A recyclable impregnant and a method for its preparation

Abstract

The application discloses a recyclable impregnating agent and a preparation method thereof, and belongs to the technical field of preparation of acrylate type impregnating agents. The recyclable impregnating agent comprises 50-60 parts of a monofunctional acrylate monomer, 25-35 parts of a bifunctional acrylate monomer, 2-4 parts of a trifunctional acrylate monomer, 10-15 parts of vinyl-modified nano-silica, 0.1-0.2 parts of a polymerization inhibitor and 0.3-0.8 parts of an initiator. The vinyl-modified nano-silica is obtained by modifying nano-silica with a vinyl silane coupling agent or an alkenyl alcohol, has strong hydrophobicity, has excellent surface activity function, can efficiently and rapidly separate the impregnating agent from cleaning water, is easy to clean and has high recovery rate. Meanwhile, the vinyl on the surface of the silica can be subjected to a polymerization reaction with a methacrylate monomer, so that the heat-cured product has high hardness, good elasticity, low volume shrinkage and high heat resistance, and therefore has excellent reinforcing effect on metal castings.

Description

Technical Field

[0001] This invention relates to the field of acrylate impregnation agent preparation technology, specifically to a recyclable impregnation agent and its preparation method, and more specifically to a highly efficient recyclable methacrylate impregnation agent with low shrinkage and high temperature resistance. Background Technology

[0002] All die-cast products must possess excellent airtightness. However, during the casting process, castings inevitably develop porosity, cracks, and sand holes, making it difficult to meet the equipment's sealing requirements. If no remedial measures are taken, the casting must be remelted, resulting in a huge waste of manpower, material resources, and financial resources. Currently, the most effective measure to remedy these defects in die-cast parts is to inject an impregnating agent into the leaking holes through vacuum impregnation. After heat curing, the impregnating agent can bond with the inner wall of the pores, thereby achieving the purpose of sealing leaks and reinforcement, allowing castings that are about to be scrapped to be recycled.

[0003] Acrylic ester vacuum impregnating agents have gradually replaced inorganic impregnating agents due to their advantages such as low viscosity, high temperature resistance, and environmental friendliness, and are now the preferred impregnating agents in this field. After impregnation with acrylic ester impregnating agents, the impregnating agent remaining on the surface of the casting is usually removed by high-pressure water washing. In addition to a large amount of monomers, the wastewater also contains emulsifiers, surfactants, chelating agents, and other organic substances that are difficult to biodegrade. Direct discharge of this wastewater not only wastes the impregnating agent, but also requires corresponding equipment and processes for subsequent treatment to meet wastewater discharge standards, which undoubtedly increases production costs.

[0004] Utilizing the hydrophobicity of acrylates and the density difference between them and water, they can be effectively separated from water and recycled. This not only improves raw material utilization and saves costs but also minimizes environmental pollution. Therefore, developing recyclable acrylate vacuum impregnation agents has become the mainstream direction in this field. Key indicators for evaluating recyclable impregnation agents include ease of washing and removal with water, and ease of separation from water to achieve a high recovery rate. Currently, recyclable impregnation agents typically achieve effective separation and recycling from water through the rational use of surfactants and separating agents.

[0005] CN114773537A discloses a highly recyclable impregnation sealing material, which is made of materials with a density of less than 1 g / cm³. 3 The patent comprises monofunctional and polyfunctional acrylate monomers, initiators, polymerization inhibitors, and surfactants. It also describes the preparation of a biodegradable surfactant formed by the high-temperature polycondensation of sodium diethyl isophthalate sulfonate, maleic anhydride, polyethylene glycol, aliphatic diamines, and aliphatic diacids. This surfactant possesses both emulsifying and cleaning-aiding functions, effectively improving the recycling efficiency of impregnated sealing materials.

[0006] CN117987042A discloses a recyclable impregnation sealing material and its preparation method. The material uses alkylbenzene ring compounds to graft and modify organic peroxides, making them into low-polarity mixtures that are easy to separate from water. While having anaerobic reactivity at room temperature, it can also recover other components and acrylate monomers simultaneously.

[0007] CN120173169A discloses a low-leakage, recyclable acrylate impregnation sealant, which is composed of monofunctional and difunctional acrylates, an initiator, a polymerization inhibitor, a stabilizer, and a surfactant. The surfactant is prepared by grafting and modifying a nonionic surfactant with acrylate, exhibiting properties such as low leakage and easy cleaning.

