A modified complex calcium sulfonate grease and a method for preparing the same

Abstract

The application belongs to the technical field of lubricating grease, and specifically provides a modified composite calcium sulfonate lubricating grease and a preparation method thereof. The modified composite calcium sulfonate lubricating grease comprises the following raw materials: base oil, calcium sulfonate, a conversion agent, a saponifying agent, a composite additive and an antioxidant. The composite additive is prepared by compounding modified boron nitride nanosheets, modified attapulgite and nano zinc oxide. The conversion agent comprises dodecylbenzenesulfonic acid, 12-hydroxystearic acid and acetic acid. The saponifying agent comprises 12-hydroxystearic acid, calcium hydroxide and boric acid. The modified composite calcium sulfonate lubricating grease prepared by the application has the advantages of good water resistance, wear resistance and self-repairing property.

Description

Technical Field

[0001] This application belongs to the field of lubricating grease technology, and in particular relates to a modified complex calcium sulfonate lubricating grease and its preparation method. Background Technology

[0002] Grease is a type of lubricant, primarily produced by thickening base oil from a semi-fluid state to a solid state using a thickener. Calcium sulfonate grease, as a high-efficiency lubricant, possesses excellent high-temperature performance, load-bearing capacity, mechanical stability, extreme pressure anti-wear properties, colloidal stability, and rust and corrosion resistance, making it widely used in the steel, automotive, mining, textile, and food industries. However, when used in the presence of water, calcium sulfonate grease exhibits high water absorption and increased viscosity, affecting its lubrication effect and posing a potential risk of lubrication failure. Furthermore, its high soap content results in a higher coefficient of friction than other types of grease, and conventional friction-reducing additives are ineffective, failing to meet practical application requirements.

[0003] To address the above issues, current methods for improving the friction reduction and water resistance of calcium sulfonate greases mainly involve improving the thickening process, adding additives, and controlling the morphology of the calcium sulfonate thickener. For example, patent application CN109135888A discloses a composite calcium sulfonate-based grease and its preparation method. This application uses base oil, high-alkalinity calcium sulfonate, composite conversion agent, low molecular weight acid A, low molecular weight acid B, and dodecyl stearic acid as base components, and adds high molecular weight polymers as structure improvers and nanomaterials such as nano-calcium carbonate as anti-wear agents to obtain a composite calcium sulfonate-based grease, which improves the water erosion resistance, high temperature performance, and mechanical stability of the composite calcium sulfonate-based grease.

[0004] The aforementioned document describes the use of added polymers and nanomaterials to improve the structural strength and stability of the complex calcium sulfonate-based grease. However, its water resistance mainly depends on the hydrophobicity and structural stability of the material itself. Under extreme conditions such as heavy water flushing or high-pressure spraying, its water resistance may be significantly weakened, leading to grease structure damage and the risk of lubrication failure. Summary of the Invention

[0005] To address the aforementioned issues and further improve the water resistance, wear resistance, and self-healing properties of lubricating grease, this application provides a modified composite calcium sulfonate lubricating grease and its preparation method.

[0006] This application first provides a modified complex calcium sulfonate grease, comprising the following raw materials: base oil, calcium sulfonate, conversion agent, saponifying agent, complex additive and antioxidant;

[0007] The composite additive is prepared by combining modified boron nitride nanosheets, modified attapulgite, and nano zinc oxide.

[0008] The conversion agent includes dodecylbenzenesulfonic acid, 12-hydroxystearic acid, and acetic acid;

[0009] The saponifying agent includes 12-hydroxystearic acid, calcium hydroxide, and boric acid.

[0010] Furthermore, the preparation method of the composite additive includes the following steps: A1, modified boron nitride nanosheets are mixed with modified attapulgite dispersion, and after hydrothermal reaction, centrifugation, washing, and drying are performed to obtain a boron nitride nanosheet-attapulgite-fumed silica composite system; A2, the boron nitride nanosheet-attapulgite-fumed silica composite system is ultrasonically dispersed in ethanol and mixed with nano zinc oxide to obtain the final product.

