A method for preparing lubricating oil filter material

Abstract

The present invention relates to the field of filter materials and discloses a method for preparing lubricating oil filter material. The method comprises: reacting polyethersulfone resin with polyacrylic acid, polyvinyl alcohol, dimethylsulfamide, and ethylenediamine to obtain a modified polyethersulfone resin, which is then dispersed in water to form a modified polyethersulfone resin emulsion. Next, a silane coupling agent aqueous solution is prepared, in which glass fibers are reacted and dried. The dried glass fibers are then exposed to a high-voltage direct current electric field and irradiated with ultraviolet light. The treated glass fibers are then mixed and dispersed with water, subjected to solid-liquid separation and dehydration to form a wet filter material. Finally, the modified polyethersulfone resin emulsion is mixed and stirred with an anionic surfactant to form a foam, which is then coated on the wet filter material and dried and solidified to obtain the lubricating oil filter material. The prepared lubricating oil filter material exhibits excellent high-temperature and water resistance, as well as good air permeability and low filtration resistance.

Description

Technical Field

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

[0002] Oil contamination is the primary factor affecting the lifespan and operational reliability of lubrication system components. Excessive levels of solid particulate contaminants in the oil can cause wear on the moving surfaces of components, reducing component performance and, in some cases, even leading to catastrophic consequences. The most direct and effective way to address oil contamination is to use filter elements made of deep-filled fiber filter material to remove solid particulate matter from the oil.

[0003] Lubrication systems in industries like steel mills, power plants, and construction machinery experience high oil temperatures (over 150°C) and sometimes infiltrate high levels of water (greater than 5%). Therefore, filter materials must be both heat-resistant and water-resistant. However, commonly used glass fiber filter materials typically use acrylic resin as a binder, which has poor heat and water resistance. Prolonged use for lubricating oil filtration can lead to filter failure.

[0004] However, there has been a lack of suitable oil-resistant filter materials that are simultaneously resistant to high temperatures, water, and have a long service life. Therefore, the market urgently needs a lubricating oil filter material that is simultaneously resistant to high temperatures, water, has a long service life, and has high permeability to meet the needs of oil filtration. Summary of the Invention

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

[0006] A method for preparing a lubricating oil filter material,

[0007] a) Preparation of a modified polyethersulfone resin emulsion: mixing a polyethersulfone resin with polyacrylic acid, polyvinyl alcohol, dimethylsulfamide, and ethylenediamine to obtain a modified polyethersulfone resin; and then dispersing the modified polyethersulfone resin in water to form a modified polyethersulfone resin emulsion;

[0008] b) surface treatment of the glass fiber: preparing an aqueous solution of a silane coupling agent; placing the glass fiber in the aqueous solution of the silane coupling agent for reaction and drying to obtain a dried glass fiber; and placing the dried glass fiber in a high-voltage direct current electric field and simultaneously irradiating it with ultraviolet light to obtain a treated glass fiber;

[0009] c) Preparation of wet filter material: mixing and dispersing the treated glass fibers obtained in step b) with water to obtain a glass fiber suspension, and subjecting the suspension to solid-liquid separation and dehydration to form a wet filter material;

[0010] d) Foam coating and molding: the modified polyethersulfone resin emulsion obtained in step a) is mixed with an anionic surfactant to form foam; the foam is coated on the wet filter material obtained in step c), and then dried and solidified to obtain the lubricating oil filter material.

[0011] Furthermore, the preparation of the modified polyethersulfone resin in step a) comprises: mixing, by weight, 8 to 10 parts of polyacrylic acid, 6 to 10 parts of polyvinyl alcohol, 3 to 5 parts of dimethylsulfamide, 3 to 5 parts of ethylenediamine, and 70 to 80 parts of polyethersulfone resin; stirring and reacting the mixture at room temperature under nitrogen protection for 10 to 12 hours; then heating the mixture to 60 to 70° C. and continuing the reaction for 24 hours;

[0012] The molecular weight of the polyethersulfone resin is 5×10 4 ~8×10 4 .

[0013] Furthermore, the formation of the modified polyethersulfone resin emulsion in step a) comprises: adding the modified polyethersulfone resin obtained in step a) into ultrapure water and dispersing it in a high-speed disperser for 4 to 6 hours.

