A polyethersulfone filter membrane with a support layer and its preparation method and use

Abstract

The invention provides a polyethersulfone filter membrane with a support layer and a preparation method and use thereof. The polyethersulfone filter membrane comprises a support layer and two polyethersulfone layers. The support layer provides a support function so that the polymer filter membrane has greater mechanical strength. The polyethersulfone layers are located on both sides of the support layer. The support layer comprises first fibers interwoven with each other to form a mesh structure and polyethersulfone materials bonded to the first fibers. The polyethersulfone materials on the first fibers are connected to the polyethersulfone layers. The thickness of the polyethersulfone materials on each side of the first fibers is at least 10 um, which accounts for at least 45% of the total thickness of the support layer. The polyethersulfone layers are tightly bonded to the support layer and have greater peeling strength, so that the polyethersulfone filter membrane can adapt to the impact of filtrate with high pressure. The polyethersulfone filter membrane is a symmetrical membrane with substantially the same properties on both sides of the surface. When assembled to a component, there is no need to distinguish between the front and back sides, so it is more convenient and quick to use.

Description

Technical Field

[0001] The invention relates to the technical field of membrane materials, and more particularly to a polyethersulfone filter membrane with a support layer and a preparation method and application thereof. Background Art

[0002] Membrane is a material with selective separation function, also known as separation membrane, which allows one or several substances in the fluid to pass through, while other substances cannot pass through, thereby playing the role of separation, purification and concentration. Membranes are classified according to the size of the retained raw water particles. The membrane pores are divided into microfiltration membrane (MF), ultrafiltration membrane (UF), nanofiltration membrane (NF) and reverse osmosis membrane (RO) from coarse to fine. The pore size of MF membrane is above 0.05μm, or the molecular weight is above 1000, and it is used to remove colloids and high molecular organic matter. The pore size of NF membrane is 100 to 1000 molecular weight. The substances it removes are between UF and RO, and it removes trihalomethanes, odor, color, pesticides, soluble organic matter, Ca, Mg, etc. The RO separation particle size is tens of molecular weights, and it is used to remove salts and inorganic salts. The pressure of RO permeate water is 1 to 2 times more than its osmotic pressure.

[0003] At present, most of the filter membranes sold on the market have good filtering functions, but unfortunately lack mechanical strength and are relatively fragile, which greatly limits the application range of these filter membranes. In order to improve the support strength of the filter membrane, researchers have added a support layer structure to the filter membrane. For example, Chinese patent application No. 200510031066.8, a large-pore polyethersulfone membrane and its preparation method and use, discloses a polyethersulfone filter membrane with a pore size of 0.05-0.35μm. By using non-woven fabric as the support layer structure, the mechanical strength of the filter membrane is greatly enhanced; in addition, Chinese patent application No. 200510031066.8, a large-pore polyethersulfone membrane and its preparation method and use, discloses a polyethersulfone filter membrane with a pore size of 0.05-0.35μm. Chinese patent No. 00910034982.5 discloses a method for manufacturing a small-pore polyethersulfone flat membrane for a membrane bioreactor, which discloses a polyethersulfone membrane with a pore size of 50nm-100nm, and also uses a non-woven fabric as a support body, thereby enhancing the mechanical strength of the filter membrane; however, the bonding between the porous layer where the polyethersulfone is located and the non-woven fabric support layer in the above-mentioned filter membrane is not tight enough, and the peel strength is not high; when encountering a high-pressure filtrate impact, it is easy to cause the support layer and the porous layer to separate, so that the polyethersulfone membrane loses its filtering effect, and the porous layer will also enter the filtrate, thereby contaminating the filtrate. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a polyethersulfone filter membrane with a support layer and a more optimized internal structure of the membrane body, and a preparation method and use thereof. The polyethersulfone layer and the support layer in the polyethersulfone filter membrane are tightly bonded and have a large peel strength, so that the polyethersulfone filter membrane can adapt to the impact of high-pressure filtrate and has a wider range of applications.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a polyethersulfone filter membrane with a support layer, comprising a support layer and two polyethersulfone layers, wherein the polyethersulfone layers are respectively located on both sides of the support layer, and the thickness of the two polyethersulfone layers is substantially the same; the support layer comprises first fibers interwoven with each other to form a network structure and polyethersulfone materials bonded to the first fibers, and the polyethersulfone materials located on the first fibers are connected to the polyethersulfone layers; the thickness of the polyethersulfone material on the first fibers on each side is at least 10 μm, and the thickness accounts for at least 45% of the total thickness of the support layer.

