A lubricating oil filter material and its manufacturing process

Abstract

The present application discloses a lubricating oil filter material and its manufacturing process, which belongs to the technical field of filter materials; The lubricating oil filter material of the present application comprises, from the outside inwards, a coarse filter layer, a dewatering layer and a fine filter layer; The coarse filter layer uses a polyester fiber filter cloth with a pore size of 5-100 μm; The fine filter layer uses glass fiber filter paper with an accuracy of 0.5-20 μm; The dewatering layer comprises a water-absorbing nanofiber membrane layer and a water-absorbing polyurethane layer adhering to the surface of the nanofiber membrane layer; The composite nanofiber membrane layer is obtained by a mixing reaction and spinning of an acrylic acid-acrylamide copolymer, citric acid-modified polyvinyl alcohol and the crosslinking agent glutaraldehyde;The water-absorbing polyurethane layer is obtained by reacting an ion-exchange resin with a core-shell structure, an isocyanate monomer, polyethylene glycol, and tris(3-hydroxypropyl)amine, followed by the addition of an antioxidant; the acrylic acid-acrylamide copolymer is obtained by copolymerization of acrylic acid, acrylamide, and 2-(bromomethyl)acrylate.

Description

2 These filter materials have a certain effect on the removal of mechanical contaminants. They can effectively retain solid particles in the lubricating oil and thus maintain the cleanliness of the lubricating oil to a certain extent. However, they have significant limitations, namely that they only have the single function of removing mechanical contaminants and are not able to treat water in the lubricating oil.

[0004] For the purification and dewatering of lubricating oil, the existing main methods are vacuum dewatering and coalescing separation. The vacuum dewatering method has low efficiency, the treatment process is time-consuming and consumes large amounts of energy. Coalescence separation can achieve dewatering to a certain extent, but the removal accuracy is limited. The effectiveness in removing tiny water droplets is not good. At the same time, its dirt-holding capacity is extremely poor. The filter material clogs easily and must be replaced frequently.More importantly, both dehydration methods require heating of the oil product. Repeated heating of the oil product can promote further oxidation of the oil product, accelerate the deterioration of the lubricating oil, reduce the service life of the oil product, and increase the operating costs and maintenance difficulties of the equipment.

[0005] In practical device applications, it is necessary both to remove water from the lubricating oil and to eliminate mechanical contaminants. To achieve these two functions, it is common to combine different functional units, i.e., to connect a drainage device and a device for removing mechanical contaminants. However, this type of combination of functional units can increase the space requirement of the devices, make the device structure more complex, increase the difficulties in installation and maintenance, and also increase the manufacturing costs and the footprint of the devices.BE2025 / 5518 3

[0006] In summary, there is a pressing market need for a lubricating oil filter material that can effectively remove solid particles in the lubricating oil and also efficiently remove water. TECHNICAL BACKGROUND 5

[0007] The present application relates to a lubricating oil filter material and its manufacturing process. CONTENTS OF THE INVENTION 10

[0008] The purpose of the present application is to provide a lubricating oil filter material and its manufacturing process to solve the technical problems mentioned above in the prior art.

[0009] The technical solution for achieving the purpose of the present application is:

[0010] In a first embodiment, the present application discloses a lubricating oil filter material. The composite filter material has a triple action: efficient dewatering, removal of acid oxides, and efficient retention of precisely solid particles. It comprises, from the outside to the inside, a coarse filter layer, a dewatering layer, and a fine filter layer.The drainage layer comprises a water-absorbing nanofiber membrane layer and a water-absorbing polyurethane layer adhering to the surface of the nanofiber membrane layer. 25

