Preparation method of high-temperature resistant microporous liquid filtering material

Abstract

The present invention discloses a preparation method of a high-temperature resistant microporous liquid filtration material, belonging to the technical field of filtration materials. The preparation method consists of the following steps: drying PBT chips, preparing water-repellent masterbatch, preparing oil-repellent masterbatch, mixing and granulating, preparing the upper-layer PBT meltblown non-woven fabric, preparing the middle-layer PBT meltblown non-woven fabric, preparing the lower-layer PBT meltblown non-woven fabric, compounding, and post-treatment; for the mixing and granulating, the dried PBT chips, water-repellent masterbatch, and oil-repellent masterbatch are added into a high-speed mixer and a twin-screw extruder for mixing and granulating, and after the granulation is completed, mixed PBT chips are obtained. The present invention can improve the processing fluidity, mechanical strength, and flame retardancy of the high-temperature resistant microporous liquid filtration material, while improving the filtration accuracy, hydrophobicity, oil repellency, and high-temperature resistance of the high-temperature resistant microporous liquid filtration material.

Description

Technical Field

[0001] The present invention relates to the technical field of filter materials, and specifically relates to a preparation method of a high-temperature resistant microporous liquid filter material. Background Art

[0002] Filter materials are key and common materials widely used in industries such as petrochemical, environmental protection, energy, automotive, and in the field of people's livelihood. Liquid filter materials refer to filter materials used for filtering liquids, and their main function is to remove impurities in the liquid to make it purer. Liquid filter materials are mainly applied in fields such as food, medicine, petrochemical industry, environmental protection, etc. Especially in the petrochemical industry, environmental protection and upstream and downstream industries, they have very wide applications. The selection of liquid filter materials plays an important role in the safe and reliable operation of equipment, the improvement of production efficiency, the reduction of energy consumption, and the guarantee of product quality.

[0003] Polybutylene terephthalate (PBT) meltblown nonwoven fabric has fine fibers, good hydrophobicity, oleophobicity, and high-temperature resistance, and is an ideal fuel filter material. It is widely used in liquid filtration in the petrochemical and environmental protection fields as a microporous liquid filter material. However, PBT has poor processing fluidity, low mechanical strength, and poor flame retardancy, which affect the production and application of PBT meltblown nonwoven fabric. To solve the above problems, the most commonly used method at present is to add additives such as flow modifiers, reinforcing fillers, and flame retardant fillers. However, the addition of additives will cause the fiber diameter to become larger, resulting in a decrease in the filtration accuracy of PBT meltblown nonwoven fabric, and will also affect the hydrophobicity, oleophobicity, and high-temperature resistance of the prepared PBT meltblown nonwoven fabric. Therefore, how to improve the processing fluidity, mechanical strength, and flame retardancy of PBT meltblown nonwoven fabric while improving the filtration accuracy, hydrophobicity, oleophobicity, and high-temperature resistance of PBT meltblown nonwoven fabric is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the present invention provides a preparation method of a high-temperature resistant microporous liquid filter material, which can improve the processing fluidity, mechanical strength, and flame retardancy of the high-temperature resistant microporous liquid filter material while improving the filtration accuracy, hydrophobicity, oleophobicity, and high-temperature resistance of the high-temperature resistant microporous liquid filter material.

[0005] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] A preparation method of a high-temperature resistant microporous liquid filter material, which consists of the following steps: drying PBT chips, preparing water-repellent masterbatch, preparing oil-repellent masterbatch, mixing and granulating, preparing the upper layer of PBT meltblown nonwoven fabric, preparing the middle layer of PBT meltblown nonwoven fabric, preparing the lower layer of PBT meltblown nonwoven fabric, laminating, and post-treatment;

[0007] The PBT chips are dried. The PBT chips are pre-crystallized at 70 - 90 °C for 1 - 2 h, and then dried at 110 - 120 °C for 4 - 5 h to obtain the dried PBT chips;

[0008] The melt flow rate of the PBT chips at 250 °C and 2.16 kg is 30 - 45 g / 10 min;

[0009] To prepare the water-repellent masterbatch, the dried PBT chips, amino-modified polydimethylsiloxane, di-sec-octyl phthalate, Fischer-Tropsch wax, and silica-coated silica are added to a high-speed mixer and a twin-screw extruder for mixing and pelletizing. The extrusion temperature of the twin-screw extruder is controlled at 230 - 240 °C, and the water-repellent masterbatch is obtained after pelletizing;

[0010] In the preparation of the water-repellent masterbatch, the mass ratio of the dried PBT chips, amino-modified polydimethylsiloxane, di-sec-octyl phthalate, Fischer-Tropsch wax, and silica-coated silica is 10 - 11:1 - 1.2:0.2 - 0.25:0.02 - 0.03:0.5 - 0.6;

[0011] The preparation method of the silica-coated silica consists of the following steps: preparing amino silica, preparing amino mesoporous silica, and coating;

[0012] To prepare the amino silica, cetyltrimethylammonium bromide, deionized water, and ammonia water are added to a reaction kettle. The temperature of the reaction kettle is controlled at 30 - 35 °C, the stirring speed is controlled at 100 - 200 rpm, and stirring is carried out for 30 - 40 min. Then tetraethyl orthosilicate and 3-aminopropyltriethoxysilane are added, and stirring is continued for 20 - 22 h. After that, freeze-drying is carried out, and the temperature of freeze-drying is controlled at -40 °C to -30 °C for 8 - 10 h. After the freeze-drying is completed, amino silica is obtained;

[0013] In the preparation of the silica-coated silica, the mass ratio of cetyltrimethylammonium bromide, deionized water, ammonia water, tetraethyl orthosilicate, and 3-aminopropyltriethoxysilane is 17 - 18:2100 - 2200:0.3 - 0.32:13 - 15:16 - 17;

[0014] The concentration of the ammonia water is 25 - 28 wt%;

[0015] To prepare the amino-functionalized mesoporous silica, amino-functionalized silica, absolute ethanol, and hydrochloric acid aqueous solution are added to a reaction kettle equipped with a reflux device. The temperature of the reaction kettle is controlled at 70 - 75 °C, and the stirring speed is controlled at 100 - 200 rpm. After reflux stirring for 9 - 10 h, centrifugation is carried out, with the centrifugation speed controlled at 8000 - 9000 rpm and the time at 6 - 8 min. After centrifugation, the precipitate is washed with absolute ethanol and deionized water with 3 - 4 times the mass respectively, and then dried at 110 - 120 °C to obtain the amino-functionalized mesoporous silica;

[0016] In the preparation of the amino-functionalized mesoporous silica, the mass ratio of amino-functionalized silica, absolute ethanol, and hydrochloric acid aqueous solution is 10 - 11:1800 - 1900:200 - 210;

[0017] The concentration of the hydrochloric acid aqueous solution is 36 - 38 wt%;