[0006] The polyethersulfone filter membrane provided by the present invention is a symmetrical membrane, comprising a support layer and two polyethersulfone layers, wherein the polyethersulfone layers are respectively located on both sides of the support layer; the present invention uses a non-woven fabric material as the support layer structure, wherein the non-woven fabric is any one of polyester non-woven fabric, polyphenylene sulfide non-woven fabric, aromatic polyamide non-woven fabric and polyimide non-woven fabric or non-woven fabric of other materials; the existence of the support layer makes the polyethersulfone filter membrane have greater mechanical strength, and the filter membrane is not easy to break; the support layer includes first fibers interwoven to form a mesh structure and polyethersulfone materials bonded to the first fibers, each side of the polyethersulfone material located in the support layer is connected to the adjacent polyethersulfone layer, and the thickness of each side of the polyethersulfone material is at least 10 μm , the thickness accounts for at least 45% of the total thickness of the support layer, that is, the total thickness of the polyethersulfone material in the support layer accounts for more than 90% of the total thickness of the support layer; preferably, the thickness of the polyethersulfone material on each side is at least 15 μm, which accounts for at least 47.5% of the total thickness of the support layer, that is, the total thickness of the polyethersulfone material in the support layer accounts for more than 95% of the total thickness of the support layer; the higher thickness of the polyethersulfone material in the support layer and its proportion ensure that the polyethersulfone layer and the support layer are very tightly bonded and have a high peel strength, so that the polyethersulfone filter membrane can adapt to the impact of high-pressure filtrate; when the filtrate is impacted by high-pressure filtrate, the polyethersulfone layer and the support layer will not separate, and the polyethersulfone filter membrane can still play a good filtering role and has a large range of applications.

[0007] The thickness of the polyethersulfone filter membrane, the thickness of the support layer, the thickness of the two polyethersulfone layers, and the thickness of the polyethersulfone material on the first fiber on each side of the present invention can be obtained by first using a scanning electron microscope to characterize the morphology of the filter membrane structure, and then using computer software (such as Matlab, NIS-Elements, etc.) or manually measuring and calculating the average value; those skilled in the art can also obtain the above parameters by other measurement methods.

[0008] As a further improvement of the present invention, the average diameter of the first fibers in the support layer is 3-11 μm, and the porosity of the mesh structure formed by the first fibers interweaving with each other in the support layer is 30-80%;

[0009] Preferably, the average diameter of the first fibers of the support layer is 4-10 μm, and the porosity of the mesh structure formed by the first fibers interweaving with each other in the support layer is 50-75%.

[0010] The fibers inside each layer of the polyethersulfone filter membrane of the present invention are roughly evenly distributed. Although the thickness of the network-like fibers is not exactly the same, the layers are still uniform as a whole, showing no obvious increasing or decreasing pattern, and there is an interface with obvious average fiber diameter mutation between two adjacent layers. The thickness of the fiber cross section can be considered as its average fiber diameter; the average diameter of the first fiber of the support layer of the present invention can be calculated by using a scanning electron microscope to characterize the membrane structure, and then using computer software (such as Matlab, NIS-Elements, etc.) or manually measuring and calculating the average value; the commonly used porosity test methods include mercury injection method, density method and dry and wet membrane weighing method;

[0011] The larger first fiber diameter ensures that the support layer can provide greater support for the polyethersulfone layer, thereby making the polyethersulfone filter membrane have greater mechanical strength and less prone to rupture; the porosity of the network structure formed by the first fibers interweaving with each other in the support layer is 30-80%, and the porosity here refers to the porosity of the support layer when the polyethersulfone material is not yet in the support layer, that is, the initial porosity of the support layer; the larger the porosity, the easier it is for the polyethersulfone material to penetrate into the support layer and combine with the first fibers on the support layer. At the same time, these polyethersulfone materials will also be connected to the polyethersulfone layer, thereby making the support layer and the polyethersulfone layer tightly bonded and having great peeling strength.

[0012] As a further improvement of the present invention, the peel strength between the polyethersulfone layer and the support layer is at least 1.0 N / mm.

