Preparation method of lubricating oil filtering material

Abstract

The invention relates to the field of filter materials, and discloses a preparation method of a lubricating oil filter material, which comprises the following steps: mixing polyethersulfone resin with polyacrylic acid, polyvinyl alcohol, dimethyl sulfinamide and ethidene diamine to react to obtain modified polyethersulfone resin, and dispersing the modified polyethersulfone resin in water to form modified polyethersulfone resin emulsion; secondly, preparing a silane coupling agent aqueous solution, placing the glass fibers in the silane coupling agent aqueous solution for reaction, drying the glass fibers, placing the dried glass fibers in a high-voltage direct-current electric field, and performing ultraviolet irradiation treatment on the dried glass fibers; then, mixing and dispersing the treated glass fibers and water, and carrying out solid-liquid separation and dehydration to form a wet filter material; and finally, mixing and stirring the modified polyethersulfone resin emulsion and an anionic surfactant to form foam, coating the wet filter material with the foam, and drying and curing to obtain the lubricating oil filter material. The prepared lubricating oil filtering material has better high temperature resistance and water resistance, and also has better air permeability and low filtering resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of filter materials, and particularly to a preparation method of a lubricating oil filter material. Background Art

[0002] Oil contamination is the most important factor affecting the service life and operation reliability of lubrication system components. Excessive solid particle contaminants in the oil will cause wear on the surfaces of the component moving pairs, reduce the performance of the components, and even cause catastrophic consequences in some cases. The most direct and effective way to solve the problem of oil contamination is to filter out the solid particles in the oil using a filter element made of a deep-type fiber filter material.

[0003] In industries such as steel mills, power plants, and construction machinery, the lubricating oil in the lubrication system has a relatively high temperature (exceeding 150 °C) and sometimes infiltrates more moisture (greater than 5%). Therefore, it is required that the filter material has characteristics such as high temperature resistance and water resistance. However, commonly used glass fiber filter materials generally use acrylic resin as an adhesive, and have poor high temperature resistance and water resistance. If used for lubricating oil filtration for a long time, it will cause filtration failure.

[0004] However, there has not been a very suitable filter material available for oil filters that simultaneously have high temperature resistance, water resistance, and a long service life. Therefore, there is an urgent need in the market for a lubricating oil filter material that simultaneously has high temperature resistance, water resistance, a long service life, and high permeability to meet the filtration requirements of the oil. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the related art. For this purpose, the present invention provides a preparation method of a lubricating oil filter material.

[0006] A preparation method of a lubricating oil filter material, a) Preparation of a modified polyethersulfone resin emulsion: Mix polyethersulfone resin with polyacrylic acid, polyvinyl alcohol, dimethylsulfoximine, and ethylenediamine for reaction to obtain a modified polyethersulfone resin; then disperse the modified polyethersulfone resin in water to form a modified polyethersulfone resin emulsion; b) Surface treatment of glass fibers: Prepare an aqueous solution of a silane coupling agent; place the glass fibers in the aqueous solution of the silane coupling agent for reaction and drying to obtain dried glass fibers; place the dried glass fibers in a high-voltage direct current electric field and simultaneously irradiate with ultraviolet light for treatment to obtain treated glass fibers; c) Preparation of a wet filter medium: Mix and disperse the treated glass fibers obtained in step b) with water to obtain a glass fiber suspension, and form a wet filter medium after solid-liquid separation and dehydration; d) Foam coating and molding: Mix and stir the modified polyethersulfone resin emulsion obtained in step a) with an anionic surfactant to form a foam; coat the foam onto the wet filter medium obtained in step c), and then dry and cure to obtain the lubricating oil filter material.

[0007] Further, the preparation of the modified polyethersulfone resin in step a) includes: by weight, mixing 8-10 parts of polyacrylic acid, 6-10 parts of polyvinyl alcohol, 3-5 parts of dimethylsulfoximine, 3-5 parts of ethylenediamine, and 70-80 parts of polyethersulfone resin, and under nitrogen protection, stirring and reacting at room temperature for 10-12 hours, then heating to 60-70 °C and continuing to react for 24 hours; The molecular weight of the polyethersulfone resin is 5×10 4 ~8×10 4 .

