High-temperature-resistant lubricating grease and preparation method thereof
By combining multifunctional modifying agents with PAO base oil and polyurea thickener, high-temperature resistant grease was prepared, solving the problem of grease oxidation at high temperatures, improving oxidation resistance and extreme pressure anti-wear properties, and extending equipment life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENZHEN HECHENG LUBRICATE MATERIALS CO LTD
- Filing Date
- 2026-02-04
- Publication Date
- 2026-05-12
AI Technical Summary
Existing greases oxidize at high temperatures, leading to increased viscosity and reduced fluidity. This makes it difficult to form an effective lubricating film between friction pairs, increasing friction and wear. Furthermore, traditional synthetic base oils are prone to corroding metal surfaces under high temperatures and with oxygen and metal catalysis.
A combination of multifunctional modifying agents, PAO base oil, and polyurea thickener is used to prepare high-temperature resistant grease through nucleophilic substitution and coupling reactions, generating a protective film of -SP- and -P=O groups to enhance oxidation resistance and high-temperature stability.
It significantly improves the oxidation resistance and extreme pressure anti-wear properties of grease, extends equipment service life, reduces the coefficient of friction, enhances high-temperature stability, and prevents the collapse of the thickener network structure.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lubricating grease technology, specifically, it relates to a high-temperature resistant lubricating grease and its preparation method. Background Technology
[0002] As modern industrial equipment develops towards high speed, heavy load, high temperature and long cycle operation, it puts forward extremely stringent requirements on the performance of greases used in key components (such as bearings, gears etc.). There are many studies on self-healing greases in the existing technology. For example, CN110257141B environmentally friendly self-healing grease and its preparation method provides an environmentally friendly self-healing grease. However, this solution does not solve the thermal stability defects of the grease.
[0003] Traditional greases, such as synthetic base oils like polyalphaolefin (PAO), possess good thermal stability. However, under high temperatures and the catalytic effects of oxygen and metals, they gradually oxidize, causing the base oil molecules to polymerize and undergo other reactions. This leads to increased viscosity, reduced fluidity, and difficulty in forming an effective lubricating film between friction pairs, thereby increasing friction and wear. It not only accelerates the degradation of the base oil itself but also corrodes metal surfaces. Therefore, developing a grease with high thermal stability is of great significance for improving the reliability and service life of high-end equipment. Summary of the Invention
[0004] The purpose of this invention is to provide a high-temperature resistant grease and its preparation method, so as to solve the problems mentioned in the background art.
[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing a high-temperature resistant lubricating grease includes the following steps: Mix the multifunctional modifier, base oil, and thickener evenly, react at 90-150℃ for 30-60 minutes, and then cool down to obtain a high-temperature resistant grease.
[0006] The preparation method of the multifunctional modifying agent is as follows: S1. Add cyanuric chloride to tetrahydrofuran, add 4-amino-2,6-di-tert-butylphenol and potassium carbonate at 0-5℃, react for 2-3 hours, filter to remove solid after reaction, and then remove solvent by rotary evaporation to obtain antioxidant.
[0007] S2. Add sodium hydrosulfide to ethanol, then add antioxidants, and react at 60-80℃ for 7-9 hours. After the reaction is complete, cool to room temperature, remove ethanol by vacuum distillation, then add to deionized water, extract with dichloromethane, dry the organic phase, and remove dichloromethane by rotary evaporation to obtain the sulfurized antioxidant.
[0008] S3. Under nitrogen protection, N-chlorosuccinimide and sulfurized antioxidant are added to acetonitrile and reacted at room temperature for 20-25 min. Then diethyl phosphite is added and reacted for another 10-15 min. After the reaction is complete, the reaction solution is precipitated with ethyl acetate, and then the solid is removed by filtration. The solvent is removed by rotary evaporation of the remaining liquid to obtain the multifunctional modified additive.
[0009] Furthermore, the base oil is at least one of PAO100, PAO6, and PAO8.
[0010] Furthermore, the thickener is a polyurea thickener.
[0011] Furthermore, the mass ratio of the multifunctional modifying agent, base oil, and thickener is 2-8:75-90:8-20.
[0012] Furthermore, in S1, the mass ratio of cyanuric chloride to 4-amino-2,6-di-tert-butylphenol is 32-36:34-39.
[0013] Furthermore, in S2, the mass ratio of antioxidant auxiliaries to sodium hydrosulfide is 20-25:6.1-7.6.
[0014] Furthermore, in S3, the mass ratio of N-chlorosuccinimide, sulfurized antioxidant, and diethyl phosphite is 4.5-7.4:6-10:4.6-7.6.
