Rare earth based grease and method for its preparation

Abstract

The present application relates to the technical field of lubricating grease, and provides a rare earth-based lubricating grease and a preparation method thereof, which is prepared from raw materials containing base lubricating grease 71-99 parts, rare earth sulfate compound 0.5-15 parts, antioxidant 0.5-5.0 parts, antirust agent 0.1-6.0 parts, and extreme pressure agent 0.1-3.0 parts. The addition of Ln2(OH)4SO4·nH2O (Ln=La, Ce, Sm) to the system improves the friction performance of the lubricating grease, and the bearing capacity P B reaches 1372 N, the extreme pressure P D reaches 4900 N at the highest, the wear scar diameter WSD is 0.32-0.50 mm, and the friction coefficient μ reaches 0.056 at the lowest, and the lubricating grease has excellent bearing, extreme pressure, wear resistance and friction reduction capacity.

Description

Technical Field

[0001] This invention relates to the field of lubricating grease technology, and in particular to a rare earth-based lubricating grease and its preparation method. Background Technology

[0002] Lubricating grease, commonly known as "butter" or "dry oil," is essentially a type of lubricating oil with added thickeners. The thickeners are uniformly dispersed in the base oil in the form of micelles or fibers, and then compounded with various functional additives. Additives are the essence of modern high-end lubricating greases, and the overall performance and service characteristics of lubricating greases are largely determined by the additives.

[0003] Solid lubricant additives are a very important class of additives in lubricating greases. Their most important function is to improve the lubricity of the grease. They can play a reinforcing role when base oils and soaps cannot form a fluid lubricating film on the friction surface, effectively preventing seizing and sintering. Currently, the most classic solid lubricants are molybdenum disulfide and graphite, which have a layered crystal structure, are easy to slip in the tangential direction, and can withstand heavy loads in the normal direction. In the lubricating grease industry, there are corresponding products with names such as Great Wall molybdenum disulfide composite lithium-based grease, graphite calcium-based grease, and Haihua molybdenum disulfide high-temperature urea-based grease (MMU) [Wang Xianhui, Lubricating Grease Selection Handbook. Machinery Industry Press, Beijing. 2011, pp. 104-115], each playing a different role for specific working conditions. With the development of modern society, various high-load equipment is increasingly used in bridge construction, road construction, tunnel construction, and other fields. The equipment operates under various harsh conditions for a long time, and the requirements for the performance of lubricating greases are becoming increasingly higher. In reality, no universal lubricant is suitable for all operating conditions. Therefore, it is imperative to develop greases containing new, high-quality solid lubricating additives to meet the needs of demanding operating conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a rare earth-based grease and its preparation method.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a rare earth-based grease, prepared from raw materials comprising the following parts by weight:

[0007] The composition includes 71-99 parts of base grease, 0.5-15 parts of rare earth sulfate compound, 0.5-5.0 parts of antioxidant, 0.1-6.0 parts of rust inhibitor, and 0.1-3.0 parts of extreme pressure agent.

[0008] Preferably, the rare earth sulfate compound is Ln2(OH)4SO4·nH2O, where Ln is La, Ce, or Sm.

[0009] Preferably, the base grease includes one or more of lithium-based grease, complex lithium-based grease, aluminum-based grease, complex aluminum-based grease, calcium-based grease, complex calcium-based grease, complex calcium sulfonate grease, polyurea-based grease, and sodium-based grease.

[0010] Preferably, the antioxidant includes one or more of 2,6-di-tert-butyl-p-cresol, N-phenyl-β-naphthylamine, tert-butylhydroquinone, 4-hexylresorcinol, diphenylamine, dilauryl thiodipropionate, phenothiazine, dibutylhydroxytoluene, and dioctadecyl thiodipropionate.

[0011] Preferably, the rust inhibitor includes one or more of alkenyl succinic acid, polyglycerol fatty acid ester, benzotriazole and barium petroleum sulfonate.

[0012] Preferably, the extreme pressure agent includes one or more of sulfurized isobutylene, sulfurized olefin cottonseed oil, and tricresyl phosphate.

[0013] The present invention also provides a method for preparing the rare earth-based grease, comprising the following steps:

[0014] The rare earth-based grease is obtained by mixing and homogenizing the above raw materials.

[0015] Preferably, the mixing speed is 100-1000 rpm, the mixing temperature is 25-200℃, and the mixing time is 1-10 h.

[0016] Preferably, the grinding time is 0.5 to 5 hours.

[0017] The present invention has the following beneficial effects:

[0018] This invention provides a rare earth-based grease comprising: 71-99 parts of a base grease, 0.5-15 parts of a rare earth sulfate compound, 0.5-5.0 parts of an antioxidant, 0.1-6.0 parts of a rust inhibitor, and 0.1-3.0 parts of an extreme pressure agent. Adding Ln2(OH)4SO4·nH2O (Ln = La, Ce, Sm) to the system improves the frictional properties of the grease. The load-carrying capacity P was tested. B It reached 1372N, extreme pressure P D With a maximum load capacity of 4900 N, a wear scar diameter (WSD) of 0.32–0.50 mm, and a minimum friction coefficient (μ) of 0.056, this grease exhibits excellent load-bearing, extreme pressure, anti-wear, and friction-reducing capabilities.