[0008] Further, the formation of the modified polyethersulfone resin emulsion in step a) includes: adding the modified polyethersulfone resin obtained in step a) to ultrapure water and dispersing it under a high-speed disperser for 4-6 hours.

[0009] Further, the preparation of the silane coupling agent aqueous solution in step b) includes: preparing the silane coupling agent into an aqueous solution with a mass concentration of 0.5%-0.8%, adding acetic acid to adjust the pH to 5.5, and standing for 2 hours; The glass fiber is placed in the silane coupling agent aqueous solution for reaction and drying, including: placing a certain amount of glass fiber in the silane coupling agent aqueous solution prepared in step b), heating in a water bath at 70-80 °C for 10-12 hours under nitrogen protection, then washing with n-hexane, and drying in a vacuum oven for 20-24 hours to obtain the dried glass fiber.

[0010] Further, the glass fiber in step b) includes submicron glass fiber and chopped glass fiber, and the mass ratio of the submicron glass fiber to the chopped glass fiber is 2:1-4:1; The average diameter of the submicron glass fiber is 0.5 μm, and the average diameter of the chopped glass fiber is 6 μm; The silane coupling agent is any one of γ-aminopropylaminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidyletheroxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane.

[0011] Further, the high-voltage DC electric field voltage in step b) is 30-40 kV, and the treatment time with ultraviolet irradiation is 7-9 hours.

[0012] Further, the step of mixing and dispersing the treated glass fiber obtained in step b) with water to obtain a glass fiber suspension includes: mixing the treated glass fiber obtained in step b) with deionized water to prepare a concentration of 0.1-0.5 wt%, followed by ultrasonic dispersion for 35-40 min, and then further diluting to a concentration of 0.02-0.05 wt% to obtain a glass fiber suspension.

[0013] Further, the step of mixing and stirring the modified polyethersulfone resin emulsion obtained in step a) with an anionic surfactant to form foam includes: diluting the modified polyethersulfone resin emulsion obtained in step a) and the anionic surfactant to a mass concentration of 0.5%-1%, then mixing and stirring for 15-20 min until foam is generated; The thickness of the foam coated on the wet filter medium is 3-5 cm; The anionic surfactant is one or more of fatty alcohol polyoxyethylene ether sulfate, sulfonated fatty acid ester salt, fatty alcohol sulfate, and secondary alkyl sulfonate.

[0014] Further, the drying and curing in step d) includes: first drying the wet filter medium with foam at 105°C for 2-4 min, and then curing and shaping at 160-180°C for 5-8 min.

[0015] Further, the basis weight of the filter medium of the lubricating oil filter material is 60±5 g / m², and the average pore size is 5-10 μm.

[0016] One or more of the above technical solutions in the embodiments of the present invention have at least one of the following technical effects: (1) In the present invention, the modified polyethersulfone resin is used as a glass fiber binder, replacing the adhesives such as acrylic resin that are not resistant to high temperature and water in traditional glass fiber filter materials, greatly improving the overall high-temperature resistance and water resistance of the glass fiber filter material, enabling it to maintain good filtration performance in high-temperature and high-water-content environments, and being widely applicable to various lubricating oil filtration fields.

[0017] (2) Compared with the traditional technologies of directly impregnating, coating, spraying, etc. with emulsions, in the present invention, by mixing the modified polyethersulfone resin emulsion with an anionic surfactant to form foam and then applying it to the surface of the wet filter medium, the dosage of the combination of the modified polyethersulfone resin emulsion and the silane coupling agent can be effectively controlled. The foam carries less and more uniform modified polyethersulfone resin emulsion. After the foam defoams, the modified polyethersulfone resin molecules and the silane coupling agent molecules react uniformly and fully. The reaction products adhere uniformly to the surface of the glass fiber, forming a nanoscale film that does not block the pore channels, ensuring good air permeability of the filter medium. While the filter material of the present invention has high-temperature resistance and water resistance, it has a low resistance.

