Calcite-type flaky calcium carbonate, grease containing same, and method for preparing same

Abstract

The invention provides a calcite type flaky calcium carbonate grease and a preparation method thereof, and the method is as follows: 20-40 parts of high-alkaline calcium sulfonate, 10-30 parts of an organic solvent and 2-10 parts of distilled water are stirred uniformly at 20-50 DEG C. Then 2-8 parts of a morphology control agent is added, CO2 gas is introduced, and the reaction is carried out for 1-3 hours. Then solid-liquid separation, washing and drying are carried out to obtain a calcium carbonate thickening agent; 20-60 parts of calcium carbonate thickening agent powder, 40-80 parts of base oil are uniformly mixed, and stirring thickening reaction is carried out at 160+ / -10 DEG C for 30-90 minutes, then the temperature is continuously kept at 200+ / -20 DEG C for 10-20 minutes, and after cooling, grinding is carried out, and the calcium carbonate grease is obtained. The method has low cost, simple raw materials and preparation process, stable production batch, and can effectively solve the problems of unstable grease batch, complex preparation process and the like. The calcium carbonate grease prepared by the method has outstanding high-temperature tribological properties, the drop point is higher than 385 DEG C, the shear stability and extreme pressure performance are excellent, and the lubrication requirements under harsh working conditions such as high temperature and high load can be met.

Description

Technical Field

[0001] This invention belongs to the field of lubricating grease technology, specifically relating to a calcite-type flaky calcium carbonate, a lubricating grease containing the same, and a method for preparing the same. Background Technology

[0002] With the advancement of industrial technology and the development of high-performance equipment, the demand for high-temperature greases has increased significantly. For example, in extreme environments such as aerospace, heavy industries such as steel and cement, and precision components such as micro motors and high-speed bearings for drones, the demand for high-temperature greases has increased. These greases are required to maintain stability above 200°C, while also possessing low volatility and long lifespan to prevent high-temperature failure.

[0003] Complex calcium sulfonate grease possesses comprehensive properties including a high dropping point, excellent thermal and oxidative stability, and superior tribological performance (CN103740435A, CN104711080B). Its thickener comprises both calcite-type calcium carbonate microparticles and organic calcium soaps (CN108949328B, CN1414076A). The calcite-type spherical calcium carbonate nanocrystals exhibit significantly higher thermal stability than organic soaps. The addition of organic calcium soaps increases the thickener content, further enhancing the high-temperature performance of the complex calcium sulfonate grease. Currently, while single inorganic rod-shaped calcium carbonate thickeners possess good thickening capabilities, their bonding strength with the base oil is weak, making it difficult for the grease to meet thermal stability standards: at high temperatures, the grease viscosity decreases significantly, increasing fluidity and making it prone to loss during friction, leading to a substantial reduction in tribological performance. Furthermore, the composition of organic-inorganic complex soap-based greases is relatively complex, and process parameters are difficult to control, posing a significant challenge to product manufacturing stability.

[0004] In recent years, researchers have focused on improving thickening processes (CN108949328B, CN108463542A), compounding with lithium-based greases and polyurea greases (CN1414076A), and adding nano-additives (CN101993767A). However, the relationship between the morphology of thickeners and the microstructure of lubricating greases has received little attention. Therefore, it is necessary to find new methods to explore the structure-property relationship between thickener morphology and lubricating grease performance, and to investigate the crucial role of thickener morphology and size in improving the thickening ability and high-temperature performance of lubricating greases, as well as optimizing the overall performance of high-temperature lubricating greases.

[0005] Based on this, this application was developed. Summary of the Invention

[0006] The purpose of this invention is to overcome the deficiencies of existing technologies and provide a calcite-type flaky calcium carbonate and a grease containing it. This grease exhibits batch-to-batch stability, a high dropping point (≥385℃), good colloidal stability (<2.5%), excellent high-temperature tribological properties, and excellent extreme pressure performance (P...). D With the characteristics of ≥7846N, it can solve the problem of grease loss and significant decrease in tribological properties caused by inorganic rod-shaped calcium carbonate grease at high temperatures. It is suitable for harsh working conditions such as high temperature and high load, and has broad application prospects in the field of grease.