[0015] A high-temperature resistant grease, prepared by any of the above preparation steps.
[0016] The beneficial effects of this invention are: 1) This invention first involves a nucleophilic substitution reaction between cyanuric chloride and 4-amino-2,6-di-tert-butylphenol to generate an antioxidant auxiliary agent; then, the antioxidant auxiliary agent is reacted with sodium hydrosulfide to obtain a sulfurized antioxidant auxiliary agent; next, the sulfurized antioxidant auxiliary agent is reacted with N-chlorosuccinimide under nitrogen protection, and then coupled with diethyl phosphite to obtain a multifunctional modified auxiliary agent; finally, the multifunctional modified auxiliary agent is blended with PAO base oil and polyurea thickener to obtain a high-temperature resistant grease, which improves the grease's antioxidant properties, extreme pressure wear resistance, and high-temperature stability.
[0017] 2) The multifunctional modified additive of this invention contains -SP- and -P=O groups. Under high temperature and high load, it can react with the metal surface to generate a sulfide and phosphate protective film with high melting point and low shear strength, which reduces the friction coefficient between moving parts, reduces wear, extends the service life of equipment (such as bearings and gears), and gives the grease extreme pressure anti-wear properties.
[0018] 3) The hindered phenol in the multifunctional modified additive of this invention provides hydrogen atoms to capture free radicals, and the oxygen atom in the -P=O group has strong electronegativity. It can stabilize the phenolic oxygen free radicals converted from hindered phenols through electronic and steric effects, and prevent them from further initiating new oxidation reactions. The two form a synergistic antioxidant system. At the same time, the stable heterocyclic structure of the triazine ring further enhances the chemical stability of the additive itself. The three work together to delay the oxidative degradation process of PAO base oil, greatly extend the service life of grease, and significantly enhance the antioxidant capacity of grease.
[0019] 4) The amino, sulfur atoms and phosphate ester polar groups in this molecule can form strong interactions with the urea groups of the polyurea thickener, thereby stabilizing the three-dimensional network structure of the thickener and effectively preventing it from collapsing or decomposing at high temperatures, thus enhancing the high-temperature stability of the grease from a structural perspective. Detailed Implementation
[0020] The technical solutions of the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments in this application specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection claimed in this application.
[0021] The raw materials used in this invention are not particularly restricted in terms of their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.
[0022] The room temperature was 25±5℃. Example
[0023] By weight, 2 parts of multifunctional modifier, 90 parts of PAO100 and 8 parts of polyurea thickener are mixed evenly and reacted at 90℃ for 60 min. After cooling, high-temperature resistant grease is obtained.
[0024] The preparation method of the multifunctional modifying agent is as follows: S1. By mass, 36 parts of cyanuric chloride were added to 300 parts of tetrahydrofuran, and 39 parts of 4-amino-2,6-di-tert-butylphenol and 12 parts of potassium carbonate were added at 5°C. The reaction was carried out for 2 hours. After the reaction was completed, the solid was removed by filtration, and then the solvent was removed by rotary evaporation to obtain the antioxidant.
[0025] S2. By mass, 7.6 parts of sodium hydrosulfide were added to 180 parts of ethanol, and then 25 parts of antioxidant were added. The mixture was reacted at 60°C for 9 hours. After the reaction was completed, the mixture was cooled to room temperature, and the ethanol was removed by vacuum distillation. Then, the mixture was added to deionized water, extracted with dichloromethane, dried, and the dichloromethane was removed by rotary evaporation to obtain the sulfurized antioxidant.
[0026] S3. By mass, under nitrogen protection, 4.5 parts of N-chlorosuccinimide and 6 parts of sulfurized antioxidant were added to 150 parts of acetonitrile and reacted at room temperature for 20 min. Then, 4.6 parts of diethyl phosphite were added and reacted for another 10 min. After the reaction was completed, the reaction solution was precipitated with ethyl acetate, and then the solid was removed by filtration. Then, the solvent was removed by rotary evaporation to obtain the multifunctional modified additive. Example
[0027] By weight, 8 parts of multifunctional modifier, 75 parts of PAO6, and 20 parts of polyurea thickener are mixed evenly and reacted at 150°C for 30 minutes. After cooling, a high-temperature resistant grease is obtained.
[0028] The preparation method of the multifunctional modifying agent is as follows: S1. By mass, 32 parts of cyanuric chloride were added to 350 parts of tetrahydrofuran, and 34 parts of 4-amino-2,6-di-tert-butylphenol and 10 parts of potassium carbonate were added at 0°C. The reaction was carried out for 3 hours. After the reaction was completed, the solid was removed by filtration, and then the solvent was removed by rotary evaporation to obtain the antioxidant.