[0018] (3) Through the multiple actions of silane coupling agent, high-voltage direct current electric field, and ultraviolet irradiation, the present invention enhances the adsorption of glass fiber to the modified polyethersulfone resin. During the entire life cycle, the modified polyethersulfone resin and the glass fiber are always firmly combined, and the filter material as a whole maintains good high-temperature resistance and water resistance.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic diagram of the preparation process of the oil filter material of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0023] As Figure 1 shown, the specific process of the preparation method of the lubricating oil filter material is shown.

[0024] The present invention provides a preparation method of a lubricating oil filter material, including the following steps: (1) By weight, 8-10 parts of polyacrylic acid, 6-10 parts of polyvinyl alcohol, 3-5 parts of dimethylsulfoxamide, 3-5 parts of ethylenediamine, and 70-80 parts of polyethersulfone resin are mixed, and then under nitrogen protection, stirred and reacted at room temperature for 10-12 hours, and then heated to 60-70 °C and continued to react for 24 hours.

[0025] Among them, the polyethersulfone resin itself is hydrophobic and difficult to form an aqueous emulsion. Adding polyacrylic acid and polyvinyl alcohol is used to improve the hydrophilicity of the polyethersulfone resin to facilitate the subsequent formation of an aqueous emulsion; dimethylsulfoxamide acts as a solvent, and ethylenediamine acts as a promoter and crosslinking agent to promote the polymerization reaction.

[0026] (2) Add the reaction product of step (1) to ultrapure water and disperse it under a high-speed disperser for 4 to 6 hours to form an emulsion; (3) Prepare an aqueous solution of silane coupling agent with a mass concentration of 0.5% to 0.8%; add acetic acid to adjust the pH to 5.5 and let it stand for 2 hours; (4) Place a certain amount of glass fiber in the aqueous solution of step (3), under the protection of nitrogen, heat it in a water bath at 70 - 80 °C for 10 to 12 hours, then wash it with n-hexane and dry it in a vacuum oven for 20 to 24 hours; (5) Place the dried glass fiber in a high-voltage direct current electric field and irradiate it with ultraviolet light for 7 to 9 hours; (6) Mix the treated glass fiber with deionized water, perform ultrasonic dispersion, and then further dilute it to obtain a glass fiber suspension; after solid-liquid separation to remove impurities, dehydrate it to form a wet filter medium; (7) Dilute and mix the emulsion of step (2) and an anionic surfactant and stir until foam is generated; then coat the foam onto the wet filter medium of step (6); dry and cure the wet filter medium with foam to obtain the filter material.

[0027] Among them, the molecular weight of the polyethersulfone resin is 5×10 4 ~ 8×10 4 .

[0028] The selection of polyethersulfone resin is based on its excellent high-temperature resistance (greater than 150 °C), but its hydrophobicity limits its application in aqueous systems. The modification process optimizes its dispersibility and binding ability with glass fiber by introducing hydrophilic monomers (such as polyacrylic acid, polyvinyl alcohol).

[0029] The silane coupling agent is any one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane.

[0030] An acidic environment promotes the hydrolysis of silane and at the same time avoids rapid polycondensation to ensure the stability of the solution.

[0031] The glass fiber includes submicron glass fiber and chopped glass fiber, and the mass ratio of the submicron glass fiber to the chopped glass fiber is 2:1 - 4:1; the average diameter of the submicron glass fiber is 0.5 μm, and the average diameter of the chopped glass fiber is 6 μm.

[0032] The submicron glass fiber provides a high specific surface area and enhances the filtration accuracy; the chopped glass fiber provides mechanical strength, and selecting an appropriate mass ratio optimizes the performance balance.

[0033] The high-voltage electric field voltage (30 - 40 kV) needs to be controlled within an appropriate range. If it is too low, the effect is insufficient; if it is too high, there is no additional benefit and the energy consumption increases.

[0034] The foam is coated onto the wet filter medium in step (6), and the coating thickness is 3 - 5 cm.

[0035] The anionic surfactant is one or more of fatty alcohol polyoxyethylene ether sulfate, sulfonated fatty acid ester salt, fatty alcohol sulfate, and secondary alkyl sulfonate.

[0036] The wet filter medium is first dried at 105 °C for 2 - 4 min, and then cured and shaped at 160 - 180 °C for 5 - 8 min.