[0007] This invention also provides a method for preparing the above-mentioned calcite-type flake calcium carbonate and grease containing it. This method is low-cost, uses simple raw materials and involves simple preparation processes, ensuring stable production batches and effectively solving the problems of unstable batches and complex preparation processes in existing greases. The calcium carbonate grease prepared by this invention exhibits outstanding high-temperature tribological properties, with a dropping point above 385 ℃, and excellent shear stability and extreme pressure performance, meeting the lubrication requirements under harsh conditions such as high temperature and high load.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing calcite-type flaky calcium carbonate includes the following steps: 1) Add high-alkalinity calcium sulfonate, organic solvent and distilled water to a flask and stir and mix evenly at 20-80℃; 2) Then add the morphology modifier, introduce CO2 gas, react for 1-3 h, after the reaction is complete, separate the solid and liquid, wash and dry to obtain the product.

[0009] Specifically, in the above-mentioned method for preparing calcite-type flaky calcium carbonate, the amount of each raw material added is as follows (by weight): 20-40 parts of high-alkali-value calcium sulfonate, 10-30 parts of organic solvent, 2-10 parts of distilled water, and 2-8 parts of morphology modifier.

[0010] Furthermore, in step 1), the total base value of the high-base-value calcium sulfonate is preferably 350-450 mgKOH / g; the organic solvent includes, but is not limited to, one or more of alkanes and cycloalkanes with fewer than 10 carbon atoms, preferably at least one of petroleum ether, n-hexane, n-heptane and cyclohexane.

[0011] Specifically, in step 2), the gas flow rate of carbon dioxide (CO2) can be 0.2-2 L / min.

[0012] Furthermore, in step 2), the morphology modifier includes, but is not limited to, one or more combinations of straight-chain and branched organic alcohols and organic amines with 1-8 carbon atoms. For example, the organic alcohol is preferably at least one of methanol, ethanol, propanol, butanol, pentanol, hexanol, etc.; the organic amine is preferably at least one of methylamine, ethylamine, propylamine, butylamine, pentanol, hexamine, etc.

[0013] This invention provides calcite-type flaky calcium carbonate prepared by the above method.

[0014] The present invention also provides the application of the above-mentioned calcite-type flaky calcium carbonate in the preparation of lubricating grease.

[0015] The present invention also provides a grease comprising, by weight, 20-60 parts of the calcite-type flaky calcium carbonate and 40-80 parts of base oil.

[0016] Furthermore, in the grease, the base oil is one or more of mineral oil and / or synthetic oil, preferably at least one of 150BS, 1200DN, 120ZNZ, etc.; and preferably at least one of PAO40, PAO100, etc.

[0017] The present invention also provides a method for preparing the above-mentioned grease, specifically as follows: take calcite-type flaky calcium carbonate powder and base oil, mix them evenly, stir and thicken the mixture at 160±10℃ for 30-90 min, then continue to keep it at 200±20℃ for 10-20 min, cool it at room temperature, and grind it to obtain the grease.

[0018] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: This invention first reacts high-alkalinity calcium sulfonate with a morphology modifier to prepare a flake-shaped calcium carbonate thickener. This preparation method is simple, low-cost, and suitable for large-scale industrial production. The prepared flake-shaped calcium carbonate thickeners are all in the calcite crystal form. The morphology and size of the calcium carbonate thickener have a significant impact on the performance of the grease. To a certain extent, changing the morphology and size of the calcium carbonate thickener increases its specific surface area, which is beneficial for increasing the adsorbed oil content in the grease structure, extending the capillary oil outflow path, and raising the grease dropping point.

[0019] The calcium carbonate grease prepared by this invention does not contain any alkali, boric acid, dodecyl stearic acid, or other complexing agents. The grease has a low raw material composition and a simple preparation method. Using a pre-processing method, base oil is added to flake calcium carbonate powder, stirred evenly, and then ground using a three-roll mill to obtain the grease. The grease prepared by this invention exhibits batch-to-batch stability, high dropping point (≥385℃), good colloidal stability (<2.5%), excellent high-temperature tribological properties, and excellent extreme pressure performance (P...). DWith the characteristics of ≥7846N, it can solve the problem of grease loss and significant decrease in tribological properties caused by inorganic rod-shaped calcium carbonate grease at high temperatures. It is suitable for harsh working conditions such as high temperature and high load, and has broad application prospects in the field of grease. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a transmission electron microscope (TEM) image of the sheet-like calcium carbonate prepared in Example 1.