[0008] Although existing recyclable acrylate-based organic impregnating agents can achieve easy washing and separation from water and obtain a high recovery rate, the surfactants are usually used in large quantities and cannot participate in the polymerization reaction of acrylate monomers. During thermosetting, they are prone to volatilization and seepage, resulting in low hardness and poor high-temperature resistance of the cured material. They are also prone to remaining on the surface of the workpiece, affecting surface cleaning and subsequent assembly processes. Summary of the Invention

[0009] The purpose of this invention is to provide a recyclable impregnating agent and its preparation method.

[0010] This invention uses low-viscosity methacrylate monomers as the main component, supplemented with vinyl-modified nano-silica particles as reactive monomers. By introducing long-chain vinyl organic groups through chemical modification, the nano-silica possesses extremely strong hydrophobicity. Although its density is greater than water, it can quickly separate from water and float on the surface after mixing. This characteristic gives it excellent surface activity, enabling efficient and rapid separation of impregnating agents from cleaning water, facilitating easy cleaning and achieving high recovery rates. Simultaneously, the vinyl groups on the silica surface can polymerize with the methacrylate monomers, resulting in thermosetting products with high hardness, good elasticity, low volume shrinkage, and high heat resistance; therefore, it provides excellent reinforcement for metal castings.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] This invention provides a recyclable impregnating agent, wherein the recyclable impregnating agent comprises the following components in parts by weight:

[0013] 50-60 parts of monofunctional acrylate monomer, 25-35 parts of difunctional acrylate monomer, 2-4 parts of trifunctional acrylate monomer, 10-15 parts of vinyl-modified nano silica, 0.1-0.2 parts of polymerization inhibitor and 0.3-0.8 parts of initiator;

[0014] The vinyl-modified nano-silica is obtained by modifying nano-silica with a vinyl silane coupling agent or an enol.

[0015] According to the recyclable impregnating agent of the present invention, preferably, the vinyl silane coupling agent is selected from at least one of vinyltrimethoxysilane (KH-171), γ-methacryloyloxypropyltrimethoxysilane (KH570), 3-(trimethoxysilyl)propyl acrylate, acryloyloxypropyltrimethoxysilane, methyl 4-[2-(trimethoxysilyl)ethyl]phenyl]-2-acrylate, methyl 4-[2-(trimethoxysilyl)ethyl]phenyl]2-methyl-2-acrylate, 1,3-bis(allyl)-5-(3-trimethoxysilylpropyl)triisocyanate and bis(3-trimethoxysilyl)fumarate; more preferably, it is KH570 or methyl 4-[2-(trimethoxysilyl)ethyl]phenyl]2-methyl-2-acrylate.

[0016] According to the recyclable impregnating agent of the present invention, preferably, the enol is selected from at least one of 1-octen-3-ol (mushroom alcohol), 3,7-dimethyl-2,6-octadien-1-ol (geraniol), cis-9-hexadecenol (palm oil alcohol), (R,Z)-octadecen-9-en-1,12-diol (ricinoleol), 4-hydroxy-3,5-dimethoxycinnamicol (sinol), octadecenol (olive oil alcohol), and cis-13-teicodienol (mustard alcohol); more preferably, palm oil alcohol or olive oil alcohol.

[0017] According to the recyclable impregnating agent of the present invention, preferably, the process of modifying nano-silica with a vinyl silane coupling agent includes:

[0018] 10-15 parts by weight of nano-silica are dispersed in toluene, and 20-30 parts by weight of the vinyl silane coupling agent are added. The mixture is heated under reflux for 10-12 hours. The solid is separated, washed, and dried to obtain the vinyl-modified nano-silica.

[0019] According to the recyclable impregnating agent of the present invention, preferably, the process of modifying nano-silica with enol includes:

[0020] 10-15 parts by weight of nano-silica are dispersed in toluene, 20-30 parts by weight of the enol and 2-3 parts by weight of p-toluenesulfonic acid catalyst are added, and the reaction is carried out at 70-90°C for 4-6 hours. The solid is separated, washed, and dried to obtain the vinyl-modified nano-silica.

[0021] In the process of modifying nano-silica with the above-mentioned vinyl silane coupling agent or enol, preferably, the amount of toluene used is 200-300 parts by weight. Preferably, the nano-silica is added to toluene and ultrasonically dispersed for 20-30 minutes. Preferably, the particle size of the nano-silica is 20-50 nm. Preferably, the washing is performed using ethanol and deionized water respectively.