[0013] Preferably, the peel strength between the polyethersulfone layer and the support layer is at least 1.4 N / mm.

[0014] The peel strength reflects the bonding strength between materials; the greater the peel strength, the tighter the bond between the materials and the less likely they are to separate; the peel strength can be measured by a universal tensile testing machine, and the test method for peel strength is well known in the art, for example, ASTM D1876-08 explains these test procedures in detail; the peel strength between the polyethersulfone layer and the support layer of the filter membrane of the present invention is at least 1.0 N / mm, indicating that the polyethersulfone layer and the support layer are tightly bonded and not easily separated.

[0015] As a further improvement of the present invention, the transverse tensile strength of the polyethersulfone filter membrane is at least 20 MPa, and the longitudinal tensile strength is at least 25 MPa.

[0016] Preferably, the polyethersulfone filter membrane has a transverse tensile strength of at least 22 MPa and a longitudinal tensile strength of at least 27 MPa.

[0017] Tensile strength refers to the ability of a material to resist permanent deformation and damage under the action of external forces; tensile strength includes transverse tensile strength and longitudinal tensile strength. The tensile strength can be measured by a universal tensile testing machine. The test method for tensile strength is well known in the art. For example, ASTM D790 or ISO178 explains the procedure for tensile strength testing in detail. The transverse tensile strength of the polyethersulfone filter membrane of the present invention is at least 20 MPa, and the longitudinal tensile strength is at least 25 MPa, which shows that the polyethersulfone filter membrane of the present invention has a large tensile strength and good mechanical properties, which can fully meet market demand.

[0018] As a further improvement of the present invention, the thickness of the polyethersulfone filter membrane is 65-140 μm, and the thickness of each polyethersulfone layer is 5-40 μm.

[0019] Preferably, the thickness of the polyethersulfone filter membrane is 70-120 μm, and the thickness of each polyethersulfone layer is 10-35 μm.

[0020] When the thickness of the polyethersulfone filter membrane is too small, the mechanical strength of the membrane will be small; at the same time, due to the short filtration time, effective filtration cannot be performed, and the filtration quality is poor; when the thickness of the polyethersulfone filter membrane is too large, the filtration time will be too long, affecting the filtration efficiency and the time cost is large. The polyethersulfone filter membrane of the present invention has a suitable thickness, on the one hand, its mechanical properties are high, and on the other hand, it can perform effective filtration and has a high filtration efficiency.

[0021] As a further improvement of the present invention, the average pore size of the polyethersulfone layer is 4-10 μm; the surface of the polyethersulfone layer away from the support layer contains first holes with a pore size of 1-20 μm, and the pore density is 40-200 holes / 10000 μm 2 .

[0022] Preferably, the average pore size of the polyethersulfone layer is 4.5-8 μm; the surface of the polyethersulfone layer away from the support layer contains first holes with a pore size of 1-20 μm, and the pore density is 55-155 holes / 10000 μm 2 .

[0023] The size of the pores can be measured by computer software (such as Matlab, NIS-Elements, etc.) or manually after the membrane structure is characterized by scanning electron microscopy; the pore size of the holes can also be measured by bubble pressure method; the pore density refers to the number of pores per unit area, and the pore density of a given membrane sample can be determined by, for example, observing a scanning electron microscope image of a given square surface area of ​​the membrane surface of interest and calculating the number of pores within the given area. The calculated number of pores within a given square area can be standardized to a specific reference area by a simple ratio; it is understood that those skilled in the art can also obtain the above parameters by other measurement means.

[0024] The average pore size of the polyethersulfone layer of the present invention is 4-10 μm, and its average pore size is relatively large, which shows that the polyethersulfone filter membrane of the present invention has a faster filtration speed and a shorter filtration time, thereby ensuring the filtration efficiency; and the surface of the polyethersulfone layer away from the support layer includes first holes with a pore size of 1-20 μm, and the pore density is 40-200 holes / 10000 μm 2 Its pore density is also large, which further ensures that the polyethersulfone filter membrane has a faster filtration speed and higher filtration efficiency.

[0025] As a further improvement of the present invention, the first pores include first macropores with a pore size of 7-20 μm and a pore density of 10-50 pores / 10000 μm. 2 The first small hole has a pore size of 1-7 μm and a pore density of 30-150 pores / 10000 μm 2 .