[0019] This invention also provides a method for preparing rare earth-based grease, which involves mixing and homogenizing a base grease, a rare earth sulfate compound, an antioxidant, a rust inhibitor, and an extreme pressure agent. This invention employs a hydrothermal synthesis method, which is simple, operates under mild conditions, and uses readily available raw materials, facilitating mass production and quality control. Attached Figure Description

[0020] Figure 1 The XRD pattern of the rare earth sulfate compound prepared in Example 1;

[0021] Figure 2 The XRD pattern of the rare earth sulfate compound prepared in Example 2;

[0022] Figure 3 The image shows the XRD pattern of the rare earth sulfate compound prepared in Example 3. Detailed Implementation

[0023] This invention provides a rare earth-based grease, prepared from raw materials comprising the following parts by weight:

[0024] The composition includes 71-99 parts of base grease, 0.5-15 parts of rare earth sulfate compound, 0.5-5.0 parts of antioxidant, 0.1-6.0 parts of rust inhibitor, and 0.1-3.0 parts of extreme pressure agent.

[0025] In this invention, the mass fraction of the base grease is preferably 75-95 parts, more preferably 77-93 parts, and even more preferably 79-91 parts.

[0026] In this invention, the rare earth sulfate compound is preferably 5 to 10 parts by mass, more preferably 6 to 9 parts, and even more preferably 7 to 8 parts by mass.

[0027] In this invention, the antioxidant is preferably 1 to 4.5 parts by mass, more preferably 1.5 to 4 parts, and even more preferably 2.5 to 3 parts by mass.

[0028] In this invention, the rust inhibitor is preferably 1 to 5 parts by weight, more preferably 2 to 4 parts, and even more preferably 2.5 to 3.5 parts by weight.

[0029] In this invention, the extreme pressure agent is preferably 1 to 2 parts by mass, more preferably 1.2 to 1.8 parts, and even more preferably 1.4 to 1.6 parts by mass.

[0030] In this invention, the base grease includes one or more of lithium-based grease, complex lithium-based grease, aluminum-based grease, complex aluminum-based grease, calcium-based grease, complex calcium-based grease, complex calcium sulfonate grease, polyurea-based grease, and sodium-based grease.

[0031] In this invention, the lithium-based grease is prepared from raw materials comprising the following parts by weight: 5-30 parts fatty acid, 70-95 parts base oil, and 0.15-3.75 parts lithium hydroxide.

[0032] In this invention, the fatty acid is preferably 10-25 parts by mass, more preferably 15-20 parts, and even more preferably 17-18 parts by mass; the base oil is preferably 75-90 parts by mass, more preferably 80-85 parts, and even more preferably 82-83 parts by mass; and the lithium hydroxide is preferably 0.5-3.5 parts by mass, more preferably 1-3 parts, and even more preferably 1.5-2.5 parts by mass.

[0033] In this invention, the composite lithium-based grease is prepared from raw materials comprising the following parts by mass: 4-10 parts fatty acid, 1-5 parts compounding agent, 1-4 parts lithium hydroxide, and 81-94 parts base oil.

[0034] In this invention, the fatty acid is preferably 5-9 parts by mass, more preferably 6-8 parts, and even more preferably 6.5-7.5 parts by mass; the composite agent is preferably 2-4 parts by mass, more preferably 2.2-3.8 parts, and even more preferably 2.5-3.5 parts by mass; the lithium hydroxide is preferably 1.5-3.5 parts by mass, more preferably 2-3 parts, and even more preferably 2.3-2.7 parts by mass; and the base oil is preferably 85-90 parts by mass, more preferably 86-89 parts, and even more preferably 87-88 parts by mass.

[0035] In this invention, the composite agent is preferably one or more of boric acid, azelaic acid, sebacic acid, salicylic acid, lactic acid, and p-hydroxybenzoic acid.

[0036] In this invention, the aluminum-based grease is prepared from raw materials comprising the following parts by weight: 10-30 parts fatty acid, 70-90 parts base oil, and 0.16-4.8 parts aluminum isopropoxy.

[0037] In this invention, the fatty acid is preferably 15-25 parts by mass, more preferably 18-22 parts, and even more preferably 19-21 parts by mass; the base oil is preferably 75-85 parts by mass, more preferably 78-82 parts, and even more preferably 79-81 parts by mass; and the aluminum isopropoxy is preferably 0.25-4.5 parts by mass, more preferably 0.5-4 parts, and even more preferably 1.5-3 parts by mass.

[0038] In this invention, the composite aluminum-based grease is prepared from raw materials comprising the following parts by weight: 5.7 to 15.5 parts stearic acid, 0.25 to 5.5 parts low molecular weight acid, 3.5 to 9.5 parts aluminum isopropoxide trimer, and 69 to 90 parts base oil.

[0039] In this invention, the stearic acid is preferably 6-15 parts by mass, more preferably 9-12 parts, and even more preferably 10-11 parts by mass; the low molecular weight acid is preferably 0.5-5 parts by mass, more preferably 1.5-4 parts, and even more preferably 2.5-3 parts by mass; the aluminum isopropoxide trimer is preferably 4-9 parts by mass, more preferably 5-8 parts, and even more preferably 6-7 parts by mass; and the base oil is preferably 75-85 parts by mass, more preferably 77-83 parts, and even more preferably 79-81 parts by mass.

[0040] In this invention, the calcium-based grease is prepared from raw materials comprising the following parts by weight: 5-20 parts of animal and vegetable fats, 80-95 parts of base oil, and 0.4-7 parts of calcium hydroxide cream.

[0041] In this invention, the animal and vegetable fats are preferably one or more of the following: tallow, mutton tallow, bone fat, lard, castor oil, peanut oil, rapeseed oil, cottonseed oil, soybean oil, and sunflower oil.

[0042] In this invention, the fatty acid is preferably 10-15 parts by mass, more preferably 11-14 parts, and even more preferably 12-13 parts by mass; the base oil is preferably 82-93 parts by mass, more preferably 80-91 parts, and even more preferably 85-86 parts by mass; and the calcium hydroxide is preferably 1-6.5 parts by mass, more preferably 2-5.5 parts, and even more preferably 3-4.5 parts by mass.