[0022] According to the recyclable impregnating agent of the present invention, preferably, the monofunctional acrylate monomer is selected from those with a density of less than 1 g / cm³. 3 Alkyl esters having 10-20 carbon atoms; preferably, this invention uses at least one of isobornyl methacrylate, octyl methacrylate, decyl methacrylate, isodecyl methacrylate, diethylene glycol ethyl ether methacrylate, lauryl methacrylate, tridecanol methacrylate, tetradecanol methacrylate, and octadecyl methacrylate. More preferably, lauryl methacrylate (0.868 g / cm³) 3 ), Isodecyl methacrylate (0.876 g / cm³) 3 At least one of the following.

[0023] According to the recyclable impregnating agent of the present invention, preferably, the difunctional acrylate monomer is selected from those with low density (0.900-1.010 g / cm³). 3 Dialkyl esters with 6-15 carbon atoms; the preferred ester in this invention is 1,6-hexanediol diacrylate (1.000 g / cm³). 3 ), 1,10-decanediol dimethacrylate (0.962 g / cm³) 3 At least one of the following.

[0024] According to the recyclable impregnating agent of the present invention, preferably, the trifunctional acrylate monomer is selected from one of the trialkyl esters with relatively low density and 10-20 carbon atoms; the present invention preferably selects at least one of trimethylolpropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETA); more preferably, trimethylolpropane triacrylate (TMPTA).

[0025] According to the recyclable impregnating agent of the present invention, preferably, the polymerization inhibitor is selected from at least one of hydroquinone, benzoquinone, anthraquinone, 1,4-naphthoquinone, tert-butylcatechol, and 2,6-dibutyl-p-cresol. More preferably, it is 2,6-dibutyl-p-cresol.

[0026] According to the recyclable impregnating agent of the present invention, preferably, the initiator is selected from peroxide or azo compounds, such as at least one selected from lauroyl peroxide, diisopropylbenzene peroxide, tert-butyl peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate. More preferably, it is dimethyl azobisisobutyrate.

[0027] Another aspect of the present invention provides a method for preparing a recyclable impregnating agent, wherein the preparation method includes the following steps:

[0028] The monofunctional acrylate monomer, difunctional acrylate monomer, trifunctional acrylate monomer, vinyl-modified nano-silica, polymerization inhibitor, and initiator are stirred and mixed evenly at room temperature to obtain the recyclable impregnating agent.

[0029] This invention introduces vinyl groups into nano-silica particles to prepare reactive monomers. These are siloxane materials with a unique molecular structure: an inorganic silicon-oxygen core surrounded by chemically bonded vinyl organic groups, representing a true inorganic-organic hybrid nanostructure. On one hand, the inorganic silicon-oxygen core, acting as the hard segment, possesses excellent mechanical properties, effectively improving the hardness and high-temperature resistance of the impregnating agent. On the other hand, the long-chain vinyl groups linked to the inorganic silicon-oxygen core not only exhibit good compatibility with methacrylate monomers but also polymerize and graft with methacrylate monomers during curing, forming a three-dimensional network structure. This reduces polymerization shrinkage, enhances heat resistance, and simultaneously improves the material's wear resistance, surface hardness, and toughness. Therefore, the impregnating sealant of this invention, after thermosetting, results in a clean die-cast surface and excellent anti-aging and leak-proof performance.

[0030] The surfactants used in existing recyclable acrylate impregnating agent technologies typically do not participate in the polymerization reaction of acrylate monomers. Therefore, after the impregnating sealant cures, they are prone to volatilization or seepage. This results in the surfactants adhering to the workpiece surface, being difficult to clean, and leading to low impregnating agent recovery rates. Furthermore, it reduces the high-temperature resistance and hardness of the cured impregnating agent, affecting the sealing performance of die-cast parts. This invention uses long-chain alkenyl organic groups grafted with nano-silica via chemical bonds. This process provides strong hydrophobicity, allowing the impregnating agent to quickly separate from water and float on the surface after mixing. Simultaneously, vinylsilane and long-chain enols are excellent surfactants, efficiently and rapidly separating the impregnating agent from the cleaning water. This makes the impregnating agent easy to clean and achieves a high recovery rate, avoiding the need for additional surfactants and separating agents in the formulation. Therefore, it effectively ensures the performance indicators of the acrylate impregnating agent during recycling and reuse. Attached Figure Description

[0031] Figure 1 The graphs show the continuous heat resistance and weight reduction curves of the 220°C curing materials in some embodiments and comparative examples. Detailed Implementation

[0032] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0033] All numerical specifications in this invention (e.g., temperature, time, concentration, and weight, including ranges for each) are generally approximate values ​​that may be changed (+) or (-) in increments of 0.1 or 1.0. All numerical specifications are to be understood as being preceded by the term "about".