[0026] The outer surface of the polyethersulfone layer of the present invention includes a certain number of first large pores and first small pores. The existence of the first large pores enables the polyethersulfone filter membrane to have a larger flow rate; when the fluid passes through the polymer filter membrane, it has a higher filtration rate and can shorten the filtration time of the material; and the existence of a certain number of first small pores ensures the filtration accuracy and plays a sufficient role in retaining undesirable substances; at the same time, it provides a supplement to the large pore flow rate, and the combination of large and small pores obtains a higher flow rate.

[0027] As a further improvement of the present invention, the water bubble point of the polyethersulfone filter membrane is 25-40KPa; preferably, the water bubble point of the polyethersulfone filter membrane is 30-40KPa;

[0028] One of the important performance characteristics of the filter membrane is the bubble point. The bubble point greatly affects the application range of the filter membrane. The test method of the bubble point is well known in the art. For example, the procedures of these tests are explained in detail in ASTM F316-70 and ANS / ASTM F316-70 (reapproved in 1976), which are incorporated herein by reference. The bubble point of the polyethersulfone filter membrane of the present invention is 25-40KPa; the relatively large bubble point also indicates that the polyethersulfone filter membrane of the present invention has a large application; it is particularly suitable for use in infusion filters in the inkjet field and the medical field; when the polyethersulfone filter membrane of the present invention is used in the inkjet field, the ink cartridge of its printer includes a large bin and a small bin, the polyethersulfone filter membrane is located between the large bin and the small bin, the large bin is used to store ink; the small bin is used to spray ink; in normal times, the ink in the large bin first enters the small bin through the polyethersulfone filter membrane, and the polyethersulfone filter membrane mainly plays a filtering role to prevent large particles in the large bin from entering the small bin, thereby affecting the inkjet quality; when performing inkjet printing, due to the high bubble point, the polyethersulfone filter membrane plays a good one-way valve role to prevent the ink in the small bin from entering the large bin, so that the small bin maintains a relatively high pressure to continuously discharge ink, thereby ensuring the inkjet quality.

[0029] As a further improvement of the present invention, the polyethersulfone layer includes second fibers, the second fibers are connected to the polyethersulfone material in the support layer, and the average diameter of the second fibers is 0.5-8 μm.

[0030] Preferably, the average diameter of the second fibers is 1-6 μm;

[0031] Under the condition that the thickness of the polyethersulfone material in the support layer is certain, the larger the diameter of the second fiber in the polyethersulfone layer, the greater the peel strength between the polyethersulfone layer and the support layer, and the tighter the bonding; the second fiber diameter of the polyethersulfone layer of the present invention is relatively large, with an average diameter of 0.5-8 μm, so that the bonding between the polyethersulfone layer and the support layer is tighter, the peel strength is further increased, and the filter membrane is further ensured to be able to adapt to the impact of the filtrate with high pressure, and the application range is wider.

[0032] On the other hand, the present invention also provides a method for preparing a polyethersulfone filter membrane with a support layer, comprising the following steps:

[0033] S1: preparing a casting solution, wherein the casting solution comprises the following materials in parts by weight: 10-20 parts of polyethersulfone; 70-90 parts of a polar solvent; and 5-20 parts of an additive;

[0034] S2: Immersing the nonwoven fabric in the casting solution to form a liquid film;

[0035] S3: placing the liquid film in a humid environment and blowing air on both sides of the liquid film at the same time; the relative speed and relative angle between the airflow on both sides and the surface of the liquid film are the same; the duration is at least 30 seconds, forming a semi-finished film;

[0036] S4: Immerse the semi-finished film in water at 20°C-40°C for solidification to form a solid film.