[0043] In this invention, the composite calcium-based grease is prepared from raw materials comprising the following parts by weight: 6-12 parts of fatty acid, 1-4 parts of low molecular weight acid, 1-5 parts of calcium hydroxide, and 80-90 parts of base oil.

[0044] In this invention, the fatty acid is preferably 7-11 parts by mass, more preferably 8-10 parts, and even more preferably 8.5-9.5 parts by mass; the low molecular weight acid is preferably 1-4 parts by mass, more preferably 1.5-3.5 parts, and even more preferably 2-3 parts by mass; the calcium hydroxide is preferably 2-4 parts by mass, more preferably 2.5-3.5 parts, and even more preferably 2.8-3.2 parts by mass; and the base oil is preferably 82-88 parts by mass, more preferably 84-86 parts, and even more preferably 84.5-85.5 parts by mass.

[0045] In this invention, the complex calcium sulfonate-based grease is prepared from raw materials comprising the following parts by weight: 4-14 parts sulfonic acid, 3-5.5 parts calcium hydroxide, 0.5-2 parts low molecular weight acid, 0.2-0.8 parts conversion agent, 1-9 parts fatty acid, and 70-90 parts base oil.

[0046] In this invention, the sulfonic acid is preferably 6-12 parts by mass, more preferably 7-11 parts, and even more preferably 9-10 parts by mass; the calcium hydroxide is preferably 3.5-5 parts by mass, more preferably 3.7-4.8 parts, and even more preferably 4-4.5 parts by mass; the low molecular weight acid is preferably 0.7-1.8 parts by mass, more preferably 0.9-1.6 parts, and even more preferably 1.2-1.3 parts by mass; the conversion agent is preferably 0.3-0.7 parts by mass, more preferably 0.4-0.6 parts, and even more preferably 0.45-0.55 parts by mass; the fatty acid is preferably 2-8 parts by mass, more preferably 3-7 parts, and even more preferably 4-6 parts by mass; and the base oil is preferably 75-85 parts by mass, more preferably 78-82 parts, and even more preferably 79-81 parts by mass.

[0047] In this invention, the conversion agent is preferably an alcohol, water, or a mixture of water and alcohol.

[0048] In this invention, the polyurea-based grease is prepared from raw materials comprising the following parts by weight: 4-19 parts of cyanate ester, 0.25-11 parts of organic amine, and 71-95 parts of base oil.

[0049] In this invention, the mass fraction of the cyanate ester is preferably 5 to 18 parts, more preferably 8 to 15 parts, and even more preferably 10 to 13 parts; the mass fraction of the organic amine is preferably 1 to 10 parts, more preferably 4 to 7 parts, and even more preferably 5 to 6 parts; and the mass fraction of the base oil is preferably 75 to 90 parts, more preferably 77 to 88 parts, and even more preferably 80 to 85 parts.

[0050] In this invention, the cyanate is preferably diphenylmethane-4,4'-diisocyanate, octadecyl isocyanate, 2,4-toluene diisocyanate or 1,6-hexanediisocyanate.

[0051] In this invention, the organic amine is preferably octadecylamine, aniline, ethylenediamine, or hexamethylenediamine.

[0052] In this invention, the sodium-based grease is prepared from raw materials comprising the following parts by weight: 3-3.5 parts sodium hydroxide, 16-19 parts animal and vegetable fats, and 77-80 parts base oil.

[0053] In this invention, the sodium hydroxide is preferably 3.1 to 3.4 parts by mass, more preferably 3.15 to 3.35 parts by mass, and even more preferably 3.2 to 3.3 parts by mass; the animal and vegetable fats are preferably 16.5 to 18.5 parts by mass, more preferably 17 to 18 parts by mass, and even more preferably 17.4 to 17.6 parts by mass; and the base oil is preferably 77.5 to 79.5 parts by mass, more preferably 78 to 79 parts by mass, and even more preferably 78.2 to 78.8 parts by mass.

[0054] In this invention, the animal and vegetable fats are preferably one or more of the following: tallow, mutton tallow, bone fat, lard, castor oil, peanut oil, rapeseed oil, cottonseed oil, soybean oil, and sunflower oil.

[0055] In this invention, the fatty acids contained in the lithium-based grease, complex lithium-based grease, aluminum-based grease, complex aluminum-based grease, calcium-based grease, complex calcium-based grease and complex sulfonic acid calcium-based grease are preferably one or more of 12-hydroxystearic acid, stearic acid, oleic acid, palmitic acid and lauric acid.

[0056] In this invention, the low molecular weight acids contained in the composite aluminum-based grease, composite calcium-based grease, and composite sulfonate calcium-based grease are preferably benzoic acid, formic acid, and glacial acetic acid.

[0057] In this invention, the base oil in lithium-based grease, complex lithium-based grease, aluminum-based grease, complex aluminum-based grease, calcium-based grease, complex calcium-based grease, complex calcium sulfonate grease, polyurea-based grease, and sodium-based grease is preferably one or more of ester-based base oil, hydrocarbon-based base oil, polyether-based base oil, and silicone-based base oil.

[0058] In this invention, the hydrocarbon base oil is preferably a naphthenic mineral oil, paraffinic mineral oil, intermediate mineral oil, synthetic hydrocarbon base oil (PAO series), or food-grade white oil.

[0059] In this invention, the ester base oil is preferably a polyol ester oil, diester oil, compound ester oil, or trimellitate oil.