[0034] Example 1

[0035] The recyclable impregnating agent in this embodiment is prepared by mixing the following weight proportions:

[0036] 50 parts lauryl methacrylate, 32 parts 1,10-decanediol dimethacrylate, 2.3 parts trimethylolpropane triacrylate, 15 parts nano SiO2-KH570, 0.5 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0037] The method for preparing the nano-SiO2-KH570 includes:

[0038] By weight, 10 parts of SiO2 with a particle size of 20 nm were added to 200 parts of toluene solution and ultrasonically dispersed until a clear solution was obtained. Then, 20 parts of KH570 were added, and the mixture was stirred thoroughly and refluxed at 110 °C for 10-15 hours. After centrifugation and washing 3-4 times, the product was dried under vacuum at 60 °C.

[0039] Example 2

[0040] The recyclable impregnating agent in this embodiment is prepared by mixing the following weight proportions:

[0041] 52 parts lauryl methacrylate, 30 parts 1,6-hexanediol diacrylate, 2.4 parts trimethylolpropane triacrylate, 15 parts nano-SiO2-[4-[2-(trimethoxysilyl)ethyl]phenyl]-2-methyl-2-acrylate, 0.4 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0042] The method for preparing the nano-SiO2-[4-[2-(trimethoxysilyl)ethyl]phenyl]-2-methyl-2-acrylate includes:

[0043] By weight, 10 parts of 20 nm silica were added to 200 parts of toluene solution and ultrasonically dispersed until a clear solution was obtained. Then, 23 parts of [4-[2-(trimethoxysilyl)ethyl]phenyl]-2-methyl-2-acrylate were added, stirred thoroughly, and refluxed at 110 °C for 10-15 hours. After centrifugation and washing 3-4 times, the product was dried under vacuum at 60 °C.

[0044] Example 3

[0045] The recyclable impregnating agent in this embodiment is prepared by mixing the following weight proportions:

[0046] 50 parts isodecyl methacrylate, 32 parts 1,10-decanediol dimethacrylate, 2.3 parts trimethylolpropane triacrylate, 15 parts nano-SiO2-palmitoyl alcohol, 0.5 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0047] The method for preparing nano-SiO2-palmole alcohol includes:

[0048] By weight, 12 parts palm oil alcohol and 2 parts p-toluenesulfonic acid catalyst were added to 200 parts toluene, stirred evenly, and then 12 parts SiO2 with a particle size of 20 nanometers were added. After ultrasonic dispersion, the mixture was reacted at 80°C for 3-5 hours. After centrifugation and washing 3-4 times, the product was dried under vacuum at 60°C.

[0049] Example 4

[0050] The recyclable impregnating agent in this embodiment is prepared by mixing the following weight proportions:

[0051] 52 parts lauryl methacrylate, 30 parts 1,6-hexanediol diacrylate, 2.4 parts trimethylolpropane triacrylate, 15 parts nano-SiO2-olive oil alcohol, 0.4 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0052] The method for preparing nano-SiO2-olic acid includes:

[0053] By weight, 13 parts of olive oil alcohol and 3 parts of p-toluenesulfonic acid were added to 200 parts of toluene, stirred evenly, and then 13 parts of silica with a particle size of 20 nanometers were added. After ultrasonic dispersion, the mixture was reacted at 80°C for 3-5 hours. After centrifugation and washing 3-4 times, the product was dried under vacuum at 60°C.

[0054] Example 5

[0055] The recyclable impregnating agent in this embodiment is prepared by mixing the following weight proportions:

[0056] 60 parts lauryl methacrylate, 25 parts 1,10-decanediol dimethacrylate, 2 parts trimethylolpropane triacrylate, 12 parts nano SiO2-KH570, 0.8 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0057] The method for preparing the nano-SiO2-KH570 includes:

[0058] By weight, 10 parts of SiO2 with a particle size of 20 nm were added to 200 parts of toluene solution and ultrasonically dispersed until a clear solution was obtained. Then, 20 parts of KH570 were added, and the mixture was stirred thoroughly and refluxed at 110 °C for 10-15 hours. After centrifugation and washing 3-4 times, the product was dried under vacuum at 60 °C.