[0037] In the above method, a casting liquid is first prepared, and the casting liquid includes polyethersulfone, a polar solvent and an additive; after the homemade casting liquid is prepared, a non-woven fabric as a support layer is immersed in the casting liquid for full impregnation, wherein the non-woven fabric is any one of polyester non-woven fabric, polyphenylene sulfide non-woven fabric, aromatic polyamide non-woven fabric and polyimide non-woven fabric or other non-woven fabric materials; during the impregnation process, the casting liquid will enter the pores of the non-woven fabric, and after the impregnation is complete, a polyethersulfone layer of approximately the same thickness is scraped out using scrapers on both sides, and then a liquid film is formed; then the liquid film is vertically placed in a humid environment with a certain humidity, and air is blown on both sides of the liquid film at the same time, and the liquid film placed in the humid environment will begin to separate phase; the purpose of blowing is to induce the liquid film to further undergo phase transformation, improve the speed and quality of phase transformation, and make it easier for holes to appear on the surface of the polyethersulfone layer; air is blown to both sides of the filter membrane, and the relative speed and relative angle between the airflow on both sides and the liquid membrane surface are the same. On the one hand, this is to ensure that the thickness of the polyether layer on both sides of the final filter membrane is basically the same, the pore size and pore density of the polyethersulfone layer surface, and the average diameter of the second fiber inside are also basically the same, which is conducive to the final polyethersulfone filter membrane being a symmetrical membrane; on the other hand, when blowing on both sides, if the relative speed and relative angle between the airflow on both sides and the liquid membrane surface are different, the liquid membrane will be subjected to uneven force, the liquid membrane will shake, and the phase transformation will be affected. The quality of conversion affects the quality of the filter membrane; if the thickness of the polyethersulfone layer scraped by the scraper on both sides is not basically the same after the immersion is complete, by placing the liquid film horizontally, with the thick polyethersulfone layer on the top and the thin polyethersulfone layer on the bottom, under the action of gravity, a polyethersulfone filter membrane with substantially the same thickness of the polyethersulfone layers on both sides can be formed in the end; in addition, the liquid film can also be placed obliquely; in fact, as long as the thickness of the polyethersulfone layers on both sides of the polyethersulfone filter membrane finally formed is substantially the same, the liquid film can be placed in any manner; the duration of step S3 is at least 30 seconds, preferably 45 seconds; finally, the semi-finished membrane is immersed in water at 20°C-40°C for curing, and the curing time lasts for at least 30 seconds, preferably The time is at least 40s. Such water temperature and duration ensure that polyethersulfone can be completely precipitated from the polar solution, thereby forming a polyethersulfone layer of a certain thickness. A certain number of holes have appeared on the surface of the polyethersulfone layer, and there is also a certain thickness of polyethersulfone material on the first fiber of the support layer. These polyethersulfone materials will be connected to the polyether layer, thereby ensuring that the polyethersulfone layer and the support layer are tightly combined and not easy to separate; solidify in water, and naturally air dry or dry or blow dry the membrane to obtain a solid polyethersulfone filter membrane; the polyethersulfone filter membrane finally obtained contains a support layer made of non-woven fabric material, so that the polyethersulfone filter membrane has greater mechanical strength and is not easy to break. Moreover, the polyethersulfone layer and the support layer of the polyethersulfone filter membrane have greater peeling strength, are very tightly combined, are not easy to separate, can adapt to the impact of large pressure filter membranes, and have a large range of applications.In addition, the polyethersulfone filter membrane of the present invention is also a symmetrical membrane, the properties of the front and back sides are basically the same, both sides can be used, and can be placed at will; there is no need to distinguish between the front and back sides when assembling the filter membrane to a component; compared with the asymmetric membrane, the performance parameters on both sides of the surface are different, and the front and back sides need to be distinguished when assembling to a component before use. The use of the filter membrane of the present invention is more convenient and quick.

[0038] As a further improvement of the present invention, the viscosity of the casting solution in S1 is 10000 cP-80000 cP;

[0039] Preferably, the viscosity of the casting liquid in S1 is 20000-60000 cP; the viscosity can be directly obtained using a viscometer; when the viscosity of the casting liquid is too large, when the non-woven fabric is immersed in the casting liquid, it is difficult for the casting liquid to penetrate into the pores inside the non-woven fabric, thereby affecting the quality of the final polyethersulfone filter membrane; when the viscosity is too small, although the casting liquid will completely penetrate into the pores of the non-woven fabric during the S2 immersion process; but when the impregnated non-woven fabric is placed in a humid environment and air is blown on both sides, due to the low viscosity of the casting liquid, the casting liquid is easily separated from the pores of the non-woven fabric, which on the one hand causes a waste of the casting liquid, and on the other hand, it will also cause the support layer and the polyethersulfone layer to be loosely bonded, and the peeling strength is relatively small.

