Composite aluminum-based prefabricated thickening agent, preparation method and application of composite aluminum-based prefabricated thickening agent, composite aluminum-based lubricating grease and preparation method of composite aluminum-based lubricating grease

Abstract

The invention belongs to the technical field of lubricating grease preparation, and provides a composite aluminum-based prefabricated thickening agent, a preparation method and application thereof, composite aluminum-based lubricating grease and a preparation method thereof. The preparation method comprises the following steps: dissolving aluminum isopropoxide to obtain an aluminum isopropoxide solution; dissolving stearic acid and benzoic acid to obtain an organic acid solution; adding the organic acid solution into the aluminum isopropoxide solution, carrying out saponification reaction, then adding water, and carrying out hydration, so as to obtain a composite aluminum thickening agent; and mixing the composite aluminum thickening agent and the dispersion oil, and drying to obtain the composite aluminum-based prefabricated thickening agent. According to the invention, the preparation of the composite aluminum-based prefabricated thickening agent is proposed for the first time, that is, the thickening agent is prepared in advance, and the obtained composite aluminum-based prefabricated thickening agent is mixed with the base oil to prepare the composite aluminum-based lubricating grease, so that complex and changeable influence factors in the traditional preparation process of the composite aluminum-based lubricating grease are avoided, and the thickening agent can be accurately metered and added; and the performance consistency of different batches of composite aluminum-based lubricating grease can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of grease preparation, and in particular to a composite aluminum-based prefabricated thickener and a preparation method and application thereof, and a composite aluminum-based grease and a preparation method thereof. Background Art

[0002] Composite aluminum-based grease is a type of high-temperature multi-effect grease with a high dropping point, good colloidal stability, shear stability, water resistance and thermal reversibility. It can ensure its flow in centralized lubrication systems and has been widely used in equipment in metallurgy, machinery, chemical industry, transportation and other industries. Composite aluminum-based grease is unique in structure and performance. It is of theoretical significance and application value to conduct more in-depth research on composite aluminum-based grease and develop new products. However, the production process of composite aluminum-based grease is more complicated than that of other types of grease. At the same time, it is challenged by composite lithium-based grease, composite calcium sulfonate-based grease and polyurea-based grease, resulting in its relatively slow development.

[0003] The related prior art discloses a composite aluminum-based grease and a preparation method thereof, wherein a thickener is added, and the thickener is prepared from stearic acid, benzoic acid and aluminum isopropoxide trimer as raw materials, or from stearic acid, terephthalic acid and aluminum isopropoxide trimer as raw materials. The preparation method of the composite aluminum-based grease is as follows: after a part of the raw materials of the base oil and the thickener are mixed and reacted, the remaining base oil and additives are added to obtain the composite aluminum-based grease. Due to the uncertainty in the process of forming the thickener from benzoic acid, stearic acid and aluminum isopropoxide or benzoic acid, stearic acid and aluminum isopropoxide trimer, the performance of different batches of composite aluminum-based grease is unstable. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a composite aluminum-based prefabricated thickener and a preparation method and application thereof, a composite aluminum-based grease and a preparation method thereof. The composite aluminum-based prefabricated thickener prepared by the preparation method provided by the present invention can be accurately measured, thereby improving the performance stability of different batches of composite aluminum-based grease.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a composite aluminum-based prefabricated thickener, comprising the following steps:

[0007] dissolving aluminum isopropoxide to obtain an aluminum isopropoxide solution;

[0008] Dissolving stearic acid and benzoic acid to obtain an organic acid solution;

[0009] Adding the organic acid solution to the aluminum isopropoxide solution to carry out a saponification reaction to obtain a saponification product;

[0010] The saponification product is mixed with water for hydration to obtain a composite aluminum thickener;

[0011] The composite aluminum thickener and the dispersing oil are mixed and then dried to obtain the composite aluminum-based prefabricated thickener.

[0012] Preferably, the molar ratio of stearic acid to benzoic acid is 1:0.8-1; the molar ratio of the total molar amount of stearic acid and benzoic acid to aluminum isopropoxide is 2:1-1.2;

[0013] The temperature of the saponification reaction is 30°C to 50°C.