[0011] Furthermore, in A1, the mass ratio of modified boron nitride nanosheets to modified attapulgite is (1-3):1.

[0012] Furthermore, in A2, the amount of nano zinc oxide added is 10-25 wt% of the boron nitride nanosheet-attapulgite-fumed silica composite system.

[0013] Furthermore, the preparation method of the modified boron nitride nanosheets includes the following steps: B1, DL-menthol reacts with acetic acid to obtain a hydrophobic eutectic solvent; B2, hexagonal boron nitride and the hydrophobic eutectic solvent are ultrasonicated, washed, and dried to obtain boron nitride nanosheets; B3, boron nitride nanosheets are mixed with fumed silica at room temperature to obtain modified boron nitride nanosheets.

[0014] Furthermore, in B3, the amount of fumed silica added is 0.5-1 wt% of boron nitride nanosheets.

[0015] Furthermore, the method for preparing the modified attapulgite includes the following steps: attapulgite and hexadecyltrimethylammonium bromide are reacted in deionized water by stirring to obtain modified attapulgite.

[0016] Furthermore, this application provides a method for preparing modified complex calcium sulfonate grease, comprising the following steps: S1, taking a portion of base oil, calcium sulfonate and a conversion agent to carry out a conversion reaction to obtain a conversion product; S2, adding a saponifying agent to the conversion product and stirring at a constant temperature to obtain a saponified product; S3, heating and dehydrating the saponified product, adding an antioxidant, stirring and heating to refine, then adding the remaining base oil for adjustment, cooling and adding composite additives, and grinding to obtain the final product.

[0017] Furthermore, in S1, the mass ratio of calcium sulfonate to base oil is (1.1-1.3):1.

[0018] Furthermore, in S3, the amount of the composite additive added is 5-10 wt% of the modified composite calcium sulfonate grease.

[0019] Compared with the prior art, this application has the following beneficial effects:

[0020] The layered structure of boron nitride nanosheets can form a lubrication transfer film on the friction contact surface, reducing frictional resistance. After modification with hexadecyltrimethylammonium bromide, the modified attapulgite has more hydrophobic groups on its surface, which can effectively block water penetration to enhance water resistance. Its rod-like structure can also repair pitting, ploughing, and plastic deformation on the worn surface, reducing additional wear caused by surface roughness and improving the structural stability of the grease. Fumed silica has a high specific surface area and abundant silanol groups on its surface. Attaching it to the surface of boron nitride nanosheets can inhibit the aggregation of boron nitride nanosheets and strengthen the bond with modified attapulgite, improving the overall dispersibility of the composite additive. Nano zinc oxide and excess 12-hydroxystearic acid in the system form hydrophobic micro-nano clusters in situ, giving the composite additive a hydrophobic layer and enhancing water resistance. At the same time, the long chain of 12-hydroxystearic acid can improve the compatibility of the composite in the modified calcium sulfonate grease. The combination of these four factors can effectively reduce the friction coefficient of the modified calcium sulfonate grease and improve its water resistance and self-healing ability. Attached Figure Description

[0021] Figure 1 The images show SEM images of the composite additive, with the left side showing Comparative Example 1 and the right side showing Example 2. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only” is used, in which case another component may be added.

[0025] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0026] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0027] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0028] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0029] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0030] Example 1

[0031] The preparation method of the modified complex calcium sulfonate grease in this embodiment is as follows:

[0032] S1. Add 80g of base oil (model 150BS) to the reactor, then add 158.4g of calcium sulfonate (high-base-value petroleum calcium sulfonate, model T106), stir and heat until the temperature reaches 50℃, then add 19.1g of dodecylbenzene sulfonic acid, stir for 10min, and raise the temperature to 60℃; add 1.6g of acetic acid and 4.8g of water, and slowly add them to the container while stirring, and keep the temperature constant for 3h.

[0033] S2, then control the temperature, add 74g of 12-hydroxystearic acid, raise the temperature to 100℃, stir until the system no longer thickens, then add 24g of calcium hydroxide aqueous emulsion (composed of 8.5g calcium hydroxide and 15.5g water), stir at constant temperature for 30min; add 11.2g of boric acid aqueous solution (composed of 2.3g boric acid and 8.9g water), stir at constant temperature for 30min.