[0040] As a further improvement of the present invention, the polar solvent is at least one of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide;

[0041] The additive is a mixture of polyvinyl pyrrolidone, triethylene glycol monobutyl ether and N,N-dimethyl-3-amino-1,2-propylene glycol, and the mass ratio thereof is 3:1:1.

[0042] Polyvinyl pyrrolidone is a good porogen, dispersant, stabilizer, and a common substance used to form a casting solution. In the selection of additives, the present invention not only adds polyvinyl pyrrolidone, but also adds two substances, triethylene glycol monobutyl ether and N,N-dimethyl-3-amino-1,2-propylene glycol. Under the synergistic effect of these three substances, not only can the hydrophilicity of polar solvents be greatly improved, but also polar solvents can be more easily dissolved by water during phase separation, thereby making polyether sulfone easier to precipitate, forming a polyether sulfone layer on the surface of the support layer, and finally obtaining a polyether sulfone filter membrane; at the same time, it can also increase the water flux and the filtration speed; in addition, it can also make the support layer and polyether sulfone more closely bonded, with greater bonding strength. These effects cannot be achieved by adding only polyvinyl pyrrolidone.

[0043] As a further improvement of the present invention, the surfactant and the casting solution also include 1-3 parts of a surfactant; the surfactant is at least one of pentaerythritol, sodium dodecylbenzene sulfonate, diethanolamine lauric acid, triethanolamine and sodium dodecyl sulfate.

[0044] As a further improvement of the present invention, in S2, the non-woven fabric is dipped into the casting liquid at an angle, and the angle of inclination between the non-woven fabric and the surface of the casting liquid is 3-40°; the temperature of the casting liquid is 20-40°C, and the immersion time is at least 40s.

[0045] Preferably, the nonwoven fabric is dipped into the casting solution at an angle of 5-30° to the surface of the casting solution; the temperature of the casting solution is 25-35° C., and the immersion time is at least 60 seconds.

[0046] When the non-woven fabric is immersed in the casting liquid, it can be immersed horizontally, vertically, or at a certain inclination angle; wherein vertical immersion means that when the non-woven fabric is immersed in the casting liquid, the inclination angle between the non-woven fabric and the liquid surface of the casting liquid is 90°. When immersed at such an angle, the casting liquid cannot be completely immersed in the pores of the non-woven fabric, because there is still a lot of air in the pores of the non-woven fabric at this time, and the air cannot be discharged from the pores, and the casting liquid cannot enter the pores of the non-woven fabric, so that the mechanical strength of the polyethersulfone filter membrane finally obtained is not high, and the peel strength between the polyethersulfone layer and the supporting layer is poor; horizontal immersion means that when the non-woven fabric is immersed in the casting liquid, the inclination angle between the non-woven fabric and the liquid surface of the casting liquid is 0°. When immersed at such an angle, the air in the pores of the non-woven fabric will be completely discharged, and the casting liquid can be completely immersed in the pores of the non-woven fabric, but such an immersion method has very high requirements on the equipment. It is also very time-consuming, and the impregnation cost is too high, which is not suitable for actual production applications. Therefore, the present invention immerses the non-woven fabric at a certain inclination angle. When the non-woven fabric is immersed in the casting liquid, the inclination angle between the non-woven fabric and the casting liquid surface is 3-40°, so that the air in the pores of the non-woven fabric can be basically discharged, and the casting liquid can basically be immersed in the pores of the non-woven fabric, so that the polyethersulfone filter membrane finally obtained has greater mechanical strength, and the peel strength between the polyethersulfone layer and the support layer is greater; and the impregnation is convenient, the equipment requirements are low, the impregnation cost is low, and it is suitable for actual production applications; by setting the temperature of the casting liquid to 20-40°C and the immersion time to at least 40s, such a setting ensures that the casting liquid can be completely immersed in the pores of the non-woven fabric, and the impregnation is more sufficient, thereby further ensuring that the polyethersulfone filter membrane has greater mechanical strength, and the peel strength between the polyethersulfone layer and the support layer is large.

[0047] As a further improvement of the present invention, in S3, the humid environment refers to an environment with an absolute humidity of 10gH2O / kg-50gH2O / kg.