[0014] Furthermore, the preparation of the silane coupling agent aqueous solution in step b) comprises: preparing the silane coupling agent into an aqueous solution with a mass concentration of 0.5% to 0.8%, adding acetic acid to adjust the pH to 5.5, and standing for 2 hours;

[0015] The glass fibers are placed in the silane coupling agent aqueous solution for reaction and drying, comprising: placing a certain amount of glass fibers 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 fibers.

[0016] Furthermore, in step b), the glass fibers 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 to 4:1;

[0017] The average diameter of submicron glass fiber is 0.5μm, and the average diameter of chopped glass fiber is 6μm;

[0018] The silane coupling agent is any one of γ-aminoethylaminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

[0019] Furthermore, in step b), the voltage of the high-voltage direct current electric field is 30-40 kV, and the treatment time of ultraviolet irradiation is 7-9 hours.

[0020] Furthermore, in step c), mixing and dispersing the treated glass fibers obtained in step b) with water to obtain a glass fiber suspension comprises: mixing the treated glass fibers obtained in step b) with deionized water to a concentration of 0.1 to 0.5 wt%, performing ultrasonic dispersion for 35 to 40 minutes, and then further diluting the mixture to a concentration of 0.02 to 0.05 wt% to obtain a glass fiber suspension.

[0021] Furthermore, in step d), the step of mixing and stirring the modified polyethersulfone resin emulsion obtained in step a) with an anionic surfactant to form foam comprises: 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 minutes until foam is generated;

[0022] The thickness of the foam applied to the wet filter material is 3 to 5 cm;

[0023] The anionic surfactant is one or more of fatty alcohol polyoxyethylene ether sulfate, sulfo fatty acid ester salt, fatty alcohol sulfate, and secondary alkyl sulfonate.

[0024] Furthermore, the drying and curing in step d) includes: drying the wet filter material with foam at 105° C. for 2 to 4 minutes, and then curing it at 160 to 180° C. for 5 to 8 minutes.

[0025] Furthermore, the filter material weight of the lubricating oil filter material is 60±5g / m², and the average pore size is 5-10μm.

[0026] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0027] (1) The present invention uses modified polyethersulfone resin as a glass fiber binder, replacing the traditional glass fiber filter material that uses acrylic resin and other binders that are not resistant to high temperatures and water. This greatly improves the overall high temperature resistance and water resistance of the glass fiber filter material, allowing it to maintain good filtering performance in high temperature and high water content environments, and can be widely used in various lubricating oil filtration fields.

[0028] (2) Compared with conventional techniques of directly dipping, coating, or spraying the emulsion, the present invention effectively controls the amount of modified polyethersulfone resin emulsion combined with the silane coupling agent by mixing the modified polyethersulfone resin emulsion with anionic surfactant to form a foam and then applying it to the surface of the wet filter material. The amount of modified polyethersulfone resin emulsion carried by the foam is small and uniform. After the foam is defoamed, the modified polyethersulfone resin molecules and the silane coupling agent molecules react uniformly and fully. The reaction product is evenly attached to the surface of the glass fiber to form a nano-scale film that does not block the pore channels, thereby ensuring good air permeability of the filter material. This allows the filter material of the present invention to have high temperature resistance and water resistance while having low resistance.

[0029] (3) The present invention enhances the adsorption of modified polyethersulfone resin by glass fiber through the multiple effects of silane coupling agent, high-voltage DC electric field and ultraviolet irradiation. During the entire life cycle, the modified polyethersulfone resin and glass fiber are always firmly combined, and the filter material as a whole maintains good high temperature resistance and water resistance.

[0030] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a schematic diagram of the preparation process of the oil filter material of the present invention. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0034] like Figure 1 As shown, the specific process of the preparation method of the lubricating oil filter material is shown.

[0035] The present invention provides a method for preparing a lubricating oil filter material, comprising the following steps:

[0036] (1) According to weight parts, 8-10 parts of polyacrylic acid, 6-10 parts of polyvinyl alcohol, 3-5 parts of dimethylsulfamide, 3-5 parts of ethylenediamine, and 70-80 parts of polyethersulfone resin are mixed, and stirred at room temperature under nitrogen protection for 10-12 hours, and then heated to 60-70°C and continued to react for 24 hours.