[0034] S3, after saponification, heat to 150℃ for dehydration for 40 minutes, add 0.8g of diphenylamine, keep warm and stir for 1 hour, thicken into fat, heat to 200℃ and refine for 5 minutes, then add 64g of base oil (model 150BS), stir and cool to 70℃, add compound additives, stir continuously to fully integrate, and after cooling to room temperature, grind 2-3 times through a three-roll mill to obtain the final product.

[0035] The preparation method of the composite additive in this embodiment is as follows:

[0036] A1. Take 10g of modified boron nitride nanosheets and add them to a dispersion containing 10g of modified attapulgite. Add 150mL of deionized water and stir at 60℃ for 12h. Then, transfer the mixture to a stainless steel high-pressure reactor lined with Teflon and carry out a hydrothermal reaction at 220℃ for 24h to promote interfacial chemical bonding through a high-temperature and high-pressure environment. After the reaction is completed, allow it to cool naturally to room temperature and centrifuge the product (8000-10000rpm, 10min). Wash the product 3-5 times alternately with deionized water and anhydrous ethanol. Dry the washed product at 60℃ for 24h to obtain the boron nitride nanosheet-attapulgite-fumed silica composite.

[0037] A2, the boron nitride nanosheet-attapulgite-fumed silica composite was ultrasonically dispersed in an ethanol solution to obtain a composite suspension. 2g of hydrophilic nano ZnO powder was slowly added to the continuously stirred composite suspension, and the mixture was magnetically stirred at 60℃ for 6h.

[0038] The preparation method of the modified boron nitride nanosheets in this embodiment is as follows:

[0039] B1, DL-menthol as hydrogen bond acceptor (HBA), acetic acid as hydrogen bond donor (HBD), 16.7g HBA and 3.2g HBD are mixed in a beaker and heated and stirred at 60°C until a homogeneous, transparent and stable solution is formed, which is the hydrophobic eutectic solvent.

[0040] B2, take 20g of hydrophobic eutectic solvent, add 5g of hexagonal boron nitride to it, sonicate for 6h, set the ultrasonic power to 200W, work for 5s, pause for 1s; after sonication, centrifuge the suspension to remove unpeeled h-BN, collect the supernatant; centrifuge the supernatant, wash the precipitate with ethanol and centrifuge several times, and dry at 60℃ for 24h to obtain boron nitride nanosheet powder.

[0041] B3, weigh out 5g of boron nitride nanosheets and 25mg of fumed silica (specific surface area 150m²). 2 Add both (g) to a double cone mixer and mix at room temperature for 2 hours (30-50 rpm) to uniformly adhere the fumed silica powder to the surface of the boron nitride nanosheets, thus obtaining modified boron nitride nanosheets.

[0042] The method for preparing the modified attapulgite in this embodiment is as follows:

[0043] Weigh 3.6g of attapulgite (325 mesh) and 1.44g of hexadecyltrimethylammonium bromide, add them to 100mL of deionized water, and stir until completely dispersed. Place the mixed solution in a 60℃ constant temperature water bath and mechanically stir for 12h to allow hexadecyltrimethylammonium bromide to be adsorbed onto the surface of attapulgite through electrostatic or hydrophobic interactions, thus obtaining modified attapulgite.

[0044] Example 2

[0045] The preparation method of the modified complex calcium sulfonate grease in this embodiment is as follows:

[0046] S1. Add 80g of base oil (model 150BS) to the reactor, then add 172.8g of calcium sulfonate (high-base-value petroleum calcium sulfonate, model T106), stir and heat until the temperature reaches 50℃, then add 19.1g of dodecylbenzene sulfonic acid, stir for 10min, and raise the temperature to 60℃; add 1.6g of acetic acid and 4.8g of water, and slowly add them to the container while stirring, and keep the temperature constant for 3h.