[0014] Preferably, the mass ratio of aluminum isopropoxide to water is 7.46:0.6; the hydration temperature is 30-50° C., and the time is 20-40 min;

[0015] After the hydration, the method further comprises: washing the obtained hydration liquid with ethanol and water in sequence to obtain the composite aluminum thickener; the number of the ethanol washing is 2 to 4 times, and the number of the water washing is 2 to 4 times.

[0016] Preferably, the mass of the dispersing oil is 50-150% of the mass of the composite aluminum thickener, and the dispersing oil is one or more of mineral oil, synthetic hydrocarbon, PAO, polyether and polysiloxane.

[0017] Preferably, the drying is vacuum drying, the temperature of the vacuum drying is 50-100° C., and the time is 4-12 hours.

[0018] The present invention also provides a composite aluminum-based prefabricated thickener prepared by the preparation method described in the above technical solution.

[0019] The present invention also provides a composite aluminum-based grease, the raw materials for its preparation include: base oil and thickener, the thickener is the composite aluminum-based prefabricated thickener described in the above technical solution; the mass of the thickener is 5-10% of the mass of the base oil.

[0020] Preferably, the base oil comprises one or more of mineral oil, synthetic hydrocarbon, PAO, synthetic ester oil, polyether and polysiloxane.

[0021] Preferably, the preparation raw material further comprises an auxiliary agent, and the auxiliary agent comprises one or more of an antioxidant, an extreme pressure anti-wear agent and an anti-corrosion agent.

[0022] The present invention also provides a method for preparing the composite aluminum-based grease described in the above technical solution, comprising the following steps:

[0023] The base oil and the composite aluminum-based prefabricated thickener are mixed, and dispersed, expanded and refined in sequence to obtain the composite aluminum-based grease;

[0024] The dispersion temperature is 100-130°C;

[0025] The puffing temperature is 150-190°C;

[0026] The refining temperature is 180-220°C.

[0027] The invention provides a method for preparing a composite aluminum-based prefabricated thickener.

[0028] The traditional preparation method of composite aluminum-based grease is to mix organic acid and aluminum isopropoxide directly in base oil and perform saponification reaction. Even if the stoichiometric ratio is strictly followed, the organic acid and isopropanol cannot react completely, making the content of the generated thickener uncertain and difficult to accurately measure the thickener, resulting in unstable performance of different batches of composite aluminum-based grease. The present invention proposes for the first time to prepare a composite aluminum-based prefabricated thickener, that is, to prepare the thickener in advance, and to mix the obtained composite aluminum-based prefabricated thickener with the base oil to prepare the composite aluminum-based grease, thereby avoiding the complex and variable influencing factors in the preparation process of the traditional composite aluminum-based grease, enabling the thickener to be accurately measured and added, making the process of the composite aluminum-based grease more simplified, improving its operational repeatability, and effectively improving the performance consistency of different batches of composite aluminum-based grease.

[0029] In the preparation method of traditional composite aluminum-based grease, additional water needs to be added for hydration, and synthetic ester oil is very easy to hydrolyze in the presence of water, thereby losing its lubricating effect; so the existing composite aluminum-based grease cannot use synthetic ester oil, and there are many types of synthetic ester oil on the market, which limits the development and application of composite aluminum-based grease. The present invention prepares the composite aluminum-based prefabricated thickener in advance, and when preparing the composite aluminum-based grease, it does not need to be hydrated again, and can be used for thickening of various common base oils, such as mineral oil, synthetic hydrocarbon, PAO, synthetic ester oil, polyether and polysiloxane, especially synthetic ester oil, which expands the application range of composite aluminum-based grease.

[0030] Furthermore, in the conventional preparation method of composite aluminum-based grease, unreacted acid and alkali still remain in the composite aluminum-based grease, which in turn has an uncertain effect on the performance of the composite aluminum-based grease. After hydration, the present invention sequentially washes the hydrated liquid with ethanol and water to remove unreacted and excess organic acid and aluminum isopropoxide. Compared with the composite aluminum-based grease prepared by the conventional method, the composite aluminum-based grease is purer and has better lubrication performance (oil separation and water resistance). BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of the preparation method of the composite aluminum-based prefabricated thickener provided by the present invention;

[0032] Figure 2 A flow chart of the preparation method of the composite aluminum-based grease provided by the present invention;

[0033] Figure 3 This is the infrared spectrum of the composite aluminum-based prefabricated thickener obtained in Example 1;

[0034] Figure 4 This is a SEM image of the composite aluminum-based prefabricated thickener obtained in Example 1;