[0037] The quantitative value of the filter medium is 60 ± 5 g / m2, and the average pore size is 5 - 10 μm.

[0038] The anionic surfactant reduces the surface tension of the emulsion, and stirring generates a stable foam structure. The foam carries a small amount of modified polyethersulfone emulsion.

[0039] The foam structure makes the emulsion distribution more uniform, reduces the coating amount, and avoids pore blockage.

[0040] Foam coating is an important step in this technology. Compared with traditional dipping, spraying, or curtain coating, foam coating significantly reduces the initial resistance and at the same time ensures the uniform distribution of the adhesive.

[0041] It should be noted that in the selection of the filter material composition, there are many chemical components to choose from. However, it is relatively difficult to simultaneously meet the requirements of high temperature resistance, water resistance, and good chemical stability. At the same time, it is also necessary to ensure that the filter pores of the filter medium are not blocked during the preparation of the filter medium. In addition to the fine selection of the filter medium composition, an appropriate processing method is also required.

[0042] For example, the polyethersulfone resin selected in the present invention is hydrophobic and difficult to form an aqueous emulsion. Polyacrylic acid and polyvinyl alcohol are added to improve the hydrophilicity of the polyethersulfone resin to facilitate the formation of an aqueous emulsion in subsequent processes; ethylenediamine is used as a promoter and crosslinking agent to promote the polymerization reaction.

[0043] If the modified polyethersulfone resin emulsion and silane coupling agent are directly attached to the wet filter medium by various methods such as dipping, curtain coating, and spraying, the obtained filter medium has poor air permeability and high resistance after drying; creatively, the foam coating method is introduced into the preparation of the filter medium. After adding an anionic surfactant to the obtained emulsion to form foam, it is then applied to the surface of the wet filter medium and dried, cured after natural defoaming to obtain the filter medium of the present invention.

[0044] By modifying to increase the hydrophilicity of the polyethersulfone resin, in combination with an anionic surfactant, the solvent is deionized water, which is the same as the solvent for treating glass fiber, and has good compatibility, enabling the modified polyethersulfone resin to be better dispersed and fused with the wet filter medium.

[0045] The technical effects of this solution will be further demonstrated through specific examples below.

[0046] Example 1 The present invention provides a preparation method of a lubricating oil filtering material, comprising the following steps: (1) By weight, 8 parts of polyacrylic acid, 6 parts of polyvinyl alcohol, 3 parts of dimethylsulfoximine, 3 parts of ethylenediamine, and 70 parts of polyethersulfone resin are mixed, and under nitrogen protection, stirred and reacted at room temperature for 10 hours, then heated to 60 °C and reacted for another 24 hours; (2) The reaction product of step (1) is added to ultrapure water and dispersed by a high-speed disperser for 4 hours to form an emulsion; (3) The silane coupling agent γ-aminopropyltriethoxysilane is formulated into an aqueous solution with a mass concentration of 0.5%; acetic acid is added to adjust the pH to 5.5, and left standing for 2 hours; (4) A certain amount of glass fiber is placed in the aqueous solution of step (3), and under nitrogen protection, heated in a water bath at 70 °C for 12 hours, then washed with n-hexane and dried in a vacuum oven for 20 hours; (5) The dried glass fiber is placed in a 30 kV high-voltage DC electric field and irradiated with ultraviolet light simultaneously for 9 hours; (6) The treated glass fiber is mixed with deionized water to a concentration of 0.1 wt%, and ultrasonically dispersed at room temperature for 35 min, and then further diluted to a concentration of 0.02 wt% to obtain a glass fiber suspension; after solid-liquid separation to remove impurities, it is dehydrated to form a wet filter medium; (7) The emulsion of step (2) and the anionic surfactant fatty alcohol polyoxyethylene ether sulfate are diluted to a mass concentration of 0.5%, mixed and stirred for 15 min until foam is generated; then the foam is coated on the wet filter medium of step (6); the wet filter medium with foam is first dried at 105 °C for 2 min, and then cured and shaped at 160 °C for 8 min to obtain the filtering material.

