An efficient anti-foaming agent for high-temperature harsh environments, its preparation method and applications

Abstract

The present application discloses a high-efficiency antifoaming agent for high-temperature harsh environments, a preparation method thereof, and an application, belonging to the technical field of antifoaming agents. The antifoaming agent of the present application comprises nano-SiO2 and a polyisooctyl acrylate-vinyl acetate polymer chain grafted onto the nano-SiO2; the preparation method thereof comprises: after cleaning and surface activation of the nano-SiO2 to prepare activated nano-SiO2, reacting the activated nano-SiO2, polyisooctyl acrylate, vinyl acetate and an initiator in a reaction solvent, and after the reaction, filtering the reaction solution, and successively washing and drying the filtered product to obtain the product. The antifoaming agent of the present application can maintain excellent defoaming performance in high-temperature environments, and can efficiently eliminate oil foam especially in high-temperature environments of 180-260 °C, and the antifoaming agent of the present application is insoluble in oil and does not affect the physical and chemical properties of the oil.

Description

Technical Field

[0001] This application belongs to the technical field of defoamers, and particularly relates to a high-efficiency anti-foaming agent for high-temperature harsh environments, a preparation method thereof, and an application thereof. Background Art

[0002] With the extensive application of synthetic oils in some high-temperature harsh environments, the related research and development of high-efficiency anti-foaming agents for high-temperature harsh environments are very necessary. At present, nano-SiO2 can be well used for defoaming oils in high-temperature harsh environments and is considered a high-performance defoaming agent that can be used in high-temperature harsh environments. However, since nano-SiO2 is an inorganic nanoparticle, its compatibility with some oils is poor and it is prone to agglomeration.

[0003] To solve the problems of poor compatibility between nano-SiO2 and oils and easy agglomeration, in related technologies, organic assistants such as dodecyltrimethoxysilane (WD-10) and perfluorooctanesulfonyl fluoride (PFOSF) can be used to carry out surface graft modification on nano-SiO2.

[0004] However, the existing surface-grafted modified nano-SiO2 has the following problems in practical applications: First, the grafted organic matter has a large pollution and high cost, which is not conducive to popularization and application; second, the nano-SiO2 surface-grafted with organic matter is prone to oxidation failure at high temperatures; third, the nano-SiO2 surface-grafted with organic matter is easily soluble in oils, which not only causes oil pollution but also reduces the oil properties. Summary of the Invention

[0005] The purpose of this application is to provide a high-efficiency anti-foaming agent for high-temperature harsh environments, a preparation method thereof, and an application thereof, aiming to solve the technical problems that the existing grafted organic matter-modified nano-SiO2 is prone to oxidation failure in high-temperature environments and is prone to cause a decline in oil properties.

[0006] To achieve the above purpose, the technical solution of this application is as follows:

[0007] The first aspect of this application provides a high-efficiency anti-foaming agent for high-temperature harsh environments, and the high-efficiency anti-foaming agent for high-temperature harsh environments includes nano-SiO2 and a polyisooctyl acrylate-vinyl acetate polymer chain grafted on the nano-SiO2.

[0008] In a preferred implementation, the particle size of the nano-SiO2 is 10-50 nm.

[0009] The second aspect of this application provides a preparation method of the high-efficiency anti-foaming agent for high-temperature harsh environments according to the first aspect, and the method includes the following steps:

[0010] Clean and surface-activate nano-SiO2 in sequence to obtain activated nano-SiO2;

[0011] React the activated nano-SiO₂ with isooctyl acrylate, vinyl acetate, and an initiator in a reaction solvent;

[0012] After the reaction, filter the reaction solution, and wash and dry the filtered product in sequence to obtain the high-efficiency antifoaming agent for high-temperature harsh environments.

[0013] In a preferred implementation, the cleaning of the nano-SiO₂ includes:

[0014] Use deionized water as a cleaning agent to perform a first cleaning of the nano-SiO₂ under ultrasonic oscillation; and,

[0015] Use a 0.1% H₂O₂ aqueous solution as a cleaning agent to perform a second cleaning of the nano-SiO₂ under ultrasonic oscillation.

[0016] In a preferred implementation, the surface activation of the nano-SiO₂ includes:

[0017] Subject the nano-SiO₂ to low-temperature annealing at a temperature of 50-200 °C.