[0037] The polyethersulfone resin itself 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 subsequent formation of an aqueous emulsion; dimethylsulfamide acts as a solvent, and ethylenediamine acts as a promoter and cross-linking agent to promote the polymerization reaction.

[0038] (2) adding the reaction product of step (1) to ultrapure water and dispersing it in a high-speed disperser for 4 to 6 hours to form an emulsion;

[0039] (3) Prepare a silane coupling agent into an aqueous solution 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;

[0040] (4) placing a certain amount of glass fiber in the aqueous solution of step (3), heating it in a water bath at 70-80°C under nitrogen protection for 10-12 hours, then washing it with n-hexane and drying it in a vacuum oven for 20-24 hours;

[0041] (5) placing the dried glass fiber in a high-voltage DC electric field and irradiating it with ultraviolet light for 7 to 9 hours;

[0042] (6) Mixing the treated glass fiber with deionized water, performing ultrasonic dispersion, and then further diluting to obtain a glass fiber suspension; performing solid-liquid separation to remove impurities and then dehydrating to form a wet filter material;

[0043] (7) The emulsion and anionic surfactant prepared in step (2) are diluted and mixed and stirred until foam is generated; the foam is then applied to the wet filter material prepared in step (6); the wet filter material with foam is dried and solidified to obtain the filter material.

[0044] Among them, the molecular weight of polyethersulfone resin is 5×10 4 ~8×10 4 .

[0045] Polyethersulfone resin was chosen for its excellent high-temperature resistance (greater than 150°C), but its hydrophobicity limits its application in water-based systems. The modification process optimizes its dispersibility and bonding ability with glass fiber by introducing hydrophilic monomers (such as polyacrylic acid and polyvinyl alcohol).

[0046] The silane coupling agent is any one of γ-aminoethylaminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

[0047] The acidic environment promotes the hydrolysis of silane while avoiding excessively rapid polycondensation to ensure solution stability.

[0048] The glass fibers include submicron glass fibers and chopped glass fibers, wherein the mass ratio of the submicron glass fibers to the chopped glass fibers is 2:1 to 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.

[0049] Submicron glass fiber provides high specific surface area and enhances filtration accuracy; chopped glass fiber provides mechanical strength, and selecting the appropriate mass ratio optimizes the performance balance.

[0050] The voltage of the high-voltage electric field (30~40kV) needs to be controlled within an appropriate range. If it is too low, the effect will be insufficient, and if it is too high, there will be no additional benefits and energy consumption will increase.

[0051] The foam is applied to the wet filter material in step (6) to a thickness of 3 to 5 cm.

[0052] The anionic surfactant is one or more of fatty alcohol polyoxyethylene ether sulfate, sulfo fatty acid ester salt, fatty alcohol sulfate, and secondary alkyl sulfonate.

[0053] The wet filter material is first dried at 105°C for 2 to 4 minutes, and then cured at 160 to 180°C for 5 to 8 minutes.

[0054] The filter material weight is 60±5g / m2 and the average pore size is 5-10μm.

[0055] The anionic surfactant reduces the surface tension of the emulsion and produces a stable foam structure by stirring. The foam carries a small amount of modified polyethersulfone emulsion.

[0056] The foam structure makes the emulsion more evenly distributed, reduces the coating amount and avoids pore clogging.

[0057] Foam coating is an important step in this technology. Compared with traditional dipping, spraying or curtain coating, foam coating significantly reduces initial resistance while ensuring uniform distribution of adhesive.

[0058] It should be noted that there are many chemical compositions to choose from when selecting filter material compositions, but it is more 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 material are not blocked during the preparation process. In addition to the careful selection of the filter material composition, it is also necessary to cooperate with appropriate processing methods.

[0059] 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 so that an aqueous emulsion can be formed in the subsequent process. Ethylenediamine is used as a promoter and crosslinking agent to promote the polymerization reaction.

[0060] If the modified polyethersulfone resin emulsion and the silane coupling agent are directly attached to the wet filter material by various methods such as dipping, curtain coating, and spraying, the filter material obtained after drying has poor air permeability and high resistance. The foam coating method is creatively introduced into the preparation of the filter material. An anionic surfactant is added to the obtained emulsion to form a foam, which is then applied to the surface of the wet filter material and subjected to natural defoaming, drying, and curing to obtain the filter material of the present invention.