[0047] In this example, the molecular weight of the polyethersulfone resin is ; the mass ratio of submicron glass fiber to the chopped glass fiber is 2:1; the average diameter of the submicron glass fiber is 0.5 μm, and the average diameter of the chopped glass fiber is 6 μm; the thickness of the foam coating is 3 cm; the basis weight of the filter medium is 55 g / m 2 , and the average pore diameter is 10 μm.

[0048] Example 2 The present invention provides a preparation method of a lubricating oil filtering material, comprising the following steps: (1) By weight, 9 parts of polyacrylic acid, 8 parts of polyvinyl alcohol, 4 parts of dimethyl sulfoxamide, 4 parts of ethylenediamine, and 75 parts of polyethersulfone resin are mixed, and then under nitrogen protection, stirred and reacted at room temperature for 11 hours, and then heated to 65 °C and reacted for another 24 hours; (2) The reaction product of step (1) is added to ultrapure water and dispersed under a high-speed disperser for 5 hours to form an emulsion; (3) Prepare an aqueous solution of the silane coupling agent γ-glycidoxypropyltrimethoxysilane with a mass concentration of 0.6%; adjust the pH to 5.5 with acetic acid and let it stand for 2 hours; (4) Place a certain amount of glass fiber into the aqueous solution of step (3), under nitrogen protection, heat it in a water bath at 75 °C for 11 hours, then wash it with n-hexane, and place it in a vacuum oven to dry for 22 hours; (5) Place the dried glass fiber in a 35 kV high-voltage DC electric field and irradiate it with ultraviolet light at the same time for 8 hours; (6) Mix the treated glass fiber with deionized water to prepare a concentration of 0.3 wt%, and perform ultrasonic dispersion at room temperature for 38 min, and then further dilute it to a concentration of 0.04 wt% to obtain a glass fiber suspension; after solid-liquid separation to remove impurities, dehydrate to form a wet filter medium; (7) Dilute the emulsion of step (2) and the anionic surfactant fatty alcohol sulfate to a mass concentration of 0.8%, mix and stir for 17 min until foam is generated; then coat the foam onto the wet filter medium of step (6); first dry the wet filter medium with foam at 105 °C for 3 min, and then cure and shape it at 170 °C for 6 min to obtain the filtering material.

[0049] In this embodiment, the molecular weight of the polyethersulfone resin is ; the mass ratio of the submicron glass fiber to the chopped glass fiber is 3:1; the average diameter of the submicron glass fiber is 0.5 μm, and the average diameter of the chopped glass fiber is 6 μm; the thickness of the foam coating is 4 cm; the basis weight of the filter medium is 60 g / m 2 , and the average pore diameter is 8 μm.

[0050] Example 3 The present invention provides a preparation method of a lubricating oil filtering material, comprising the following steps: (1)Mix 10 parts of polyacrylic acid, 10 parts of polyvinyl alcohol, 5 parts of dimethylsulfoxamide, 5 parts of ethylenediamine, and 70 parts of polyethersulfone resin by weight. Under nitrogen protection, stir and react at room temperature for 12 hours, then raise the temperature to 70 °C and continue to react for 24 hours; (2)Add the reaction product of step (1) to ultrapure water and disperse it under a high-speed disperser for 6 hours to form an emulsion; (3)Prepare an aqueous solution of the silane coupling agent γ-methacryloxypropyltrimethoxysilane with a mass concentration of 0.8%; adjust the pH to 5.5 with acetic acid and let it stand for 2 hours; (4)Place a certain amount of glass fiber in the aqueous solution of step (3). Under nitrogen protection, heat it in a water bath at 80 °C for 10 hours, then wash it with n-hexane and dry it in a vacuum oven for 24 hours; (5)Place the dried glass fiber in a 40 kV high-voltage DC electric field and irradiate it with ultraviolet light for 7 hours; (6)Mix the treated glass fiber with deionized water to a concentration of 0.5 wt%, and perform ultrasonic dispersion at room temperature for 40 min, then further dilute it to a concentration of 0.05 wt% to obtain a glass fiber suspension; after solid-liquid separation to remove impurities, dehydrate it to form a wet filter medium; (7)Dilute the emulsion of step (2) and the anionic surfactant secondary alkyl sulfonate to a mass concentration of 1%, mix and stir for 20 min until foam is generated; then coat the foam onto the wet filter medium of step (6); first dry the wet filter medium with foam at 105 °C for 4 min, and then cure and shape it at 180 °C for 5 min to obtain the filter material.