[0022] Figure 2 The image shows the XRD pattern of the flaky calcium carbonate prepared in Example 1.

[0023] Figure 3 The high-temperature friction coefficient curves of the grease prepared in Example 1 and the grease in Comparative Example 1 are compared. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the following examples, all raw materials used were commercially available products that could be directly purchased, or could be prepared using conventional techniques in the art. The high-alkalinity calcium sulfonate, with a total base value of 3400 mgKOH / g, model RF1106E, was purchased from Xinxiang Ruifeng New Materials Co., Ltd.

[0026] Unless otherwise specified, in the following examples and comparative examples, the parts mentioned in the raw materials refer to parts by weight, and each part weighs 1 g. Example 1

[0027] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 24 parts of high-alkalinity calcium sulfonate, 16 parts of petroleum ether and 4 parts of distilled water to a flask and stir evenly at 50°C.

[0028] (2) Then add 4 parts of propanol as a morphology modifier, and then introduce CO2 gas (CO2 gas flow rate is 0.5 L / min) and react for 1 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0029] (3) Take 45 parts of calcium carbonate thickener powder and 55 parts of synthetic oil PAO40, mix them evenly, and continue to stir and thicken the mixture at 160℃ for 60 min, and then continue to keep it at 200℃ for 10 min. After cooling at room temperature, grind it three times with a three-roll mill to obtain flake calcium carbonate grease.

[0030] Transmission electron microscopy images of the prepared calcium carbonate grease are shown below. Figure 1 .Depend on Figure 1 It can be seen that the prepared calcium carbonate grease thickener is in the form of flakes, about 185 nm long and about 15 nm thick.

[0031] The XRD pattern of the prepared calcium carbonate grease is shown in the figure. Figure 2 .from Figure 2 As can be seen from the data, the flaky calcium carbonate thickener is in the calcite crystal form and has no other crystal forms. Example 2

[0032] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 30 parts of high-alkalinity calcium sulfonate, 20 parts of petroleum ether and 3 parts of distilled water to a flask and stir evenly at 50°C.

[0033] (2) Then add 4 parts of morphology modifier pentanol, and then pass CO2 gas (CO2 gas flow rate is 0.8 L / min) and react for 2 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0034] (3) Take 40 parts of calcium carbonate thickener powder and 60 parts of mineral oil 150BS, mix them evenly, and continue to stir and thicken at 160℃ for 60 min, then continue to keep warm at 200℃ for 10 min. After cooling at room temperature, grind three times with a three-roll mill to obtain flake calcium carbonate grease. Example 3

[0035] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 20 parts of high-alkalinity calcium sulfonate, 16 parts of petroleum ether and 4 parts of distilled water to a flask and stir evenly at 80°C.

[0036] (2) Then add 5 parts of morphology modifier methanol, and then pass CO2 gas (CO2 gas flow rate is 1 L / min) and react for 1 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0037] (3) Take 40 parts of calcium carbonate thickener powder and 60 parts of mineral oil 1200DN, mix them evenly, and continue to stir and thicken the mixture at 160℃ for 60 min, and then continue to keep it at 200℃ for 10 min. After cooling at room temperature, grind it three times with a three-roll mill to obtain flake calcium carbonate grease. Example 4

[0038] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 35 parts of high-alkalinity calcium sulfonate, 30 parts of n-hexane and 8 parts of distilled water to a flask and stir evenly at 60°C.

[0039] (2) Then add 2 parts of hexanol as a morphology modifier, and then pass CO2 gas (CO2 gas flow rate is 0.8 L / min) and react for 1 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0040] (3) Take 35 parts of calcium carbonate thickener powder and 65 parts of synthetic oil PAO40, mix them evenly, and continue to stir and thicken at 160℃ for 60 min, then continue to keep warm at 200℃ for 10 min. After cooling at room temperature, grind three times with a three-roll mill to obtain flake calcium carbonate grease. Example 5

[0041] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 40 parts of high-alkalinity calcium sulfonate, 30 parts of petroleum ether and 6 parts of distilled water to a flask and stir evenly at 50 °C.