[0018] In a preferred implementation, when the activated nano-SiO₂ reacts with isooctyl acrylate, vinyl acetate, and an initiator in a reaction solvent, the mass ratio of the isooctyl acrylate, the vinyl acetate, and the initiator is 5:4.8:0.2.

[0019] In a preferred implementation, the reaction is carried out under nitrogen protection, and the temperature of the reaction is 50-70 °C.

[0020] In a preferred implementation, the sequential washing of the filtered product includes:

[0021] Rinse the filtered product with toluene, ethanol, and deionized water in sequence.

[0022] The third aspect of this application also provides the application of the high-efficiency antifoaming agent for high-temperature harsh environments described in the first aspect in defoaming lubricating oil, hydraulic oil, and antifreeze.

[0023] In a preferred implementation, the addition amount of the high-efficiency antifoaming agent for high-temperature harsh environments in lubricating oil, hydraulic oil, and antifreeze is not greater than 0.1 g / L.

[0024] Compared with the prior art, the advantages or beneficial effects of this application at least include:

[0025] The high-efficiency antifoaming agent for high-temperature harsh environments provided by the first aspect of the present application, through the compounding of the contained nano-SiO2 with the high molecular chain of isooctyl acrylate-vinyl acetate and its graft modification, on the one hand, significantly improves the compatibility between nano-SiO2 and the oil product, effectively solves the problem of easy agglomeration of nano-SiO2 in the oil product, and polymerizes and modifies with isooctyl acrylate and vinyl acetate as raw material monomers, effectively reducing the pollution and cost in the preparation process, which is conducive to popularization and application; on the other hand, through the compounding and graft modification described above, it can effectively enhance the antioxidant performance of the antifoaming agent, enabling the obtained antifoaming agent to maintain excellent defoaming performance in high-temperature harsh environments, so that the elimination of oil product foam can be efficiently achieved in high-temperature harsh environments of 180-260 °C; thirdly, the antifoaming agent obtained through the compounding and graft modification described above is insoluble in the oil product, does not affect the physical and chemical properties of the oil product, and can ensure the inherent performance of the oil product. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 SEM diagram of the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments provided by the embodiment of the present application;

[0028] Figure 2 Comparison of defoaming effects between the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments provided by the embodiment of the present application and nano-SiO2;

[0029] Figure 3 Comparison of defoaming effects between the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments provided by the embodiment of the present application and the EHA / VAC antifoaming agent. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0031] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and the situation where A and B exist simultaneously. Where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0032] In the following description of this embodiment, the term "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or its similar expressions refer to any combination of these items, including any combination of single item(s) or plural item(s). For example, "at least one of a, b, or c", or, "at least one of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or plural respectively.

[0033] In the following description of this embodiment, terms such as "grafting" and "isooctyl acrylate - vinyl acetate polymer chain" are understood according to their general meanings in the art. For example, grafting refers to the reaction state in which the isooctyl acrylate - vinyl acetate polymer chain is bonded to nano - SiO₂ through chemical bonds; the isooctyl acrylate - vinyl acetate polymer chain refers to a chain - like molecule formed by connecting isooctyl acrylate monomers and vinyl acetate monomers through polycondensation or addition polymerization reactions.

[0034] Those skilled in the art should understand that in the following description of the embodiments of this application, the sequence numbers do not mean the sequence of execution. Some or all steps can be executed in parallel or sequentially, and the execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0035] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms "a" and "the" used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0036] In a first aspect, an embodiment of this application provides a high - efficiency anti - foaming agent for high - temperature harsh environments. The high - efficiency anti - foaming agent for high - temperature harsh environments includes nano - SiO₂ and an isooctyl acrylate - vinyl acetate polymer chain grafted onto the nano - SiO₂.

[0037] Among them, through the mutual compounding and graft modification of the contained nano-SiO₂ and the polymer chains of isooctyl acrylate-vinyl acetate, on the one hand, the compatibility between nano-SiO₂ and the oil product is significantly improved, effectively solving the problem of easy agglomeration of nano-SiO₂ in the oil product. And by using isooctyl acrylate and vinyl acetate as raw material monomers for polymerization modification, the pollution and cost in the preparation process are effectively reduced, which is convenient for popularization and application. On the other hand, through the compounding and graft modification described above, the antioxidant performance of the antifoaming agent can be effectively enhanced, enabling it to maintain excellent defoaming performance under high-temperature and harsh environments, so that efficient elimination of oil product foam can be achieved under high-temperature and harsh environments of 180-260°C. Thirdly, the antifoaming agent obtained through the compounding and graft modification described above is insoluble in the oil product and will not affect the physical and chemical properties of the oil product, and can ensure the inherent performance of the oil product.