[0035] Figure 5 This is the EDS image of the composite aluminum-based prefabricated thickener obtained in Example 1;

[0036] Figure 6 This is the infrared spectrum of the composite aluminum-based prefabricated thickener obtained in Example 2;

[0037] Figure 7 This is a SEM image of the composite aluminum-based prefabricated thickener obtained in Example 2;

[0038] Figure 8 This is the EDS image of the composite aluminum-based prefabricated thickener obtained in Example 2;

[0039] Fig. 9 The friction coefficient curve of the composite aluminum-based grease obtained in Example 3 and Comparative Example 1 is shown;

[0040] Fig.10 The friction coefficient curve of the composite aluminum-based grease obtained in Example 4 and Comparative Example 2 is shown;

[0041] Fig.11 This is a friction coefficient curve of the composite aluminum-based grease obtained in Example 5. DETAILED DESCRIPTION

[0042] Figure 1 The flow chart of the preparation method of the composite aluminum-based prefabricated thickener provided by the present invention is as follows: Figure 1 The preparation method of the composite aluminum-based prefabricated thickener provided by the present invention is described in detail.

[0043] The present invention provides a method for preparing a composite aluminum-based prefabricated thickener, comprising the following steps:

[0044] dissolving aluminum isopropoxide to obtain an aluminum isopropoxide solution;

[0045] Dissolving stearic acid and benzoic acid to obtain an organic acid solution;

[0046] Adding the organic acid solution to the aluminum isopropoxide solution to carry out a saponification reaction to obtain a saponification product;

[0047] The saponification product is mixed with water for hydration to obtain a composite aluminum thickener;

[0048] The composite aluminum thickener and the dispersing oil are mixed and then dried to obtain the composite aluminum-based prefabricated thickener.

[0049] Unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0050] The present invention dissolves aluminum isopropoxide (referred to as the first dissolution) to obtain an aluminum isopropoxide solution.

[0051] In the present invention, the first dissolving solvent preferably includes one or more of petroleum ether, xylene, ethanol and dichloromethane, and petroleum ether is further preferred. In the present invention, the solvent can dissolve aluminum isopropoxide, stearic acid and benzoic acid well, which is conducive to the formation of a homogeneous chemical reaction of the raw materials in the solvent. At the same time, the solvent has a low boiling point and is easy to volatilize and remove.

[0052] In the present invention, the temperature of the first dissolution is preferably 50-90°C, and specifically preferably 50°C, 60°C, 70°C, 80°C or 90°C.

[0053] The present invention dissolves stearic acid and benzoic acid (referred to as the second dissolution) to obtain an organic acid solution.

[0054] In the present invention, the solvent of the second dissolution is preferably the same as the solvent of the first dissolution, which will not be described in detail herein.

[0055] In the present invention, the temperature of the second dissolution is preferably 30-50°C, and specifically preferably 30°C, 35°C, 40°C, 45°C or 50°C.

[0056] After obtaining the aluminum isopropoxide solution and the organic acid solution, the present invention adds the organic acid solution into the aluminum isopropoxide solution to carry out a saponification reaction to obtain a saponification product.

[0057] In the present invention, the molar ratio of stearic acid to benzoic acid is preferably 1:0.8-1, and more preferably 1:0.8, 1:0.9 or 1:1. In the present invention, the molar ratio of the total molar amount of stearic acid and benzoic acid to aluminum isopropoxide is preferably 2:1-1.2, and more preferably 2:1, 2:1.1 or 2:1.2.

[0058] In the present invention, the organic acid solution is preferably added dropwise, and the process of adding the organic acid solution undergoes a saponification reaction, that is, the process of adding the organic acid is preferably the process of the saponification reaction; after the organic acid solution is added, the present invention preferably directly performs the subsequent hydration process without any post-treatment.

[0059] In the present invention, the temperature of the saponification reaction is preferably 30°C to 50°C.

[0060] After obtaining the saponification product, the present invention mixes the saponification product with water to hydrate the product to obtain a composite aluminum thickener.

[0061] In the present invention, the water is preferably distilled water. In the present invention, the mass ratio of the aluminum isopropoxide to water is preferably 7.46:0.6.