[0042] (2) Then add 3 parts of morphology modifier ethanol, and then pass CO2 gas (CO2 gas flow rate is 1 L / min) and react for 1 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0043] (3) Take 55 parts of calcium carbonate thickener powder and 45 parts of synthetic oil PAO100, mix them evenly, and continue to stir and thicken at 160℃ for 60 min, then continue to keep warm at 200℃ for 10 min. After cooling at room temperature, grind three times with a three-roll mill to obtain flake calcium carbonate grease. Example 6

[0044] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 20 parts of high-alkalinity calcium sulfonate, 10 parts of n-heptane and 4 parts of distilled water to a flask and stir evenly at 20 °C.

[0045] (2) Then add 5 parts of morphology modifier methanol, and then introduce CO2 gas (CO2 gas flow rate is 1 L / min) and react for 2 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0046] (3) Take 50 parts of calcium carbonate thickener powder and 50 parts of mineral oil 150BS, mix them evenly, and continue to stir and thicken at 160℃ for 60 min, then continue to keep warm at 200℃ for 10 min. After cooling at room temperature, grind it 3 times with a three-roll mill to obtain flake calcium carbonate grease. Example 7

[0047] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 24 parts of high-alkalinity calcium sulfonate, 16 parts of cyclohexane and 5 parts of distilled water to a flask and stir evenly at 50°C.

[0048] (2) Then add 8 parts of morphology modifier methanol, and then introduce CO2 gas (CO2 gas flow rate is 1.5 L / min) and react for 1 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0049] (3) Take 25 parts of calcium carbonate thickener powder and 75 parts of synthetic oil PAO100, mix them evenly, and continue to stir and thicken at 160℃ for 60 min, then continue to keep warm at 200℃ for 10 min. After cooling at room temperature, grind three times with a three-roll mill to obtain flake calcium carbonate grease. Example 8

[0050] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 38 parts of high-alkalinity calcium sulfonate, 30 parts of petroleum ether and 8 parts of distilled water to a flask and stir evenly at 80 °C.

[0051] (2) Then add 8 parts of morphology modifier methanol, and then introduce CO2 gas (CO2 gas flow rate is 2 L / min) and react for 3 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0052] (3) Take 50 parts of calcium carbonate thickener powder and 50 parts of synthetic oil PAO40, mix them evenly, and continue to stir and thicken the mixture at 160℃ for 60 min, and then continue to keep it at 200℃ for 10 min. After cooling at room temperature, grind it three times with a three-roll mill to obtain flake calcium carbonate grease. Example 9

[0053] A method for preparing a calcite-type flake calcium carbonate grease, comprising the following steps: (1) Add 30 parts of high-alkalinity calcium sulfonate, 30 parts of n-heptane and 10 parts of distilled water to a flask and stir evenly at 80 °C.

[0054] (2) Then add 6 parts of morphology modifier pentanol, and then pass CO2 gas (CO2 gas flow rate is 1.2 L / min) and react for 1 h. Then centrifuge, wash twice with petroleum ether, and dry to obtain calcium carbonate thickener.

[0055] (3) Take 55 parts of calcium carbonate thickener powder and 45 parts of mineral oil 150BS, mix them evenly, and continue to stir and thicken at 160℃ for 60 min, then continue to keep warm at 200℃ for 10 min. After cooling at room temperature, grind it 3 times with a three-roll mill to obtain flake calcium carbonate grease.

[0056] Comparative Example 1

[0057] A method for preparing a rod-shaped calcium carbonate grease, comprising the following steps: (1) Add 60g of distilled water to 3.7g of calcium hydroxide, stir evenly at 20℃, then add 0.025g of citric acid, pass carbon dioxide gas through, and react for 1h.

