A composite aluminum-based grease composition for centralized lubrication system and preparation method thereof

Abstract

The present invention relates to the field of grease technology, and in particular to a composite aluminum-based grease composition for a centralized lubrication system and a preparation method thereof. The preparation method of a composite aluminum-based grease composition for a centralized lubrication system of the present invention can improve the colloidal stability and mechanical stability of the product by reasonably setting the formula and process. The prepared grease composition is applied to the centralized lubrication system of the steel industry. The grease amount can be saved on the basis of ensuring good lubrication by extending the greasing interval, thereby reducing the grease cost for customers and improving the market competitiveness of the product.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating grease, and in particular to a composite aluminum-based lubricating grease composition for a centralized lubrication system and a preparation method thereof. Background Art

[0002] Aluminum-complex grease is a high-dropping-point grease specially classified and counted by the National Lubricating Grease Institute (NLGI). It is widely used in the metallurgical steel industry due to its good high temperature resistance, water resistance and pumping performance. In particular, it is widely used in the centralized lubrication system of the steel industry due to its excellent pumping performance. However, after investigating the use of grease in the centralized lubrication system of the steel industry, it is known that aluminum-complex grease has a problem of high grease consumption compared with other high-dropping-point greases (such as polyurea grease or calcium sulfonate-complex grease). According to research, the factors affecting the amount of grease used in the centralized lubrication system include the characteristics of the grease for the working conditions of the lubrication points (such as high temperature resistance and water resistance), and the colloidal stability and mechanical stability of the grease product are also one of the main factors. In the centralized lubrication system, the grease products used have a long retention time in the main pipeline of the system and are subject to a certain system pressure. Especially for the intelligent centralized lubrication system, the system pressure it bears will be higher; in the centralized lubrication system used for high-temperature equipment, some main pipelines are close to the high-temperature parts, and the temperature of the main pipeline will also be higher. Therefore, the grease used in the centralized lubrication system needs to have excellent colloidal stability so that it can maintain structural stability after being stored for a long time under certain pressure and temperature conditions. In addition, the grease used in the centralized system needs to withstand the mechanical shearing effect of the normal operation of the system grease pump and equipment lubrication points, especially when applied to some bearing parts with faster running speeds, such as the conveyor cooling roller bearing parts after steel rolling in the steel industry. The grease used needs to have good mechanical stability.

[0003] Therefore, in order to address the problem of excessive use of composite aluminum-based grease products in centralized lubrication systems, in addition to improving the grease's properties for lubrication point operating conditions (such as high temperature resistance and water resistance), it is also necessary to improve its properties for centralized lubrication systems (such as colloid stability and mechanical stability). Summary of the invention

[0004] The present invention provides a composite aluminum-based grease composition for a centralized lubrication system and a preparation method thereof, so as to solve the problem that the existing composite aluminum-based grease products are used in a centralized lubrication system and have a large amount of grease.

[0005] According to a first aspect of the present invention, the present invention provides a method for preparing a composite aluminum-based grease composition for a centralized lubrication system, comprising the following steps:

[0006] In part of the base oil, stearic acid and 40%-60% of the total mass of the carboxylated aluminum oxide compound are added to react at 90°C-110°C for 60min-100min; then 40%-60% of benzoic acid is added to react at 110°C-140°C for 15min-35min; then the remaining carboxylated aluminum oxide compound is added to react at 110°C-140°C for 50min-80min; the remaining benzoic acid is continued to be added to react at 110°C-140°C for 15min-35min; then the temperature is raised to the refining temperature of 190°C-210°C and kept at a constant temperature for 3min-5min; after refining, the temperature is lowered to 150°C-170°C and the remaining base oil and additives are added.