[0062] In the present invention, the hydration temperature is preferably 30-50°C, specifically preferably 30°C, 35°C, 40°C, 45°C or 50°C; the time is preferably 20-40 min, specifically preferably 20 min, 30 min or 40 min. In the present invention, the hydration is preferably carried out under stirring.

[0063] After the hydration, the present invention preferably further comprises: washing the obtained hydration liquid with ethanol and water in sequence to obtain the composite aluminum thickener. In the present invention, the temperature of the ethanol washing is preferably 30 to 50°C, specifically preferably 30°C, 40°C or 50°C; the number of the ethanol washing is preferably 2 to 4 times, more preferably 3 times; after each ethanol washing, it is preferably filtered. In the present invention, the temperature of the water washing is preferably 30 to 50°C, specifically preferably 30°C, 40°C or 50°C; the number of the water washing is preferably 2 to 4 times, more preferably 3 times; after each water washing, it is preferably filtered.

[0064] In the present invention, the reaction formula for saponification and hydration of aluminum isopropoxide, stearic acid and benzoic acid is as follows:

[0065]

[0066] In the above formula:

[0067] R is

[0068] R 1 COOH is

[0069] R 2 COOH is

[0070] After obtaining the composite aluminum thickener, the present invention mixes the composite aluminum thickener and dispersing oil, and then dries the mixture to obtain the composite aluminum-based prefabricated thickener.

[0071] In the present invention, the dispersion oil is preferably one or more of mineral oil, synthetic hydrocarbon, PAO, polyether and polysiloxane. In the present invention, the mass of the dispersion oil is 50-150% of the mass of the composite aluminum thickener, preferably 80-100%, and specifically preferably 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140% or 150%. In the present invention, too little addition of the dispersion oil affects the thickening ability, and too much addition affects the preparation performance of the grease composition.

[0072] In the present invention, the temperature for mixing the composite aluminum thickener and the dispersant oil is preferably 50-70°C, more preferably 60°C; the time is preferably 5-15 minutes, more preferably 10 minutes; and the mixing is preferably carried out under stirring conditions.

[0073] In the present invention, the drying is preferably vacuum drying, and the vacuum drying temperature is preferably 50-100°C, specifically preferably 50°C, 60°C, 70°C, 80°C, 90°C or 100°C; the time is preferably 4-12h, specifically preferably 4h, 6h, 8h, 10h or 12h.

[0074] After the drying, the present invention preferably further comprises pulverization. The present invention does not specifically limit the parameters of the pulverization, as long as the particle size of the obtained composite aluminum-based prefabricated thickener is preferably 50 to 200 μm.

[0075] The present invention also provides a composite aluminum-based prefabricated thickener prepared by the preparation method described in the above technical solution.

[0076] The present invention also provides a composite aluminum-based grease, comprising the following preparation raw materials: base oil and thickener, wherein the thickener is the composite aluminum-based prefabricated thickener described in the above technical solution; the mass of the thickener is 5-10% of the mass of the base oil.

[0077] The raw materials for preparing the composite aluminum-based grease provided by the present invention include base oil, and the base oil preferably includes one or more of mineral oil, synthetic hydrocarbon, PAO, synthetic ester oil, polyether and polysiloxane.

[0078] The raw materials for preparing the composite aluminum-based grease provided by the present invention include a thickener, and the thickener is the composite aluminum-based prefabricated thickener described in the above technical solution; the mass of the thickener is 5-10% of the mass of the base oil, and is preferably 5%, 6%, 7%, 8%, 9% or 10%. In the present invention, when the amount of the composite aluminum-based prefabricated thickener is less than 5%, the consistency is insufficient; when it exceeds 10%, the composite aluminum-based grease is too hard and is not suitable for use.

[0079] The raw materials for preparing the composite aluminum-based grease provided by the present invention preferably also include additives, which include but are not limited to antioxidants, extreme pressure anti-wear agents and corrosion inhibitors. The present invention does not specifically limit the types and addition amounts of the antioxidants, extreme pressure anti-wear agents and corrosion inhibitors, and operations familiar to those skilled in the art may be used.

[0080] Figure 2 The preparation method of the composite aluminum-based grease provided by the present invention is shown in the following figure. Figure 2 The preparation method of the composite aluminum-based grease provided by the present invention is described in detail.

[0081] The present invention also provides a method for preparing the composite aluminum-based grease described in the above technical solution, comprising the following steps:

[0082] The base oil and the composite aluminum-based prefabricated thickener are mixed, dispersed, expanded and refined in sequence to obtain the composite aluminum-based grease.