[0060] In this invention, the polyether base oil is preferably a polyethylene glycol or polyglycerol series synthetic oil.

[0061] In this invention, the silicone oil base oil is preferably methyl silicone oil, toluene silicone oil, ethyl silicone oil or diphenyl silicone oil.

[0062] In this invention, the rare earth sulfate compound is preferably Ln2(OH)4SO4·nH2O, and Ln is preferably La, Ce or Sm.

[0063] The rare earth sulfate compounds used in this invention have good compatibility with various types of basic lubricating greases and have broad application prospects. At the same time, they provide high-value-added application scenarios for rare earth resources.

[0064] The present invention also provides a method for preparing the rare earth sulfate compound, comprising the following steps:

[0065] The rare earth source and sulfur source are subjected to a hydrothermal reaction, followed by filtration, washing, and drying to obtain the product.

[0066] In this invention, the rare earth source is preferably lanthanum oxide, lanthanum acetate, lanthanum chloride, lanthanum carbonate, lanthanum hydroxide, cerium oxide, cerium acetate, cerium chloride, cerium carbonate, cerium hydroxide, samarium oxide, samarium acetate, samarium chloride, samarium carbonate, or samarium hydroxide.

[0067] In this invention, the sulfur source is preferably sodium sulfate, sodium bisulfate, sodium thiosulfate, sodium sulfide, ammonium sulfate, ammonium persulfate, ammonium bisulfate, or ammonium thiosulfate.

[0068] In this invention, the temperature of the hydrothermal reaction is preferably 25-300°C, more preferably 100-200°C, and even more preferably 140-160°C. The time of the hydrothermal reaction is preferably 0.1-10 days, more preferably 2-8 days, and even more preferably 4-6 days.

[0069] This invention uses a hydrothermal synthesis method to prepare rare earth sulfate compounds. The synthesis method is simple, the conditions are mild, and the raw materials are readily available, which facilitates the mass production and quality control of the products.

[0070] In this invention, the antioxidant includes one or more of 2,6-di-tert-butyl-p-cresol, N-phenyl-β-naphthylamine, tert-butylhydroquinone, 4-hexylresorcinol, diphenylamine, dilauryl thiodipropionate, phenothiazine, dibutylhydroxytoluene, and dioctadecyl thiodipropionate.

[0071] In this invention, the rust inhibitor includes one or more of alkenyl succinic acid, polyglycerol fatty acid ester, benzotriazole and barium petroleum sulfonate.

[0072] In this invention, the extreme pressure agent includes one or more of sulfurized isobutylene, sulfurized olefin cottonseed oil, and tricresyl phosphate.

[0073] The present invention also provides a method for preparing the rare earth-based grease, comprising the following steps:

[0074] The rare earth-based grease is obtained by mixing and homogenizing the above raw materials.

[0075] In this invention, the mixing and stirring rate is preferably 100-1000 rpm, more preferably 400-700 rpm, and even more preferably 500-600 rpm.

[0076] In this invention, the mixing temperature is preferably 25-200°C, more preferably 75-150°C, and even more preferably 100-125°C. The mixing time is preferably 1-10 hours, more preferably 4-7 hours, and even more preferably 5-6 hours.

[0077] In this invention, the homogenizing instrument is selected as a three-roll mill or a high-pressure homogenizer.

[0078] In this invention, the homogenization time is preferably 0.5 to 5 hours, more preferably 1.5 to 4 hours, and even more preferably 2.0 to 3.5 hours.

[0079] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0080] The base greases used in this invention are all prepared by the following methods:

[0081] Preparation method of lithium-based grease: Pour base oil into a grease-making kettle, start the stirrer, heat to 70-80℃, add fatty acids, and wait for the fatty acids to completely dissolve. Then add lithium hydroxide solution pre-dissolved in water, and control the temperature between 120-130℃ for 1-5 hours. After saponification, add base oil, and control the temperature between 200-220℃ for 10 minutes, then stop heating. When the temperature drops to 160-190℃, add base oil again. When the system cools down to 100℃, stop stirring and homogenize with a three-roll mill or high-pressure homogenizer to obtain lithium-based grease. For detailed preparation methods, please refer to [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 528-549].

[0082] Preparation method of complex lithium-based grease: Add base oil and fatty acids to the grease preparation vessel, heat to melt, maintain the temperature at 80-115℃, slowly add lithium hydroxide aqueous solution, after the addition is complete, raise the temperature to 130-180℃ to completely dehydrate the soap base. Then cool the material to 90-115℃, add the composite agent, stir for 10 minutes, slowly add lithium hydroxide aqueous solution to saponify the composite agent, raise the temperature to 130-180℃ and maintain for 1 hour to completely dehydrate, rapidly raise the temperature to 200-220℃ and maintain for 20 minutes, add base oil, rapidly cool the grease base, continue stirring and cooling to 66℃, homogenize with a three-roll mill or high-pressure homogenizer to obtain complex lithium-based grease. For detailed preparation method, please refer to [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 560-570].

[0083] Preparation method of aluminum-based grease: Pour aluminum isopropoxy and base oil into a grease-making kettle and mix evenly. Heat and melt the mixture while stirring. Add fatty acids and maintain the temperature of the grease-making kettle at 95-105℃ for 1-1.5 hours. After saponification, maintain the temperature at 100℃ and slowly add water to carry out a displacement reaction, releasing the remaining isopropanol. Continue heating until the temperature of the contents of the kettle reaches 150℃. Add the remaining base oil and continue heating to the highest refining temperature, maintaining it for 5-30 minutes. After cooling to 25℃, homogenize the mixture using a three-roll mill or a high-pressure homogenizer to obtain aluminum-based grease. For detailed preparation methods, please refer to [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 650-653].