[0051] In this example, the molecular weight of the polyethersulfone resin is ; the mass ratio of the submicron glass fiber to the chopped glass fiber is 4:1; the average diameter of the submicron glass fiber is 0.5 μm, and the average diameter of the chopped glass fiber is 6 μm; the thickness of the foam coating is 5 cm; the basis weight of the filter medium is 65 g / m 2 , and the average pore diameter is 5 μm.

[0052] Comparative Example 1 Other steps are the same as in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, in step (3), the silane coupling agent is prepared into an aqueous solution with a mass concentration of 0.4%.

[0053] Comparative Example 2 Other steps are the same as in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, in step (3), the silane coupling agent is prepared into an aqueous solution with a mass concentration of 0.9%.

[0054] Comparative Example 3 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, steps (3) and (4) are absent.

[0055] Comparative Example 4 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, step (5) is absent.

[0056] Comparative Example 5 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, there is no ultraviolet irradiation in step (5).

[0057] Comparative Example 6 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, there is no high-voltage electric field in step (5).

[0058] Comparative Example 7 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, the high-voltage electric field voltage in step (5) is 25 kV.

[0059] Comparative Example 8 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, the high-voltage electric field voltage in step (5) is 45 kV.

[0060] Comparative Example 9 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, the emulsion and anionic surfactant in step (5) are diluted to a mass concentration of 0.4%.

[0061] Comparative Example 10 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, the emulsion and anionic surfactant in step (5) are diluted to a mass concentration of 1.1%.

[0062] Comparative Example 11 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, no anionic surfactant is added in step (7). After the emulsion is diluted, the wet filter material in step (6) is impregnated.

[0063] Comparative Example 12 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, no anionic surfactant is added in step (7). After the emulsion is diluted, the wet filter material in step (6) is sprayed.

[0064] Comparative Example 13 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, in step (7), no anionic surfactant is added. After the emulsion is diluted, the wet filter medium in step (6) is subjected to curtain coating.

[0065] Comparative Example 14 Other steps are the same as those in Example 1. The difference between this comparative example and Example 1 lies in that in the preparation method, there is no step (1), and in step (2), the reaction product in step (1) is changed to a polyacrylic resin.

[0066] Measurement items and methods: (1) Temperature resistance test (test results are shown in Table 1) Test method: First, in accordance with Section 5.4 of Standard GB / T14041.2 - 2007, soak the filter media of Examples 1 - 3 and Comparative Examples 1 - 14 in lubricating oil at 215°C for 72h, and then test the following items together with the filter media not soaked in high - temperature oil: Filtration accuracy (β(c)): Refer to the test standard: Chapter 11 of GB / T18853 - 2015, and conduct it on the test bench with the filter medium passing through multiple times.

[0067] Initial resistance: Refer to the test standard: Chapter 11 of GB / T18853 - 2015, and conduct it on the test bench with the filter medium passing through multiple times.

[0068] Test conditions: Flow rate: 3L / min, upstream contamination degree: 10mg / L, specimen area: 100cm2, termination pressure drop: 400kPa.

[0069] Table 1 Temperature resistance test results

[0070] As can be seen from the results in Table 1, for the filter media of Example 1, Example 2, and Example 3, before and after soaking in high - temperature oil, the filtration accuracy and initial resistance remain stable, showing good high - temperature resistance performance.

[0071] Compared with Comparative Example 1 and Comparative Example 2, it can be seen that if the mass concentration of the silane coupling agent is too low, the high-temperature resistance performance will be reduced. If the mass concentration is too high, although the high-temperature resistance performance will not be reduced, the initial resistance will increase. Therefore, the mass concentration of the silane coupling agent must be within a suitable range. Compared with Comparative Example 3, it can be seen that it is necessary to add a silane coupling agent. Otherwise, the bonding between the modified polyethersulfone resin and the glass fiber will be unstable. During the experiment, under the impact of the oil liquid, part of the modified polyethersulfone resin will fall off, resulting in a decrease in filtration accuracy. The phenomenon of resin shedding can be inferred from the decrease in filtration accuracy. Compared with Comparative Example 4, Comparative Example 5 and Comparative Example 6, it can be seen that both the high-voltage electric field and ultraviolet irradiation can enhance the bonding effect between the modified polyethersulfone resin and the glass fiber and improve the high-temperature resistance performance of the filter medium.