[0061] The hydrophilicity of the polyethersulfone resin is increased by modification, and anionic surfactant is added. The solvent is deionized water, which is consistent with the solvent used to treat the glass fiber. It has good compatibility and can better disperse and fuse the modified polyethersulfone resin with the wet filter material.

[0062] The technical effects of this solution will be further demonstrated through specific examples below.

[0063] Example 1

[0064] The present invention provides a method for preparing a lubricating oil filter material, comprising the following steps:

[0065] (1) According to parts by weight, 8 parts of polyacrylic acid, 6 parts of polyvinyl alcohol, 3 parts of dimethylsulfamide, 3 parts of ethylenediamine, and 70 parts of polyethersulfone resin were mixed, and stirred at room temperature for 10 hours under nitrogen protection, and then heated to 60°C and continued to react for 24 hours;

[0066] (2) adding the reaction product of step (1) to ultrapure water and dispersing it in a high-speed disperser for 4 hours to form an emulsion;

[0067] (3) Prepare a silane coupling agent, γ-aminoethylaminopropyltrimethoxysilane, into an aqueous solution with a mass concentration of 0.5%; add acetic acid to adjust the pH to 5.5, and let it stand for 2 hours;

[0068] (4) placing a certain amount of glass fiber in the aqueous solution of step (3), heating it in a water bath at 70°C for 12 hours under nitrogen protection, then washing it with n-hexane and drying it in a vacuum oven for 20 hours;

[0069] (5) The dried glass fiber was placed in a 30 kV high voltage DC electric field and irradiated with ultraviolet light for 9 hours;

[0070] (6) The treated glass fibers were 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; solid-liquid separation was performed to remove impurities and then dehydrated to form a wet filter material;

[0071] (7) The emulsion of step (2) and the anionic surfactant fatty alcohol polyoxyethylene ether sulfate are diluted to a mass concentration of 0.5%, and mixed and stirred for 15 minutes until foam is generated; then the foam is applied to the wet filter material of step (6); the wet filter material with foam is first dried at 105°C for 2 minutes, and then cured at 160°C for 8 minutes to obtain the filter material.

[0072] In this embodiment, 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 filter material is 55 g / m 2 , with an average pore size of 10 μm.

[0073] Example 2

[0074] The present invention provides a method for preparing a lubricating oil filter material, comprising the following steps:

[0075] (1) According to parts by weight, 9 parts of polyacrylic acid, 8 parts of polyvinyl alcohol, 4 parts of dimethylsulfamide, 4 parts of ethylenediamine, and 75 parts of polyethersulfone resin were mixed, and stirred at room temperature for 11 hours under nitrogen protection, and then heated to 65°C and continued to react for 24 hours;

[0076] (2) adding the reaction product of step (1) to ultrapure water and dispersing it in a high-speed disperser for 5 hours to form an emulsion;

[0077] (3) Prepare a silane coupling agent, γ-glycidyloxypropyltrimethoxysilane, into an aqueous solution with a mass concentration of 0.6%; add acetic acid to adjust the pH to 5.5, and let it stand for 2 hours;

[0078] (4) placing a certain amount of glass fiber in the aqueous solution of step (3), heating it in a water bath at 75°C for 11 hours under nitrogen protection, then washing it with n-hexane and drying it in a vacuum oven for 22 hours;

[0079] (5) The dried glass fiber was placed in a 35 kV high voltage DC electric field and irradiated with ultraviolet light for 8 hours;

[0080] (6) The treated glass fibers were mixed with deionized water to a concentration of 0.3 wt%, and ultrasonically dispersed at room temperature for 38 min, and then further diluted to a concentration of 0.04 wt% to obtain a glass fiber suspension; solid-liquid separation was performed to remove impurities and then dehydrated to form a wet filter material;

[0081] (7) The emulsion prepared in step (2) and the anionic surfactant fatty alcohol sulfate are diluted to a mass concentration of 0.8%, and the mixture is stirred for 17 minutes until foam is generated; the foam is then applied to the wet filter material prepared in step (6); the wet filter material with foam is first dried at 105° C. for 3 minutes, and then cured at 170° C. for 6 minutes to obtain the filter material.