[0007] The present invention discloses a method for preparing a composite aluminum-based grease composition for a centralized lubrication system. The whole amount of stearic acid is first mixed with a carboxylated aluminum oxide compound accounting for 40%-60% of the total mass of the carboxylated aluminum oxide compound, and the mixture is reacted in a base oil at 90°C-110°C for 60min-100min to obtain a first reaction product. By reasonably limiting the temperature and time during the synthesis of the first reaction product, the molecular structure of the obtained first reaction product can be controlled within a reasonable range, which is beneficial to improving the colloidal stability and mechanical stability of the product. If the reaction time is less than 60min, the molecular structure of the obtained first reaction product is unstable, which is not conducive to improving the colloidal stability and mechanical stability of the product. If the reaction time exceeds 100min, the performance improvement is not obvious. Furthermore, the preparation method of the present invention mixes the first reaction product with benzoic acid accounting for 40%-60% of the total mass of benzoic acid and reacts at 110°C-140°C for 15min-35min to obtain a second reactant; then mixes the second reactant with the remaining carboxylated aluminum oxide compound and reacts at 110°C-140°C for 50min-80min to obtain a third reaction product; by reasonably limiting the temperature and time during the synthesis of the third reaction product, the molecular structure of the obtained third reaction product can be controlled within a reasonable range, which is beneficial to improving the colloidal stability and mechanical stability of the product. If the reaction time is less than 50min, the molecular structure of the obtained third reaction product is unstable, which is not conducive to improving the colloidal stability and mechanical stability of the product. If the reaction time exceeds 80min, the performance improvement is not obvious. Furthermore, the preparation method of the present invention comprises mixing the third reaction product with the remaining benzoic acid and reacting them at 110°C-140°C for 15min-35min; heating to a refining temperature of 190°C-210°C and maintaining the temperature for 3min-5min; after refining, cooling to 150°C-170°C and adding the remaining base oil and additives. By controlling the above reaction temperature and time, the molecular structure of the obtained product is controlled within a reasonable range, which is beneficial to improving the colloidal stability and mechanical stability of the product. Controlling the temperature at which the remaining base oil is added is particularly important, because a chemical reaction is still taking place inside the reaction product during the cooling process after refining. If the base oil is added at a temperature that is too low or too high, it is not conducive to the reaction, resulting in an unstable molecular structure of the formed product, which will have an adverse effect on the colloidal stability and mechanical stability of the product.The invention reasonably limits the process parameters of each step in the preparation process so that the steps can play a synergistic role, so that the colloidal stability and mechanical stability of the obtained product are significantly improved, which is specifically reflected in three indicators: oil separation amount (pressure filtration method) (40°C, 168h) (NB / SH / T 6027), oil separation amount (cone-net method, 100°C, 24h) (NB / SH / T 0324) and the difference between the extended working cone penetration (100,000 times) and the working cone penetration (GB / T 269). The oil separation amount (pressure filtration method) and the oil separation amount (cone-net method) indicators reflect the colloidal stability of the product, and the difference between the extended working cone penetration (100,000 times) and the working cone penetration reflects the mechanical stability of the product, which corresponds to the working condition requirements of the centralized lubrication system.

[0008] Furthermore, the amounts of raw materials used in preparing the grease composition are as follows by weight: 3-4.5 parts of carboxylated aluminum oxide, 1-2.5 parts of stearic acid, 90-95 parts of base oil, and 0.2-1.0 parts of additives.

[0009] In the above scheme, by limiting the amount of raw materials used in the preparation of the grease composition within a reasonable range, the components can play a better synergistic role, so that the obtained product has better colloidal stability and mechanical stability.

[0010] Furthermore, the molecular formula of the carboxylated aluminum oxide compound is as shown in the following formula (I):

[0011]

[0012] Wherein, R represents the straight chain saturated alkyl group in stearic acid;

[0013] The carboxylic acid molar ratio of stearic acid to benzoic acid is (1.0-1.3): 1.0;

[0014] The ratio of the total molar number of carboxylic acid of stearic acid and benzoic acid to the molar number of aluminum element in the carboxylated aluminum oxide compound is (1.9-2.0):1.0.

[0015] In the above scheme, the present application selects a carboxylated aluminum oxide compound of a specific molecular formula. The carboxylated aluminum oxide compound is obtained by replacing the isopropoxy group in the isopropanol aluminum trimer with carboxylic acids such as stearic acid and benzoic acid. The above carboxylated aluminum oxide compound is also called an environmentally friendly aluminum source, and its commercial products include Kolate 6030 of FedChem. There is no isopropanol emission in the process of preparing composite aluminum-based grease using the above carboxylated aluminum oxide compound. At the same time, the above scheme reasonably limits the ratio of the carboxylic acid molar ratio of stearic acid to benzoic acid, the total carboxylic acid molar number of stearic acid and benzoic acid, and the molar number of aluminum element in the carboxylated aluminum oxide compound, which can improve the overall performance of the product. When the carboxylic acid molar ratio of stearic acid to benzoic acid is less than 1.0:1, the oil separation of the grease increases, resulting in a decrease in the colloidal stability of the product. When the molar ratio is greater than 1.3:1, the dropping point of the product decreases, and the mechanical stability also gradually decreases. When the ratio of the total carboxylic acid molar number of stearic acid and benzoic acid to the molar number of aluminum element in the carboxylated aluminum oxide compound is less than 1.9:1, the amount of thickener required for the grease increases, resulting in higher costs. When the molar ratio is greater than 2:1, the grease contains an excess of carboxylic acid, which will accelerate product oxidation and shorten its service life.