[0072] Compared with Comparative Example 7 and Comparative Example 8, it can be seen that if the voltage of the high-voltage electric field is too low, its effect will be weakened and the high-temperature resistance performance of the filter medium will be reduced; if the voltage is too high, the high-temperature resistance performance will not be improved, and the energy consumption will increase. Therefore, the voltage of the high-voltage electric field must be within a suitable range.

[0073] Compared with Example 1, Comparative Example 9 and Comparative Example 10, it can be seen that if the dilution concentrations of the emulsion and anionic surfactant are too low, although the initial resistance decreases slightly, the high-temperature resistance performance will also be weakened, resulting in a certain reduction in filtration accuracy.

[0074] Compared with Example 1, Comparative Example 11, Comparative Example 12 and Comparative Example 13, it can be seen that using traditional impregnation, spraying or curtain coating will cause a significant increase in the initial resistance, indicating that the foam coating process of the present invention is beneficial to reducing the initial resistance.

[0075] Compared with Comparative Example 14, it can be seen that the modified polyethersulfone resin of the present invention as an adhesive has a significantly improved high-temperature resistance performance compared with the traditional polyacrylic resin. The polyacrylic resin is likely to fall off from the surface of the glass fiber at high temperatures, resulting in a decrease in filtration accuracy and a slight reduction in the initial resistance.

[0076] (2)Water resistance test (test results are shown in Table 2) Test method: Inject pure water into the ultrasonic tank, immerse the filter media of Examples 1 to 3 and Comparative Examples 1 to 14 in it, turn on the ultrasonic oscillation, and observe the change in the appearance of the filter media every half hour.

[0077] Test conditions: Water temperature: room temperature; immersion time: 2 h.

[0078] Table 2 Water resistance test results

[0079] As can be seen from the results in Table 2, the filter materials of Example 1, Example 2 and Example 3 all have good water resistance.

[0080] Comparing Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3, it can be seen that the concentration of the silane coupling agent aqueous solution has no effect on water resistance, but a silane coupling agent must be present, otherwise the water resistance will be reduced. Comparing Example 1, Comparative Example 4 to Comparative Example 8, it can be seen that high-voltage electric field and ultraviolet irradiation play important roles in enhancing the bonding strength between the modified polyethersulfone and the glass fiber, and neither can be absent, otherwise the water resistance will be reduced. In addition, too low a voltage of the high-voltage electric field will also reduce the water resistance. Comparing Example 1, Comparative Example 9 and Comparative Example 10, it can be seen that the mass concentration of the emulsion and the anionic surfactant has no effect on water resistance. Comparing Example 1, Comparative Example 11 to Comparative Example 13, it can be seen that the coating method of the modified polyethersulfone has no effect on water resistance. Comparing Example 1 and Comparative Example 14, it can be seen that the modified polyethersulfone can improve the water resistance of the filter material compared with the traditional polyacrylic resin.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention 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 for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A preparation method of a lubricating oil filter material, characterized in that, a) Preparation of a modified polyethersulfone resin emulsion: Mix polyethersulfone resin with polyacrylic acid, polyvinyl alcohol, dimethylsulfoximine and ethylenediamine for reaction to obtain a modified polyethersulfone resin; then disperse the modified polyethersulfone resin in water to form a modified polyethersulfone resin emulsion; b) Surface treatment of glass fibers: Prepare an aqueous solution of a silane coupling agent; place the glass fibers in the aqueous solution of the silane coupling agent for reaction and drying to obtain dried glass fibers; place the dried glass fibers in a high-voltage direct-current electric field and irradiate with ultraviolet light simultaneously for treatment to obtain treated glass fibers; c) Preparation of a wet filter medium: Mix and disperse the treated glass fibers obtained in step b) with water to obtain a glass fiber suspension, and form a wet filter medium after solid-liquid separation and dehydration; d) Foam coating and molding: Mix and stir the modified polyethersulfone resin emulsion obtained in step a) with an anionic surfactant to form a foam; coat the foam onto the wet filter medium obtained in step c), and then dry and cure to obtain the lubricating oil filter material.