[0018] For the coating, amino-functionalized mesoporous silica and deionized water are mixed and then subjected to ultrasonic oscillation. The frequency of ultrasonic oscillation is controlled at 20 - 30 kHz, and the time is 15 - 20 min. After ultrasonic oscillation, a dispersion is obtained. The dispersion, rhodanine, and aniline hydrochloride are added to a reaction kettle. The temperature of the reaction kettle is controlled at 75 - 80 °C, and the stirring speed is controlled at 100 - 200 rpm. After stirring for 10 - 20 min, ammonium persulfate is added, and stirring is continued for 2 - 3 h. Then, filtration is carried out, and the filter residue is washed with deionized water with 3 - 4 times the mass for 2 - 3 times, and then dried at 110 - 120 °C to obtain the coated silica;

[0019] In the coating process, the mass ratio of amino-functionalized mesoporous silica, deionized water, rhodanine, aniline hydrochloride, and ammonium persulfate is 10 - 11:200 - 210:0.8 - 1:2.5 - 3:2 - 2.5;

[0020] To prepare the oil-repellent masterbatch, the dried PBT chips, di-sec-octyl phthalate, Fischer-Tropsch wax, and modified kaolin are added to a high-speed mixer and a twin-screw extruder for mixing and pelletizing. The extrusion temperature of the twin-screw extruder is controlled at 230 - 240 °C, and the pelletizing is completed to obtain the oil-repellent masterbatch;

[0021] In the preparation of the water-repellent masterbatch, the mass ratio of the dried PBT chips, di-sec-octyl phthalate, Fischer-Tropsch wax, and modified kaolin is 10 - 11:0.2 - 0.25:0.02 - 0.03:1 - 1.2;

[0022] The preparation method of the modified kaolin is as follows: Add kaolin, potassium acetate, and deionized water added for the first time into a reaction kettle, control the temperature to 40 - 50 °C, control the stirring speed to 200 - 300 rpm, after stirring for 1 - 2 h, let it stand at 40 - 50 °C for 28 - 30 h, filter after standing, wash the filter residue 3 - 4 times with 2 - 3 times the mass of deionized water to obtain nano - kaolin. Add the nano - kaolin, polyethylene glycol 400, and deionized water added for the second time into the reaction kettle, control the temperature to 15 - 35 °C, control the stirring speed to 200 - 300 rpm, stir for 20 - 30 min to obtain a kaolin mixture; Add amphoteric ion polyacrylamide, nano - magnesium hydroxide, nano - aluminum hydroxide, silane coupling agent KH560, and deionized water added for the third time into the reaction kettle, control the temperature of the reaction kettle to 40 - 50 °C, control the stirring speed to 200 - 300 rpm, after stirring for 20 - 30 min, slowly add the kaolin mixture into the reaction kettle while stirring, control the addition speed to 10 - 12 g / min, continue to stir for 1 - 1.5 h after the addition, filter, wash the filter residue 3 - 4 times with 3 - 4 times the mass of deionized water, and then dry it at 110 - 120 °C to obtain the modified kaolin;

[0023] In the preparation of the modified kaolin, the mass ratio of kaolin, potassium acetate, deionized water added for the first time, polyethylene glycol 400, deionized water added for the second time, amphoteric ion polyacrylamide, nano - magnesium hydroxide, nano - aluminum hydroxide, silane coupling agent KH560, and deionized water added for the third time is 10 - 11:14 - 15:13 - 15:0.4 - 0.5:150 - 160:2 - 2.5:30 - 35:8 - 10:2 - 3:200 - 220;

[0024] The particle size of the nano - magnesium hydroxide is 40 - 50 nm;

[0025] For the mixing and granulation, add the dried PBT chips, water - repellent masterbatch, and oil - repellent masterbatch into a high - speed mixer and a twin - screw extruder for mixing and granulation, control the extrusion temperature of the twin - screw extruder to 230 - 240 °C, and obtain the mixed PBT chips after granulation;

[0026] In the mixing and granulation, the mass ratio of the dried PBT chips, water - repellent masterbatch, and oil - repellent masterbatch is 10 - 11:0.5 - 0.6:0.7 - 0.8;

[0027] For the preparation of the upper - layer PBT melt - blown non - woven fabric, add the mixed PBT chips into a twin - screw extruder for melting, then feed them into a spinning pack for spinning, after being ejected from a spinneret plate, they are drawn by a high - speed hot air stream to form melt - blown ultrafine fibers with a fineness of 1 - 2 μm, and the melt - blown ultrafine fibers are made into the upper - layer PBT melt - blown non - woven fabric through negative - pressure agglomeration and hot rolling;

[0028] The extrusion temperature of the twin-screw extruder is 240 - 260 °C, the spinning speed is 800 - 900 m / min, and the aperture of the spinneret holes is 0.2 - 0.25 mm;

[0029] The areal density of the upper-layer PBT meltblown nonwoven fabric is 70 - 80 g / m 2 ;

[0030] To prepare the middle-layer PBT meltblown nonwoven fabric, the mixed PBT chips are added to a twin-screw extruder for melting, then fed into a spinning pack for spinning. After being ejected from the spinneret plate, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers with a fineness of 2 - 3 μm. The meltblown ultrafine fibers are obtained as the middle-layer PBT meltblown nonwoven fabric after negative-pressure agglomeration and hot rolling;

[0031] The extrusion temperature of the twin-screw extruder is 240 - 260 °C, the spinning speed is 700 - 800 m / min, and the aperture of the spinneret holes is 0.25 - 0.3 mm;

[0032] The areal density of the middle-layer PBT meltblown nonwoven fabric is 60 - 70 g / m 2 ;

[0033] To prepare the lower-layer PBT meltblown nonwoven fabric, the mixed PBT chips are added to a twin-screw extruder for melting, then fed into a spinning pack for spinning. After being ejected from the spinneret plate, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers with a fineness of 3 - 4 μm. The meltblown ultrafine fibers are obtained as the lower-layer PBT meltblown nonwoven fabric after negative-pressure agglomeration and hot rolling;

[0034] The extrusion temperature of the twin-screw extruder is 240 - 260 °C, the spinning speed is 600 - 700 m / min, and the aperture of the spinneret holes is 0.25 - 0.3 mm;

[0035] The areal density of the lower-layer PBT meltblown nonwoven fabric is 40 - 60 g / m 2 ;

[0036] For the lamination, the upper-layer PBT meltblown nonwoven fabric, the middle-layer PBT meltblown nonwoven fabric, and the lower-layer PBT meltblown nonwoven fabric are laminated together from top to bottom and then hot-pressed into shape using a dot-type embossing roller. Control the pressure of the hot-pressing to be 2 - 3 MPa and the temperature to be 200 - 220 °C. After the hot-pressing is completed, the primary liquid filtration material is obtained;

[0037] For the post-treatment, a sodium alginate solution is evenly sprayed on the upper surface of the primary liquid filtration material. Control the dosage of the sodium alginate solution to be 30 - 35 g / m 2 , and after the spraying of the sodium alginate solution is completed, a calcium chloride solution is sprayed. Control the dosage of the calcium chloride solution to be 30 - 35 g / m 2, after the spraying of the calcium chloride solution, ultraviolet light irradiation is carried out. The wavelength of the ultraviolet light irradiation is controlled to be 320 - 360 nm, the temperature is 50 - 60 °C, and the time is 2 - 3 h. After the ultraviolet light irradiation, it is dried at 110 - 130 °C to obtain a high-temperature resistant microporous liquid filtration material;