[0082] In this embodiment, the molecular weight of the polyethersulfone resin is The mass ratio of 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 filter material is 60 g / m 2 , the average pore size is 8μm.

[0083] Example 3

[0084] The present invention provides a method for preparing a lubricating oil filter material, comprising the following steps:

[0085] (1) According to parts by weight, 10 parts of polyacrylic acid, 10 parts of polyvinyl alcohol, 5 parts of dimethylsulfamide, 5 parts of ethylenediamine, and 70 parts of polyethersulfone resin were mixed, and stirred at room temperature under nitrogen protection for 12 hours, and then heated to 70°C and continued to react for 24 hours;

[0086] (2) adding the reaction product of step (1) to ultrapure water and dispersing it in a high-speed disperser for 6 hours to form an emulsion;

[0087] (3) Prepare a silane coupling agent, γ-methacryloxypropyltrimethoxysilane, into an aqueous solution with a mass concentration of 0.8%; add acetic acid to adjust the pH to 5.5, and let it stand for 2 hours;

[0088] (4) placing a certain amount of glass fiber in the aqueous solution of step (3), heating it in a water bath at 80°C for 10 hours under nitrogen protection, then washing it with n-hexane and drying it in a vacuum oven for 24 hours;

[0089] (5) The dried glass fiber was placed in a 40 kV high voltage DC electric field and irradiated with ultraviolet light for 7 hours;

[0090] (6) The treated glass fibers were mixed with deionized water to a concentration of 0.5 wt %, and ultrasonically dispersed at room temperature for 40 min, and then further diluted to a concentration of 0.05 wt % to obtain a glass fiber suspension; solid-liquid separation was performed to remove impurities and then dehydrated to form a wet filter material;

[0091] (7) The emulsion prepared in step (2) and the anionic surfactant secondary alkyl sulfonate are diluted to a mass concentration of 1%, and the mixture is stirred for 20 minutes until foam is generated; the foam is then applied to the wet filter material prepared in step (6); the wet filter material with foam is first dried at 105° C. for 4 minutes, and then cured at 180° C. for 5 minutes to obtain the filter material.

[0092] In this embodiment, the molecular weight of the polyethersulfone resin is The mass ratio of 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 filter material is 65 g / m 2 , the average pore size is 5μm.

[0093] Comparative Example 1

[0094] The other steps are the same as those 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%.

[0095] Comparative Example 2

[0096] The other steps are the same as those 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%.

[0097] Comparative Example 3

[0098] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that the preparation method does not include step (3) and step (4).

[0099] Comparative Example 4

[0100] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that there is no step (5) in the preparation method.

[0101] Comparative Example 5

[0102] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, there is no ultraviolet irradiation in step (5).

[0103] Comparative Example 6

[0104] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, there is no high voltage electric field in step (5).

[0105] Comparative Example 7

[0106] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, the high voltage electric field voltage in step (5) is 25 kV.

[0107] Comparative Example 8

[0108] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, the high voltage electric field voltage in step (5) is 45 kV.

[0109] Comparative Example 9

[0110] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, the emulsion and the anionic surfactant in step (5) are diluted to a mass concentration of 0.4%.

[0111] Comparative Example 10

[0112] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, the emulsion and the anionic surfactant in step (5) are diluted to a mass concentration of 1.1%.

[0113] Comparative Example 11

[0114] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, no anionic surfactant is added in step (7), and the wet filter material in step (6) is impregnated after the emulsion is diluted.

[0115] Comparative Example 12

[0116] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, no anionic surfactant is added in step (7), and after the emulsion is diluted, the wet filter material in step (6) is sprayed.

[0117] Comparative Example 13

[0118] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, no anionic surfactant is added in step (7), and after the emulsion is diluted, the wet filter material in step (6) is curtain coated.

[0119] Comparative Example 14

[0120] The other steps are the same as those in Example 1. The difference between this comparative example and Example 1 is that in the preparation method, step (1) is omitted, and in step (2), the reaction product of step (1) is replaced with polyacrylic acid resin.