[0016] Furthermore, the base oil is one or more of paraffin-based mineral oil, naphthenic mineral oil and poly-alpha-olefin synthetic oil.

[0017] In the above scheme, by selecting the appropriate type of base oil, it is beneficial to improve the product's colloidal stability, mechanical stability, lubrication performance and other properties.

[0018] Furthermore, the kinematic viscosity of the base oil at 100°C is 5 mm 2 / s-35mm 2 / s.

[0019] In the above scheme, by selecting a base oil with a suitable kinematic viscosity, it is beneficial to improve the colloidal stability, mechanical stability, lubrication performance and other properties of the product. When the kinematic viscosity exceeds this range, the colloidal stability and mechanical stability of the product tend to deteriorate, and if the viscosity is too low, the lubrication performance of the product decreases, and if the viscosity is too high, the pumping resistance of the product increases.

[0020] Furthermore, in the grease composition of the present invention, required additives can be added according to the requirements of the use conditions, etc. The additives include antioxidants and rust inhibitors; preferably, the antioxidant is an amine antioxidant, and the rust inhibitor is a sulfonate and / or a long-chain organic carboxylic acid; more preferably, the antioxidant is diphenylamine or alkyl diphenylamine; and the rust inhibitor is a barium sulfonate salt and / or dodecenylsuccinic acid.

[0021] In the above scheme, the anti-oxidation and anti-rust effects of the grease composition can be better exerted by using the above types of antioxidants and rust inhibitors.

[0022] Furthermore, after refining, the remaining base oil and antioxidant are added after the temperature drops to 150°C-170°C, and the rust inhibitor is added after the temperature drops to below 80°C.

[0023] Furthermore, in the base oil accounting for 75%-90% of the total mass of the base oil, stearic acid is first added and mixed evenly, the temperature is raised to 70° C.-90° C., and then the carboxylated aluminum oxide compound is added and mixed evenly.

[0024] Furthermore, after adding the rust inhibitor, a homogenization step is also included.

[0025] The homogenization treatment in the above scheme can be performed by a three-roll mill or the like.

[0026] According to the second aspect of the present invention, the present invention also provides a composite aluminum-based grease composition for a centralized lubrication system, which is prepared by the above-mentioned preparation method.

[0027] The present invention also provides the use of the above-mentioned grease composition or the grease composition prepared by the above-mentioned preparation method in lubricating machines, machinery or their parts.

[0028] Preferably, the machine, machinery or its parts are used in centralized lubrication systems, including but not limited to roller bearings of hot rolling conveying cooling rollers in the steel industry.

[0029] The technical solution provided by the present invention has the following beneficial effects:

[0030] The preparation method of the composite aluminum-based grease composition for a centralized lubrication system of the present invention can improve the colloidal stability and mechanical stability of the product by reasonably setting the formula and process. The prepared grease composition is applied to the centralized lubrication system of the steel industry. The grease amount can be saved on the basis of ensuring good lubrication by extending the greasing interval, thereby reducing the grease cost for customers and improving the market competitiveness of the product. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The commercial products of the carboxylated aluminum oxide used in the following examples usually contain about half of the mass of diluent oil, so the mass of the carboxylated aluminum oxide actually added was calculated by the aluminum content.

[0033] In the following examples, the stearic acid product is a saturated straight-chain carboxylic acid mainly composed of C16 and C18, so the amount of carboxylic acid is calculated by the acid value, and the ratio of the amount of stearic acid to benzoic acid is called the carboxylic acid molar ratio, represented by FA:BA. The ratio of the total molar number of carboxylic acids of stearic acid and benzoic acid to the molar number of aluminum in the carboxylated aluminum oxide compound is called the total acid to aluminum molar ratio, represented by TA:AL.

[0034] Example 1

[0035] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, and its raw material composition is as follows: 42g of carboxylated aluminum oxide, 21g of stearic acid, 11g of benzoic acid, 924g of polyalphaolefin synthetic oil, 1g of antioxidant, and 1g of rust inhibitor. Among them, FA:BA=1.3:1, TA:AL=1.90:1, and the mass percentage of thickener is 7.4%.