[0084] The specific preparation method of composite aluminum-based grease is as follows: Stearic acid, low molecular weight acid, and base oil are added to a grease-making kettle and mixed. Aluminum isopropoxide trimer is added to the above organic acid-base oil mixture. The material is heated to 185-190°C at a rate of 22-28°C / min for saponification reaction for 1 hour. The remaining base oil is added to the grease-making kettle and mixed with the grease produced by the reaction. The mixture is then cooled to 65-76°C. After the reaction is completed, the mixture is homogenized using a three-roll mill or a high-pressure homogenizer to obtain the composite aluminum-based grease. For detailed preparation methods, please refer to [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 653-679].

[0085] The specific preparation method of calcium-based grease is as follows: First, put some base oil, fat, calcium hydroxide cream and water into a kettle, heat to 130-140℃ for saponification reaction for 30-40 minutes, adjust the free acid and base to meet the requirements, cool down with water, increase the stirring speed to hydrate until the material becomes obviously thickened into grease, stir for 10-20 minutes after phase change, add the remaining base oil to adjust the appropriate cone penetration, and homogenize with a three-roll mill or high-pressure homogenizer to obtain calcium-based grease. For detailed preparation method, please refer to [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 816-838].

[0086] The specific preparation method of compound calcium-based grease is as follows: Add a portion of base oil, fatty acids, low molecular weight acids, calcium hydroxide cream and water to a grease-making kettle, mix and heat to 100-110℃, saponify for 3-4 hours; add the remaining base oil, heat to the highest refining temperature of 210-220℃, after the reaction is complete, homogenize with a three-roll mill or high-pressure homogenizer to obtain compound calcium-based grease [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 837-860].

[0087] The specific preparation method of complex calcium sulfonate-based grease is as follows: Carbon dioxide is added to a system of mixed neutral sulfonic acid, calcium hydroxide, base oil, and conversion agent. After complete carbonization, non-Newtonian high-alkalinity calcium sulfonate is obtained. Then, base oil, fatty acid, and calcium hydroxide are added to carry out a saponification reaction. After the reaction is completed, the mixture is homogenized by a three-roll mill or a high-pressure homogenizer to obtain complex calcium sulfonate-based grease. For detailed preparation methods, please refer to [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 896-911].

[0088] The specific preparation method of polyurea-based grease is as follows: Add base oil and organic amine to a grease-making kettle, mix and heat to 80-120℃; slowly add isocyanate-base oil mixture to the grease-making kettle and react with organic amine-base oil mixture under stirring conditions, and control the reaction temperature at 20-200℃. After the reaction is completed, homogenize with a three-roll mill or high-pressure homogenizer to obtain polyurea-based grease. For detailed preparation methods, please refer to [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 588-628].

[0089] The specific preparation method of sodium-based grease is as follows: Add animal and vegetable fats and base oils to the grease-making kettle, stir and heat to 80°C, add sodium hydroxide, and control the temperature at 100-110°C for saponification reaction for 3 hours; after saponification, heat up to dehydrate, take a sample at 160°C to test the free alkali of the soap base, and if qualified, continue to heat the material to 190-200°C and add the remaining base oil for thickening. After thickening, continue to heat up; after the material in the saponification kettle reaches the highest refining temperature, keep it at the temperature, and then filter the grease into the intermediate kettle for reflux cooling; under stirring conditions in the intermediate kettle, reflux cool for 2-4 hours, cool to about 100°C, and homogenize with a three-roll mill or high-pressure homogenizer to obtain sodium-based grease. For detailed preparation methods, please refer to [Zhu Tingbin, Complete Guide to Grease Technology (Second Edition) (M), Beijing: China Petrochemical Press, 2009, 866-877].

[0090] Example 1

[0091] Pour 30.8g of methyl silicone oil into a grease-making vessel, start the stirrer, and heat to 75°C. Add 7.6g of stearic acid and wait for it to completely dissolve. Then add a lithium hydroxide solution (containing 0.5g of lithium hydroxide) pre-dissolved in water. Maintain the temperature at 125°C and react for 4 hours. After saponification, add 31.8g of methyl silicone oil and maintain the temperature at 210°C for 10 minutes. Then stop heating. When the temperature drops to 180°C, add another 31.8g of methyl silicone oil. When the system cools to 100°C, stop stirring and homogenize using a three-roll mill to obtain lithium-based grease.

[0092] Lanthanum chloride and sodium sulfate were added to a 30 mL polytetrafluoroethylene stainless steel reactor, and a hydrothermal reaction was carried out in an aqueous solution. The reaction was carried out at 120 °C for 2 days. After filtration, washing with distilled water, and drying at 25 °C, the rare earth sulfate compound La2(OH)4SO4·nH2O was obtained.

[0093] The rare earth sulfate compound La2(OH)4SO4·nH2O prepared in this embodiment was subjected to XRD analysis. The specific results are as follows: Figure 1 As shown.

[0094] The rare earth sulfate compound 5.0 g, tert-butylhydroquinone 2.0 g, alkenyl succinic acid 0.1 g and sulfurized isobutylene 0.1 g were stirred with the lithium-based grease at 25°C and 100 rpm for 5 h, and then homogenized in a three-roll mill for 3 h to obtain the rare earth-based grease.