[0059] Example 6

[0060] The recyclable impregnating agent in this embodiment is prepared by mixing the following weight proportions:

[0061] 60 parts lauryl methacrylate, 25 parts 1,10-decanediol dimethacrylate, 2 parts trimethylolpropane triacrylate, 12 parts nano-SiO2-olive alcohol, 0.8 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0062] The method for preparing nano-SiO2-olic acid includes:

[0063] By weight, 13 parts of olive oil alcohol and 3 parts of p-toluenesulfonic acid were added to 200 parts of toluene, stirred evenly, and then 13 parts of silica with a particle size of 20 nanometers were added. After ultrasonic dispersion, the mixture was reacted at 80°C for 3-5 hours. After centrifugation and washing 3-4 times, the product was dried under vacuum at 60°C.

[0064] Comparative Example 1

[0065] The impregnating agent in this comparative example was prepared by mixing the following parts by weight:

[0066] 50 parts lauryl methacrylate, 32 parts 1,10-decanediol dimethacrylate, 2.3 parts trimethylolpropane triacrylate, 15 parts coated nano-SiO2 mixture, 0.5 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0067] The preparation method of the coated nano-SiO2 mixture is as follows: add 6 parts of dipropylene glycol to a container, then add 3 parts of SiO2 with a particle size of 15 nanometers, stir evenly, and then add 1 part of γ-glycidoxypropyltrimethoxysilane and stir until uniform.

[0068] Comparative Example 2

[0069] The impregnating agent in this comparative example is based on Example 1, without the addition of nano-SiO2-KH570, and is actually prepared by mixing the following weight fractions:

[0070] 60 parts lauryl methacrylate, 35 parts 1,10-decanediol dimethacrylate, 4 parts trimethylolpropane triacrylate, 0.8 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0071] Comparative Example 3

[0072] The impregnating agent in this comparative example is based on Example 1 and is actually prepared by mixing the following weight proportions:

[0073] 55 parts lauryl methacrylate, 35 parts 1,10-decanediol dimethacrylate, 4 parts trimethylolpropane triacrylate, 5 parts nano SiO2-KH570, 0.8 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0074] Comparative Example 4

[0075] The impregnating agent in this comparative example is based on Example 1 and is actually prepared by mixing the following weight proportions:

[0076] 50 parts lauryl methacrylate, 27 parts 1,10-decanediol dimethacrylate, 2 parts trimethylolpropane triacrylate, 20 parts nano SiO2-KH570, 0.8 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0077] Comparative Example 5

[0078] This comparative impregnating agent is based on Example 3 and is actually prepared by mixing the following weight proportions:

[0079] 52 parts isodecyl methacrylate, 32 parts decanediol dimethacrylate, 15 parts nano-SiO2-palm oil alcohol, 0.8 parts dimethyl azobisisobutyrate, and 0.2 parts 2,6-dibutyl-p-cresol.

[0080] Explanation of the differences between the examples and comparative examples: The difference between the examples and comparative examples is that all six examples used vinyl-modified nano-SiO2; Comparative example 1 prepared coated nano-SiO2 according to patent (202310642430.2); Comparative example 2 was based on example 1, but without using nano-SiO2; Comparative example 3 was based on example 1, but the amount of nano-SiO2-KH570 was reduced to below the lower limit; Comparative example 4 was based on example 1, but the amount of nano-SiO2-KH570 was increased to above the upper limit; Comparative example 5 was based on example 3, but lacked the trifunctional monomer trimethylolpropane triacrylate.

[0081] The products obtained in Examples 1-6 and Comparative Examples 1-5 were tested according to the following standards, and the results are shown in Tables 1 and 2.

[0082] 1) Density: Tested according to GB / T13354-1992 Determination of density of liquid adhesives by weight cup method.

[0083] 2) Viscosity: Tested according to GB / T2794-2013 Adhesives Viscosity Determination by Single-Cylinder Rotation Viscometer Method.

[0084] 3) Curing hardness: Tested according to GB / T531.1-2008 Shore hardness tester method.

[0085] 4) Volume shrinkage rate: Tested according to GB / T 24148.9-2014 Determination of total volume shrinkage rate of unsaturated polyester resin by density method.