[0036] This embodiment also provides a method for preparing the above-mentioned composite aluminum-based grease composition, which specifically comprises the following steps:

[0037] Step (1): Add 90% of base oil (accounting for 90% of the total mass of the base oil, the calculation method of the following raw material addition amount is the same here) into the reactor, then add all the mass of stearic acid, stir and heat to 70-75°C, then add 60% of the mass of carboxylated aluminum oxide, heat to 90-95°C and react for 95-100 minutes.

[0038] Step (2): then raise the temperature to 110-115° C., add 60% by weight of benzoic acid and react for 15-20 minutes, continue to add the remaining carboxylated aluminum oxide compound (accounting for 40% of the total amount of carboxylated aluminum oxide compound) and react at 115-120° C. for 60-65 minutes.

[0039] Step (3): then add the remaining benzoic acid and react at 120-125°C for 30-35 minutes, and finally raise the temperature to the highest refining temperature of 200-205°C and keep it constant for 3-5 minutes.

[0040] Step (4): Then cool the mixture to 165-170°C and add the remaining base oil and antioxidant. After the temperature drops below 80°C, add the rust inhibitor, and then homogenize the mixture through a three-roll mill to obtain the final grease product.

[0041] Example 2

[0042] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, and its raw material composition is as follows: 30.5g of carboxylated aluminum oxide, 13g of stearic acid, 10.5g of benzoic acid, 940g of naphthenic mineral oil, 3g of antioxidant, and 3g of rust inhibitor. Among them, FA:BA=1.0:1, TA:AL=2:1, and the mass percentage of thickener is 5.4%.

[0043] This embodiment also provides a method for preparing the above-mentioned composite aluminum-based grease composition, which specifically comprises the following steps:

[0044] Step (1): Add 75% of base oil (accounting for 75% of the total mass of the base oil, and the calculation method of the following raw material addition amount is the same here) into the reactor, then add all the mass of stearic acid, stir and heat to 75-80°C, then add 40% of the mass of carboxylated aluminum oxide, heat to 95-100°C and react for 85-90 minutes.

[0045] Step (2): then raise the temperature to 115-120° C., add 40% by weight of benzoic acid and react for 30-35 minutes, and continue to add the remaining carboxylated aluminum oxide compound and react at 120-125° C. for 65-70 minutes.

[0046] Step (3): then add the remaining benzoic acid and react at 125-130°C for 15-20 minutes, and finally raise the temperature to the highest refining temperature of 195-200°C and keep the temperature constant for 3-5 minutes.

[0047] Step (4): Then cool the mixture to 160-165°C and add the remaining base oil and antioxidant. After the temperature drops below 80°C, add the rust inhibitor, and then homogenize the mixture through a three-roll mill to obtain the final grease product.

[0048] Example 3

[0049] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, and its raw material composition is as follows: 36g of carboxylated aluminum oxide compound, 17.5g of stearic acid, 10.5g of benzoic acid, 926g of paraffin-based mineral oil, 5g of antioxidant, and 5g of rust inhibitor. Among them, FA:BA=1.2:1, TA:AL=1.95:1, and the mass percentage of the thickener is 6.4%.

[0050] This embodiment also provides a method for preparing the above-mentioned composite aluminum-based grease composition, which specifically comprises the following steps:

[0051] Step (1): Add 85% of base oil (accounting for 85% of the total mass of the base oil, the calculation method of the following raw material addition amount is the same here) into the reactor, then add all the mass of stearic acid, stir and heat to 80-85°C, then add 50% of the mass of carboxylated aluminum oxide, heat to 100-105°C and react for 75-80 minutes.

[0052] Step (2): then raise the temperature to 120-125° C., add 50% by weight of benzoic acid and react for 30-35 minutes, and continue to add another 50% by weight of the carboxylated aluminum oxide compound (i.e. the remaining carboxylated aluminum oxide compound) and react at 125-130° C. for 55-60 minutes.

[0053] Step (3): then add another 50% by weight of benzoic acid and react at 135-140° C. for 30-35 minutes, and finally raise the temperature to the highest refining temperature of 200-205° C. and keep it constant for 3-5 minutes.

[0054] Step (4): Then cool the mixture to 155-160°C and add the remaining base oil and antioxidant. After the temperature drops below 80°C, add the rust inhibitor, and then homogenize the mixture through a three-roll mill to obtain the final grease product.