[0047] S2, then control the temperature, add 74g of 12-hydroxystearic acid, raise the temperature to 100℃, stir until the system no longer thickens, then add 24g of calcium hydroxide aqueous emulsion (composed of 8.5g calcium hydroxide and 15.5g water), stir at constant temperature for 30min; add 11.2g of boric acid aqueous solution (composed of 2.3g boric acid and 8.9g water), stir at constant temperature for 30min.

[0048] S3, after saponification, heat to 150℃ for dehydration for 40 minutes, add 0.8g of diphenylamine, keep warm and stir for 1 hour, thicken into fat, heat to 200℃ and refine for 5 minutes, then add 64g of base oil (model 150BS), stir and cool to 70℃, add compound additives, stir continuously to fully integrate, and after cooling to room temperature, grind 2-3 times through a three-roll mill to obtain the final product.

[0049] The preparation method of the composite additive in this embodiment is as follows:

[0050] A1. Take 8.3g of modified boron nitride nanosheets and add them to a dispersion containing 16.7g of modified attapulgite. Add 150mL of deionized water and stir at 60℃ for 12h. Then, transfer the mixture to a stainless steel high-pressure reactor lined with Teflon and carry out a hydrothermal reaction at 220℃ for 24h to promote interfacial chemical bonding through a high-temperature and high-pressure environment. After the reaction is completed, cool naturally to room temperature and centrifuge the product (8000-10000rpm, 10min). Wash the product 3-5 times alternately with deionized water and anhydrous ethanol. Dry the washed product at 60℃ for 24h to obtain the boron nitride nanosheet-attapulgite-fumed silica composite.

[0051] A2, the boron nitride nanosheet-attapulgite-fumed silica composite was ultrasonically dispersed in an ethanol solution to obtain a composite suspension. 3.75g of hydrophilic nano ZnO powder was slowly added to the continuously stirred composite suspension, and the mixture was magnetically stirred at 60℃ for 6h.

[0052] The preparation method of the modified boron nitride nanosheets in this embodiment is as follows:

[0053] B1, DL-menthol as hydrogen bond acceptor (HBA), acetic acid as hydrogen bond donor (HBD), 16.7g HBA and 3.2g HBD are mixed in a beaker and heated and stirred at 60°C until a homogeneous, transparent and stable solution is formed, which is the hydrophobic eutectic solvent.

[0054] B2, take 20g of hydrophobic eutectic solvent, add 5g of hexagonal boron nitride to it, sonicate for 6h, set the ultrasonic power to 200W, work for 5s, pause for 1s; after sonication, centrifuge the suspension to remove unpeeled h-BN, collect the supernatant; centrifuge the supernatant, wash the precipitate with ethanol and centrifuge several times, and dry at 60℃ for 24h to obtain boron nitride nanosheet powder.

[0055] B3, weigh out 5g of boron nitride nanosheets and 37.5mg of fumed silica (specific surface area 150m²). 2Add both (g) to a double cone mixer and mix at room temperature for 2 hours (30-50 rpm) to uniformly adhere the fumed silica powder to the surface of the boron nitride nanosheets, thus obtaining modified boron nitride nanosheets.

[0056] The method for preparing the modified attapulgite in this embodiment is as follows:

[0057] Weigh 3.6g of attapulgite (325 mesh) and 1.44g of hexadecyltrimethylammonium bromide, add them to 100mL of deionized water, and stir until completely dispersed. Place the mixed solution in a 60℃ constant temperature water bath and mechanically stir for 12h to allow hexadecyltrimethylammonium bromide to be adsorbed onto the surface of attapulgite through electrostatic or hydrophobic interactions, thus obtaining modified attapulgite.

[0058] Example 3

[0059] The preparation method of the modified complex calcium sulfonate grease in this embodiment is as follows:

[0060] S1. Add 80g of base oil (model 150BS) to the reactor, then add 187.2g of calcium sulfonate (high-base-value petroleum calcium sulfonate, model T106), stir and heat until the temperature reaches 50℃, then add 19.1g of dodecylbenzene sulfonic acid, stir for 10min, and raise the temperature to 60℃; add 1.6g of acetic acid and 4.8g of water, and slowly add them to the container while stirring, and keep the temperature constant for 3h.