2. The preparation method of the lubricating oil filter material according to claim 1, characterized in that, The preparation of the modified polyethersulfone resin in step a) includes: Mix 8-10 parts of polyacrylic acid, 6-10 parts of polyvinyl alcohol, 3-5 parts of dimethylsulfoximine, 3-5 parts of ethylenediamine, and 70-80 parts of polyethersulfone resin by weight, and stir and react at room temperature for 10-12 hours under nitrogen protection, and then raise the temperature to 60-70 °C and continue to react for 24 hours; The molecular weight of the polyethersulfone resin is 5×10 4 ~8×10 4 .

3. The preparation method of the lubricating oil filter material according to claim 2, characterized in that, The formation of the modified polyethersulfone resin emulsion in step a) includes: Add the modified polyethersulfone resin obtained in step a) to ultrapure water and disperse it with a high-speed disperser for 4-6 hours.

4. The preparation method of the lubricating oil filter material according to claim 1, characterized in that, The preparation of the aqueous solution of the silane coupling agent in step b) includes: Prepare an aqueous solution of the silane coupling agent with a mass concentration of 0.5%-0.8%, add acetic acid to adjust the pH to 5.5, and let it stand for 2 hours; Placing the glass fibers in the aqueous solution of the silane coupling agent for reaction and drying includes: Place a certain amount of glass fibers in the aqueous solution of the silane coupling agent prepared in step b), heat in a water bath at 70-80 °C for 10-12 hours under nitrogen protection, then wash with n-hexane, and place in a vacuum oven to dry for 20-24 hours to obtain the dried glass fibers.

5. The preparation method of the lubricating oil filter material according to claim 4, characterized in that, The glass fibers in step b) include submicron glass fibers and chopped glass fibers, and the mass ratio of the submicron glass fibers to the chopped glass fibers is 2:1-4:1; The average diameter of the submicron glass fibers is 0.5 μm, and the average diameter of the chopped glass fibers is 6 μm; The silane coupling agent is any one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

6. The preparation method of the lubricating oil filter material according to claim 5, wherein in step b), the high-voltage DC electric field voltage is 30 to 40 kV, and the treatment time under ultraviolet irradiation is 7 to 9 hours.

7. The preparation method of the lubricating oil filter material according to claim 1, wherein the step of mixing and dispersing the treated glass fiber obtained in step b) with water to obtain a glass fiber suspension includes: mixing the treated glass fiber obtained in step b) with deionized water to prepare a concentration of 0.1 to 0.5 wt%, followed by ultrasonic dispersion for 35 to 40 min, and then further diluting to a concentration of 0.02 to 0.05 wt% to obtain a glass fiber suspension.

8. The preparation method of the lubricating oil filter material according to claim 1, wherein the step of mixing and stirring the modified polyethersulfone resin emulsion obtained in step a) with an anionic surfactant to form foam includes: diluting the modified polyethersulfone resin emulsion obtained in step a) and the anionic surfactant to a mass concentration of 0.5% to 1% and then mixing and stirring for 15 to 20 min until foam is generated; the thickness of the foam coated on the wet filter material is 3 to 5 cm; the anionic surfactant is one or more of fatty alcohol polyoxyethylene ether sulfate, sulfonated fatty acid ester salt, fatty alcohol sulfate, and secondary alkyl sulfonate.

9. The preparation method of the lubricating oil filter material according to claim 8, wherein the drying and curing in step d) include: first drying the wet filter material with foam at 105 °C for 2 to 4 min, and then curing and shaping at 160 to 180 °C for 5 to 8 min.

10. The preparation method of the lubricating oil filter material according to claim 1, wherein the basis weight of the filter material of the lubricating oil filter material is 60 ± 5 g / m², and the average pore size is 5 to 10 μm.

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