[0055] Example 4

[0056] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, and its raw material composition is as follows: 34.5g of carboxylated aluminum oxide compound, 15g of stearic acid, 10.5g of benzoic acid, 400g of paraffin-based mineral oil, 535g of naphthenic mineral oil, 2g of antioxidant, and 3g of rust inhibitor. Among them, FA:BA=1.1:1, TA:AL=1.94:1, and the mass percentage of thickener is 6%.

[0057] This embodiment also provides a method for preparing the above-mentioned composite aluminum-based grease composition, which specifically comprises the following steps:

[0058] Step (1): Add 75% of base oil (accounting for 75% of the total mass of the base oil, and the calculation method of the following raw material addition amount is the same here) into the reactor, then add all the mass of stearic acid, stir and heat to 85-90° C., then add 40% of the mass of carboxylated aluminum oxide, heat to 105-110° C. and react for 60-65 minutes.

[0059] Step (2): then raise the temperature to 110-115° C., add 60% by weight of benzoic acid and react for 15-20 minutes, and continue to add the remaining carboxylated aluminum oxide compound and react at 115-120° C. for 70-75 minutes.

[0060] Step (3): then add the remaining benzoic acid and react at 125-130°C for 15-20 minutes, and finally raise the temperature to the highest refining temperature of 195-200°C and keep the temperature constant for 3-5 minutes.

[0061] Step (4): Then cool to 150-155°C and add the remaining base oil and antioxidant. After the temperature drops below 80°C, add the rust inhibitor, and then homogenize through a three-roll mill to obtain the final grease product.

[0062] Example 5

[0063] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, and its raw material composition is as follows: 38g of carboxylated aluminum oxide, 17.5g of stearic acid, 11.5g of benzoic acid, 600g of polyalphaolefin synthetic oil, 328g of naphthenic mineral oil, 3g of antioxidant, and 2g of rust inhibitor. Among them, FA:BA=1.1:1, TA:AL=1.98:1, and the mass percentage of thickener is 6.7%.

[0064] This embodiment also provides a method for preparing the above-mentioned composite aluminum-based grease composition, which specifically comprises the following steps:

[0065] Step (1): add 80% of base oil (accounting for 80% of the total mass of the base oil, the calculation method of the following raw material addition amount is the same here) into the reactor, then add all the mass of stearic acid, stir and heat to 75-80°C, then add 60% of the mass of carboxylated aluminum oxide, heat to 100-105°C and react for 80-85 minutes.

[0066] Step (2): then raise the temperature to 125-130° C., add 40% by weight of benzoic acid and react for 25-30 minutes, and continue to add the remaining carboxylated aluminum oxide compound and react at 130-135° C. for 55-60 minutes.

[0067] Step (3): then add the remaining benzoic acid and react at 135-140°C for 25-30 minutes, and finally raise the temperature to the highest refining temperature of 190-195°C and keep it constant for 3-5 minutes.

[0068] Step (4): Then cool the mixture to 160-165°C and add the remaining base oil and antioxidant. After the temperature drops below 80°C, add the rust inhibitor, and then homogenize the mixture through a three-roll mill to obtain the final grease product.

[0069] Example 6

[0070] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, and its raw material composition is as follows: 40.5g of carboxylated aluminum oxide, 19g of stearic acid, 11.5g of benzoic acid, 321g of paraffin-based mineral oil, 600g of polyalphaolefin synthetic oil, 4g of antioxidant, and 4g of rust inhibitor. Among them, FA:BA=1.2:1, TA:AL=1.92:1, and the mass percentage of thickener is 7.1%.

[0071] This embodiment also provides a method for preparing the above-mentioned composite aluminum-based grease composition, which specifically comprises the following steps:

[0072] Step (1): add 85% of base oil (accounting for 85% of the total mass of the base oil, the calculation method of the following raw material addition amount is the same here) into the reactor, then add all the mass of stearic acid, stir and heat to 80-85°C, then add 50% of the mass of carboxylated aluminum oxide, heat to 90-95°C and react for 95-100 minutes.

[0073] Step (2): then raise the temperature to 130-135° C., add 50% by weight of benzoic acid and react for 20-25 minutes, and then continue to add another 50% by weight of carboxylated aluminum oxide and react at 135-140° C. for 50-55 minutes.

