for a constant velocity drive shaft assembly. The NVH performance of the lubricating grease is determined by measuring the axial derived force values ​​at eight points (0°, 2.5°, 5°, 7.5°, 10°, 12.5°, 15°, and 17.5°) under conditions of 200 rpm and 400 N, and then measuring the average and variance. If the average value is less than 20 N and the variance is less than 50, the NVH performance is considered excellent; if the average value is less than 20 N or the variance is less than 50, the NVH performance is considered good; and if the average value is greater than 20 N and the variance is greater than 50, the NVH performance is considered poor.

[0072] The fourth aspect of this invention provides the application of the grease described herein in the ball joint of a new energy vehicle.

[0073] Preferably, the inner ball cage universal joint has a three-pin structure.

[0074] According to a particularly preferred embodiment of the present invention, a method for preparing a lubricating grease is provided, the method comprising the following steps:

[0075] (1) In base oil, monoamine and diisocyanate are mixed and saponified to obtain base lipid system;

[0076] (2) The base grease system is expanded, then additives are added and mixed evenly to obtain lubricating grease;

[0077] The additives consist of antioxidants, corrosion inhibitors, rust inhibitors, polyols, organic molybdenum friction modifiers, and extreme pressure anti-wear agents.

[0078] The mass ratio of the monoamine to the diisocyanate is (0.8-2):1;

[0079] Wherein, the monoamine is a mixture of cyclohexylamine and octylamine, and the mass ratio of cyclohexane to octylamine is (0.5-2):1;

[0080] Wherein, the diisocyanate is toluene diisocyanate;

[0081] The mass ratio of the total mass of the monoamine and diisocyanate to the mass of the base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organic molybdenum friction modifier, and extreme pressure anti-wear agent is 1:(4.5-15):(0.01-0.09):(0.01-0.07):(0.05-0.45):(0.05-0.9):(0.05-0.7):(0.02-0.45).

[0082] The conditions for the saponification reaction include: a temperature of 50-80℃ and a time of 0.5-1h.

[0083] The conditions for the puffing process include: a temperature of 150-180℃ and a time of 1-3 hours.

[0084] The mixing conditions include a temperature of 70-90℃ and a time of 1-2 hours.

[0085] The present invention will be described in detail below through embodiments.

[0086] Unless otherwise specified, all raw materials used in the following examples and comparative examples are commercially available.

[0087] The kinematic viscosity of base oils, hydrocarbon oils and ester oils at 40℃ was calculated according to GB / T265-1988 Petroleum Products: Determination of Kinematic Viscosity and Calculation of Dynamic Viscosity.

[0088] Example 1

[0089] (1) Add 24.5g of octylamine and 22.9g of cyclohexylamine to 100g of hydrocarbon oil, and then add 52.6g of toluene diisocyanate to 800g of base oil (80wt% hydrocarbon oil and 20wt% ester oil), and saponify at 50℃ for 0.5h to obtain the base lipid system.

[0090] The base oil has a kinematic viscosity of 100 mm at 40°C. 2 / s; The hydrocarbon oil is PAO, with a kinematic viscosity of 120 mm at 40℃. 2 / s; the ester oil is trimethylolpropane oleate, with a kinematic viscosity of 47 mm at 40°C. 2 / s;

[0091] (2) Heat the base grease system to 150°C and perform expansion treatment for 1 hour. Then, reduce the temperature of the base grease system to 120°C. Add 5g of antioxidant (diisooctyl diphenylamine), 2g of preservative (benzotriazole), 10g of rust inhibitor (barium dodecyl sulfonate, with an alkalinity of 320mgKOH / g), 20g of polyol (glycerol), 20g of organic molybdenum friction modifier (dibutyl dithiodiol molybdenum), and 20g of extreme pressure anti-wear agent (octyl butyl sulfophosphorus zinc salt) in sequence. Stir and mix at 90°C for 1 hour. Grind in a three-wheel mill to obtain grease A1.

[0092] Example 2

[0093] (1) Add 32.0g of octylamine and 16.3g of cyclohexylamine to 100g of hydrocarbon oil, and then add 51.7g of toluene diisocyanate to 800g of base oil (90wt% hydrocarbon oil and 10wt% ester oil) and saponify at 65℃ for 1h to obtain the base lipid system.