[0038] In some embodiments, the particle size of nano-SiO₂ is preferably 10-50 nm to suit the viscosity of different application materials. Among them, different particle sizes can be selected according to the application materials with different viscosities. For example, when used in lubricating oil, the particle size of nano-SiO₂ is not more than 50 nm; when used in hydraulic oil, the particle size of nano-SiO₂ is not more than 30 nm; when used in antifreeze, the particle size of nano-SiO₂ is not more than 20 nm.

[0039] Secondly, the embodiments of the present application provide a preparation method of a high-efficiency antifoaming agent for use in the high-temperature and harsh environment described in the first aspect. The method includes:

[0040] Clean and surface-activate nano-SiO₂ in sequence to obtain activated nano-SiO₂;

[0041] React the activated nano-SiO₂ with isooctyl acrylate, vinyl acetate, and an initiator in a reaction solvent;

[0042] After the reaction, filter the reaction solution, and wash and dry the filtered product in sequence to obtain the high-efficiency antifoaming agent for the high-temperature and harsh environment.

[0043] Among them, the preparation method of the embodiments of the present application can enable isooctyl acrylate and vinyl acetate to effectively carry out a polymerization reaction on the surface of nano-SiO₂, so that the surface of nano-SiO₂ is uniformly and regularly grafted with polymer chains of isooctyl acrylate and vinyl acetate. On the one hand, it improves the compatibility between nano-SiO₂ and various oil products and solves the problem of easy agglomeration of nano-SiO₂ in the oil product. On the other hand, it can effectively improve the problem that the polymer chains of isooctyl acrylate and vinyl acetate are easily oxidized and inactivated under high-temperature environments, so that the obtained antifoaming agent can maintain excellent defoaming ability under high-temperature and harsh environments of 180-260°C.

[0044] In specific embodiments, the method for cleaning nano-SiO₂ preferably includes:

[0045] Using deionized water as a cleaning agent, perform the first cleaning of nano-SiO₂ under ultrasonic oscillation; and,

[0046] Using a 0.1% H₂O₂ aqueous solution as a cleaning agent, perform the second cleaning of the nano-SiO₂ under ultrasonic oscillation.

[0047] Among them, the first cleaning uses deionized water as a cleaning agent for ultrasonic oscillation, which can effectively remove the water-soluble impurities attached to the surface of nano-SiO₂; the second cleaning uses a 0.1% H₂O₂ aqueous solution as a cleaning agent for ultrasonic oscillation, which can effectively remove the oily impurities attached to the surface of nano-SiO₂. Therefore, through the combined use of the first cleaning and the second cleaning, the impurities on the surface of nano-SiO₂ are completely removed, avoiding the intervention of impurity components in the subsequent polymerization reaction and ensuring the grafting purity of the isooctyl acrylate-vinyl acetate polymer chain.

[0048] In a specific embodiment, the surface activation of nano-SiO₂ preferably includes: performing low-temperature annealing treatment on nano-SiO₂ at a temperature of 50-200 °C. Among them, performing low-temperature annealing treatment on nano-SiO₂ can activate the hydroxyl groups on the surface of nano-SiO₂, thereby facilitating the grafting and loading of the isooctyl acrylate-vinyl acetate polymer chain.

[0049] In a specific embodiment, when reacting activated nano-SiO₂ with isooctyl acrylate, vinyl acetate, and an initiator in a reaction solvent, the mass ratio of isooctyl acrylate, vinyl acetate, and the initiator is 5:4.8:0.2. Among them, this ratio helps to achieve a good degree of grafting chemical reaction and ensures that the grafting rate reaches more than 90%.

[0050] In a specific embodiment, it is preferably to carry out the reaction under nitrogen protection, and the reaction temperature is preferably 50-70 °C. Among them, carrying out the reaction under nitrogen protection can avoid oxidation and ensure the purity of the isooctyl acrylate-vinyl acetate polymer chain; carrying out the reaction at a temperature of 50-70 °C not only facilitates the progress of the polymerization reaction but also can avoid oxidation and the occurrence of harmful side reactions.