[0061] S2, then control the temperature, add 74g of 12-hydroxystearic acid, raise the temperature to 100℃, stir until the system no longer thickens, then add 24g of calcium hydroxide aqueous emulsion (composed of 8.5g calcium hydroxide and 15.5g water), stir at constant temperature for 30min; add 11.2g of boric acid aqueous solution (composed of 2.3g boric acid and 8.9g water), stir at constant temperature for 30min.

[0062] S3, after saponification, heat to 150℃ for dehydration for 40 minutes, add 0.8g of diphenylamine, keep warm and stir for 1 hour, thicken into fat, heat to 200℃ and refine for 5 minutes, then add 64g of base oil (model 150BS), stir and cool to 70℃, add compound additives, stir continuously to fully integrate, and after cooling to room temperature, grind 2-3 times through a three-roll mill to obtain the final product.

[0063] The preparation method of the composite additive in this embodiment is as follows:

[0064] A1. Take 7.5g of modified boron nitride nanosheets and add them to a dispersion containing 22.5g of modified attapulgite. Add 150mL of deionized water and stir at 60℃ for 12h. Then, transfer the mixture to a stainless steel high-pressure reactor lined with Teflon and carry out a hydrothermal reaction at 220℃ for 24h to promote interfacial chemical bonding through a high-temperature and high-pressure environment. After the reaction is completed, cool naturally to room temperature and centrifuge the product (8000-10000rpm, 10min). Wash the product 3-5 times alternately with deionized water and anhydrous ethanol. Dry the washed product at 60℃ for 24h to obtain the boron nitride nanosheet-attapulgite-fumed silica composite.

[0065] A2, the boron nitride nanosheet-attapulgite-fumed silica composite was ultrasonically dispersed in an ethanol solution to obtain a composite suspension. 6g of hydrophilic nano-ZnO powder was slowly added to the continuously stirred composite suspension, and the mixture was magnetically stirred at 60℃ for 6h.

[0066] The preparation method of the modified boron nitride nanosheets in this embodiment is as follows:

[0067] B1, DL-menthol as hydrogen bond acceptor (HBA), acetic acid as hydrogen bond donor (HBD), 16.7g HBA and 3.2g HBD are mixed in a beaker and heated and stirred at 60°C until a homogeneous, transparent and stable solution is formed, which is the hydrophobic eutectic solvent.

[0068] B2, take 20g of hydrophobic eutectic solvent, add 5g of hexagonal boron nitride to it, sonicate for 6h, set the ultrasonic power to 200W, work for 5s, pause for 1s; after sonication, centrifuge the suspension to remove unpeeled h-BN, collect the supernatant; centrifuge the supernatant, wash the precipitate with ethanol and centrifuge several times, and dry at 60℃ for 24h to obtain boron nitride nanosheet powder.

[0069] B3, weigh out 5g of boron nitride nanosheets and 45mg of fumed silica (specific surface area 150m²). 2 Add both (g) to a double cone mixer and mix at room temperature for 2 hours (30-50 rpm) to uniformly adhere the fumed silica powder to the surface of the boron nitride nanosheets, thus obtaining modified boron nitride nanosheets.

[0070] The method for preparing the modified attapulgite in this embodiment is as follows:

[0071] Weigh 3.6g of attapulgite (325 mesh) and 1.44g of hexadecyltrimethylammonium bromide, add them to 100mL of deionized water, and stir until completely dispersed. Place the mixed solution in a 60℃ constant temperature water bath and mechanically stir for 12h to allow hexadecyltrimethylammonium bromide to be adsorbed onto the surface of attapulgite through electrostatic or hydrophobic interactions, thus obtaining modified attapulgite.