[0038] The preparation method of the sodium alginate solution is as follows: sodium alginate, L-lysine, sodium sulfate, and deionized water are added to a reaction kettle. The temperature of the reaction kettle is controlled to 40 - 50 °C, the stirring speed is controlled to 100 - 200 rpm, and stirring is carried out for 50 - 60 min to obtain a sodium alginate solution;

[0039] In the preparation of the sodium alginate solution, the mass ratio of sodium alginate, L-lysine, sodium sulfate, and deionized water is 7 - 8:0.6 - 0.8:10 - 12:100 - 105;

[0040] The preparation method of the calcium chloride solution is as follows: calcium chloride and deionized water are added to a reaction kettle. The temperature of the reaction kettle is controlled to 40 - 50 °C, the stirring speed is controlled to 100 - 200 rpm, and stirring is carried out for 20 - 40 min to obtain a calcium chloride solution;

[0041] In the preparation of the calcium chloride solution, the mass ratio of calcium chloride to deionized water is 15 - 16:100 - 105.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] (1) In the preparation method of the high-temperature resistant microporous liquid filtration material of the present invention, by adding coated silica in the water-repellent masterbatch and modified kaolin in the oil-repellent masterbatch, the processing fluidity of the prepared high-temperature resistant microporous liquid filtration material can be improved. The melt flow rate of the mixed PBT chips in the high-temperature resistant microporous liquid filtration material prepared by the present invention is 45 - 48 g / 10 min;

[0044] (2) In the preparation method of the high-temperature resistant microporous liquid filtration material of the present invention, by adding coated silica in the water-repellent masterbatch, modified kaolin in the oil-repellent masterbatch, and post-treating the primary liquid filtration material, the mechanical strength of the prepared high-temperature resistant microporous liquid filtration material can be improved. The transverse tensile strength of the prepared high-temperature resistant microporous liquid filtration material is 5.9 - 6.5 MPa, the longitudinal tensile strength is 3.7 - 4.1 MPa, the transverse breaking strength is 28.4 - 29.5 MPa, the longitudinal breaking strength is 22.1 - 22.7 MPa, the transverse elongation at break is 25.7 - 26.8%, and the longitudinal elongation at break is 11.2 - 11.6%;

[0045] (3)The preparation method of the high-temperature resistant microporous liquid filtering material of the present invention, the limiting oxygen index of the prepared high-temperature resistant microporous liquid filtering material is 32 - 34;

[0046] (4)The preparation method of the high-temperature resistant microporous liquid filtering material of the present invention can improve the filtering precision of the prepared high-temperature resistant microporous liquid filtering material by adding silica-coated particles to the water-repellent masterbatch, adding modified kaolin to the oil-repellent masterbatch, and post-treating the primary liquid filtering material. The particulate matter filtering efficiency of the high-temperature resistant microporous liquid filtering material prepared by the present invention is 99.75 - 99.84%, and the oil-water separation efficiency is 99.8 - 99.9%;

[0047] (5)The preparation method of the high-temperature resistant microporous liquid filtering material of the present invention can improve the hydrophobicity and oleophobicity of the prepared high-temperature resistant microporous liquid filtering material by adding silica-coated particles to the water-repellent masterbatch and adding modified kaolin to the oil-repellent masterbatch. The water contact angle of the high-temperature resistant microporous liquid filtering material prepared by the present invention is 135 - 141°, and the cutting oil contact angle is 112 - 117°;

[0048] (6)The preparation method of the high-temperature resistant microporous liquid filtering material of the present invention can improve the high-temperature resistance of the prepared high-temperature resistant microporous liquid filtering material by post-treating the primary liquid filtering material. The heat-resistant temperature of the high-temperature resistant microporous liquid filtering material prepared by the present invention is 150 - 160 °C. Specific Embodiments

[0049] In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention are now described.

[0050] Example 1

[0051] A preparation method of a high-temperature resistant microporous liquid filtering material is specifically as follows:

[0052] 1. Drying of PBT chips: Place the PBT chips at 70 °C for pre-crystallization for 1 h, and then dry them at 110 °C for 4 h to obtain the dried PBT chips;

[0053] The melt flow rate of the PBT chips at 250 °C and 2.16 kg is 30 g / 10 min;

[0054] 2. Preparation of water-repellent masterbatch: Add 10 kg of dried PBT chips, 1 kg of amino-modified polydimethylsiloxane, 0.2 kg of di-sec-octyl phthalate, 0.02 kg of Fischer-Tropsch wax, and 0.5 kg of silica-coated particles to a high-speed mixer and a twin-screw extruder for mixing and pelletizing. Control the extrusion temperature of the twin-screw extruder at 230 °C, and obtain the water-repellent masterbatch after pelletizing;

[0055] The preparation method of the silica-coated material is as follows: Add 17 g of cetyltrimethylammonium bromide, 2100 g of deionized water, and 0.3 g of ammonia water into a reaction kettle. Control the temperature of the reaction kettle to 30 °C, the stirring speed to 100 rpm, and stir for 30 min. Then add 13 g of tetraethyl orthosilicate and 16 g of 3-aminopropyltriethoxysilane, and continue stirring for 20 h. After that, perform freeze-drying, control the temperature of freeze-drying to -40 °C and the time to 8 h. After the freeze-drying is completed, amino silica is obtained. Take 10 g of amino silica, 1800 g of absolute ethanol, and 200 g of hydrochloric acid aqueous solution and add them into a reaction kettle equipped with a reflux device. Control the temperature of the reaction kettle to 70 °C, the stirring speed to 100 rpm, and reflux and stir for 9 h. Then centrifuge, control the centrifugation speed to 8000 rpm and the time to 6 min. After centrifugation, wash the precipitate with 3 times the mass of absolute ethanol and 3 times the mass of deionized water respectively, and then dry it at 110 °C to obtain amino mesoporous silica. Take 10 g of amino mesoporous silica and 200 g of deionized water, mix them and perform ultrasonic oscillation. Control the frequency of ultrasonic oscillation to 20 kHz and the time to 15 min. After the ultrasonic oscillation is completed, a dispersion liquid is obtained. Add the dispersion liquid, 0.8 g of rhodanine, and 2.5 g of aniline hydrochloride into a reaction kettle. Control the temperature of the reaction kettle to 75 °C, the stirring speed to 100 - 200 rpm, and stir for 10 min. Then add 2 g of ammonium persulfate and continue stirring for 2 h. Filter, wash the filter residue with 3 times the mass of deionized water twice, and dry it at 110 °C to obtain the silica-coated material;

[0056] The concentration of the ammonia water is 25 wt%;

[0057] The concentration of the hydrochloric acid aqueous solution is 36 wt%;

[0058] 3. Prepare the oil-repellent masterbatch: Add 10 kg of dried PBT chips, 0.2 kg of di-sec-octyl phthalate, 0.02 kg of Fischer-Tropsch wax, and 1 kg of modified kaolin into a high-speed mixer and a twin-screw extruder for mixing and pelletizing. Control the extrusion temperature of the twin-screw extruder to 230 °C. After pelletizing, the oil-repellent masterbatch is obtained;