[0074] Step (3): then add another 50% by weight of benzoic acid and react at 135-140° C. for 20-25 minutes, and finally raise the temperature to the highest refining temperature of 205-210° C. and keep the temperature constant for 3-5 minutes.

[0075] Step (4): Then cool the mixture to 160-165°C and add the remaining base oil and antioxidant. After the temperature drops below 80°C, add the rust inhibitor, and then homogenize the mixture through a three-roll mill to obtain the final grease product.

[0076] Comparative Example 1

[0077] This comparative example provides a composite aluminum-based grease composition, the raw material composition of which is as follows: 35.5g of carboxylated aluminum oxide compound, 12g of stearic acid, 12.5g of benzoic acid, 300g of paraffin-based mineral oil, 635g of naphthenic mineral oil, 2g of antioxidant, and 3g of rust inhibitor. Among them, FA:BA=0.9:1, TA:AL=1.94:1, and the mass percentage of thickener is 6%.

[0078] The preparation method of the composite aluminum-based grease composition described above specifically comprises the following steps: adding 75% of the base oil (accounting for 75% of the total mass of the base oil, the calculation method of the following raw material addition amount is the same here) into the reactor, then adding all the mass of stearic acid, stirring and heating to 85-90°C, then adding 40% of the mass of the carboxylated aluminum oxide compound, heating to 105-110°C for reaction for 20-25 minutes, then heating to 110-115°C, adding 60% of the mass of benzoic acid and reacting After 15 to 20 minutes, continue to add the remaining carboxylated aluminum oxide compound and react at 115 to 120 ° C for 20 to 25 minutes. Then add the remaining benzoic acid and react at 125 to 130 ° C for 15 to 20 minutes. Finally, raise the temperature to the highest refining temperature of 195 to 200 ° C and keep the temperature for 3 to 5 minutes. Then cool down to 125 ° C and add the remaining base oil and antioxidant. After the temperature drops below 80 ° C, add the rust inhibitor, and then pass through a three-roll mill for homogenization to obtain the final grease product.

[0079] Comparative Example 2

[0080] This comparative example provides a composite aluminum-based grease composition, the raw material composition of which is as follows: 38g of carboxylated aluminum oxide compound, 14g of stearic acid, 13g of benzoic acid, 930g of paraffin-based mineral oil, 2g of antioxidant, and 3g of rust inhibitor. Among them, FA:BA=0.95:1, TA:AL=1.97:1, and the mass percentage of thickener is 6.5%.

[0081] The preparation method of the composite aluminum-based grease composition described above specifically comprises the following steps: adding 75% of the base oil (accounting for 75% of the total mass of the base oil, the calculation method of the following raw material addition amount is the same here) into the reactor, then adding all the mass of stearic acid, stirring and heating to 75-80°C, then adding 40% of the mass of the carboxylated aluminum oxide compound, heating to 105-110°C for reaction for 20-25 minutes, then heating to 115-120°C, adding 60% of the mass of benzoic acid and reacting After 15 to 20 minutes, continue to add the remaining carboxylated aluminum oxide compound and react at 115 to 120 ° C for 20 to 25 minutes, then add the remaining benzoic acid and react at 125 to 130 ° C for 20 to 25 minutes, finally raise the temperature to the highest refining temperature of 195 to 200 ° C and keep the temperature for 3 to 5 minutes, then cool to 125 ° C and add the remaining base oil and antioxidant, add the rust inhibitor after the temperature drops below 80 ° C, and then pass through a three-roll mill for homogenization to obtain the final grease product.

[0082] Comparative Example 3

[0083] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, which is different from Embodiment 1 in that, in step (1), the temperature is raised to 90-95° C. for reaction for 35 minutes, and the rest of the formulation process remains unchanged.

[0084] Comparative Example 4

[0085] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, which is different from Embodiment 1 in that, in step (2), the remaining carboxylated aluminum oxide compound (accounting for 40% of the total amount of carboxylated aluminum oxide compound) is added to react at 115-120°C for 35 minutes, and the rest of the formulation process remains unchanged.

[0086] Comparative Example 5

[0087] This embodiment provides a composite aluminum-based grease composition for a centralized lubrication system, which is different from Embodiment 1 in that, in step (4), the temperature is lowered to 125° C. and the remaining base oil and antioxidant are added, and the rest of the formulation process remains unchanged.

[0088] The results of the analysis and inspection data are shown in Table 1.