[0086] 5) High temperature resistance: Tested according to ISO 11358:1997 Thermogravimetric analysis (TG) of plastic polymers - General principles.

[0087] This invention employs thermogravimetric analysis (TGA) under isothermal conditions: 2.4000-2.5000g of impregnating agent is heated and cured to form a glue rod. The glue rod is then placed in a constant-temperature aging chamber to test its heat resistance stability at a continuous constant temperature of 220℃. The results are as follows: Figure 1 As shown, from Figure 1 As can be seen, after 100 hours of continuous high temperature at 220°C, the residual weight of the glue rod made with the impregnating agent of Example 1 was 96.35%, and the weight loss rate was only 3.65%, indicating that the impregnating agent has high high temperature resistance (220°C). After 100 hours of continuous high temperature at 220°C, the residual weight of the glue rod made with the impregnating agent of Example 3 was 94.40%, and the weight loss rate was 5.60%, also indicating that the impregnating agent has high high temperature resistance (220°C). Generally, the high temperature resistance of acrylate impregnating agents without added vinyl functionalized silica is only 200°C. However, after 100 hours of continuous high temperature at 220°C, the residual weight of the glue rod made with Comparative Example 1 was 78.10%, and the weight loss rate reached 21.9%, indicating that the impregnating agent cannot withstand the high temperature of 220°C. Therefore, aluminum alloy castings sealed with this impregnating agent are prone to losing their sealing performance at 220°C.

[0088] 6) High-temperature sealing performance at 204℃: The test ring is impregnated with the organic impregnating agent specified in MIL-I-17563C. After curing, it is placed in a constant temperature aging chamber at 204℃ for 42 days. After the aging period, it is taken out, cooled to room temperature, and then the sealing performance is tested using the sealing performance test device specified in MIL-I-17563C. If there is no leakage, it means that the test sample has good high-temperature performance at 204℃; otherwise, the high-temperature performance at 204℃ is poor.

[0089] 7) Washability: Drill a 20mm deep M8 threaded hole vertically on the top, bottom, and left sides of a 30mm×30mm×30mm aluminum block. Immerse the specimen in the impregnating agent and then remove it. Swing and wash it in a tap water tank for 5 minutes, then place it in a 90℃ hot water tank to cure for 15 minutes. Remove it and observe whether there is any residual adhesive on the surface of the specimen and in the threaded hole.

[0090] Table 1. Comparison of impregnating agent performance between the examples and comparative examples.

[0091]

[0092] Table 2 Comparison of cleaning properties and recovery effects of the impregnating agents in the examples and comparative examples

[0093]

[0094] As shown in Table 1, the vinyl-modified nano-SiO2 in Examples 1-6 exhibited good compatibility with the methacrylic acid monomer solution, with no sedimentation occurring within 30 days. However, the nano-SiO2 particles in Comparative Example 1 showed sedimentation, indicating that the SiO2 particles, physically adsorbed by the binder, were destroyed in the acrylate solution, making them highly prone to aggregation. Comparative Example 4 used vinyl-functionalized nano-silica particles exceeding the applicable range, resulting in slight sedimentation and uneven dispersion during prolonged storage. The volume shrinkage rate after curing in Examples 1-6 ranged from 2.89% to 4.19%, indicating excellent sealing performance and low leakage risk. The volume shrinkage rate of Comparative Example 1 was 8.93%, while the volume shrinkage rate of Comparative Example 2 was as high as 16.61%, significantly higher than the examples, thus posing a high risk of leakage during impregnation. Comparative Example 3, due to its low content of vinyl-functionalized silica particles, resulted in increased curing volume shrinkage and poor sealing performance. Comparative Example 4, with its high content of vinyl-functionalized silica particles, suffered from uneven dispersion, also leading to high curing volume shrinkage and poor sealing performance. After impregnation and sealing of the die-cast parts, Examples 1-6 showed no oil seepage after curing, while Comparative Example 1 showed oil seepage, indicating that dipropylene glycol and γ-glycidyl etheroxypropyltrimethoxysilane in the system did not participate in the polymerization reaction and were difficult to cure, thus causing seepage. High-temperature sealing tests showed that Examples 1-6 exhibited good high-temperature sealing performance, while Comparative Examples 1-4 showed poor performance.