[0059] The preparation method of the modified kaolin is as follows: Add 10 g of kaolin, 14 g of potassium acetate, and 13 g of deionized water into a reaction kettle, control the temperature to 40 °C, control the stirring speed to 200 rpm, stir for 1 h, then let it stand at 40 °C for 28 h. After standing, filter, and wash the filter residue 3 times with deionized water with a mass 2 times that of the filter residue to obtain nano kaolin. Add the nano kaolin, 0.4 g of polyethylene glycol 400, and 150 g of deionized water into a reaction kettle, control the temperature to 15 °C, control the stirring speed to 200 rpm, and stir for 20 min to obtain a kaolin mixture; Add 2 g of zwitterionic polyacrylamide, 30 g of nano magnesium hydroxide, 8 g of nano aluminum hydroxide, 2 g of silane coupling agent KH560, and 200 g of deionized water into a reaction kettle, control the temperature of the reaction kettle to 40 - 50 °C, control the stirring speed to 200 rpm, stir for 20 min, then slowly add the kaolin mixture into the reaction kettle while stirring, control the addition speed to 10 g / min, continue to stir for 1 h after the addition, filter, wash the filter residue 3 times with deionized water with a mass 3 times that of the filter residue, and then dry it at 110 °C to obtain the modified kaolin;

[0060] The particle size of the nano magnesium hydroxide is 40 nm;

[0061] 4. Mixing and pelletizing: Add 10 kg of dried PBT chips, 0.5 kg of water-repellent masterbatch, and 0.7 kg of oil-repellent masterbatch into a high-speed mixer and a twin-screw extruder for mixing and pelletizing, control the extrusion temperature of the twin-screw extruder to 230 °C, and obtain mixed PBT chips after pelletizing;

[0062] 5. Preparation of the upper-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then feed them into a spinning pack for spinning. After being ejected from a spinneret plate, they are drawn by a high-speed hot air flow to form meltblown ultrafine fibers with a fineness of 2 μm. The meltblown ultrafine fibers are subjected to negative pressure agglomeration and hot rolling to obtain the upper-layer PBT meltblown nonwoven fabric;

[0063] The extrusion temperature of the twin-screw extruder is 240 °C, the spinning speed is 800 m / min, and the aperture of the spinneret hole is 0.25 mm;

[0064] The areal density of the upper-layer PBT meltblown nonwoven fabric is 70 g / m 2 ;

[0065] 6. Preparation of the middle-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then feed them into a spinning pack for spinning. After being ejected from a spinneret plate, they are drawn by a high-speed hot air flow to form meltblown ultrafine fibers with a fineness of 3 μm. The meltblown ultrafine fibers are subjected to negative pressure agglomeration and hot rolling to obtain the middle-layer PBT meltblown nonwoven fabric;

[0066] The extrusion temperature of the twin-screw extruder is 240 °C, the spinning speed is 700 m / min, and the aperture of the spinneret holes is 0.3 mm;

[0067] The areal density of the middle-layer PBT meltblown nonwoven fabric is 60 g / m 2 ;

[0068] 7. Preparation of the lower-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then feed them into a spinning pack for spinning. After being ejected from the spinneret plate, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers with a fineness of 4 μm. The meltblown ultrafine fibers are obtained as the lower-layer PBT meltblown nonwoven fabric after negative pressure agglomeration and hot rolling;

[0069] The extrusion temperature of the twin-screw extruder is 240 °C, the spinning speed is 600 m / min, and the aperture of the spinneret holes is 0.3 mm;

[0070] The areal density of the lower-layer PBT meltblown nonwoven fabric is 40 g / m 2 ;

[0071] 8. Lamination: Stack the upper-layer PBT meltblown nonwoven fabric, the middle-layer PBT meltblown nonwoven fabric, and the lower-layer PBT meltblown nonwoven fabric together from top to bottom and then use a dot pattern embossing roller for hot pressing. Control the pressure of the hot pressing to be 2 MPa and the temperature to be 200 °C. After the hot pressing is completed, a primary liquid filtration material is obtained;

[0072] 9. Post-treatment: Uniformly spray a sodium alginate solution on the upper surface of the primary liquid filtration material. Control the dosage of the sodium alginate solution to be 30 g / m 2 , and after the spraying of the sodium alginate solution, spray a calcium chloride solution. Control the dosage of the calcium chloride solution to be 30 g / m 2 , and after the spraying of the calcium chloride solution, perform ultraviolet light irradiation. Control the wavelength of the ultraviolet light irradiation to be 320 nm, the temperature to be 50 °C, and the time to be 2 h. After the ultraviolet light irradiation is completed, dry it at 110 °C to obtain a high-temperature resistant microporous liquid filtration material;

[0073] The preparation method of the sodium alginate solution is as follows: Add 7 g of sodium alginate, 0.6 g of L-lysine, 10 g of sodium sulfate, and 100 g of deionized water into a reaction kettle. Control the temperature of the reaction kettle to 40 °C and the stirring speed to 100 rpm, and stir for 50 min to obtain the sodium alginate solution;

[0074] The preparation method of the calcium chloride solution is as follows: Add 15 g of calcium chloride and 100 g of deionized water into a reaction kettle. Control the temperature of the reaction kettle to 40 °C and the stirring speed to 100 rpm, and stir for 20 min to obtain the calcium chloride solution.

[0075] Example 2

[0076] A preparation method of a high-temperature resistant microporous liquid filtering material, specifically as follows:

[0077] 1. Drying of PBT chips: Place the PBT chips at 80 °C for pre-crystallization for 1.5 h, and then place them at 115 °C for drying for 4.5 h to obtain the dried PBT chips;

[0078] The melt flow rate of the PBT chips at 250 °C and 2.16 kg is 40 g / 10 min;

[0079] 2. Preparation of water-repellent masterbatch: Add 10.5 kg of the dried PBT chips, 1.1 kg of amino-modified polydimethylsiloxane, 0.22 kg of di-sec-octyl phthalate, 0.02 kg of Fischer-Tropsch wax, and 0.55 kg of silica-coated into a high-speed mixer and a twin-screw extruder for mixing and pelletizing. Control the extrusion temperature of the twin-screw extruder to be 235 °C. After pelletizing, water-repellent masterbatch is obtained;