[0048] Preferably, in S3, the humid environment refers to an environment with an absolute humidity of 15 gH2O / kg-40 gH2O / kg.

[0049] As a further improvement of the present invention, the relative speed between the airflow and the liquid film surface is at least 0.3 m / s; and the angle between the airflow direction and the liquid film surface is 0-30°.

[0050] Preferably, the relative speed between the airflow and the liquid film surface is at least 0.5 m / s; the angle between the airflow direction and the liquid film surface is 0-20°;

[0051] Blowing air on both sides of the liquid membrane can improve the speed and quality of phase separation of the liquid membrane; blowing air on both sides of the liquid membrane instead of blowing air on one side is to ensure that the phase separation degree of the polyethersulfone layers on both sides is basically the same, and the average pore size and other properties of the polyethersulfone layers on both sides are also basically the same, which is conducive to the final polyethersulfone membrane being a symmetrical membrane with basically the same performance on both sides of the membrane. In practical applications, there is no need to distinguish the surface of the filter membrane, which is faster and more convenient to use; when the relative speed between the airflow and the liquid membrane surface is at least 0.3m / s, it is ensured that the average pore size of the surface of the polyethersulfone layer is large, reaching 4-10μm; at the same time, the pore density of the holes with a pore size of 1-15μm on the surface is 30-90 holes / 10000μm 2 In this way, the polyethersulfone filter membrane has a faster filtration speed, short filtration time and higher filtration efficiency.

[0052] The angle between the airflow direction and the liquid film surface is 0-30°. This angle setting ensures that the air blowing can effectively improve the speed and quality of liquid film phase separation, and ensure that the phase separation is as complete and sufficient as possible.

[0053] In addition, the present invention also provides the use of a polyethersulfone filter membrane, which is used in an infusion filter in the medical field; the infusion filter comprises a shell, the shell has an inlet and an outlet, and the polyethersulfone filter membrane is located between the inlet and the outlet.

[0054] The polyethersulfone filter membrane can remove the micro-particles in the drug solution, while the effective ingredients in the drug solution can pass through the polyethersulfone filter membrane and then enter the human blood circulation system to treat the affected area; and the polyethersulfone filter membrane has a faster filtration speed and a short filtration time, which ensures the normal delivery speed of the drug solution.

[0055] The polyethersulfone filter membrane is used in a printer in the inkjet field; the ink cartridge of the printer includes a large bin and a small bin, the large bin is used to store ink; the small bin is used to spray ink; the polyethersulfone filter membrane is located between the large bin and the small bin;

[0056] The average pore size of the polyethersulfone layer surface is 4.5-8 μm; the pore density of the surface pore size is 1-15 μm and the pore density is 60-150 pores / 10000 μm. 2 .

[0057] Normally, the ink in the large chamber will first pass through the polyethersulfone filter membrane and then enter the small chamber. The polyethersulfone filter membrane mainly plays a filtering role to prevent large particles in the large chamber from entering the small chamber and then affecting the inkjet quality. During inkjet printing, the polyethersulfone filter membrane mainly plays the role of a valve to prevent the ink in the small chamber from entering the large chamber, so that the small chamber maintains a higher pressure to continuously discharge ink and ensure the inkjet quality.

[0058] Beneficial effects of the present invention: The polyethersulfone filter membrane provided by the present invention is a symmetrical membrane, comprising two polyethersulfone layers and a supporting layer, the supporting layer provides a supporting effect, so that the polyethersulfone filter membrane has a large mechanical strength; at the same time, the polyethersulfone layer and the supporting layer in the polyethersulfone filter membrane are tightly combined and have a large peeling strength, so that the polyethersulfone filter membrane can adapt to the impact of high-pressure filtrate, and its application range is wider, especially suitable for the inkjet field and the medical field; the preparation method provided by the present invention can conveniently, quickly and effectively prepare the above-mentioned polyethersulfone filter membrane, and at the same time, the polyethersulfone filter membrane with bilateral symmetry is prepared by adopting the method of blowing on both sides, so that the polyethersulfone filter layer has a large average pore size, the filtration speed of the polyethersulfone filter membrane is large, and the filtration time is short. In addition, since the polyethersulfone filter membrane of the present invention is a symmetrical membrane, the properties of the surfaces on both sides are basically the same. When assembling it to the component, there is no need to distinguish between the front and back sides, and it is more convenient and quick to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a scanning electron microscope (SEM) image of the longitudinal section of the polyethersulfone filter membrane prepared in Example 1, wherein the magnification is 500×;