[0089] Table 1 Performance evaluation results of the composite aluminum-based grease compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 5

[0090]

[0091] As can be seen from Table 1 above, the data of the oil separation (cone mesh method, 100°C, 24h) and oil separation (pressure filtration method) (40°C, 168h) of the composite aluminum-based grease compositions of Examples 1 to 6 are relatively small, wherein the data of the cone mesh method is less than 2.5%, and the data of the pressure filtration method is less than 6%. However, the data of the comparative examples 1 to 5 which do not use the formulation process of the present invention are relatively large, wherein the data of the cone mesh method is greater than 4%, and the data of the pressure filtration method is greater than 10%. This shows that the composite aluminum-based grease composition of the present invention has good performance under the working conditions of the centralized lubrication system. It has better colloid stability; the results of the difference between the extended working cone penetration (100,000 times) and the working cone penetration show that the difference of the composite aluminum-based grease samples of Examples 1 to 6 is small, less than 30 (0.1 mm), while the data of Comparative Examples 1-5 that do not use the formula and process of the present invention are all large, greater than 40 (0.1 mm), indicating that the composite aluminum-based grease composition of the present invention has better mechanical stability and is not prone to softening and loss due to the mechanical shearing effect of frequent working operations.

[0092] In summary, the composite aluminum-based grease composition prepared by the present invention has better colloidal stability and mechanical stability, can better meet the working requirements of the centralized lubrication system, and can save grease while ensuring good lubrication by extending the greasing interval.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a composite aluminum-based grease composition for a centralized lubrication system, It is characterized in that The steps include: In a part of the base oil, stearic acid and 40%-60% of the total mass of the carboxylated aluminum oxide compound are added to react at 90°C-110°C for 60min-100min; then 40%-60% of the total mass of benzoic acid is added to react at 110°C-140°C for 15min-35min; then the remaining carboxylated aluminum oxide compound is added to react at 110°C-140°C for 50min-80min; the remaining benzoic acid is continued to be added to react at 110°C-140°C for 15min-35min; then the temperature is raised to the refining temperature of 190°C-210°C and kept at a constant temperature for 3min-5min; after refining, the temperature is lowered to 150°C-170°C and then the remaining base oil and additives are added; The raw materials used in the preparation of the grease composition are as follows in parts by weight: 3-4.5 parts of carboxylated aluminum oxide, 1-2.5 parts of stearic acid, 90-95 parts of base oil, and 0.2-1.0 parts of additives; The molecular formula of the carboxylated aluminum oxide compound is shown in the following formula (I): Wherein, R represents the straight chain saturated alkyl group in stearic acid; The carboxylic acid molar ratio of stearic acid to benzoic acid is (1.0-1.3): 1.0; The ratio of the total molar number of carboxylic acid of stearic acid and benzoic acid to the molar number of aluminum element in the carboxylated aluminum oxide compound is (1.9-2.0):1.

0.

2. The preparation method according to claim 1, It is characterized in that The base oil is one or more of paraffin-based mineral oil, naphthenic mineral oil and poly-alpha-olefin synthetic oil.

3. The preparation method according to claim 1, It is characterized in that The kinematic viscosity of the base oil at 100°C is 5 mm 2 / s-35mm 2 / s.

4. The preparation method according to any one of claims 1 to 3, It is characterized in that The additives include antioxidants and rust inhibitors.

5. The preparation method according to claim 4, It is characterized in that The antioxidant is an amine antioxidant, and the rust inhibitor is a sulfonate and / or a long-chain organic carboxylic acid.

6. The preparation method according to claim 5, It is characterized in that The antioxidant is diphenylamine or alkyl diphenylamine; the rust inhibitor is barium sulfonate and / or dodecenylsuccinic acid.

7. The preparation method according to claim 4, It is characterized in that After refining, the remaining base oil and antioxidant are added after the temperature drops to 150℃-170℃, and the rust inhibitor is added after the temperature drops below 80℃.

8. The preparation method according to claim 1, It is characterized in that In the base oil accounting for 75%-90% of the total mass of the base oil, stearic acid is first added and mixed evenly, the temperature is raised to 70° C.-90° C., and then the carboxylated aluminum oxide compound is added and mixed evenly.

9. The preparation method according to claim 1, It is characterized in that After adding the rust inhibitor, a homogenization step is also included.

10. A composite aluminum-based grease composition for a centralized lubrication system, It is characterized in that The preparation method is described in any one of claims 1 to 9.

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