[0011] The lubricating oil filter material of the present application comprises, from the outside inwards, a coarse filter layer, a drainage layer and a fine filter layer. BE2025 / 5518 4 The drainage layer comprises a water-absorbing nanofiber membrane layer and a water-absorbing polyurethane layer adhering to the surface of the nanofiber membrane layer, thereby increasing the water absorption capacity of the drainage layer. Dewatering of lubricating oil can 5 already take place at room temperature. During the filtration of lubricating oil, the oil is first passed through the coarse filter layer to retain large solid particles. It then passes through the drainage layer for dewatering. Finally, it passes through the fine filter layer to retain and filter any remaining smaller solid particles in the dehydrated lubricating oil.This allows the effective removal of solid particles from the lubricating oil and the efficient removal of water from the lubricating oil to be achieved by using only the lubricating oil filter material produced in the present application for filtration of lubricating oil. 15

[0012] Furthermore, the coarse filter layer uses a polyester fiber filter cloth with a pore size of 5~100μm to retain large solid particles.

[0013] Furthermore, the water-absorbing nanofiber membrane layer is obtained by mixing reaction and spinning of acrylic acid, acrylamide, 2-20 (bromomethyl) acrylate, citric acid-modified polyvinyl alcohol, and the crosslinking agent glutaraldehyde. Modifying polyvinyl alcohol with citric acid produces a citric acid-modified polyvinyl alcohol with a branched structure, where citric acid serves as the branching center and polyvinyl alcohol as the side chain. Simultaneously, acrylic acid, acrylamide, and 2-(bromomethyl)acrylate are polymerized to form a water-absorbing nanofiber membrane layer with an interpenetrating network.BE2025 / 5518 5 This simultaneously increases the water absorption capacity of the water-absorbing nanofiber membrane layer and effectively improves its water resistance.

[0014] Furthermore, the water-absorbing polyurethane layer is obtained by reacting a core-shell ion exchange resin, an isocyanate monomer, polyethylene glycol, and tris(3-hydroxypropyl)amine, and subsequently combining it with an antioxidant. The amino groups on the surface of the core-shell ion exchange resin, the hydroxyl groups on polyethylene glycol, and tris(3-hydroxypropyl)amine react with the isocyanate groups of the isocyanate monomer and form a water-absorbing polyurethane with a branched structure, wherein the core-shell ion exchange resin and tris(3-hydroxypropyl)amine serve as branching centers and polyethylene glycol urethane as side chains.By introducing cavities, the water-absorbing polyurethane can simultaneously ensure good water absorption capacity, further filter out solid particle impurities in the lubricating oil, and effectively improve the water resistance of the water-absorbing polyurethane layer. Furthermore, the introduction of the core-shell ion exchange resin results in the surface of the water-absorbing polyurethane layer having a micro- / nano-structured hydrophilic surface with protrusions. When the dewatering layer comes into contact with undrained lubricating oil, water comes into contact with the hydrophilic micro- / nano-surface structure and is trapped within the structure. A water film forms on the surface of the dewatering layer. By exploiting the incompatibility of oil and water, the oil phase and the water phase in the lubricating oil are separated, thereby achieving a dehydration effect and an effect of the residue-free oil phase on the dehydration layer after separation.30 BE2025 / 5518 6 The introduction of the antioxidant ensures that the lubricating oil is less susceptible to oxidation during the filtration process.

[0015] The core-shell ion exchange resin is produced by first producing polystyrene microspheres by emulsion polymerization.5 Subsequently, the polystyrene microspheres are sulfonated. Then, a hydrolysis reaction with tetraethyl orthosilicate is carried out on the surface of the sulfonated polystyrene microspheres to form a silicon dioxide layer. After that, a modification is carried out with 1,2-bis(trimethoxysilyl)ethane, 3-[2-(imidazol-1-yl)ethyl]propyltriethoxysilane, and 10,3-aminopropyltriethoxysilane. Furthermore, the surfactant cetyltrimethylammonium bromide (CTAB) is removed from the reaction process by solvent extraction, thereby forming an esoporous silicon dioxide shell layer to obtain the core-shell ion exchange resin.By modifying the sulfonated polystyrene microspheres coated with a silicon dioxide layer with the silicon dioxide layer formed by hydrolysis of 3-[2-(imidazol-1-yl)ethyl]propyltriethoxysilane, 3-aminopropyltriethoxysilane and 1,2-bis(trimethoxysilyl)ethane, the hydrophilicity of the sulfonated polystyrene microspheres and their dispersibility in the water-absorbing polyurethane layer can be effectively improved.