[0051] In a specific embodiment, the sequential washing of the filtered product includes: rinsing the filtered product successively with toluene, ethanol, and deionized water. Among them, rinsing with toluene can effectively remove the unreacted substances and ensure the product purity; rinsing with ethanol can effectively remove the toluene solvent containing impurities and avoid the mixing of toluene solvent into the product; deionized water is used to remove the ethanol containing impurities. Through the combined use of toluene, ethanol, and deionized water, the impurities in the product can be effectively removed, thereby ensuring the purity of the product.

[0052] Thirdly, the embodiments of the present application also provide an application of the high-efficiency antifoaming agent for high-temperature harsh environments in the first aspect in defoaming lubricating oil, hydraulic oil, and antifreeze. Among them, considering that the high-efficiency antifoaming agent for high-temperature harsh environments in the first aspect has the advantages of excellent oil compatibility and strong defoaming ability in high-temperature environments, after the high-efficiency antifoaming agent for high-temperature harsh environments is used for defoaming treatment of lubricating oil, hydraulic oil, and antifreeze, it can effectively eliminate the foam in the oil products or avoid the generation of foam in the oil products.

[0053] In a specific embodiment, the addition amount of the high-efficiency antifoaming agent for high-temperature harsh environments in lubricating oil, hydraulic oil, and antifreeze is preferably not more than 0.1 g / L. Among them, by controlling the addition amount of the high-efficiency antifoaming agent for high-temperature harsh environments in lubricating oil, hydraulic oil, and antifreeze to be not more than 0.1 g / L, the dosage of the additive can be reduced on the premise of avoiding agglomeration, and the foam in the oil products can be effectively eliminated on the premise of the lowest cost and the least impact on the oil product performance.

[0054] Example 1

[0055] This example provides a preparation method of a high-efficiency antifoaming agent YB-1 for high-temperature harsh environments, which specifically includes the following steps S101-S106:

[0056] S101: Using deionized water as a cleaning agent, ultrasonically oscillate and clean the nano-SiO2 with a particle size of 50 nm for 10 min, filter out the water, and repeat the cleaning 2-3 times according to the cleanliness of the water;

[0057] S102: Using 0.1% H2O2 aqueous solution as a cleaning agent, ultrasonically oscillate and clean the nano-SiO2 after the cleaning in step S101, filter out the cleaning agent, and repeat the cleaning 2-3 times according to the cleanliness of the cleaning agent;

[0058] S103: After putting the nano-SiO2 after the cleaning in step S102 into a vacuum oven, perform low-temperature annealing at a temperature of 200 °C for 10-20 min, take it out and cool it to obtain activated nano-SiO2;

[0059] S104: Put 100 g of activated nano-SiO2 into a 1000 mL round-bottom flask, and successively add 10 g of isooctyl acrylate (analytical pure), 9.6 g of vinyl acetate (analytical pure), and 0.4 g of benzoyl peroxide (analytical pure) initiator, and then add 500 mL of toluene (analytical pure) as a reaction solvent to obtain a reaction system; carry out a polymerization reaction on the reaction system at a temperature of 70 °C for 8 h, wherein, nitrogen is introduced for protection during the polymerization reaction (flow rate: 20 mL / min);

[0060] S105: After the reaction is completed, filter the reaction solution, and after rinsing the filtered product successively with 20 mL of toluene (analytical grade), 20 mL of ethanol (analytical grade), and 20 mL of deionized water, place it in a vacuum oven at 70 °C for drying to obtain the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments.

[0061] Example 2

[0062] This example provides a preparation method of a high-efficiency antifoaming agent YB-2 for high-temperature harsh environments, specifically including the following steps S101 - S106:

[0063] S101: Use deionized water as a cleaning agent to ultrasonically oscillate and clean the nano-SiO₂ with a particle size of 30 nm for 10 min, filter out the water, and repeat the cleaning 2 - 3 times according to the cleanliness of the water.

[0064] S102: Use 0.1% H₂O₂ aqueous solution as a cleaning agent to ultrasonically oscillate and clean the nano-SiO₂ after being cleaned in step S101, filter out the cleaning agent, and repeat the cleaning 2 - 3 times according to the cleanliness of the cleaning agent.

[0065] S103: After putting the nano-SiO₂ cleaned in step S102 into a vacuum oven, perform low-temperature annealing at a temperature of 120 °C for 10 - 20 min, take it out and cool it to obtain activated nano-SiO₂.