[0095] Example 2

[0096] 27.0g of synthetic hydrocarbon base oil (PAO8) and 10.0g of 12-hydroxystearic acid were added to the grease-making kettle and heated to melt. A lithium hydroxide aqueous solution (containing 2.0g of lithium hydroxide) was slowly added at 115℃. After the lithium hydroxide solution was added, the temperature was rapidly increased to 180℃ to ensure complete dehydration of the soap base. The material was then rapidly cooled to 90℃, and 5.0g of salicylic acid was added. The mixture was stirred for 10 minutes, and the lithium hydroxide aqueous solution (containing 2.0g of lithium hydroxide) was slowly added to saponify the salicylic acid. The temperature was increased to 180℃ and maintained for 1 hour to ensure complete dehydration. The temperature was then rapidly increased to 200℃ and maintained for 20 minutes. 54.0g of synthetic hydrocarbon base oil (PAO8) was added, and the grease base was rapidly cooled. Stirring was continued, and the mixture was cooled to 66℃. The mixture was then homogenized using a three-roll mill to obtain the composite lithium-based grease.

[0097] Cerium carbonate and ammonium sulfate were added to a 30 mL polytetrafluoroethylene stainless steel reactor, and a hydrothermal reaction was carried out in water. The reaction was carried out at 25 °C for 10 days. After filtration, washing with distilled water, and drying at 25 °C, the rare earth sulfate compound Ce2(OH)4SO4·nH2O was obtained.

[0098] The rare earth sulfate compound Ce2(OH)4SO4·nH2O prepared in this embodiment was subjected to XRD analysis. The specific results are as follows: Figure 2 As shown.

[0099] 15g of the above rare earth sulfate compound, 5.0g of 2,6-di-tert-butyl-p-cresol, 6.0g of benzotriazole, 3.0g of sulfurized isobutylene, and 71.0g of the above composite lithium-based grease were mixed at 150°C and 500rpm for 4 hours, and then homogenized using a high-pressure homogenizer for 0.5 hours to obtain the rare earth-based grease.

[0100] Example 3

[0101] In an atmospheric pressure vessel, 3.0 g of aluminum isopropoxy and 26.7 g of polyethylene glycol 200 were poured into a grease-making vessel and mixed thoroughly. The mixture was heated to melt with stirring, and 20.0 g of oleic acid was added, maintaining the temperature at 105°C for 1.0 h. After saponification, the temperature was maintained at 100°C, and 3 mL of water was slowly added to initiate a displacement reaction, releasing the remaining isopropanol. The temperature was further increased, and when the contents of the vessel reached 150°C, the remaining 53.3 g of polyethylene glycol 200 was added. The temperature was continued to rise to the maximum refining temperature and maintained for 15 min. After cooling to room temperature, the mixture was homogenized using a three-roll mill to obtain the aluminum-based grease.

[0102] Samarium carbonate and ammonium thiosulfate were added to a 30 mL polytetrafluoroethylene stainless steel reactor and subjected to a hydrothermal reaction in water. The reaction was carried out at 180 °C for 3.5 days. After filtration, washing with distilled water, and drying at 25 °C, the rare earth sulfate compound Sm2(OH)4SO4·nH2O was obtained.

[0103] The rare earth sulfate compound Sm2(OH)4SO4·nH2O prepared in this embodiment was subjected to XRD analysis. The specific results are as follows: Figure 3 As shown.

[0104] The rare earth sulfate compound 0.5g, dilauryl thiodipropionate 0.5g, sulfurized olefin cottonseed oil 3.0g, benzotriazole 3.0g and the aluminum-based grease 93.0g were stirred and mixed at 190°C and 300 rpm for 3 hours. After homogenization in a high-pressure homogenizer for 1 hour, the rare earth-based grease was obtained.

[0105] Example 4

[0106] Pour 35.5g of diphenyl silicone oil into a grease-making vessel, start the stirrer, add 14.5g of stearic acid and 5.5g of benzoic acid, and wait for them to dissolve completely. Then add 9.0g of pre-prepared aluminum isopropoxide trimer and heat the material to 190℃ at a rate of 28℃ / min for 1 hour of saponification. After saponification, add 35.5g of diphenyl silicone oil and mix it with the grease produced by the reaction. Cool down to 76℃. After the reaction is complete, stop stirring and homogenize with a three-roll mill to obtain the composite aluminum-based grease.

[0107] Lanthanum acetate and sodium bisulfate were added to a 30 mL polytetrafluoroethylene stainless steel reactor, and a hydrothermal reaction was carried out in water. The reaction was carried out at 150 °C for 3 days. After filtration, washing with distilled water, and drying at 25 °C, the rare earth sulfate compound La2(OH)4SO4·nH2O was obtained.

[0108] Add 5.0g of the above rare earth sulfate compound, 3.0g of dioctadecyl thiodipropionate, 5.0g of polyglycerol fatty acid ester, 1.0g of thioolefin cottonseed oil and 86.0g of the above composite aluminum-based grease, stir and mix at 1000rpm for 10h at 25℃, and homogenize for 0.5h using a high-pressure homogenizer to obtain the rare earth-based grease.

[0109] Example 5

[0110] First, add 30.0g trimellitate oil, 5.0g cottonseed oil, 5.0g calcium hydroxide cream and 5.0mL water to a kettle, heat to 130℃ and saponify for 40min. Adjust the free acid and base to meet the requirements, then pass water to cool down and increase the stirring speed to hydrate until the material becomes obviously thickened into grease. After phase change, stir for 20min, add 55.0g trimellitate oil to adjust the appropriate cone penetration, and homogenize with a high-pressure homogenizer to obtain calcium-based grease.

[0111] Cerium hydroxide and ammonium bisulfate were added to a 30 mL polytetrafluoroethylene stainless steel reactor, and a hydrothermal reaction was carried out in water. The temperature was 200℃, and the reaction was carried out for 1 day. After filtration, washing with distilled water, and drying at 25℃, the rare earth sulfate compound Ce2(OH)4SO4·nH2O was obtained.