[0083] In the present invention, the dispersion temperature is 100-130°C, preferably 100°C, 110°C, 120°C or 130°C; the dispersion time is preferably 20-40 min, more preferably 30 min.

[0084] In the present invention, the puffing temperature is 150-190°C, and is preferably 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C or 190°C; the puffing time is preferably 5-15 min, and is more preferably 10 min.

[0085] In the present invention, the refining temperature is 180-220°C, and is preferably 180°C, 190°C, 200°C, 210°C or 220°C; the refining time is preferably 5-15 min, and is more preferably 10 min.

[0086] After the refining, the present invention preferably further comprises: cooling the refined product to room temperature and then grinding and homogenizing. In the present invention, the grinding and homogenizing is preferably performed on a three-roll mill, and the number of the grinding and homogenizing is preferably 1 to 6 times, more preferably 3 times.

[0087] The composite aluminum-based prefabricated thickener and its preparation method and application, composite aluminum-based grease and its preparation method provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0088] The sources of raw materials used in the following examples and comparative examples include:

[0089] Petroleum ether was purchased from Chengdu Kelong Chemical Co., Ltd., with a boiling range of 90°C to 120°C;

[0090] Xylene was purchased from Xilong Science Co., Ltd., analytical grade;

[0091] Anhydrous ethanol was purchased from Li’an Long Bohua (Tianjin) Pharmaceutical Chemistry Co., Ltd., analytical grade;

[0092] Aluminum isopropoxide was purchased from Yangzhou Zhongtianli New Materials Co., Ltd., with an aluminum content of 12.5% ​​to 14.9%;

[0093] Stearic acid was 1801 type stearic acid from Southern Acids Industries Sdn Bhd of Malaysia;

[0094] Benzoic acid was purchased from Tianjin Dongda Chemical Group Co., Ltd., with a content of 99.8%;

[0095] 150BS base oil was purchased from IRPC, Thailand, with a kinematic viscosity of 496 mm at 40°C. 2 / s, kinematic viscosity at 100℃ is 31.94mm 2 / s;

[0096] PAO10 base oil was purchased from ExxonMobil, and the kinematic viscosity at 40°C was 10.0 mm 2 / s, kinematic viscosity at 100℃ is 66mm 2 / s;

[0097] 3970 synthetic base oil was purchased from Heda Chemicals (Shanghai) Co., Ltd., with a kinematic viscosity of 4.4 mm at 40 °C. 2 / s, kinematic viscosity at 100℃ is 20mm 2 / s;

[0098] Distilled water was homemade.

[0099] Example 1

[0100] Preparation of composite aluminum-based prefabricated thickener:

[0101] 7.46 g of aluminum isopropoxide was added to 100 mL of petroleum ether, and the mixture was stirred and dissolved at 50° C. to form an aluminum isopropoxide solution; 9.10 g of stearic acid and 3.90 g of benzoic acid were added to 100 mL of petroleum ether, and the mixture was stirred and dissolved at 50° C. to form an organic acid solution; the organic acid solution was slowly added dropwise to the aluminum isopropoxide solution at 50° C., and a saponification product was obtained after the addition was completed; 0.60 g of distilled water was then added, and the mixture was hydrated for 30 min under stirring. After the hydration was completed, 50° C. ethanol was added for washing and vacuum filtration (washed 3 times, 100 mL of ethanol each time); 50° C. distilled water was added for washing and vacuum filtration (washed 3 times, 100 mL of distilled water each time), and the solid product obtained by filtration was a composite aluminum thickener; 14.84 g of PAO10 is used as the dispersing oil (the mass of PAO10 is 100% of the mass of the composite aluminum thickener), stirred and mixed at 60°C for 10 minutes, and then vacuum dried at 80°C for 8 hours to obtain a gelled solid, which is crushed into powder to obtain a composite aluminum-based prefabricated thickener with a particle size of 50 to 200 μm.

[0102] The raw material composition ratio of the above-mentioned composite aluminum-based prefabricated thickener is: the molar ratio of stearic acid to benzoic acid is 1:1, and the molar ratio of aluminum isopropoxide to total acid is 1.14:2. Theoretically, about 14.84g of pure composite aluminum thickener can be prepared.