[0094] The base oil has a kinematic viscosity of 125 mm at 40°C. 2 / s; The hydrocarbon oil is a cycloalkane mineral oil with a kinematic viscosity of 140 mm at 40°C. 2 / s; the ester oil is trimellitate, with a kinematic viscosity of 75 mm at 40°C. 2 / s;

[0095] (2) Heat the base grease system to 160℃ and perform expansion treatment for 2 hours. Then, reduce the temperature of the base grease system to 100℃. Add 2g of antioxidant (N-phenyl-β-naphthylamine), 3g of preservative (methylbenzotriazole), 20g of rust inhibitor (calcium dodecyl naphthalene sulfonate, with an alkalinity of 380mgKOH / g), 30g of polyol (ethylene glycol), 30g of organic molybdenum friction modifier (ammonium molybdenum naphthalene sulfonate), and 5g of extreme pressure anti-wear agent (tetradecyl thiophosphoric zinc salt) in sequence. Stir and mix at 80℃ for 2 hours. Grind in a three-wheel mill to obtain grease A2.

[0096] Example 3

[0097] (1) Add 32.0g of octylamine and 16.3g of cyclohexylamine to 100g of hydrocarbon oil, and then add 51.7g of toluene diisocyanate to 800g of base oil (80wt% hydrocarbon oil and 20wt% ester oil) and saponify at 80℃ for 0.75h to obtain the base lipid system.

[0098] The base oil has a kinematic viscosity of 150 mmHg at 40°C. 2 / s; The hydrocarbon oil is an alkane mineral oil with a kinematic viscosity of 200 mm at 40°C. 2 / s; the ester oil is diisooctyl sebacate, with a kinematic viscosity of 14 mm at 40℃. 2 / s;

[0099] (2) Heat the base grease system to 180°C and perform expansion treatment for 1.5 hours. Then, reduce the temperature of the base grease system to 70°C. Add 3g of antioxidant (diisooctyl diphenylamine), 3g of corrosion inhibitor (benzotriazole), 30g of rust inhibitor (barium octadecyl sulfonate, with an alkalinity of 300mgKOH / g), 20g of polyol (pentaerythritol), 20g of organic molybdenum friction modifier (dioctyl dithiodiol molybdenum), and 20g of extreme pressure anti-wear agent (hexadecyl thiophosphoric zinc salt) in sequence. Stir and mix at 70°C for 1 hour. Grind the mixture in a three-wheel mill to obtain grease A3.

[0100] Example 4

[0101] The method of Example 1 is followed, except that the mass ratio of hydrocarbon oil to ester oil in the base oil is 1:1, to obtain grease A4.

[0102] Example 5

[0103] The method of Example 1 is followed, except that the mass ratio of urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organic molybdenum friction modifier and extreme pressure anti-wear agent is 1:8.1:0.09:0.18:0.05:0.009:0.05:0.55 to obtain grease A5.

[0104] Example 6

[0105] The method of Example 1 is followed, except that the polyol is replaced with oleic acid to obtain grease A6.

[0106] Example 7

[0107] The method of Example 1 is followed, except that the extreme pressure anti-wear agent is sulfurized isobutylene, and grease A7 is obtained.

[0108] Comparative Example 1

[0109] Following the method of Example 1, except that the grease composition does not contain polyols, grease B1 is obtained.

[0110] Test Example 1

[0111] The performance of greases A1-A7 and B1 in Examples 1-7 and Comparative Example 1 was tested, and the results are shown in Table 1.

[0112] The coefficient of friction of the grease was determined by the "SH / T 0721-2016 Determination of Friction and Wear Properties of Grease by High Frequency Linear Vibration Tester (SRV) Method".

[0113] The extreme pressure anti-wear properties of grease were determined according to GB / T 12583-1998 Determination of Extreme Pressure Properties of Lubricants (Four-Ball Method).