[0066] S104: Put 100 g of activated nano-SiO₂ into a 1000 mL round-bottom flask, and successively add 20 g of isooctyl acrylate (analytical grade), 19.2 g of vinyl acetate (analytical grade), and 0.8 g of benzoyl peroxide (analytical grade) initiator, then add 500 mL of toluene (analytical grade) as a reaction solvent to obtain a reaction system; carry out a polymerization reaction on the reaction system at a temperature of 60 °C for 10 h, wherein nitrogen is introduced for protection during the polymerization reaction (flow rate: 20 mL / min).

[0067] S105: After the reaction is completed, filter the reaction solution, and after rinsing the filtered product successively with 20 mL of toluene (analytical grade), 20 mL of ethanol (analytical grade), and 20 mL of deionized water, place it in a vacuum oven at 60 °C for drying to obtain the high-efficiency antifoaming agent YB-2 for high-temperature harsh environments.

[0068] Example 3

[0069] This example provides a preparation method of a high-efficiency antifoaming agent YB-3 for high-temperature harsh environments, specifically including the following steps S101 - S106:

[0070] S101: Use deionized water as a cleaning agent, ultrasonically oscillate and clean nano - SiO₂ with a particle size of 20 nm for 10 min, filter out the moisture, and repeat the cleaning 2 - 3 times according to the cleanliness of the moisture.

[0071] S102: Use 0.1% H₂O₂ aqueous solution as a cleaning agent, ultrasonically oscillate and clean the nano - SiO₂ after the cleaning in step S101, filter out the cleaning agent, and repeat the cleaning 2 - 3 times according to the cleanliness of the cleaning agent.

[0072] S103: Put the nano - SiO₂ after the cleaning in step S102 into a vacuum oven, perform low - temperature annealing at 80 °C for 10 - 20 min, take it out and cool it to obtain activated nano - SiO₂.

[0073] S104: Put 100 g of activated nano - SiO₂ into a 1000 mL round - bottom flask, and successively add 30 g of isooctyl acrylate (analytical pure), 28.8 g of vinyl acetate (analytical pure) and 1.2 g of benzoyl peroxide (analytical pure) initiator, then add 500 mL of toluene (analytical pure) as a reaction solvent to obtain a reaction system; carry out a polymerization reaction on the reaction system at 50 °C for 12 h, and during the polymerization reaction, introduce nitrogen for protection (flow rate: 20 mL / min).

[0074] S105: After the reaction is completed, filter the reaction solution, and successively rinse the filtered product with 20 mL of toluene (analytical pure), 20 mL of ethanol (analytical pure), and 20 mL of deionized water, then place it in a vacuum oven at 50 °C to dry, and obtain the high - efficiency anti - foaming agent YB - 3 for high - temperature harsh environments.

[0075] To verify the technical effects of the high - efficiency anti - foaming agent for high - temperature harsh environments, this application conducts structural characterization and performance testing on the high - efficiency anti - foaming agent YB - 1 prepared in the example, specifically including:

[0076] 1.1 SEM characterization

[0077] Conduct SEM characterization on the high - efficiency anti - foaming agent YB - 1 for high - temperature harsh environments, and the results are Figure 1 as shown. Among them, Figure 1 shows the SEM of the high - efficiency anti - foaming agent YB - 1 for high - temperature harsh environments.

[0078] According to Figure 1 it can be known that the high - efficiency anti - foaming agent YB - 1 for high - temperature harsh environments is a spherical structure, and the size distribution is uniform, which is beneficial to dispersion and lubrication in oil products.

[0079] 1.2 Defoaming performance test

[0080] Using Mobil thermal oil (model: MobilTherm 603) as the heat conduction medium, the high-temperature foam characteristics of the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments, nano-SiO2 (50 nm), and the antifoaming agent of isooctyl acrylate-vinyl acetate (EHA / VAC) were measured. The specific method includes:

[0081] Dry air with a flow rate of 200 ± 5 mL / min was introduced into 200 mL of PAO4 base oil containing the above antifoaming agents respectively (the oil product was placed in a 1000 mL graduated cylinder) through a 5 μm porous stainless steel diffuser head. After 5 minutes, the air supply was stopped, and the foam volume was read using the scale of the graduated cylinder. The results are Figures 2-3 as shown. Among them, Figure 2 shows the comparison of the defoaming effects between the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments and nano-SiO2 (SiO2-P); Figure 3 shows the comparison of the defoaming effects between the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments and the EHA / VAC antifoaming agent.