[0103] The infrared spectrum of the obtained composite aluminum-based prefabricated thickener is as follows: Figure 3 As shown by Figure 3 It can be seen that there are three characteristic absorption peaks of the composite aluminum-based prefabricated thickener, which are 3670 cm -1 The hydroxyl stretching vibration absorption peaks are around 1565-1610 cm -1 The carbonyl triplet peak between 1000 cm -1 The stretching vibration absorption peak of the aluminum-oxygen bond is around 1700cm -1 There is no characteristic peak of carboxylic acid remaining, which indicates that the acid-base reaction is complete and carboxylate aluminum soap is generated, and the composite aluminum-based preformed thickener has a high purity.

[0104] The SEM image of the obtained composite aluminum-based prefabricated thickener is as follows: Figure 4 As shown, from Figure 4 It can be seen that the composite aluminum-based prefabricated thickener presents an irregular colloid structure of several tens of microns in size.

[0105] The EDS image of the obtained composite aluminum-based prefabricated thickener is as follows: Figure 5 As shown, from Figure 5 It can be seen that the mass percentage of Al element in the obtained composite aluminum-based prefabricated thickener is 5.45%, and the atomic concentration is 2.67%.

[0106] Example 2

[0107] Preparation of composite aluminum-based prefabricated thickener:

[0108] 7.46 g of aluminum isopropoxide was added to 100 mL of xylene, and the mixture was stirred and dissolved at 50° C. to form an aluminum isopropoxide solution; 9.10 g of stearic acid and 3.90 g of benzoic acid were added to 100 mL of xylene, and the mixture was stirred and dissolved at 50° C. to form an organic acid solution; the organic acid solution was slowly added dropwise to the aluminum isopropoxide solution at 50° C., and a saponification product was obtained after the addition was completed; 0.60 g of distilled water was then added, and the mixture was hydrated for 30 min under stirring. After the hydration was completed, 50° C. ethanol was added for washing and vacuum filtration (washed 3 times, 100 mL of ethanol each time); 50° C. distilled water was added for washing and vacuum filtration (washed 3 times, 100 mL of distilled water each time), and the solid product obtained by filtration was a composite aluminum thickener; 14.84 g of PAO10 is used as the dispersing oil (the mass of PAO10 is 100% of the mass of the composite aluminum thickener), stirred and mixed at 60°C for 10 minutes, and then vacuum dried at 80°C for 8 hours to obtain a gelled solid, which is crushed into powder to obtain a composite aluminum-based prefabricated thickener with a particle size of 50 to 200 μm.

[0109] The raw material composition ratio of the above-mentioned composite aluminum-based prefabricated thickener is: the molar ratio of stearic acid to benzoic acid is 1:1, and the molar ratio of aluminum isopropoxide to total acid is 1.14:2. Theoretically, about 14.84 g of pure composite aluminum thickener can be prepared.

[0110] The infrared spectrum of the obtained composite aluminum-based prefabricated thickener is as follows: Figure 6 As shown, from Figure 6 It can be seen that the three characteristic absorption peaks of the composite aluminum-based prefabricated thickener are 3670 cm -1 The hydroxyl stretching vibration absorption peaks are around 1565-1610 cm -1 The carbonyl triplet peak between 1000 cm -1 The stretching vibration absorption peak of the aluminum-oxygen bond is around 1700cm -1 There is no characteristic peak of carboxylic acid remaining, which indicates that the acid-base reaction is complete and carboxylate aluminum soap is generated, and the composite aluminum-based preformed thickener has a high purity.

[0111] The SEM image of the obtained composite aluminum-based prefabricated thickener is as follows: Figure 7 As shown, from Figure 7 It can be seen that the obtained composite aluminum-based prefabricated thickener presents an irregular colloid structure of a size of tens of microns.

[0112] The EDS image of the obtained composite aluminum-based prefabricated thickener is as follows: Figure 8 As shown, from Figure 8It can be seen that the mass percentage of Al element in the obtained composite aluminum-based prefabricated thickener is 5.70%, and the atomic concentration is 2.78%.

[0113] Example 3

[0114] The composite aluminum-based grease is prepared by composite aluminum-based prefabricated thickener and PAO10 base oil.