[0080] The preparation method of the silica-coated is as follows: Add 17.5 g of cetyltrimethylammonium bromide, 2150 g of deionized water, and 0.31 g of ammonia water into a reaction kettle. Control the temperature of the reaction kettle to 30 - 35 °C, and the stirring speed to 1500 rpm. Stir for 35 min, add 14 g of tetraethyl orthosilicate and 16.5 g of 3-aminopropyltriethoxysilane, continue to stir for 21 h, then perform freeze-drying. Control the temperature of freeze-drying to -35 °C and the time to 9 h. After freeze-drying, amino-silica is obtained; Take 10.5 g of amino-silica, 1850 g of absolute ethanol, and 205 g of hydrochloric acid aqueous solution and add them into a reaction kettle with a reflux device. Control the temperature of the reaction kettle to 72 °C and the stirring speed to 150 rpm. After reflux stirring for 9.5 h, centrifuge, control the centrifuge speed to 9000 rpm and the time to 7 min. After centrifugation, wash the precipitate with 4 times the mass of absolute ethanol and 4 times the mass of deionized water respectively, and then dry at 115 °C to obtain amino-mesoporous silica; Take 10.5 g of amino-mesoporous silica and 205 g of deionized water, mix them and perform ultrasonic oscillation. Control the frequency of ultrasonic oscillation to 25 kHz and the time to 18 min. After ultrasonic oscillation, a dispersion liquid is obtained. Add the dispersion liquid, 0.9 g of rhodanine, and 2.8 g of aniline hydrochloride into a reaction kettle. Control the temperature of the reaction kettle to 78 °C and the stirring speed to 150 rpm. After stirring for 15 min, add 2.2 g of ammonium persulfate, continue to stir for 2.5 h, filter, wash the filter residue 3 times with 4 times the mass of deionized water, and dry at 115 °C to obtain silica-coated;

[0081] The concentration of the ammonia water is 27 wt%;

[0082] The concentration of the hydrochloric acid aqueous solution is 37 wt%;

[0083] 3. Preparation of oil-repellent masterbatch: Add 10.5 kg of dried PBT chips, 0.22 kg of di-sec-octyl phthalate, 0.02 kg of Fischer-Tropsch wax, and 1.1 kg of modified kaolin into a high-speed mixer and a twin-screw extruder for mixing and pelletizing. Control the extrusion temperature of the twin-screw extruder at 235 °C. After pelletizing, the oil-repellent masterbatch is obtained;

[0084] The preparation method of the modified kaolin is as follows: Add 10.5 g of kaolin, 14.5 g of potassium acetate, and 14 g of deionized water into a reaction kettle. Control the temperature at 45 °C and the stirring speed at 250 rpm. After stirring for 1.5 h, let it stand at 45 °C for 29 h. After standing, filter, and wash the filter residue 3 times with 3 times the mass of deionized water to obtain nano-kaolin. Add the nano-kaolin, 0.45 g of polyethylene glycol 400, and 155 g of deionized water into a reaction kettle. Control the temperature at 20 °C and the stirring speed at 250 rpm. Stir for 25 min to obtain a kaolin mixture; Add 2.2 g of zwitterionic polyacrylamide, 32 g of nano-magnesium hydroxide, 9 g of nano-aluminum hydroxide, 2.5 g of silane coupling agent KH560, and 210 g of deionized water into a reaction kettle. Control the temperature of the reaction kettle at 45 °C and the stirring speed at 250 rpm. After stirring for 25 min, slowly add the kaolin mixture into the reaction kettle while stirring, control the addition speed at 11 g / min. After the addition, continue to stir for 1.2 h, filter, wash the filter residue 4 times with 4 times the mass of deionized water, and then dry it at 115 °C to obtain the modified kaolin;

[0085] The particle size of the nano-magnesium hydroxide is 40 nm;

[0086] 4. Mixing and pelletizing: Add 10.5 kg of dried PBT chips, 0.55 kg of oil-repellent masterbatch, and 0.75 kg of oil-repellent masterbatch into a high-speed mixer and a twin-screw extruder for mixing and pelletizing. Control the extrusion temperature of the twin-screw extruder at 235 °C. After pelletizing, the mixed PBT chips are obtained;

[0087] 5. Preparation of the upper-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then feed them into a spinning pack for spinning. After being ejected from the spinneret plate, they are drawn by a high-speed hot air stream to form meltblown ultra-fine fibers with a fineness of 1.5 μm. The meltblown ultra-fine fibers are subjected to negative pressure agglomeration and hot rolling to obtain the upper-layer PBT meltblown nonwoven fabric;

[0088] The extrusion temperature of the twin-screw extruder is 250 °C, the spinning speed is 850 m / min, and the aperture of the spinneret hole is 0.2 mm;

[0089] The basis weight of the upper-layer PBT meltblown nonwoven fabric is 75 g / m 2;

[0090] 6. Preparation of the middle-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then feed them into a spinning pack for spinning. After being ejected from the spinneret plate, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers with a fineness of 2.5 μm. The meltblown ultrafine fibers are obtained as the middle-layer PBT meltblown nonwoven fabric after negative pressure agglomeration and hot rolling;

[0091] The extrusion temperature of the twin-screw extruder is 250 °C, the spinning speed is 750 m / min, and the aperture of the spinneret holes is 0.25 mm;

[0092] The areal density of the middle-layer PBT meltblown nonwoven fabric is 65 g / m 2 ;

[0093] 7. Preparation of the lower-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then feed them into a spinning pack for spinning. After being ejected from the spinneret plate, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers with a fineness of 3.5 μm. The meltblown ultrafine fibers are obtained as the lower-layer PBT meltblown nonwoven fabric after negative pressure agglomeration and hot rolling;

[0094] The extrusion temperature of the twin-screw extruder is 250 °C, the spinning speed is 650 m / min, and the aperture of the spinneret holes is 0.3 mm;

[0095] The areal density of the lower-layer PBT meltblown nonwoven fabric is 50 g / m 2 ;

[0096] 8. Lamination: Stack the upper-layer PBT meltblown nonwoven fabric, middle-layer PBT meltblown nonwoven fabric, and lower-layer PBT meltblown nonwoven fabric from top to bottom, and then use a dot-type flower roller for hot pressing and forming. Control the pressure of the hot pressing and forming to be 2.5 MPa and the temperature to be 210 °C. After the hot pressing and forming is completed, the primary liquid filtration material is obtained;

[0097] 9. Post-treatment: Uniformly spray sodium alginate solution on the upper surface of the primary liquid filtration material, control the dosage of the sodium alginate solution to be 32 g / m 2 , after spraying the sodium alginate solution, spray calcium chloride solution, control the dosage of the calcium chloride solution to be 32 g / m 2 , after spraying the calcium chloride solution, conduct ultraviolet light irradiation, control the wavelength of the ultraviolet light irradiation to be 350 nm, the temperature to be 55 °C, and the time to be 2.5 h. After the ultraviolet light irradiation is completed, dry it at 120 °C to obtain a high-temperature resistant microporous liquid filtration material;

[0098] The preparation method of the sodium alginate solution is as follows: Add 7.5 g of sodium alginate, 0.7 g of L-lysine, 11 g of sodium sulfate, and 102 g of deionized water into a reaction kettle, control the temperature of the reaction kettle to 45 °C, control the stirring speed to 150 rpm, and stir for 55 min to obtain the sodium alginate solution;

[0099] The preparation method of the calcium chloride solution is as follows: Add 15.5 g of calcium chloride and 102 g of deionized water into a reaction kettle, control the temperature of the reaction kettle to 45 °C, control the stirring speed to 150 rpm, and stir for 30 min to obtain the calcium chloride solution.