[0121] Measurement items and methods:

[0122] (1) Temperature resistance test (see Table 1 for test results)

[0123] Test method:

[0124] First, according to Section 5.4 of GB / T14041.2-2007, the filter materials of Examples 1-3 and Comparative Examples 1-14 were immersed in lubricating oil at 215°C for 72 hours. Then, the following parameters were tested together with the filter materials that were not immersed in the high-temperature oil:

[0125] Filtration accuracy (β (c)): Refer to the test standard: GB / T18853-2015 Chapter 11, and the filter material is passed through the test bench multiple times.

[0126] Initial resistance: Refer to the test standard: GB / T18853-2015 Chapter 11, and perform the test after the filter material passes through the test bench multiple times.

[0127] Test conditions:

[0128] Flow rate: 3 L / min, upstream contamination: 10 mg / L, sample area: 100 cm2, termination pressure drop: 400 kPa.

[0129] Table 1 Temperature resistance test results

[0130]

[0131] From the results in Table 1, it can be seen that the filtration accuracy and initial resistance of the filter materials of Examples 1, 2 and 3 remain stable before and after being immersed in high-temperature oil, and they have good high-temperature resistance.

[0132] Compared with Comparative Examples 1 and 2, it can be seen that if the mass concentration of the silane coupling agent is too low, the high temperature resistance will be reduced. If the mass concentration is too high, although it will not reduce the high temperature resistance, it will cause an increase in initial resistance. Therefore, the mass concentration of the silane coupling agent must be within an appropriate range. Compared with Comparative Example 3, it can be seen that it is necessary to add a silane coupling agent, otherwise the modified polyethersulfone resin will not be firmly bonded to the glass fiber. During the experiment, under the impact of the oil, part of the modified polyethersulfone resin will fall off, which will cause a decrease in filtration accuracy. According to the decrease in filtration accuracy, it can be inferred that the resin has fallen off. Compared with Comparative Examples 4, 5 and 6, it can be seen that both high-voltage electric field and ultraviolet irradiation can enhance the bonding effect of the modified polyethersulfone resin and the glass fiber, thereby improving the high temperature resistance of the filter material.

[0133] Comparing Example 1 with Comparative Examples 7 and 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 of the filter material will be reduced; if the voltage is too high, the high-temperature resistance will not be improved and energy consumption will be increased. Therefore, the voltage of the high-voltage electric field must be within an appropriate range.

[0134] Comparing Example 1, Comparative Example 9 and Comparative Example 10, it can be seen that the dilution concentration of the emulsion and the anionic surfactant is too low. Although the initial resistance is slightly reduced, the high temperature resistance is weakened, resulting in a decrease in filtration accuracy.

[0135] Comparing Example 1, Comparative Example 11, Comparative Example 12 and Comparative Example 13, it can be seen that the use of traditional dipping, spraying or curtain coating will cause a significant increase in initial resistance, indicating that the foam coating process of the present invention is beneficial to reducing initial resistance.

[0136] Comparing Example 1 with Comparative Example 14, it can be seen that the modified polyethersulfone resin of the present invention, as a binder, significantly improves high-temperature resistance compared to conventional polyacrylic resin. Polyacrylic resin tends to fall off the glass fiber surface at high temperatures, resulting in reduced filtration accuracy, while also reducing initial resistance.

[0137] (2) Water resistance test (see Table 2 for test results)

[0138] Test method:

[0139] Pure water was poured into an ultrasonic tank, and the filter materials of Examples 1 to 3 and Comparative Examples 1 to 14 were immersed therein. Ultrasonic oscillation was turned on, and changes in the appearance of the filter materials were observed every half an hour.

[0140] Test conditions:

[0141] Water temperature: room temperature; soaking time: 2h.

[0142] Table 2 Water resistance test results

[0143]

[0144] From the results in Table 2, it can be seen that the filter materials of Examples 1, 2 and 3 all have good water resistance.

[0145] 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 the silane coupling agent must be present, otherwise the water resistance will be reduced. Comparing Example 1, Comparative Examples 4 to Comparative Examples 8, it can be seen that the high-voltage electric field and ultraviolet irradiation play an important role in enhancing the bonding strength between the modified polyethersulfone and the glass fiber, and neither of them can be missing, otherwise the water resistance will be reduced. In addition, too low a high-voltage electric field voltage 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 Examples 11 to Comparative Examples 13, it can be seen that the modified polyethersulfone coating method 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 to traditional polyacrylic resin.