[0072] Comparative Example 1

[0073] The preparation method of the modified complex calcium sulfonate grease in this comparative example is as follows:

[0074] S1. Add 80g of base oil (model 150BS) to the reactor, then add 172.8g of calcium sulfonate (high-base-value petroleum calcium sulfonate, model T106), stir and heat until the temperature reaches 50℃, then add 19.1g of dodecylbenzene sulfonic acid, stir for 10min, and raise the temperature to 60℃; add 1.6g of acetic acid and 4.8g of water, and slowly add them to the container while stirring, and keep the temperature constant for 3h.

[0075] S2, then control the temperature, add 74g of 12-hydroxystearic acid, raise the temperature to 100℃, stir until the system no longer thickens, then add 24g of calcium hydroxide aqueous emulsion (composed of 8.5g calcium hydroxide and 15.5g water), stir at constant temperature for 30min; add 11.2g of boric acid aqueous solution (composed of 2.3g boric acid and 8.9g water), stir at constant temperature for 30min.

[0076] S3, after saponification, heat to 150℃ for dehydration for 40 minutes, add 0.8g of diphenylamine, keep warm and stir for 1 hour, thicken into fat, heat to 200℃ and refine for 5 minutes, then add 64g of base oil (model 150BS), stir and cool to 70℃, add compound additives, stir continuously to fully integrate, and after cooling to room temperature, grind 2-3 times through a three-roll mill to obtain the final product.

[0077] The preparation method of the composite additive in this comparative example is as follows:

[0078] B1, DL-menthol as hydrogen bond acceptor (HBA), acetic acid as hydrogen bond donor (HBD), 16.7g HBA and 3.2g HBD are mixed in a beaker and heated and stirred at 60°C until a homogeneous, transparent and stable solution is formed, which is the hydrophobic eutectic solvent.

[0079] B2, take 20g of hydrophobic eutectic solvent, add 5g of hexagonal boron nitride to it, sonicate for 6h, set the ultrasonic power to 200W, work for 5s, pause for 1s; after sonication, centrifuge the suspension to remove unpeeled h-BN, collect the supernatant; centrifuge the supernatant, wash the precipitate with ethanol and centrifuge several times, and then dry it at 60℃ for 24h to obtain the product.

[0080] Comparative Example 2

[0081] The preparation method of the modified complex calcium sulfonate grease in this comparative example is as follows:

[0082] S1. Add 80g of base oil (model 150BS) to the reactor, then add 172.8g of calcium sulfonate (high-base-value petroleum calcium sulfonate, model T106), stir and heat until the temperature reaches 50℃, then add 19.1g of dodecylbenzene sulfonic acid, stir for 10min, and raise the temperature to 60℃; add 1.6g of acetic acid and 4.8g of water, and slowly add them to the container while stirring, and keep the temperature constant for 3h.

[0083] S2, then control the temperature, add 74g of 12-hydroxystearic acid, raise the temperature to 100℃, stir until the system no longer thickens, then add 24g of calcium hydroxide aqueous emulsion (composed of 8.5g calcium hydroxide and 15.5g water), stir at constant temperature for 30min; add 11.2g of boric acid aqueous solution (composed of 2.3g boric acid and 8.9g water), stir at constant temperature for 30min.

[0084] S3, after saponification, heat to 150℃ for dehydration for 40 minutes, add 0.8g of diphenylamine, keep warm and stir for 1 hour, thicken into fat, heat to 200℃ and refine for 5 minutes, then add 64g of base oil (model 150BS), stir and cool to 70℃, add compound additives, stir continuously to fully integrate, and after cooling to room temperature, grind 2-3 times through a three-roll mill to obtain the final product.

[0085] The preparation method of the composite additive in this comparative example is as follows:

[0086] A1. Take 8.3g of modified boron nitride nanosheets and add them to a dispersion containing 16.7g of modified attapulgite. Add 150mL of deionized water and stir at 60℃ for 12h. Then, transfer the mixture to a stainless steel high-pressure reactor lined with Teflon and carry out a hydrothermal reaction at 220℃ for 24h to promote interfacial chemical bonding through a high-temperature and high-pressure environment. After the reaction is completed, allow it to cool naturally to room temperature and centrifuge the product (8000-10000rpm, 10min). Wash the product 3-5 times alternately with deionized water and anhydrous ethanol. Dry the washed product at 60℃ for 24h to obtain the composite additive.