[0100] Example 3

[0101] A preparation method of a high-temperature resistant microporous liquid filtration material is specifically as follows:

[0102] 1. Drying of PBT chips: Place the PBT chips at 90 °C for pre-crystallization for 2 h, and then place them at 120 °C for drying for 5 h to obtain the dried PBT chips;

[0103] The melt flow rate of the PBT chips at 250 °C and 2.16 kg is 45 g / 10 min;

[0104] 2. Preparation of water-repellent pellets: Add 11 kg of the dried PBT chips, 1.2 kg of amino-modified polydimethylsiloxane, 0.25 kg of di-sec-octyl phthalate, 0.03 kg of Fischer-Tropsch wax, and 0.6 kg of silica-coated into a high-speed mixer and a twin-screw extruder for mixing and pelletizing, control the extrusion temperature of the twin-screw extruder to 240 °C, and obtain the water-repellent pellets after pelletizing;

[0105] The preparation method of the silica-coated material is as follows: Add 18 g of cetyltrimethylammonium bromide, 2200 g of deionized water, and 0.32 g of ammonia water into a reaction kettle. Control the temperature of the reaction kettle to 35 °C, the stirring speed to 200 rpm, and stir for 40 min. Then add 15 g of tetraethyl orthosilicate and 17 g of 3-aminopropyltriethoxysilane, and continue stirring for 22 h. After that, perform freeze-drying, control the temperature of freeze-drying to -30 °C and the time to 10 h. After the freeze-drying is completed, amino silica is obtained. Take 11 g of amino silica, 1900 g of absolute ethanol, and 210 g of hydrochloric acid aqueous solution and add them into a reaction kettle with a reflux device. Control the temperature of the reaction kettle to 75 °C, the stirring speed to 200 rpm, and reflux and stir for 10 h. Then centrifuge, control the centrifugation speed to 9000 rpm and the time to 8 min. After centrifugation, wash the precipitate with absolute ethanol and deionized water with 4 times the mass respectively, and then dry it at 120 °C to obtain amino mesoporous silica. Take 11 g of amino mesoporous silica and 210 g of deionized water, mix them and perform ultrasonic oscillation. Control the frequency of ultrasonic oscillation to 30 kHz and the time to 20 min. After the ultrasonic oscillation is completed, a dispersion liquid is obtained. Add the dispersion liquid, 1 g of rhodanine, and 3 g of aniline hydrochloride into the reaction kettle. Control the temperature of the reaction kettle to 80 °C, the stirring speed to 200 rpm, and stir for 20 min. Then add 2.5 g of ammonium persulfate and continue stirring for 3 h. Filter, wash the filter residue with deionized water with 4 times the mass for 3 times, and dry it at 120 °C to obtain the silica-coated material;

[0106] The concentration of the ammonia water is 28 wt%;

[0107] The concentration of the hydrochloric acid aqueous solution is 38 wt%;

[0108] 3. Preparation of the oil-repellent masterbatch: Add 11 kg of dried PBT chips, 0.25 kg of di-sec-octyl phthalate, 0.03 kg of Fischer-Tropsch wax, and 1.2 kg of modified kaolin into a high-speed mixer and a twin-screw extruder for mixing and granulation. Control the extrusion temperature of the twin-screw extruder to 240 °C. After granulation, the oil-repellent masterbatch is obtained;

[0109] The preparation method of the modified kaolin is as follows: Add 11 g of kaolin, 15 g of potassium acetate, and 15 g of deionized water into a reaction kettle, control the temperature to 50 °C, control the stirring speed to 300 rpm, stir for 2 h, then let it stand at 50 °C for 30 h. After standing, filter, and wash the filter residue 4 times with 3 times the mass of deionized water to obtain nano kaolin. Add the nano kaolin, 0.5 g of polyethylene glycol 400, and 160 g of deionized water into a reaction kettle, control the temperature to 35 °C, control the stirring speed to 300 rpm, and stir for 30 min to obtain a kaolin mixture; Add 2.5 g of zwitterionic polyacrylamide, 35 g of nano magnesium hydroxide, 10 g of nano aluminum hydroxide, 3 g of silane coupling agent KH560, and 220 g of deionized water into a reaction kettle, control the temperature of the reaction kettle to 50 °C, control the stirring speed to 300 rpm, stir for 30 min, then slowly add the kaolin mixture into the reaction kettle while stirring, control the addition speed to 12 g / min, continue to stir for 1.5 h after the addition, filter, wash the filter residue 4 times with 4 times the mass of deionized water, and then dry it at 120 °C to obtain the modified kaolin;

[0110] The particle size of the nano magnesium hydroxide is 50 nm;

[0111] 4. Mixing and granulation: Add 11 kg of dried PBT chips, 0.6 kg of water-repellent masterbatch, and 0.8 kg of oil-repellent masterbatch into a high-speed mixer and a twin-screw extruder for mixing and granulation, control the extrusion temperature of the twin-screw extruder to 240 °C, and obtain mixed PBT chips after granulation;

[0112] 5. Preparation of the upper-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then pass them into a spinning pack for spinning. After being ejected from the spinneret, they are drawn by a high-speed hot air flow to form meltblown ultrafine fibers with a fineness of 1 μm. The meltblown ultrafine fibers are subjected to negative pressure agglomeration and hot rolling to obtain the upper-layer PBT meltblown nonwoven fabric;

[0113] The extrusion temperature of the twin-screw extruder is 260 °C, the spinning speed is 900 m / min, and the aperture of the spinneret hole is 0.2 mm;

[0114] The basis weight of the upper-layer PBT meltblown nonwoven fabric is 80 g / m 2 ;

[0115] 6. Preparation of the middle-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then pass them into a spinning pack for spinning. After being ejected from the spinneret, they are drawn by a high-speed hot air flow to form meltblown ultrafine fibers with a fineness of 2 μm. The meltblown ultrafine fibers are subjected to negative pressure agglomeration and hot rolling to obtain the middle-layer PBT meltblown nonwoven fabric;

[0116] The extrusion temperature of the twin-screw extruder is 260 °C, the spinning speed is 800 m / min, and the aperture of the spinneret holes is 0.25 mm;

[0117] The areal density of the middle-layer PBT meltblown nonwoven fabric is 70 g / m 2 ;

[0118] 7. Preparation of the lower-layer PBT meltblown nonwoven fabric: Add the mixed PBT chips into a twin-screw extruder for melting, then feed them into a spinning pack for spinning. After being ejected from the spinneret plate, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers with a fineness of 3 μm. The meltblown ultrafine fibers are subjected to negative pressure agglomeration and hot rolling to obtain the lower-layer PBT meltblown nonwoven fabric;

[0119] The extrusion temperature of the twin-screw extruder is 260 °C, the spinning speed is 700 m / min, and the aperture of the spinneret holes is 0.25 mm;

[0120] The areal density of the lower-layer PBT meltblown nonwoven fabric is 60 g / m 2 ;

[0121] 8. Lamination: Stack the upper-layer PBT meltblown nonwoven fabric, the middle-layer PBT meltblown nonwoven fabric, and the lower-layer PBT meltblown nonwoven fabric together from top to bottom, and then use a dot-type flower roller for hot pressing and forming. Control the pressure of the hot pressing and forming to be 3 MPa and the temperature to be 220 °C. After the hot pressing and forming is completed, a primary liquid filtration material is obtained;