[0029] S2. By mass, add 6.1 parts of sodium hydrosulfide to 200 parts of ethanol, then add 20 parts of antioxidant auxiliaries, react at 80℃ for 7 hours. After the reaction is completed, cool to room temperature, remove ethanol by vacuum distillation, then add to deionized water, extract with dichloromethane, dry the organic phase, and remove dichloromethane by rotary evaporation to obtain the sulfurized antioxidant auxiliaries.
[0030] S3. By mass, under nitrogen protection, 7.4 parts of N-chlorosuccinimide and 10 parts of sulfurized antioxidant were added to 100 parts of acetonitrile and reacted at room temperature for 25 min. Then, 7.6 parts of diethyl phosphite were added and reacted for another 15 min. After the reaction was completed, the reaction solution was precipitated with ethyl acetate, and then the solid was removed by filtration. Then, the solvent was removed by rotary evaporation to obtain the multifunctional modified additive. Example
[0031] By weight, 6 parts of multifunctional modifier, 89 parts of PAO8, and 15 parts of polyurea thickener were mixed evenly and reacted at 120°C for 45 minutes. After cooling, high-temperature resistant grease was obtained.
[0032] The preparation method of the multifunctional modifying agent is as follows: S1. By mass, 34 parts of cyanuric chloride were added to 325 parts of tetrahydrofuran. Then, 36 parts of 4-amino-2,6-di-tert-butylphenol and 11 parts of potassium carbonate were added at 3°C. The reaction was allowed to proceed for 2.5 hours. After the reaction was complete, the solid was removed by filtration, and the solvent was removed by rotary evaporation to obtain the antioxidant.
[0033] S2. By mass, 7.0 parts of sodium hydrosulfide were added to 150 parts of ethanol, and then 23 parts of antioxidant were added. The mixture was reacted at 75°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, and the ethanol was removed by vacuum distillation. Then, the mixture was added to deionized water, extracted with dichloromethane, dried, and the dichloromethane was removed by rotary evaporation to obtain the sulfurized antioxidant.
[0034] S3. By mass, under nitrogen protection, 5.9 parts of N-chlorosuccinimide and 8 parts of sulfurized antioxidant were added to 120 parts of acetonitrile and reacted at room temperature for 23 min. Then, 6.1 parts of diethyl phosphite were added and reacted for another 13 min. After the reaction was completed, the reaction solution was diluted with ethyl acetate, and then the solid was removed by filtration. Then, the solvent was removed by rotary evaporation to obtain the multifunctional modified additive. Example
[0035] By weight, 7 parts of multifunctional modifier, 80 parts of PAO100 and 13 parts of polyurea thickener are mixed evenly and reacted at 95°C for 35 minutes. After cooling, high-temperature resistant grease is obtained.
[0036] The preparation method of the multifunctional modifying agent is as follows: S1. By mass, 33 parts of cyanuric chloride were added to 340 parts of tetrahydrofuran, and 35 parts of 4-amino-2,6-di-tert-butylphenol and 15 parts of potassium carbonate were added at 2°C. The reaction was carried out for 2 hours. After the reaction was completed, the solid was removed by filtration, and then the solvent was removed by rotary evaporation to obtain the antioxidant.
[0037] S2. By mass, 6.8 parts of sodium hydrosulfide were added to 185 parts of ethanol, and then 21 parts of antioxidant were added. The mixture was reacted at 75°C for 7.5 hours. After the reaction was completed, the mixture was cooled to room temperature, and the ethanol was removed by vacuum distillation. Then, the mixture was added to deionized water, extracted with dichloromethane, dried, and the dichloromethane was removed by rotary evaporation to obtain the sulfurized antioxidant.
[0038] S3. By mass, under nitrogen protection, 6.3 parts of N-chlorosuccinimide and 6.8 parts of sulfurized antioxidant were added to 134 parts of acetonitrile and reacted at room temperature for 22 min. Then, 5.1 parts of diethyl phosphite were added and reacted for another 12 min. After the reaction was completed, the reaction solution was precipitated with ethyl acetate, and then the solid was removed by filtration. Then, the solvent was removed by rotary evaporation to obtain the multifunctional modified additive. Example
[0039] By weight, 4 parts of multifunctional modifier, 87 parts of PAO100 and 9 parts of polyurea thickener are mixed evenly and reacted at 100℃ for 55 minutes. After cooling, high-temperature resistant grease is obtained.