[0016] Furthermore, the fine filter layer uses glass fiber filter paper with an accuracy of 0.5 to 20 μm to further filter the dehydrated lubricating oil and retain any remaining smaller solid particles in the dehydrated lubricating oil.

[0017] Furthermore, the lubricating oil filter material can also be used for the filtration and purification of gasoline, diesel, and other organic liquids. BE2025 / 5518 7

[0018] In a second embodiment, a manufacturing process for a lubricating oil filter material according to the first embodiment, characterized by the following manufacturing steps:

[0019] S1.The water-absorbing nanofiber membrane layer is immersed in water-absorbing polyurethane for 4-6 minutes and then pulled out vertically. Subsequently, it is dried in an oven at 60°C for 23-25 ​​hours and stored in a sealed environment for 2 days to obtain the drainage layer. In this step, a water-absorbing polyurethane layer forms on the surface of the water-absorbing nanofiber membrane layer. Simultaneously, imidazole and tertiary amine in the polyurethane layer react with bromoethane in the water-absorbing nanofiber membrane layer, consuming hydrophobic bromoethane and forming hydrophilic imidazolium salts and quaternary ammonium salts. This gives the drainage layer good antibacterial properties, further enhances the water absorption capacity of the drainage layer, and simultaneously adheres the water-absorbing polyurethane layer firmly to the surface of the water-absorbing nanofiber membrane layer, thereby improving the water resistance of the drainage layer.

[0020] S3.From the outside in, the coarse filter layer, the dewatering layer produced in step S1, and the fine filter layer are successively layered on top of each other. They are then folded into a continuous W-shape to obtain the lubricating oil filter material.

[0021] The manufacturing steps of the water-absorbing nanofiber membrane layer further comprise: BE2025 / 5518 8

[0022] A1.2 parts by mass of polyvinyl alcohol are mixed with 20 parts by mass of deionized water. The mixture is heated to 88-92°C while stirring. After complete dissolution of polyvinyl alcohol in deionized water, the mixture is cooled to a reaction temperature of 58–62 °C. A 0.8–0.9 g / mL citric acid-5 water solution comprising 18–20 parts by mass is then added dropwise at a rate of 1 drop per second. After completion of the dropwise addition, the mixture is held at temperature for 3 hours. Stirring is then stopped. Absolute ethanol is added as a precipitant to precipitate the product from the solution. The mixture is then filtered off.Then, it is extracted for 11.5–12.5 hours with 10% absolute ethanol in a Soxhlet extractor. It is vacuum-dried at 28–32°C to obtain citric acid-modified polyvinyl alcohol; 1 part by mass of citric acid-modified polyvinyl alcohol is mixed with 9 parts by mass of deionized water, stirred, and heated to 90–95°C. Stirring is continued until the citric acid-modified polyvinyl alcohol is dissolved to obtain a 10% aqueous solution of citric acid-modified polyvinyl alcohol.

[0023] A2. In an ice-water bath, 3 parts by mass of acrylic acid are neutralized with a 20% sodium hydroxide solution. Then, at room temperature, 1 to 1.5 parts by mass of acrylamide are added and mixed evenly. Next, 0.07 to 0.09 parts by mass of emulsifier are added, stirred evenly, and dispersed. Then, 0.1 to 0.3 parts by mass of 2-(bromomethyl)acrylate are added, and stirring and dispersing are continued.Then, 7–8 parts by mass of a 10% aqueous solution of citric acid-modified polyvinyl alcohol, 25 parts by mass of initiator potassium persulfate, and 23–24 parts by mass of deionized water are added. The mixture is stirred at 90 rpm for 25–35 minutes under a nitrogen atmosphere at 38–42 °C. It is then heated to 68–72 °C and stirred for 55–65 minutes. Next, it is heated to 78–82 °C and stirred at 130–140 rpm for 25–35 minutes. After the reaction is complete, the mixture is cooled to 58–62 °C while stirring and 0.18–0.20 parts by mass of a 25% glutaraldehyde-water solution are added to obtain the spinning solution.