[0058] (2) After the carbonation reaction is completed, the temperature is raised to 80 °C, 0.15 g of calcium stearate is added, the reaction is stirred for 1 hour, the reaction is stopped, the solvent and impurities are removed and dried to obtain calcium carbonate powder.

[0059] (3) Take 25 parts of calcium carbonate powder and 75 parts of base oil, mix them evenly, and grind them three times with a three-roll mill to obtain rod-shaped calcium carbonate grease.

[0060] The performance indicators of the grease samples prepared in Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0061] Table 1 Performance indicators of the grease samples prepared in Examples 1-3 and Comparative Example 1

[0062] As can be seen from Table 1, the grease prepared by this invention generally has a significantly higher dropping point (above 385 °C), exhibiting excellent high-temperature performance. Combined with... Figure 1 The transmission images show that the calcium carbonate thickeners are all in flake form, with a maximum length of 200 nm and an average thickness of 15 nm, and have a large aspect ratio (1-40). Therefore, they can easily form a stable three-dimensional structure in the grease, resulting in a high dropping point and a low oil separation rate. Figure 2 As can be seen, the prepared calcium carbonate is in the calcite crystal form.

[0063] Figure 3The high-temperature friction coefficient curves of the greases prepared in Example 1 and Comparative Example 1 are presented. As can be seen from the figure, at a high temperature of 150 °C, the friction coefficient of the grease prepared in Example 1 is relatively stable, remaining around 0.09. However, the rod-shaped calcium carbonate grease prepared in Comparative Example 1 experienced grease loss during friction, causing the friction coefficient to increase sharply after 2000 s.

[0064] In summary, the calcite-type flake calcium carbonate grease described in this invention has a high dropping point (≥385℃), good colloidal stability (<2.5%), excellent high-temperature tribological properties, and excellent extreme pressure performance (P). D With the characteristics of ≥7846N, it can solve the problem of grease loss and significant decrease in tribological properties caused by inorganic rod-shaped calcium carbonate grease at high temperatures. It is suitable for harsh working conditions such as high temperature and high load, and has broad application prospects in the field of grease.

Claims

1. A method for preparing calcite-type flaky calcium carbonate, characterized in that, Includes the following steps: 1) Mix high-alkalinity calcium sulfonate, organic solvent, and distilled water thoroughly at 20-80℃; 2) Then add the morphology modifier, introduce CO2 gas, react for 1-3 h, after the reaction is complete, separate the solid and liquid, wash and dry to obtain the product.

2. The method for preparing calcite-type platy calcium carbonate as described in claim 1, characterized in that, By weight, the ingredients are: 20-40 parts high-alkalinity calcium sulfonate, 10-30 parts organic solvent, 2-10 parts distilled water, and 2-8 parts morphology modifier.

3. The method for preparing calcite-type platy calcium carbonate as described in claim 1, characterized in that, In step 1), the total alkalinity of the high-alkalinity calcium sulfonate is 350-450 mgKOH / g; the organic solvent is one or more alkanes or cycloalkanes with fewer than 10 carbon atoms.

4. The method for preparing calcite-type platy calcium carbonate as described in claim 1, characterized in that, In step 2), the CO2 gas flow rate is 0.2-2 L / min.

5. The method for preparing calcite-type platy calcium carbonate as described in claim 1, characterized in that, In step 2), the morphology modifier is one or more of straight-chain and branched organic alcohols and organic amines with 1-8 carbon atoms.

6. Calcite-type flaky calcium carbonate prepared by any one of the methods described in claims 1 to 5.

7. The use of the calcite-type flaky calcium carbonate of claim 6 in the preparation of lubricating grease.

8. A lubricating grease, characterized in that, The product comprises, by weight, 20-60 parts of the calcite-type flaky calcium carbonate as described in claim 6 and 40-80 parts of base oil.

9. The lubricating grease as described in claim 8, characterized in that, The base oil is one or more of mineral oils and / or synthetic oils.

10. The method for preparing the lubricating grease according to claim 8 or 9, characterized in that, Take calcite-type flaky calcium carbonate powder and base oil, mix them evenly, stir and thicken at 160±10℃ for 30-90 min, then continue to keep warm at 200±20℃ for 10-20 min, cool at room temperature, and grind to obtain the final product.

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