[0095] As shown in Table 2, the vinyl-modified nano-SiO2 used in Examples 1-6 facilitates demulsification, making it easier to separate and recover the acrylate monomers from the washing water, thus avoiding the adverse effects of using surfactants and separating agents on the reuse of acrylates. In Comparative Examples 1-2, the absence of surfactants resulted in emulsification after washing, leading to poor separation and low recovery rates. Comparative Example 3 used a smaller amount of vinyl-functionalized silica particles, resulting in a slightly worse separation effect than the examples. In contrast, Comparative Example 4 used a larger amount of vinyl-functionalized silica particles, resulting in a better separation effect than the examples.

[0096] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A recyclable impregnant, characterized in that, The recyclable impregnant comprises the following components in mass fraction: monofunctional acrylate monomer 50-60 parts, difunctional acrylate monomer 25-35 parts, trifunctional acrylate monomer 2-4 parts, vinyl modified nano-silica 10-15 parts, polymerization inhibitor 0.1-0.2 parts and initiator 0.3-0.8 parts; The vinyl modified nano-silica is obtained by modifying nano-silica with a vinyl silane coupling agent or an enol.

2. The recyclable impregnant of claim 1, wherein The vinyl silane coupling agent is selected from at least one of vinyl trimethoxysilane, γ-methacryloxypropyltrimethoxysilane, 3-(trimethoxysilyl)propyl acrylate, acryloxypropyltrimethoxysilane, [4-[2-(trimethoxysilyl)ethyl]phenyl]-2-propenoic acid methyl ester, [4-[2-(trimethoxysilyl)ethyl]phenyl]-2-methyl-2-propenoic acid methyl ester, 1,3-bis(allyl)-5-(3-trimethoxysilylpropyl)trimer isocyanate and bis(3-trimethoxysilylpropyl) fumarate. The enol is selected from at least one of 1-octen-3-ol, 3,7-dimethyl-2,6-octadien-1-ol, cis-9-hexadecenol, (R,Z)-octadeca-9-en-1,12-diol, 4-hydroxy-3,5-dimethoxycinnamyl alcohol, octadecenol and cis-13-docosenol.

3. The recyclable impregnant of claim 2, wherein, The process of modifying nano-silica with a vinyl silane coupling agent comprises: 10-15 parts of nano-silica are dispersed in toluene, 20-30 parts of the vinyl silane coupling agent are added, and the reaction is heated to reflux for 10-12 hours, and the obtained solid is separated, washed and dried to obtain the vinyl modified nano-silica.

4. The recyclable infiltrant of claim 2, wherein, The process of modifying nano-silica with an enol comprises: 10-15 parts of nano-silica are dispersed in toluene, 20-30 parts of the enol and 2-3 parts of p-toluenesulfonic acid catalyst are added, and the reaction is carried out at 70-90°C for 4-6 hours, and the obtained solid is separated, washed and dried to obtain the vinyl modified nano-silica.

5. The recyclable infiltrant of claim 1, wherein, The monofunctional acrylate monomer is selected from at least one of isobornyl methacrylate, octyl methacrylate, decyl methacrylate, isodecyl methacrylate, diethylene glycol ethyl ether methacrylate, lauryl methacrylate, tridecanol methacrylate, tetradecanol methacrylate and octadecanol methacrylate.

6. The recyclable infiltrant of claim 1, wherein, The difunctional acrylate monomer is selected from at least one of 1,6-hexanediol diacrylate and 1,10-decanediol dimethacrylate.

7. The recyclable infiltrant of claim 1, wherein, The trifunctional acrylate monomer is selected from at least one of trimethylolpropane triacrylate and pentaerythritol triacrylate.

8. The recyclable infiltrant of claim 1, wherein, The polymerization inhibitor is selected from at least one of hydroquinone, benzoquinone, anthraquinone, 1,4-naphthoquinone, tert-butyl hydroquinone and 2,6-dibutyl-p-cresol.

9. The recyclable infiltrant of claim 1, wherein, The initiator is selected from at least one of lauroyl peroxide, dicumyl peroxide, tert-butyl peroxybenzoate, azobisisobutyronitrile, azobisisoheptyl nitrile and dimethyl azobis isobutyrate.

10. A method of preparing the recyclable impregnant according to any one of claims 1 to 9, characterized in that, The preparation method comprises the following steps: The monofunctional acrylic ester monomer, difunctional acrylic ester monomer trifunctional acrylic ester monomer, vinyl modified nanosilica, polymerization inhibitor and initiator are stirred and mixed uniformly at room temperature to obtain the recyclable impregnant.

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