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a lubricating oil filter material, characterized in that: a) Preparation of a modified polyethersulfone resin emulsion: mixing a polyethersulfone resin with polyacrylic acid, polyvinyl alcohol, dimethylsulfamide, and ethylenediamine to obtain a modified polyethersulfone resin; and then dispersing the modified polyethersulfone resin in water to form a modified polyethersulfone resin emulsion; b) surface treatment of the glass fiber: preparing an aqueous solution of a silane coupling agent; placing the glass fiber in the aqueous solution of the silane coupling agent for reaction and drying to obtain a dried glass fiber; and placing the dried glass fiber in a high-voltage direct current electric field and simultaneously irradiating it with ultraviolet light to obtain a treated glass fiber; c) Preparation of wet filter material: mixing and dispersing the treated glass fibers obtained in step b) with water to obtain a glass fiber suspension, and subjecting the suspension to solid-liquid separation and dehydration to form a wet filter material; d) Foam coating and molding: the modified polyethersulfone resin emulsion obtained in step a) is mixed with an anionic surfactant to form foam; the foam is coated on the wet filter material obtained in step c), and then dried and solidified to obtain the lubricating oil filter material.

2. The method for preparing the lubricating oil filter material according to claim 1, characterized in that: The preparation of the modified polyethersulfone resin in step a) comprises: mixing, by weight, 8 to 10 parts of polyacrylic acid, 6 to 10 parts of polyvinyl alcohol, 3 to 5 parts of dimethylsulfamide, 3 to 5 parts of ethylenediamine, and 70 to 80 parts of polyethersulfone resin; stirring and reacting the mixture at room temperature for 10 to 12 hours under nitrogen protection; then heating the mixture to 60 to 70° C. and continuing the reaction for 24 hours; The molecular weight of the polyethersulfone resin is 5×10 4 ~8×10 4 .

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

4. The method for preparing the lubricating oil filter material according to claim 1, characterized in that: The preparation of the silane coupling agent aqueous solution in step b) comprises: preparing the silane coupling agent into an aqueous solution with a mass concentration of 0.5% to 0.8%, adding acetic acid to adjust the pH to 5.5, and standing for 2 hours; The glass fibers are placed in the silane coupling agent aqueous solution for reaction and drying, comprising: placing a certain amount of glass fibers 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 fibers.

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

6. The method for preparing the lubricating oil filter material according to claim 5, characterized in that: The voltage of the high-voltage direct current electric field in step b) is 30-40 kV, and the ultraviolet irradiation treatment time is 7-9 hours.

7. The method for preparing the lubricating oil filter material according to claim 1, characterized in that: The step c) of mixing and dispersing the treated glass fibers obtained in step b) with water to obtain a glass fiber suspension comprises: mixing the treated glass fibers obtained in step b) with deionized water to a concentration of 0.1 to 0.5 wt%, ultrasonically dispersing the mixture for 35 to 40 minutes, and then further diluting the mixture to a concentration of 0.02 to 0.05 wt% to obtain a glass fiber suspension.

8. The method for preparing the lubricating oil filter material according to claim 1, characterized in that: The step d) of mixing and stirring the modified polyethersulfone resin emulsion obtained in step a) with an anionic surfactant to form foam comprises: 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 minutes until foam is generated; The thickness of the foam applied to the wet filter material is 3 to 5 cm; The anionic surfactant is one or more of fatty alcohol polyoxyethylene ether sulfate, sulfo fatty acid ester salt, fatty alcohol sulfate, and secondary alkyl sulfonate.

9. The method for preparing the lubricating oil filter material according to claim 8, characterized in that: The drying and curing in step d) comprises: drying the wet filter material with foam at 105° C. for 2 to 4 minutes, and then curing it at 160 to 180° C. for 5 to 8 minutes.

10. The method for preparing the lubricating oil filter material according to claim 1, characterized in that: The filter material basis weight of the lubricating oil filter material is 60±5g / m², and the average pore size is 5-10μm.

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