[0087] The preparation method of the modified boron nitride nanosheets in this comparative example is as follows:

[0088] B1, DL-menthol as hydrogen bond acceptor (HBA), acetic acid as hydrogen bond donor (HBD), 16.7g HBA and 3.2g HBD are mixed in a beaker and heated and stirred at 60°C until a homogeneous, transparent and stable solution is formed, which is the hydrophobic eutectic solvent.

[0089] B2, take 20g of hydrophobic eutectic solvent, add 5g of hexagonal boron nitride to it, sonicate for 6h, set the ultrasonic power to 200W, work for 5s, pause for 1s; after sonication, centrifuge the suspension to remove unpeeled h-BN, collect the supernatant; centrifuge the supernatant, wash the precipitate with ethanol and centrifuge several times, and dry at 60℃ for 24h to obtain boron nitride nanosheet powder.

[0090] B3, weigh out 5g of boron nitride nanosheets and 37.5mg of fumed silica (specific surface area 150m²). 2 Add both (g) to a double cone mixer and mix at room temperature for 2 hours (30-50 rpm) to uniformly adhere the fumed silica powder to the surface of the boron nitride nanosheets, thus obtaining modified boron nitride nanosheets.

[0091] The modified attapulgite in this comparative example is prepared by the following method:

[0092] Weigh 3.6g of attapulgite (325 mesh) and 1.44g of hexadecyltrimethylammonium bromide, add them to 100mL of deionized water, and stir until completely dispersed. Place the mixed solution in a 60℃ constant temperature water bath and mechanically stir for 12h to allow hexadecyltrimethylammonium bromide to be adsorbed onto the surface of attapulgite through electrostatic or hydrophobic interactions, thus obtaining modified attapulgite.

[0093] Performance testing

[0094] Working cone penetration test: According to GB / T 269—2023 standard, the modified complex calcium sulfonate grease (24℃) was tested after 60 reciprocating cycles in the grease working instrument, and the cone penetration value was read and recorded.

[0095] Dropping point test: Tested according to GB / T 3498—2008 standard, record the temperature of the thermometer and the aluminum block furnace when one drop of modified complex calcium sulfonate grease falls from the grease cup into the test tube, and calculate the temperature to an accuracy of 1℃.

[0096] Stencil oil separation test: According to the NB / SH / T 0324—2010 standard, the modified complex calcium sulfonate grease sample is loaded into the stencil, and the loaded stencil oil separator is placed in a constant temperature chamber at 100℃ for 24 hours. The oil separation volume is then weighed and calculated.

[0097] Copper sheet corrosion test: According to GB / T 7326—1987 standard, the polished copper sheet was completely immersed in the modified composite calcium sulfonate grease sample at 100℃ for 24 hours, and the copper sheet was observed to show any green or black changes.

[0098] Water resistance test: According to the SH / T 0109-2004 standard, 4±0.05g of modified complex calcium sulfonate grease sample was loaded into the ball bearing, the ball bearing was installed in the bearing sleeve, the bearing speed was maintained at 600r / min, the water temperature was 79±2℃, the water flow rate was 5±0.5mL / s, and it was run for 1h. After drying, it was weighed.

[0099] Wear resistance test: Tested according to SH / T 0204-1992 standard, temperature: 75℃, spindle speed: 1200r / min, load: 392N, test time: 60min, measure the wear mark diameter of three steel balls and calculate the average wear mark diameter.