[0115] 8.00 g of the composite aluminum-based prefabricated thickener prepared in Example 1 was added to 42.00 g of PAO10 synthetic base oil, the temperature was raised to 120°C and stirred for 30 min, the temperature was continued to be raised to 165°C and expanded for 10 min, and finally the temperature was raised to 210°C and refined for 10 min. The mixture was naturally cooled to room temperature and ground and homogenized on a three-roll mill for 3 times to obtain a composite aluminum-based grease.

[0116] The mass percentage of the composite aluminum thickener in the composite aluminum-based grease is 8.00%.

[0117] Example 4

[0118] The composite aluminum-based grease is prepared by using the composite aluminum-based prefabricated thickener and 150BS base oil.

[0119] 8.00 g of the composite aluminum-based prefabricated thickener prepared in Example 1 was added to 42.00 g of 150BS mineral base oil, the temperature was raised to 120°C and stirred for 30 min, the temperature was continued to be raised to 165°C and expanded for 10 min, and finally the temperature was raised to 210°C and refined for 10 min. The mixture was naturally cooled to room temperature and ground and homogenized on a three-roll mill for 3 times to obtain a composite aluminum-based grease.

[0120] The mass percentage of the composite aluminum thickener in the composite aluminum-based grease is 8.00%.

[0121] Example 5

[0122] Aluminum-complex preformed thickener and 3970 base oil are used to prepare aluminum-complex grease.

[0123] 8.00 g of the composite aluminum-based prefabricated thickener prepared in Example 1 was added to 42.00 g of 3970 synthetic ester oil, the temperature was raised to 120°C and stirred for 30 min, the temperature was continued to be raised to 165°C and expanded for 10 min, and finally the temperature was raised to 210°C and refined for 10 min. The mixture was naturally cooled to room temperature and ground and homogenized on a three-roll mill for 3 times to obtain a composite aluminum-based grease.

[0124] The mass percentage of the composite aluminum thickener in the composite aluminum-based grease is 8.00%.

[0125] Comparative Example 1

[0126] The composite aluminum-based grease with PAO10 as the base oil is prepared by traditional process.

[0127] Mix 7.46 g aluminum isopropoxide and 170.66 g PAO10 and heat to 120°C. After the aluminum isopropoxide melts, slowly add 9.10 g stearic acid and stir to react for 30 min. Then add 3.90 g benzoic acid and react at 120°C for 1 h. Then cool to 96°C and slowly add 0.60 g distilled water and react for 1 h. Then heat to 210°C and keep for 10 min. Then naturally cool to 60°C and grind to obtain a composite aluminum-based grease.

[0128] The above process can obtain 185.50g of composite aluminum-based grease, and the mass percentage of thickener is 8.00%.

[0129] Comparative Example 2

[0130] The composite aluminum-based grease with 150BS as the base oil is prepared by traditional technology.

[0131] Mix 1.83g of aluminum isopropoxide and 170.66g of 150BS and heat to 120°C. After the aluminum isopropoxide melts, slowly add 2.63g of stearic acid and stir to react for 30min. Then add 1.14g of benzoic acid and react at 120°C for 1h. Then cool to 96°C and slowly add 0.60g of distilled water and react for 1h. Then heat to 210°C and keep for 10min. Then naturally cool to 60°C and grind to obtain a composite aluminum-based grease.

[0132] The above process can obtain 185.50g of composite aluminum-based grease, and the mass percentage of thickener is 8.00%

[0133] The basic physical and chemical properties of the composite aluminum-based greases prepared in Example 3, Example 4, Example 5, and Comparative Example 1 and Comparative Example 2 were tested. The results are shown in Table 1.

[0134] Table 1 Performance test results of composite aluminum-based grease prepared in Examples and Comparative Examples

[0135]

[0136] As can be seen from Table 1, the composite aluminum-based prefabricated thickener can achieve the thickening of various base oils including synthetic ester oils, thereby obtaining a grease product with excellent performance. The composite aluminum-based grease obtained by the composite aluminum-based prefabricated thickener provided by the method of the present invention has a dropping point greater than 260°C, and its basic physical and chemical properties such as oil separation and water resistance are better than those of the composite aluminum-based grease obtained by the traditional process. The composite aluminum-based grease obtained by the present invention has good adaptability to various commonly used additives such as antioxidants, extreme pressure anti-wear agents and corrosion inhibitors. The composite aluminum-based grease can contain various additives in normal amounts as needed.