[0024] A3. The spinning solution is sonicated and deaerated for 25-30 minutes using an ultrasonic cleaner. It is then placed in an electrospinning machine and spun with aluminum foil as a collector screen. After spinning, it is treated at 155-160°C for 28-32 minutes. Subsequently, it is immediately placed in a vacuum storage container, evacuated, and stored to preserve the water-absorbing nanofiber membrane layer.

[0025] The manufacturing steps of the water-absorbing polyurethane layer further comprise:

[0026] 5 parts by mass of polyethylene glycol, 1.2 to 1.3 parts by mass of tris(3-hydroxypropyl)amine, and 50 to 55 parts by mass of N,N-dimethylacetamide are mixed and then heated to 58 to 62 °C and stirred for 55 to 65 minutes. Subsequently, 0.3 to 0.8 parts by mass of core-shell ion exchange resin are added and ultrasonically treated and dispersed for 55 to 65 minutes. Then, 14 to 18 parts by mass of isophorone diisocyanate and 0.0002 to 0.0004 parts by mass of catalyst dibutyltin(IV) dilaurate are added. It is heated to 78 to 82 °C and The reaction continues for 4.5–5.5 hours with stirring. It is then cooled to 38–42°C and a 10–20% N,N-dimethylacetamide-water solution is added. The reaction is continued for 23–25 hours. After cooling to room temperature, 0.02–0.04 parts by mass of antioxidant are added to obtain the water-absorbing polyurethane layer with a solids content of 20–40%.

[0027] The manufacturing steps of the core-shell ion exchange resin further comprise: BE2025 / 5518 10

[0028] (1) 0.55–0.65 parts by mass of polyvinylpyrrolidone are dissolved in 50 parts by mass of deionized water. Then 5.90–5.92 parts by mass of styrene are added. It is heated to 74–76 °C and heated for 8–12 minutes. The mixture is held under a nitrogen atmosphere for a long time. Finally, the initiator solution, prepared by dissolving 0.14–0.16 parts by mass of potassium persulfate in 20 parts by mass of water, is added. The reaction continues for 23–25 hours. The mixture is centrifuged and washed 2–4 times with deionized water and absolute ethanol. It is then dried in a freeze dryer to obtain polystyrene microspheres.

[0029] (2) Under nitrogen protection, stirring and reflux cooling, 10 0.15-0.25 parts by mass of polystyrene microspheres are added to a mixture consisting of 265-266 parts by mass of dichloromethane and 17-18 parts by mass of chlorosulfonic acid. The mixture is then sulfonated at 55-65°C for 5-7 hours. Finally, it is washed with deionized water until the pH is neutral.15. Then it is centrifuged and washed 2-4 times with absolute ethanol. Subsequently, it is dried overnight in a freeze dryer to obtain sulfonated polystyrene microspheres;

[0030] (3) 0.2 parts by mass of sulfonated polystyrene microspheres, 60 parts by mass of deionized water, 15-16 parts by mass of absolute ethanol, 0.15-0.25 parts by mass of cetyltrimethylammonium bromide (CTAB) and 0.65-0.69 parts by mass of 10% ammonia solution are treated ultrasonically for 13-17 min and then heated to 48-52°C. Stirring continues for 25-35 min. Then 0.4-0.6 parts by mass of tetraethyl orthosilicate are added and the reaction is carried out for 1.5-2.5 h while stirring. Afterward, a solution consisting of 0.07-0.09 parts by mass of CTAB and 0.18-0.20 parts by mass of 10% ammonia solution is added. Ammonia water, in 2.3–2.4 parts by mass of ethanol, is added and stirred for 0.4–0.6 hours. BE2025 / 5518 11. Subsequently, a solution of 0.2–0.3 parts by mass of 1,2-bis(trimethoxysilyl)ethanine and 1.5–1.7 parts by mass of absolute ethanol is added. After 4–6 minutes.Stirring, 0.07–0.09 parts by mass of 3-[2-(imidazol-1-yl)ethyl]propyltriethoxysilane and 0.076–0.080 parts by mass of 3-aminopropyltriethoxysilane are added. The reaction is carried out for 1–2 hours at 45–55°C. Finally, the temperature is increased to 78–82°C and the reaction is carried out for 55–65 minutes. The mixture is centrifuged and purified 4–6 times with absolute ethanol and deionized water. Subsequently, the resulting microspheres are dispersed uniformly in 79–80 parts by mass of acetone. After reacting at 70°C for 11–13 hours, they are centrifuged and washed 5–7 times with 10 parts by mass of deionized water and absolute ethanol. to obtain the ion exchange resin with core-shell structure.