[0122] 9. Post-treatment: Uniformly spray a sodium alginate solution on the upper surface of the primary liquid filtration material. Control the dosage of the sodium alginate solution to be 35 g / m 2 , after the spraying of the sodium alginate solution is completed, spray a calcium chloride solution. Control the dosage of the calcium chloride solution to be 35 g / m 2 , after the spraying of the calcium chloride solution is completed, perform ultraviolet light irradiation. Control the wavelength of the ultraviolet light irradiation to be 360 nm, the temperature to be 60 °C, and the time to be 3 h. After the ultraviolet light irradiation is completed, dry it at 130 °C to obtain a high-temperature resistant microporous liquid filtration material;

[0123] The preparation method of the sodium alginate solution is as follows: Add 8 g of sodium alginate, 0.8 g of L-lysine, 12 g of sodium sulfate, and 105 g of deionized water into a reaction kettle. Control the temperature of the reaction kettle to 50 °C and the stirring speed to 200 rpm, and stir for 60 min to obtain the sodium alginate solution;

[0124] The preparation method of the calcium chloride solution is as follows: Add 16 g of calcium chloride and 105 g of deionized water into a reaction kettle. Control the temperature of the reaction kettle to 50 °C and the stirring speed to 200 rpm, and stir for 40 min to obtain the calcium chloride solution.

[0125] Comparative Example 1

[0126] The preparation method of the high-temperature resistant microporous liquid filtration material described in Example 2 is adopted, and the difference is that: in the preparation of the water-repellent masterbatch in the second step, the equal mass of coated silica is replaced by amino mesoporous silica;

[0127] The preparation method of the amino mesoporous silica is changed to: add 17.5 g of cetyltrimethylammonium bromide, 2150 g of deionized water, and 0.31 g of ammonia water into the reaction kettle, control the temperature of the reaction kettle to 30 - 35 °C, control the stirring speed to 1500 rpm, stir for 35 min, add 14 g of tetraethyl orthosilicate and 16.5 g of 3-aminopropyltriethoxysilane, continue to stir for 21 h, then carry out freeze-drying, control the temperature of freeze-drying to -35 °C and the time to 9 h, and obtain amino silica after the end of freeze-drying; take 10.5 g of amino silica, 1850 g of absolute ethanol, and 205 g of hydrochloric acid aqueous solution and add them into the reaction kettle with a reflux device, control the temperature of the reaction kettle to 72 °C, control the stirring speed to 150 rpm, reflux and stir for 9.5 h, then centrifuge, control the centrifugation speed to 9000 rpm and the time to 7 min, after centrifugation, wash with 4 times the mass of absolute ethanol and 4 times the mass of deionized water respectively, and then dry at 115 °C to obtain amino mesoporous silica;

[0128] In the preparation of the oil-repellent masterbatch in the third step, 1.1 kg of modified kaolin is replaced by 0.86 kg of nano magnesium hydroxide and 0.24 kg of nano aluminum hydroxide.

[0129] Comparative Example 2

[0130] The preparation method of the high-temperature resistant microporous liquid filtration material described in Example 2 is adopted, and the difference is that: the ninth post-treatment step is omitted, that is, the primary liquid filtration material obtained in the eighth step of compounding is used as the high-temperature resistant microporous liquid filtration material.

[0131] Test Example 1

[0132] The melt flow rate of the mixed PBT chips obtained by the fourth step of mixing and granulation of the high-temperature resistant microporous liquid filtration materials prepared in Examples 1 - 3 and Comparative Examples 1 - 2 was tested, and the test results are as follows:

[0133]

[0134] It can be seen from the above results that the test result of the melt flow rate of Comparative Example 1 is poor, indicating that by adding coated silica in the water-repellent masterbatch and adding modified kaolin in the oil-repellent masterbatch, the processing fluidity of the prepared high-temperature resistant microporous liquid filtration material can be improved.

[0135] Test Example 2

[0136] The transverse tensile strength, longitudinal tensile strength, transverse breaking strength, longitudinal breaking strength, transverse elongation at break, longitudinal elongation at break, limiting oxygen index, particulate filtration efficiency, oil-water separation efficiency, water contact angle, cutting oil contact angle, and heat resistance temperature of the high-temperature resistant microporous liquid filtration materials prepared in Examples 1-3 and Comparative Examples 1-2 were tested, and the test results are as follows:

[0137]

[0138] It can be seen from the above results that the test results of the transverse tensile strength, longitudinal tensile strength, transverse breaking strength, longitudinal breaking strength, transverse elongation at break, longitudinal elongation at break, particulate filtration efficiency, oil-water separation efficiency, water contact angle, and cutting oil contact angle of Comparative Example 1 are poor; the test results of the transverse tensile strength, longitudinal tensile strength, transverse breaking strength, longitudinal breaking strength, transverse elongation at break, longitudinal elongation at break, particulate filtration efficiency, oil-water separation efficiency, and heat resistance temperature of Comparative Example 2 are poor;

[0139] It shows that by adding coated silica in the water-repellent masterbatch and modified kaolin in the oil-repellent masterbatch, the mechanical strength, filtration accuracy, hydrophobicity, and oleophobicity of the prepared high-temperature resistant microporous liquid filtration material can be improved; by post-treating the primary liquid filtration material, the mechanical strength, filtration accuracy, and high-temperature resistance of the prepared high-temperature resistant microporous liquid filtration material can be improved.

[0140] Unless otherwise specified, the percentages used in the present invention are all mass percentages.

[0141] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a high-temperature resistant microporous liquid filtration material, characterized in that, It consists of the following steps: drying PBT chips, preparing water-repellent masterbatch, preparing oil-repellent masterbatch, mixing and granulating, preparing the upper-layer PBT meltblown non-woven fabric, preparing the middle-layer PBT meltblown non-woven fabric, preparing the lower-layer PBT meltblown non-woven fabric, compounding, and post-treatment; For the preparation of the water-repellent masterbatch, the dried PBT chips, amino-modified polydimethylsiloxane, di-sec-octyl phthalate, Fischer-Tropsch wax, and silica-coated silica are added to a high-speed mixer and a twin-screw extruder for mixing and granulating. After granulation, the water-repellent masterbatch is obtained; The preparation method of the silica-coated silica consists of the following steps: preparing amino silica, preparing amino mesoporous silica, and coating; For the preparation of the oil-repellent masterbatch, the dried PBT chips, di-sec-octyl phthalate, Fischer-Tropsch wax, and modified kaolin are added to a high-speed mixer and a twin-screw extruder for mixing and granulating. After granulation, the oil-repellent masterbatch is obtained; For the mixing and granulating, the dried PBT chips, water-repellent masterbatch, and oil-repellent masterbatch are added to a high-speed mixer and a twin-screw extruder for mixing and granulating. After granulation, the mixed PBT chips are obtained.

2. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 1, characterized in that, For the drying of the PBT chips, the PBT chips are pre-crystallized and dried to obtain the dried PBT chips; For the preparation of the upper-layer PBT meltblown non-woven fabric, the mixed PBT chips are added to a twin-screw extruder for melting, then fed into a spinning assembly for spinning. After being ejected from the spinneret, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers. The meltblown ultrafine fibers are coagulated under negative pressure and hot-rolled to obtain the upper-layer PBT meltblown non-woven fabric; For the preparation of the middle-layer PBT meltblown non-woven fabric, the mixed PBT chips are added to a twin-screw extruder for melting, then fed into a spinning assembly for spinning. After being ejected from the spinneret, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers. The meltblown ultrafine fibers are coagulated under negative pressure and hot-rolled to obtain the middle-layer PBT meltblown non-woven fabric; For the preparation of the lower-layer PBT meltblown non-woven fabric, the mixed PBT chips are added to a twin-screw extruder for melting, then fed into a spinning assembly for spinning. After being ejected from the spinneret, they are drawn by a high-speed hot air stream to form meltblown ultrafine fibers. The meltblown ultrafine fibers are coagulated under negative pressure and hot-rolled to obtain the lower-layer PBT meltblown non-woven fabric; For the compounding, the upper-layer PBT meltblown non-woven fabric, the middle-layer PBT meltblown non-woven fabric, and the lower-layer PBT meltblown non-woven fabric are stacked together from top to bottom and then hot-pressed into shape using a dot-type flower roller to obtain a primary liquid filtration material.

3. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 1, characterized in that, In the preparation of the water-repellent masterbatch, the mass ratio of the dried PBT chips, amino-modified polydimethylsiloxane, di-sec-octyl phthalate, Fischer-Tropsch wax, and silica-coated silica is 10-11:1-1.2:0.2-0.25:0.02-0.03:0.5-0.

6.

4. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 1, characterized in that, For the preparation of the amino silica, cetyltrimethylammonium bromide, deionized water, and ammonia water are added to a reaction kettle. The temperature of the reaction kettle is controlled at 30-35 °C, stirred, tetraethyl orthosilicate and 3-aminopropyltriethoxysilane are added, and after continuous stirring for 20-22 h, freeze-drying is carried out to obtain the amino silica; To prepare the amino-functionalized mesoporous silica, amino-functionalized silica, absolute ethanol, and hydrochloric acid aqueous solution are added into a reaction kettle equipped with a reflux device. The temperature of the reaction kettle is controlled at 70 - 75 °C, and reflux stirring is carried out. After centrifugation, the precipitate is washed and dried to obtain the amino-functionalized mesoporous silica; For the coating, amino-functionalized mesoporous silica and deionized water are mixed and then subjected to ultrasonic oscillation to obtain a dispersion. The dispersion, rhodanine, and aniline hydrochloride are added into the reaction kettle. The temperature of the reaction kettle is controlled at 75 - 80 °C, and stirring is carried out. Ammonium persulfate is added, and stirring is continued. Then, filtration is carried out, and the filter residue is washed and dried to obtain the coated silica.

5. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 4, characterized in that, In the preparation of the coated silica, the mass ratio of cetyltrimethylammonium bromide, deionized water, ammonia water, tetraethyl orthosilicate, and 3-aminopropyltriethoxysilane is 17 - 18:2100 - 2200:0.3 - 0.32:13 - 15:16 - 17; The concentration of the ammonia water is 25 - 28 wt%; In the preparation of the amino-functionalized mesoporous silica, the mass ratio of amino-functionalized silica, absolute ethanol, and hydrochloric acid aqueous solution is 10 - 11:1800 - 1900:200 - 210; The concentration of the hydrochloric acid aqueous solution is 36 - 38 wt%; In the coating process, the mass ratio of amino-functionalized mesoporous silica, deionized water, rhodanine, aniline hydrochloride, and ammonium persulfate is 10 - 11:200 - 210:0.8 - 1:2.5 - 3:2 - 2.5; In the preparation of the oil-repellent masterbatch, the mass ratio of the dried PBT chips, di-sec-octyl phthalate, Fischer-Tropsch wax, and modified kaolin is 10 - 11:0.2 - 0.25:0.02 - 0.03:1 - 1.

2.

6. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 1, characterized in that, The preparation method of the modified kaolin is as follows: Kaolin, potassium acetate, and the first addition of deionized water are added into the reaction kettle. The temperature is controlled at 40 - 50 °C, and stirring is carried out. After standing, filtration is carried out, and the filter residue is washed to obtain nano-kaolin. Nano-kaolin, polyethylene glycol 400, and the second addition of deionized water are added into the reaction kettle. The temperature is controlled at 15 - 35 °C, and stirring is carried out to obtain a kaolin mixture; Amphoteric ion polyacrylamide, nano-magnesium hydroxide, nano-aluminum hydroxide, silane coupling agent KH560, and the third addition of deionized water are added into the reaction kettle. The temperature of the reaction kettle is controlled at 40 - 50 °C, and stirring is carried out. While stirring, the kaolin mixture is slowly added into the reaction kettle. After the addition, stirring is continued. Then, filtration is carried out, and the filter residue is washed and dried to obtain the modified kaolin.

7. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 6, characterized in that, In the preparation of the modified kaolin, the mass ratio of kaolin, potassium acetate, the first addition of deionized water, polyethylene glycol 400, the second addition of deionized water, amphoteric ion polyacrylamide, nano-magnesium hydroxide, nano-aluminum hydroxide, silane coupling agent KH560, and the third addition of deionized water is 10 - 11:14 - 15:13 - 15:0.4 - 0.5:150 - 160:2 - 2.5:30 - 35:8 - 10:2 - 3:200 - 220; The particle size of the nano-magnesium hydroxide is 40 - 50 nm; The addition rate of the kaolin mixture is 10 - 12 g / min; In the mixing and granulation, the mass ratio of the dried PBT chips, water-repellent masterbatch, and oil-repellent masterbatch is 10 - 11:0.5 - 0.6:0.7 - 0.

8.

8. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 1, wherein In the post-treatment, a sodium alginate solution is evenly sprayed on the upper surface of the primary liquid filter material. After the spraying of the sodium alginate solution is completed, a calcium chloride solution is sprayed. After the spraying of the calcium chloride solution is completed, ultraviolet light irradiation is carried out, and then drying is performed to obtain a high-temperature resistant microporous liquid filter material.

9. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 8, characterized in that, In the post-treatment, the dosage of the sodium alginate solution is 30-35 g / m 2 ; The dosage of calcium chloride solution is 30 - 35 g / m 2 ; When performing the ultraviolet light irradiation, the wavelength of the ultraviolet light is 320 - 360 nm, the temperature is 50 - 60 °C, and the time is 2 - 3 h.

10. The preparation method of the high-temperature resistant microporous liquid filtering material according to claim 8, characterized in that, The preparation method of the sodium alginate solution is as follows: Sodium alginate, L-lysine, sodium sulfate, and deionized water are added to a reaction kettle and stirred evenly to obtain a sodium alginate solution; In the preparation of the sodium alginate solution, the mass ratio of sodium alginate, L-lysine, sodium sulfate, and deionized water is 7 - 8:0.6 - 0.8:10 - 12:100 - 105; The preparation method of the calcium chloride solution is as follows: Calcium chloride and deionized water are added to a reaction kettle and stirred evenly to obtain a calcium chloride solution; In the preparation of the calcium chloride solution, the mass ratio of calcium chloride to deionized water is 15 - 16:100 - 105.

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