[0114] The NVH performance of the lubricating grease was measured using an axial derived force test bench for constant velocity drive shaft assembly. Axial derived force values ​​were measured at eight points (0°, 2.5°, 5°, 7.5°, 10°, 12.5°, 15°, and 17.5°) at 200 rpm and 400 N. The average and variance were measured. If the average value was below 20 N and the variance was less than 50, the NVH performance was considered excellent; if the average value was less than 20 N or the variance was less than 50, the NVH performance was considered good; and if the average value was greater than 20 N and the variance was greater than 50, the NVH performance was considered poor.

[0115] Table 1

[0116] Example coefficient of friction Wear scar diameter / mm NVH performance Example 1 0.062 0.38 excellent Example 2 0.058 0.38 excellent Example 3 0.064 0.37 excellent Example 4 0.074 0.41 good Example 5 0.091 0.43 Difference Example 6 0.085 0.41 good Example 7 0.094 0.48 Difference Comparative Example 1 0.115 0.51 Difference

[0117] As can be seen from the results in Table 1, the greases prepared using the methods in Examples 1, 2, and 3 of this invention have a low coefficient of friction and wear scar diameter, as well as excellent NVH performance. In Example 4, the mass ratio of hydrocarbon oil to ester oil in the base oil is outside the scope of the claims, resulting in an increase in the coefficient of friction and wear scar diameter of the grease, and a deterioration in NVH performance. In Example 5, the mass ratio of urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organic molybdenum friction modifier, and extreme pressure anti-wear agent is outside the scope of the claims, resulting in an increase in the coefficient of friction and wear scar diameter of the grease, and a deterioration in NVH performance. In Example 6, replacing the polyol with oleic acid resulted in an increase in the coefficient of friction and wear scar diameter of the grease, and a deterioration in NVH performance. In Example 7, replacing the extreme pressure anti-wear agent with sulfurized isobutylene resulted in an increase in the coefficient of friction and wear scar diameter of the grease, and a deterioration in NVH performance.

[0118] Compared to Examples 1-3, the grease in Comparative Example 1 does not contain polyols, which leads to an increase in the coefficient of friction and wear scar diameter of the grease in Comparative Example 1, resulting in poorer NVH performance.

[0119] In summary, the greases prepared using the methods of Examples 1, 2, and 3 of this invention have good anti-wear properties, excellent coefficient of friction, and NVH performance.

[0120] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A lubricating grease composition, characterized in that, The composition comprises a urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organic molybdenum friction modifier, and extreme pressure anti-wear agent.

2. The grease composition according to claim 1, wherein, The mass ratio of the urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organic molybdenum friction modifier, and extreme pressure anti-wear agent is 1:(4.5-15):(0.01-0.09):(0.01-0.07):(0.05-0.45):(0.05-0.9):(0.05-0.7):(0.02-0.45); Preferably, the mass ratio of the urea-based thickener, base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organic molybdenum friction modifier, and extreme pressure anti-wear agent is 1:(4.5-13):(0.02-0.05):(0.02-0.05):(0.2-0.3):(0.2-0.3):(0.2-0.3):(0.05-0.2).

3. The grease composition according to claim 1 or 2, wherein, The base oil is a hydrocarbon oil and an ester oil; Preferably, the kinematic viscosity of the base oil at 40°C is 100-150 mmHg. 2 / s; the kinematic viscosity of the hydrocarbon oil at 40°C is 120-200 mm. 2 / s; the kinematic viscosity of the ester oil at 40°C is 10-80 mm. 2 / s; Preferably, based on the total mass of the base oil, the content of the hydrocarbon oil is 80-95 wt%, and the content of the ester oil is 5-20 wt%. Preferably, the hydrocarbon oil is selected from at least one of alkane mineral oil, cycloalkane mineral oil, and polyalphaolefin; Preferably, the ester oil is selected from at least one of diisooctyl sebacate, pentaerythritol sebacate, trimellitate, and trimethylolpropane oleate.

4. The grease composition according to any one of claims 1-3, wherein, The urea-based thickener is selected from tetraurea thickeners and / or bisurea-based thickeners, preferably bisurea-based thickeners; More preferably, the diurea-based thickener is prepared by reacting a monoamine with a diisocyanate; And / or, the antioxidant is an amine-type antioxidant; Preferably, the amine antioxidant is selected from at least one of diisooctyl diphenylamine, alkylated diphenylamine, and N-phenyl-β-naphthylamine; And / or, the preservative is selected from benzotriazole and / or methylbenzotriazole.