[0031] After applying the above-described technical solution, the present application has the following advantageous effects:

[0032] (1)The lubricating oil filter material of the present application comprises, from the outside inwards, a coarse filter layer, a dewatering layer and a fine filter layer.The dewatering layer comprises a water-absorbing nanofiber membrane layer and a water-absorbing polyurethane layer adhering to the surface of the nanofiber membrane layer, thereby increasing the water absorption capacity of the dewatering layer. Dewatering of lubricating oil can take place even at room temperature. During the filtration of lubricating oil, the oil is first passed through the coarse filter layer to retain large solid particles. It then passes through the dewatering layer for dewatering. Finally, it passes through the fine filter layer to retain and filter out any remaining smaller solid particles in the dewatered lubricating oil. BE2025 / 5518 12 Thus, by using only the lubricating oil filter material produced in the present application for the filtration of lubricating oil, the effective removal of solid particles from the lubricating oil and the efficient removal of water from the lubricating oil can be achieved.

[0033] (2) The coarse filter layer of the present application uses a polyester fiber filter cloth with a pore size of 5 ~ 100 μm to retain large solid particles.

[0034] (3) The water-absorbing nanofiber membrane layer of the present application is obtained by mixing reaction and spinning of acrylic acid, acrylamide, 2-(bromomethyl)acrylate, citric acid-modified polyvinyl alcohol, and the crosslinking agent glutaraldehyde. The modification of polyvinyl alcohol with citric acid forms a citric acid-modified polyvinyl alcohol with a branched structure, where citric acid serves as the branching center and polyvinyl alcohol as the side chain. Simultaneously, acrylic acid, acrylamide, and 2-(bromomethyl)acrylate are polymerized to form a water-absorbing nanofiber membrane layer with an interpenetrating network. This simultaneously increases the water absorption capacity of the water-absorbing nanofiber membrane layer and effectively improves its water resistance.20

[0035] (4)The water-absorbing polyurethane layer of the present application is obtained by reaction of an ion exchange resin with a core-shell structure, an isocyanate monomer, polyethylene glycol and tris(3-hydroxypropyl)amine and subsequent composition with an antioxidant.25 BE2025 / 5518 13 The amino groups on the surface of the ion exchange resin with a core-shell structure, the hydroxyl groups on polyethylene glycol and tris(3-hydroxypropyl)amine react with the isocyanate groups of the isocyanate monomer and form a water-absorbing polyurethane with a branched structure, wherein the ion exchange resin with a core-shell structure and tris(3-hydroxypropyl)amine serve as branching centers and polyethylene glycol urethane as side chains. By introducing cavities, the water-absorbing polyurethane can simultaneously ensure good water absorption capacity, further filter out solid particle impurities in the lubricating oil, and effectively improve the water resistance of the water-absorbing polyurethane layer.Furthermore, the introduction of the core-shell ion exchange resin creates adsorption sites in the water-absorbing polyurethane layer that adsorb soluble paint film. Through hydrogen ion exchange, the sulfonic acid groups in the core-shell ion exchange resin remove metallic cations and basic impurities in the lubricating oil, as well as soluble paint film and paint film precursors containing metallic cations. Additionally, the introduction of the core-shell ion exchange resin results in the surface of the water-absorbing polyurethane layer exhibiting a micro- / nanostructured hydrophilic surface with protrusions. When the drainage layer comes into contact with undrained lubricating oil, water interacts with the hydrophilic micro- / nano surface structure and is trapped within it. A water film forms on the surface of the drainage layer.By exploiting the incompatibility of oil and water, the oil phase and the water phase in the lubricating oil are separated, thereby achieving a dehydration effect and an effect of the residue-free oil phase on the dehydration layer after separation. The introduction of the antioxidant ensures that the lubricating oil is less susceptible to oxidation during the filtration process. BE2025 / 5518 14