[0100] Table 1. Performance test results of the modified calcium sulfonate greases in Examples 1-3 and Comparative Examples 1-2

[0101]

[0102] Analysis of Examples 1-3 and Comparative Examples 1-2, combined with Tables 1-3, shows that by dispersing boron nitride nanosheets in fumed silica and connecting them with attapulgite, and simultaneously preparing a superhydrophobic layer in situ with nano-zinc oxide and excess 12-hydroxystearic acid, the modified composite calcium sulfonate grease exhibits good water resistance, wear resistance, and self-healing properties. The modified composite calcium sulfonate grease prepared in Comparative Example 1, compared to Examples 1-3, only added boron nitride nanosheets, lacking a composite structure and superhydrophobic layer. The nanomaterials were prone to agglomeration, resulting in poor stability of the modified composite calcium sulfonate grease. Consequently, the water leaching, wear scar diameter, and copper mesh oil separation of the modified composite calcium sulfonate grease in Comparative Example 1 increased significantly. The modified composite calcium sulfonate grease prepared in Comparative Example 2, compared to Examples 1-3, did not add nano-zinc oxide, failing to form a superhydrophobic layer and reducing water resistance. Consequently, the water leaching of the modified composite calcium sulfonate grease in Comparative Example 2 increased significantly.

[0103] The SEM morphology of the composite additives prepared in Example 2 and Comparative Example 1 was observed and analyzed, and the results are as follows: Figure 1 As shown. From Figure 1 As can be seen, compared to the only sheet-like structure in Comparative Example 1, the composite additive in Example 2 is composed of modified attapulgite and modified boron nitride nanosheets connected by fumed silica. It can be seen that the fibrous and sheet-like structures are tightly connected, which improves the stability and functionality of the composite additive.

[0104] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A modified composite calcium sulfonate grease, characterized in that, The ingredients include: base oil, calcium sulfonate, conversion agent, saponifying agent, compound additives, and antioxidants; The conversion agent includes dodecylbenzenesulfonic acid, 12-hydroxystearic acid, and acetic acid; The saponifying agent includes 12-hydroxystearic acid, calcium hydroxide, and boric acid; The preparation method of the composite additive includes the following steps: A1, modified boron nitride nanosheets are mixed with modified attapulgite dispersion, and after hydrothermal reaction, they are centrifuged, washed, and dried to obtain a boron nitride nanosheet-attapulgite-fumed silica composite system; A2, the boron nitride nanosheet-attapulgite-fumed silica composite system is ultrasonically dispersed in ethanol and mixed with nano zinc oxide to obtain the composite additive. The method for preparing the modified boron nitride nanosheets includes the following steps: B1, DL-menthol reacts with acetic acid to obtain a hydrophobic eutectic solvent; B2, hexagonal boron nitride and the hydrophobic eutectic solvent are ultrasonicated, washed, and dried to obtain boron nitride nanosheets; B3, boron nitride nanosheets are mixed with fumed silica at room temperature to obtain modified boron nitride nanosheets. The method for preparing the modified attapulgite includes the following steps: attapulgite and hexadecyltrimethylammonium bromide are reacted in deionized water by stirring to obtain the modified attapulgite.

2. The modified composite calcium sulfonate grease according to claim 1, characterized in that, In A1, the mass ratio of modified boron nitride nanosheets to modified attapulgite is (1-3):

1.

3. The modified composite calcium sulfonate grease according to claim 1, characterized in that, In A2, the amount of nano zinc oxide added is 10-25 wt% of the boron nitride nanosheet-attapulgite-fumed silica composite system.

4. The modified composite calcium sulfonate grease according to claim 1, characterized in that, In B3, the amount of fumed silica added is 0.5-1 wt% of boron nitride nanosheets.

5. A method for preparing the modified complex calcium sulfonate grease as described in any one of claims 1-4, characterized in that, The process includes the following steps: S1, taking a portion of base oil, calcium sulfonate and conversion agent to carry out conversion reaction to obtain conversion product; S2, adding saponifying agent to conversion product and stirring at constant temperature to obtain saponified product; S3, heating and dehydrating saponified product, adding antioxidant, stirring and heating to refine, then adding the remaining base oil for adjustment, cooling and adding compound additives, and grinding to obtain the final product.

6. The method for preparing a modified composite calcium sulfonate grease according to claim 5, characterized in that, In S1, the mass ratio of calcium sulfonate to base oil is (1.1-1.3):

1.

7. The method for preparing a modified composite calcium sulfonate grease according to claim 5, characterized in that, In S3, the amount of composite additive added is 5-10 wt% of the modified composite calcium sulfonate grease.

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