[0040] The preparation method of the multifunctional modifying agent is as follows: S1. By mass, 35 parts of cyanuric chloride were added to 320 parts of tetrahydrofuran, and 38 parts of 4-amino-2,6-di-tert-butylphenol and 14 parts of potassium carbonate were added at 3°C. The reaction was carried out for 3 hours. After the reaction was completed, the solid was removed by filtration, and then the solvent was removed by rotary evaporation to obtain the antioxidant.
[0041] S2. By mass, 7.3 parts of sodium hydrosulfide were added to 175 parts of ethanol, and then 22 parts of antioxidant were added. The mixture was reacted at 65°C for 8.5 hours. After the reaction was completed, the mixture was cooled to room temperature, and the ethanol was removed by vacuum distillation. Then, the mixture was added to deionized water, extracted with dichloromethane, dried, and the dichloromethane was removed by rotary evaporation to obtain the sulfurized antioxidant.
[0042] S3. By mass, under nitrogen protection, 5.6 parts of N-chlorosuccinimide and 8.5 parts of sulfurized antioxidant were added to 112 parts of acetonitrile and reacted at room temperature for 23 min. Then, 7.3 parts of diethyl phosphite were added and reacted for another 13 min. After the reaction was completed, the reaction solution was precipitated with ethyl acetate, and then the solid was removed by filtration. Then, the solvent was removed by rotary evaporation to obtain the multifunctional modified additive. Example
[0043] By weight, 3 parts of multifunctional modifier, 88 parts of PAO100 and 9 parts of polyurea thickener were mixed evenly and reacted at 101℃ for 56 minutes. After cooling, high-temperature resistant grease was obtained.
[0044] The preparation method of the multifunctional modifying agent is as follows: S1. By mass, 31 parts of cyanuric chloride were added to 323 parts of tetrahydrofuran, and 37 parts of 4-amino-2,6-di-tert-butylphenol and 14.5 parts of potassium carbonate were added at 2°C. The reaction was carried out for 3 hours. After the reaction was completed, the solid was removed by filtration, and then the solvent was removed by rotary evaporation to obtain the antioxidant.
[0045] S2. By mass, 7.2 parts of sodium hydrosulfide were added to 178 parts of ethanol, and then 21 parts of antioxidant were added. The mixture was reacted at 65°C for 8.5 hours. After the reaction was completed, the mixture was cooled to room temperature, and the ethanol was removed by vacuum distillation. Then, the mixture was added to deionized water, extracted with dichloromethane, dried, and the dichloromethane was removed by rotary evaporation to obtain the sulfurized antioxidant.
[0046] S3. By mass, under nitrogen protection, 5.8 parts of N-chlorosuccinimide and 8.2 parts of sulfurized antioxidant were added to 118 parts of acetonitrile and reacted at room temperature for 23 min. Then, 7.3 parts of diethyl phosphite were added and reacted for another 13 min. After the reaction was completed, the reaction solution was precipitated with ethyl acetate, and then the solid was removed by filtration. Then, the solvent was removed by rotary evaporation to obtain the multifunctional modified additive.
[0047] Comparative Example 1 By mass, 92 parts of PAO100 and 8 parts of polyurea thickener were mixed evenly and reacted at 90°C for 60 minutes. After cooling, the grease was obtained.
[0048] Comparative Example 2 By mass, 2 parts of 2,6-di-tert-butyl-p-cresol, 90 parts of PAO100, and 8 parts of polyurea thickener are mixed evenly and reacted at 90°C for 60 minutes. After cooling, the grease is obtained.
[0049] Comparative Example 3 By mass, 2 parts of dibutyloctyl dithiophosphate zinc, 90 parts of PAO100 and 8 parts of polyurea thickener are mixed evenly and reacted at 90°C for 60 minutes. After cooling, the grease is obtained.
[0050] Comparative Example 4 By mass, 2 parts of 2,6-di-tert-butyl-p-cresol, 2 parts of dibutyloctyl dithiophosphate zinc, 88 parts of PAO100, and 8 parts of polyurea thickener are mixed evenly and reacted at 90°C for 60 minutes. After cooling, the grease is obtained.
[0051] Experimental Example 1 The greases in Examples 1-3 and Comparative Examples 1-4 were subjected to the following performance tests, and the test results are shown in Table 1.
[0052] 1. High-temperature stability test: The change in cone penetration of the grease before and after being placed in an oven at 180℃ for 72 hours was tested in accordance with the national standard GB / T269-2023 "Determination of Cone Penetration of Lubricating Grease and Petroleum Grease". (The smaller the change, the stronger the consistency retention ability of the grease in high-temperature environment, thus proving that the three-dimensional skeleton formed by the thickener is not easy to collapse at high temperature, so that the grease as a whole is not easy to soften, run off or be structurally damaged due to high temperature, and is suitable for high-temperature working conditions). The results are shown in Table 1.