5. The grease composition according to any one of claims 1-4, wherein, The rust inhibitor is an organic sulfonate; Preferably, the basicity of the organic sulfonate is 300-400 mg KOH / g; Preferably, the organic sulfonate is selected from calcium organic sulfonate and / or barium organic sulfonate; More preferably, the organic calcium sulfonate is selected from calcium dodecylbenzene sulfonate and / or calcium dodecylnaphthalene sulfonate; More preferably, the barium organic sulfonate is selected from at least one of barium dodecyl sulfonate, barium hexadecyl sulfonate, and barium octadecyl sulfonate.

6. The grease composition according to any one of claims 1-5, wherein, The polyol is selected from at least one of ethylene glycol, 1,2-propanediol, 1,4-butanediol, glycerol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, and pentaerythritol, preferably at least one of ethylene glycol, glycerol, trimethylolpropane, and pentaerythritol; And / or, the organic molybdenum friction modifier is selected from at least one of sodium molybdenum naphthalene sulfonate, calcium molybdenum naphthalene sulfonate, ammonium molybdenum naphthalene sulfonate, dibutyl dithiodiol molybdenum, diisobutyl dithiodiol molybdenum, dioctyl dithiodiol molybdenum, dioctyl dithiophosphate molybdenum, and dioctyl dithiophosphate molybdenum, preferably at least one of dioctyl dithiodiol molybdenum, ammonium molybdenum naphthalene sulfonate, and dibutyl dithiodiol molybdenum; And / or, the extreme pressure anti-wear agent is a sulfur-phosphorus-zinc salt; Preferably, the zinc thiophosphate salt is selected from at least one of octyl butyl zinc thiophosphate salt, tetradecyl zinc thiophosphate salt, and hexadecyl zinc thiophosphate salt.

7. A method for preparing a lubricating grease, characterized in that, The method includes the following steps: (1) In base oil, monoamine and diisocyanate are mixed and saponified to obtain base lipid system; (2) The base grease system is expanded, then additives are added and mixed evenly to obtain lubricating grease; The additives consist of antioxidants, corrosion inhibitors, rust inhibitors, polyols, organic molybdenum friction modifiers, and extreme pressure anti-wear agents.

8. The preparation method according to claim 7, wherein, The mass ratio of the monoamine to the diisocyanate is (0.8-2):1; Preferably, the monoamine is selected from at least one of octadecylamine, hexadecylamine, dodecylamine, octylamine, aniline, naphthylamine, p-toluidine and cyclohexylamine, more preferably a mixture of cyclohexylamine and octylamine, and even more preferably, the mass ratio of cyclohexane to octylamine is (0.5-2):1; Preferably, the diisocyanate is selected from at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, methane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate, and more preferably toluene diisocyanate; And / or, the total mass ratio of the monoamine and diisocyanate to the mass ratio of the base oil, antioxidant, corrosion inhibitor, rust inhibitor, polyol, organomolybdenum friction modifier, and extreme pressure anti-wear agent is 1:(4.5-15):(0.01-0.09):(0.01-0.07):(0.05-0.45):(0.05-0.9):(0.05-0.7):(0.02-0.45).

9. The preparation method according to claim 8, wherein, The conditions for the saponification reaction include: a temperature of 50-80℃ and a time of 0.5-1h; And / or, the conditions for the puffing treatment include: a temperature of 150-180°C and a time of 1-3 hours; And / or, the mixing conditions include: a temperature of 70-90°C and a time of 1-2 hours.

10. A lubricating grease prepared by the method according to any one of claims 7-9; Preferably, the average value of the axial derived force at eight points (0°, 2.5°, 5°, 7.5°, 10°, 12.5°, 15°, and 17.5°) measured by the grease at 200 rpm and 400 N is <20 N, and the variance of the axial derived force value is <50.

11. The application of the lubricating grease according to claim 10 in the ball joint of a new energy vehicle; Preferably, the inner ball cage universal joint has a three-pin structure.