[0112] Add 5.0g of the above rare earth sulfate compound, 3.0g of phenothiazine, 5.0g of barium petroleum sulfonate, 2.0g of tricresyl phosphate and 85.0g of the above calcium-based grease, and stir and mix at 800rpm for 3 hours at 200℃. After homogenization using a three-roll mill for 1 hour, the rare earth-based grease is obtained.

[0113] Example 6

[0114] Pour 51.5g of polyol ester oil into a grease-making vessel, start the stirrer, add 11.5g of palmitic acid, and wait for the palmitic acid to completely dissolve. Then add 3.5g of glacial acetic acid and 4.0g of calcium hydroxide, and control the temperature at 100℃ for saponification for 4 hours. After saponification, add 33.0g of polyol ester oil, control the temperature at 220℃, and continue heating for 10 minutes before stopping. After the reaction is complete, stop stirring and homogenize using a three-roll mill to obtain the composite calcium-based grease.

[0115] Samarium hydroxide and sodium sulfide were added to a 30 mL polytetrafluoroethylene stainless steel reactor, and a hydrothermal reaction was carried out in water. The reaction was carried out at 240℃ for 5 days. After filtration, washing with distilled water, and drying at 25℃, the rare earth sulfate compound Sm2(OH)4SO4·nH2O was obtained.

[0116] Add 7.0g of the above rare earth sulfate compound, 2.5g of diphenylamine, 5.0g of polyglycerol fatty acid ester, 3.0g of tricresyl phosphate, and 82.5g of the above composite calcium-based grease. Stir and mix at 200rpm for 4 hours at 180°C. Homogenize using a high-pressure homogenizer for 3 hours to obtain the rare earth-based grease.

[0117] Example 7

[0118] 23.3g of naphthenic mineral oil, 13.5g of sulfonic acid, 2.0g of calcium hydroxide, 2.0g of formic acid, and 0.8g of isopropanol were added to a grease-making kettle and heated to 90°C. Carbon dioxide was introduced into the system, and after complete carbonization, a non-Newtonian high-alkalinity calcium sulfonate was obtained. Then, 46.7g of naphthenic mineral oil, 8.5g of lauric acid, and 3.2g of calcium hydroxide were added, and a saponification reaction was carried out at 130°C. After the reaction was completed, the mixture was homogenized using a high-pressure homogenizer to obtain a composite calcium sulfonate-based grease.

[0119] Lanthanum carbonate and sodium thiosulfate were added to a 30 mL polytetrafluoroethylene stainless steel reactor and subjected to a hydrothermal reaction in water. The reaction was carried out at 70 °C for 8 days. After filtration, washing with distilled water, and drying at 25 °C, the rare earth sulfate compound La2(OH)4SO4·nH2O was obtained.

[0120] Add 2.0g of the above rare earth sulfate compound, 0.5g of 4-hexylresorcinol, 1.0g of alkenyl succinic acid, 1.0g of tricresyl phosphate, and 95.5g of the above complex calcium sulfonate grease. Stir and mix at 70°C and 600rpm for 1 hour. Homogenize using a three-roll mill for 2 hours to obtain the rare earth grease.

[0121] Example 8

[0122] 40.0g of liquid paraffin and 10.0g of aniline were added to a grease-making kettle, mixed, and heated to 120°C. 40.0g of liquid paraffin and 10.0g of diphenylmethane-4,4'-diisocyanate were mixed in an automatic mixer and heated to 200°C. The diphenylmethane-4,4'-diisocyanate-liquid paraffin mixture was slowly added to the grease-making kettle and reacted with the aniline-liquid paraffin mixture under stirring conditions. The reaction temperature was controlled at 40°C. After the reaction was completed, the mixture was homogenized using a three-roll mill to obtain polyurea-based grease.

[0123] Cerium acetate and ammonium persulfate were added to a 30 mL polytetrafluoroethylene stainless steel reactor, and a hydrothermal reaction was carried out in water. The reaction was carried out at 40 °C for 10 days. After filtration, washing with distilled water, and drying at 25 °C, the rare earth sulfate compound Ce2(OH)4SO4·nH2O was obtained.

[0124] Add 3.5g of the above rare earth sulfate compound, 1.0g of dibutylhydroxytoluene, 1.5g of barium petroleum sulfonate, 2.5g of sulfurized isobutylene, and 91.5g of the above polyurea-based grease. Stir and mix at 800rpm for 5 hours at 100°C. Homogenize using a three-roll mill for 5 hours to obtain the rare earth-based grease.

[0125] Example 9

[0126] First, 26.8g of food-grade white oil and 16.5g of tallow were added to a kettle, and the temperature was raised to 80℃. 3.0g of sodium hydroxide was added, and saponification was carried out at 100℃ for about 3 hours. After saponification, the temperature was raised to dehydrate the product. A sample was taken at 160℃ to measure the free alkali of the soap base, and the free acid and alkali were adjusted to meet the requirements. The temperature was then raised to 200℃, and 51.0g of food-grade white oil was added for thickening. After thickening, the temperature was raised again. The material in the saponification kettle was raised to 220℃ and kept at that temperature for 5 minutes. Then, the grease was filtered and pumped into an intermediate kettle for reflux cooling. The grease was refluxed and cooled in the intermediate kettle with stirring for 2 hours. After cooling to about 100℃, it was homogenized using a three-roll mill to obtain sodium-based grease.