[0082] According to Figure 2 it can be known that under the harsh working conditions with a temperature of 180 - 260 °C, the foam volume of the PAO4 base oil containing the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments is always much smaller than that of the PAO4 base oil containing nano-SiO2, indicating that the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments has better high-temperature defoaming performance than nano-SiO2.

[0083] According to Figure 3 it can be known that under the harsh working conditions with a temperature of 180 - 260 °C, the foam volume of the PAO4 base oil containing the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments is always much smaller than that of the PAO4 base oil containing the EHA / VAC antifoaming agent, indicating that the high-efficiency antifoaming agent YB-1 for high-temperature harsh environments has better high-temperature defoaming performance than the EHA / VAC antifoaming agent.

[0084] To sum up, through the compounding and modification of the contained nano-SiO2 and the high molecular chain of isooctyl acrylate-vinyl acetate, the high-efficiency antifoaming agent prepared in the embodiment of the present application, on the one hand, significantly improves the compatibility between nano-SiO2 and the oil product, effectively improves the problem of nano-SiO2 agglomeration in the oil product, and polymerizes and modifies with isooctyl acrylate and vinyl acetate as monomers, reducing the pollution and cost in the preparation process, which is conducive to popularization and application; on the other hand, it can enhance the antioxidant performance while improving the defoaming performance at high temperatures, enabling the defoaming agent to efficiently eliminate the oil product foam under the high-temperature working conditions of 180 - 260 °C; on the third hand, the antifoaming agent is insoluble in the oil product and can only be dispersed in the oil product, thus not affecting the physical and chemical properties of the oil product and ensuring the inherent performance of the oil product.

[0085] The various embodiments in this specification are described in a progressive manner. For the same or similar parts among the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments.

[0086] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. An efficient anti-foaming agent for high-temperature harsh environments, characterized in that, It includes nano-SiO2 and the polyisooctyl acrylate-vinyl acetate polymer chain grafted on the nano-SiO2.

2. The high-efficiency anti-foaming agent for high-temperature harsh environments according to claim 1, wherein The particle size of the nano-SiO2 is 10-50 nm.

3. A preparation method of an efficient anti-foaming agent for high-temperature harsh environments according to claim 1, characterized in that, It includes: Clean and surface-activate the nano-SiO2 in sequence to obtain activated nano-SiO2; React the activated nano-SiO2 with isooctyl acrylate, vinyl acetate, and initiator in a reaction solvent; After the reaction, filter the reaction solution, and wash and dry the filtered product in sequence to obtain the high-efficiency antifoaming agent for high-temperature harsh environments.

4. The preparation method according to claim 3, wherein The cleaning of the nano-SiO2 includes: Use deionized water as the cleaning agent to conduct the first cleaning of the nano-SiO2 under ultrasonic oscillation; and, Use 0.1% H2O2 aqueous solution as the cleaning agent to conduct the second cleaning of the nano-SiO2 under ultrasonic oscillation.

5. The preparation method according to claim 3, wherein, The surface activation of the nano-SiO2 includes: Anneal the nano-SiO2 at a temperature of 50-200 °C for low-temperature annealing.

6. The preparation method according to claim 3, characterized in that, When the activated nano-SiO2 reacts with isooctyl acrylate, vinyl acetate, and initiator in a reaction solvent, the mass ratio of the isooctyl acrylate, the vinyl acetate, and the initiator is 5:4.8:0.

2.

7. The preparation method according to claim 3, characterized in that, Conduct the reaction under nitrogen protection, and the temperature of the reaction is 50-70 °C.

8. The preparation method according to claim 3, characterized in that, The sequential washing of the filtered product includes: Rinse the filtered product with toluene, ethanol, and deionized water in sequence.

9. Application of the high-efficiency antifoaming agent for high-temperature harsh environments according to claim 1 in defoaming treatment of lubricating oil, hydraulic oil, and antifreeze.

10. The application according to claim 9, characterized in that, The addition amount of the high-efficiency antifoaming agent for high-temperature harsh environments in lubricating oil, hydraulic oil, and antifreeze is not more than 0.1 g / L.

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