[0137] The friction coefficient of the composite aluminum-based grease prepared in Example 3, Example 4, Example 5, Comparative Example 1 and Comparative Example 2 was tested using an Rtec5000 multifunctional friction and wear tester. The friction pair contact mode was ball / surface point contact, the upper test ball was a SAE52100 steel ball with a diameter of 6 mm, and the lower test surface was a SAE52100 steel block with a size of 30 mm×15 mm×5 mm. The test conditions were: load of 150 N, reciprocating frequency of 20 Hz, stroke of 1 mm, test time of 30 min, and test temperature of room temperature.

[0138] Fig. 9 The friction coefficient curve of the composite aluminum-based grease prepared in Example 3 and Comparative Example 1 is shown in FIG. Fig.10 The friction coefficient curve diagram of the composite aluminum-based grease prepared in Example 4 and Comparative Example 2 shows that the composite aluminum-based grease with PAO 10 as base oil or mineral-based 150BS as base oil and the addition of a composite aluminum-based prefabricated thickener has basically the same tribological properties as the composite aluminum-based grease prepared by the traditional process.

[0139] Fig.11 This is a friction coefficient curve of the composite aluminum-based grease prepared in Example 5. Since synthetic ester oils are prone to hydrolysis in a water environment and lose their lubricating properties, the traditional composite aluminum-based grease preparation process is usually not used to thicken synthetic ester oils, which also affects the application field of composite aluminum-based grease; however, composite aluminum-based prefabricated thickeners can break through the restrictions on base oil types and achieve higher performance and wider applications.

[0140] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a composite aluminum-based prefabricated thickener, comprising the following steps: dissolving aluminum isopropoxide to obtain an aluminum isopropoxide solution; Dissolving stearic acid and benzoic acid to obtain an organic acid solution; Adding the organic acid solution to the aluminum isopropoxide solution to carry out a saponification reaction to obtain a saponification product; The saponification product is mixed with water for hydration to obtain a composite aluminum thickener; The composite aluminum thickener and the dispersing oil are mixed and then dried to obtain the composite aluminum-based prefabricated thickener.

2. The preparation method according to claim 1, characterized in that: The molar ratio of stearic acid to benzoic acid is 1:0.8-1; the molar ratio of the total molar amount of stearic acid and benzoic acid to aluminum isopropoxide is 2:1-1.2; The temperature of the saponification reaction is 30°C to 50°C.

3. The preparation method according to claim 1, characterized in that: The mass ratio of aluminum isopropoxide to water is 7.46:0.6; the hydration temperature is 30-50° C., and the time is 20-40 min; After the hydration, the method further comprises: washing the obtained hydration liquid with ethanol and water in sequence to obtain the composite aluminum thickener; the number of the ethanol washing is 2 to 4 times, and the number of the water washing is 2 to 4 times.

4. The preparation method according to claim 1 or 3, characterized in that: The mass of the dispersing oil is 50-150% of the mass of the composite aluminum thickener, and the dispersing oil is one or more of mineral oil, synthetic hydrocarbon, PAO, polyether and polysiloxane.

5. The preparation method according to claim 1, characterized in that: The drying is vacuum drying, the temperature of the vacuum drying is 50-100° C., and the time is 4-12 hours.

6. A composite aluminum-based prefabricated thickener obtained by the preparation method according to any one of claims 1 to 5.

7. A composite aluminum-based grease, characterized in that: The raw materials for preparation include: base oil and thickener, wherein the thickener is the composite aluminum-based prefabricated thickener as claimed in claim 6; the mass of the thickener is 5-10% of the mass of the base oil.

8. The aluminum-complex grease according to claim 7, characterized in that: The base oil includes one or more of mineral oil, synthetic hydrocarbon, PAO, synthetic ester oil, polyether and polysiloxane.

9. The aluminum-complex grease according to claim 7, characterized in that: The preparation raw materials also include auxiliary agents, and the auxiliary agents include one or more of antioxidants, extreme pressure anti-wear agents and anti-corrosion agents.

10. The method for preparing the composite aluminum-based grease according to any one of claims 7 to 9, characterized in that: The following steps are involved: The base oil and the composite aluminum-based prefabricated thickener are mixed, and dispersed, expanded and refined in sequence to obtain the composite aluminum-based grease; The dispersion temperature is 100-130°C; The puffing temperature is 150-190°C; The refining temperature is 180-220°C.

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