[0127] Samarium chloride and ammonium persulfate were added to a 30 mL polytetrafluoroethylene stainless steel reactor and subjected to a hydrothermal reaction in water at 300 °C for 0.1 days. After filtration, washing with distilled water, and drying at 25 °C, the rare earth sulfate compound Sm2(OH)4SO4·nH2O was obtained.

[0128] Add 5.0g of the above rare earth sulfate compound, 2.5g of N-phenyl-β-naphthylamine, 5.0g of alkenyl succinic acid, 2.0g of sulfurized olefin cottonseed oil and 85.5g of the above sodium-based grease, stir and mix at 700rpm for 3h at 150℃, and then homogenize using a high-pressure homogenizer for 2h to obtain the rare earth-based grease.

[0129] The base greases prepared in Examples 1 to 9 were tested for lubrication according to the SH / T 0202-92 method for determining extreme pressure performance of grease (four-ball tester) and the SH / T 0202-92 method for determining anti-wear performance of grease (four-ball tester). The specific results are shown in Table 1.

[0130] Table 1. Performance test results of the basic lubricating greases in Examples 1-9

[0131] <![CDATA[P B (N)]]> <![CDATA[P D (N)]]> WSD(mm) μ Example 1 353 1235 0.70 0.103 Example 2 353 1235 0.72 0.096 Example 3 353 1235 0.59 0.099 Example 4 353 1568 0.68 0.097 Example 5 353 1235 0.62 0.098 Example 6 392 1235 0.61 0.095 Example 7 392 1568 0.66 0.096 Example 8 353 1235 0.60 0.095 Example 9 353 1235 0.69 0.102

[0132] The rare earth-based greases prepared in Examples 1 to 9 were tested for lubrication performance according to the standards SH / T 0202-92 Extreme Pressure Performance Test Method for Grease (Four-ball Test Method) and SH / T 0202-92 Anti-wear Performance Test Method for Grease (Four-ball Test Method). The specific results are shown in Table 2.

[0133] Table 2. Performance test results of rare earth-based greases prepared in Examples 1-9

[0134] <![CDATA[P B (N)]]> <![CDATA[P D (N)]]> WSD(mm) μ Example 1 980 2450 0.50 0.066 Example 2 1372 4900 0.45 0.062 Example 3 1235 2450 0.32 0.060 Example 4 1078 3920 0.46 0.060 Example 5 1078 3087 0.41 0.066 Example 6 1372 3087 0.35 0.056 Example 7 1235 3920 0.42 0.060 Example 8 1078 3920 0.40 0.065 Example 9 1078 3087 0.45 0.067

[0135] As can be seen from Table 2, the rare earth-based grease prepared in this invention has a load-carrying capacity P. B It reached 1372N, extreme pressure P D With a maximum of 4900N, a wear scar diameter (WSD) of 0.32–0.50 mm, and a minimum friction coefficient (μ) of 0.056, the grease possesses excellent load-bearing, extreme pressure, anti-wear, and friction-reducing capabilities.

[0136] As can be seen from the above embodiments, the present invention provides a rare earth-based grease comprising 71-99 parts of a base grease, 0.5-15 parts of a rare earth sulfate compound, 0.5-5.0 parts of an antioxidant, 0.1-6.0 parts of a rust inhibitor, and 0.1-3.0 parts of an extreme pressure agent. Adding Ln2(OH)4SO4·nH2O (Ln = La, Ce, Sm) to the system improves the frictional properties of the grease, and the load-carrying capacity P is tested. B It reached 1372N, extreme pressure P D With a maximum load capacity of 4900 N, a wear scar diameter (WSD) of 0.32–0.50 mm, and a minimum friction coefficient (μ) of 0.056, this grease exhibits excellent load-bearing, extreme pressure, anti-wear, and friction-reducing capabilities.

[0137] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A rare earth-based grease, characterized in that, It is prepared from the following parts by mass of raw materials: The composition includes 71-99 parts of base grease, 0.5-15 parts of rare earth sulfate compound, 0.5-5.0 parts of antioxidant, 0.1-6.0 parts of rust inhibitor, and 0.1-3.0 parts of extreme pressure agent. The rare earth sulfate compound is Ln2(OH)4SO4·nH2O, where Ln is La, Ce, or Sm. The base grease includes one or more of the following: lithium-based grease, complex lithium-based grease, aluminum-based grease, complex aluminum-based grease, calcium-based grease, complex calcium-based grease, complex calcium sulfonate grease, polyurea-based grease, and sodium-based grease.

2. The rare earth-based grease as described in claim 1, characterized in that, The antioxidants include one or more of the following: 2,6-di-tert-butyl-p-cresol, N-phenyl-β-naphthylamine, tert-butylhydroquinone, 4-hexylresorcinol, diphenylamine, dilauryl thiodipropionate, phenothiazine, dibutylhydroxytoluene, and dioctadecyl thiodipropionate.

3. The rare earth-based grease as described in claim 2, characterized in that, The rust inhibitor includes one or more of alkenyl succinic acid, polyglycerol fatty acid ester, benzotriazole, and barium petroleum sulfonate.

4. The rare earth-based grease as described in claim 2 or 3, characterized in that, The extreme pressure agent includes one or more of sulfurized isobutylene, sulfurized olefin cottonseed oil, and tricresyl phosphate.

5. The method for preparing the rare earth-based grease according to any one of claims 1 to 4, characterized in that, Includes the following steps: The rare earth-based grease is obtained by mixing and homogenizing the above raw materials.

6. The preparation method according to claim 5, characterized in that, The mixing speed is 100-1000 rpm, the mixing temperature is 25-200℃, and the mixing time is 1-10 h.

7. The preparation method according to claim 6, characterized in that, The homogenization time is 0.5 to 5 hours.

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