[0053] 2. Antioxidant performance test: Referring to the industry standard SH / T0335-1992 "Determination of Chemical Stability of Lubricating Grease", 5g of lubricating grease sample was weighed for each group and evenly filled into the sample cup of the oxygen bomb using a syringe. Oxygen was then introduced into the oxygen bomb to make the initial pressure reach 3.50MPa. The oxygen bomb was placed in the oxygen bomb oxidation instrument, the experimental temperature was set to 180℃, and the experimental time was 200h. The decrease in oxygen pressure in the oxygen bomb before and after the experiment was calculated (pressure drop below 0.050 according to industry standard is considered as good antioxidant performance). The results are shown in Table 1.
[0054] 3. Extreme Pressure Anti-wear Performance Test: Referring to industry standard SH / T0202-1992 "Determination of Extreme Pressure Performance of Lubricating Grease (Four-ball machine method)", the PB value (maximum seizure load, referring to the maximum load that the lubricating grease can withstand in the four-ball machine test, under which the metal friction pair surface will not experience seizure, reflecting the lubricating grease's ability to prevent initial seizure under load; the higher the PB value, the better the anti-seizure performance of the lubricating grease) and PD value (minimum sintering load, the minimum load that the lubricating grease cannot withstand in the four-ball machine test, under which the metal friction pair surface will sinter, reflecting the lubricating grease's ability to resist metal surface sintering under high load; the higher the PD value, the stronger the extreme pressure performance of the lubricating grease, and the better it can adapt to more demanding high-load friction conditions). The results are shown in Table 1:
[0055] As can be seen from Comparative Examples 1-6, the multifunctional modified additive of the present invention has better high-temperature stability and antioxidant properties, and has a significant effect on improving the extreme pressure anti-wear ability of lubricating grease. Although Comparative Example 4 also added a variety of functional additives, the improvement effect was significantly weaker than that of Examples 1-6. The reason is that the modification method of the present invention, which integrates the functions of various functional additives, effectively improves the atomic utilization rate of the additives, and can play a better role with a lower addition amount.
[0056] The descriptions of the above embodiments are merely illustrative of the methods and core ideas of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for preparing a high-temperature resistant lubricating grease, characterized in that, Includes the following steps: Mix the multifunctional modifier, base oil, and thickener evenly, react at 90-150℃ for 30-60 minutes, and then cool down to obtain a high-temperature resistant grease. The preparation method of the multifunctional additive is as follows: S1. A nucleophilic substitution reaction is carried out between cyanuric chloride and 4-amino-2,6-di-tert-butylphenol to obtain an antioxidant auxiliary agent; S2. A nucleophilic substitution reaction occurs between the antioxidant auxiliaries and sodium hydrosulfide to obtain sulfurized antioxidant auxiliaries. S3. The sulfurized antioxidant is first reacted with N-chlorosuccinimide and then coupled with diethyl phosphite to obtain a multifunctional modified additive.
2. The method for preparing a high-temperature resistant grease according to claim 1, characterized in that, The mass ratio of the multifunctional modifier, base oil, and thickener is 2-8:75-90:8-20.
3. The method for preparing a high-temperature resistant lubricating grease according to claim 1, characterized in that, In S1, the mass ratio of cyanuric chloride to 4-amino-2,6-di-tert-butylphenol is 32-36:34-39.
4. The method for preparing a high-temperature resistant lubricating grease according to claim 1, characterized in that, In S2, the mass ratio of antioxidant auxiliaries to sodium hydrosulfide is 20-25:6.1-7.
6.
5. The method for preparing a high-temperature resistant lubricating grease according to claim 1, characterized in that, The reaction temperature for S1 is 0-5℃, and the reaction time is 2-3 hours.
6. The method for preparing a high-temperature resistant lubricating grease according to claim 1, characterized in that, The S2 reaction temperature is 60-80℃, and the reaction time is 7-9h.
7. The method for preparing a high-temperature resistant lubricating grease according to claim 1, characterized in that, In S3, the mass ratio of N-chlorosuccinimide, sulfurized antioxidant, and diethyl phosphite is 4.5-7.4:6-10:4.6-7.
6.
8. The method for preparing a high-temperature resistant lubricating grease according to claim 1, characterized in that, The base oil is at least one of PAO100, PAO6, and PAO8.
9. The method for preparing a high-temperature resistant grease according to claim 1, characterized in that, The thickener is a polyurea thickener.
10. A high-temperature resistant lubricating grease, characterized in that, High-temperature resistant grease is prepared by the preparation method described in any one of claims 1-9.