[0036] (5) The core-shell ion exchange resin of the present application is produced by first producing polystyrene microspheres by emulsion polymerization. The polystyrene microspheres are then sulfonated. A hydrolysis reaction with tetraethyl orthosilicate is then carried out on the surface of the five sulfonated polystyrene microspheres to form a silicon dioxide layer. This is followed by a modification with 1,2-bis(trimethoxysilyl)ethane, 3-[2-(imidazol-1-yl)ethyl]propyltriethoxysilane, and 3-aminopropyltriethoxysilane.Furthermore, the surfactant cetyltrimethylammonium bromide (CTAB) is removed from the reaction process by 10 solvent extractions, which forms an esoporous silicon dioxide shell layer to obtain the core-shell ion exchange resin. By modifying the silicon dioxide-coated sulfonated polystyrene microspheres with the silicon dioxide layer formed by hydrolysis of 3-[2-15 (imidazol-1-yl)ethyl]propyltriethoxysilane, 3-aminopropyltriethoxysilane, and 1,2-bis(trimethoxysilyl)ethane, the hydrophilicity of the sulfonated polystyrene microspheres and their dispersibility in the water-absorbing polyurethane layer can be effectively improved. 20

[0037] (6) The fine filter layer of the present application uses glass fiber filter paper with an accuracy of 0.5–20 μm to further filter the dehydrated lubricating oil and to retain remaining smaller solid particles in the dehydrated lubricating oil.

[0038] (7)In the production of the drainage layer of the present 25 application, the water-absorbing nanofiber membrane layer is immersed in water-absorbing polyurethane to form a water-absorbing polyurethane layer on its surface. BE2025 / 5518 15 Simultaneously, imidazole and tertiary amine in the polyurethane layer react with bromoethane in the water-absorbing nanofiber membrane layer, consuming hydrophobic bromoethane and forming hydrophilic imidazolium salts and quaternary ammonium salts. This gives the drainage layer good antibacterial properties, further enhances the water absorption capacity of the drainage layer, and simultaneously ensures that the water-absorbing polyurethane layer adheres firmly to the surface of the water-absorbing nanofiber membrane layer, thereby improving the water resistance of the drainage layer. In addition, the introduced imidazolium and ammonium salts lead to the adsorption of anionic impurities such as sulfate, chloride, organic acid residues, and other acidic impurities.They remove acid oxides and organic acids contained in oxidized and degraded lubricating oils.

[0039] (8) The lubricating oil filter material produced according to the present application can also be used for the filtration and purification of gasoline, diesel, and other organic liquids.

[0040] FIGURES

[0041] To make the contents of the present application easier to understand, the present application is further described below with reference to specific embodiments and with reference to the figure, wherein:

[0042] Figure 1 shows a schematic representation of the structure of the lubricating oil filter material of the present application.

[0043] The reference numerals in the figure denote: Coarse filter layer 1, Dehydration layer 2, Fine filter layer 3; BE2025 / 5518 16 SPECIFIC EXECUTIONS

[0044] In order to better understand the technical solution described above, it is described in detail below with reference to the drawings and specific execution forms.5

[0045] In order to more clearly illustrate the purpose, the technical solution and the advantages of the embodiment of the present application, the embodiments of the present application are described clearly and completely below with reference to the drawings of the present application. It is obvious that the 10 embodiments described represent a part of the embodiments of the present application and not all embodiments. Components of the embodiment of the present application, which are described and illustrated in the drawings attached herein, can be in various different configurations.