[0060] Figure 2 This is a scanning electron microscope (SEM) image of one surface of the polyethersulfone filter membrane prepared in Example 1, wherein the magnification is 500×;

[0061] Figure 3 This is a scanning electron microscope (SEM) image of another surface of the polyethersulfone filter membrane prepared in Example 1, wherein the magnification is 500×;

[0062] Figure 4 It is a schematic diagram of a water bubble point testing device for a polyethersulfone filter membrane of the present invention;

[0063] Figure 5 It is a schematic diagram of a polyethersulfone flow rate testing device of the present invention;

[0064] Figure 6 It is a schematic diagram of a polyethersulfone filter membrane filtration accuracy testing device of the present invention;

[0065] Figure 7 This is a schematic diagram of the structure of the polyethersulfone filter membrane of the present invention used in the inkjet field;

[0066] Figure 8 It is a schematic diagram of the structure of the polyethersulfone filter membrane of the present invention when used in an infusion set in the medical field. DETAILED DESCRIPTION

[0067] In order to more clearly explain the overall concept of the application, the following is described in detail by way of embodiment. In the following description, a large amount of specific details are provided so as to provide a more thorough understanding of the application. However, it is obvious to those skilled in the art that the application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the application, some technical features well known in the art are not described.

[0068] Unless otherwise specified, in the following examples, the raw materials and equipment used to prepare the filter membrane can be purchased from commercial sources. The present invention uses a scanning electron microscope model S-5500 provided by Hitachi to characterize the structure and morphology of the filter membrane.

[0069] Example 1

[0070] Example 1 provides a polyethersulfone filter membrane with a support layer, which is prepared by the following method:

[0071] S1: preparing a casting solution, wherein the casting solution comprises the following materials in parts by weight: 15 parts of polyethersulfone; 80 parts of a polar solvent; 2 parts of a surfactant; and 12 parts of an additive; the viscosity of the casting solution is 40,000 cP; the polar solvent is N,N-dimethylacetamide; the surfactant is pentaerythritol; and the additive is a mixture of polyvinyl pyrrolidone, triethylene glycol monobutyl ether, and N,N-dimethyl-3-amino-1,2-propylene glycol, and the mass ratio thereof is 3:1:1;

[0072] S2: The non-woven fabric is immersed in the casting liquid and fully immersed. After the immersion is complete, a polyethersulfone layer with approximately the same thickness on both sides is scraped out with a scraper to form a liquid film; wherein the inclination angle between the non-woven fabric and the casting liquid surface is 15°, the temperature of the casting liquid is 30°C, and the immersion time is 60s;

[0073] S3: The liquid film is exposed to a humid environment with an absolute humidity of 30gH2O / kg. The liquid film is placed vertically and air is blown on both sides of the liquid film at the same time. The angle between the airflow direction and the liquid film surface is 10°, the relative speed between the airflow and the liquid film surface is 0.5m / s, and the duration is 45s to form a semi-finished film;

[0074] S4: The semi-finished membrane is immersed in water at 30° C. for 45 seconds, thereby forming a solid membrane.

[0075] Example 2

[0076] Example 2 provides a polyethersulfone filter membrane with a support layer, which is prepared by the following method:

[0077] S1: preparing a casting solution, wherein the casting solution comprises the following materials in parts by weight: 10 parts of polyethersulfone; 70 parts of a polar solvent; 8 parts of an additive; the viscosity of the casting solution is 20000 cP; the polar solvent is N,N-dimethylacetamide; the surfactant is sodium dodecyl sulfate; the additive is a mixture of polyvinyl pyrrolidone, triethylene glycol monobutyl ether and N,N-dimethyl-3-amino-1,2-propylene glycol, and the mass ratio thereof is 3:1:1;

[0078] S2: The non-woven fabric is immersed in the casting liquid and fully immersed. After the immersion is complete, a polyethersulfone layer with approximately the same thickness on both sides is scraped out with a scraper to form a liquid film; wherein the inclination angle between the non-woven fabric and the casting liquid surface is 35°, the temperature of the casting liquid is 30°C, and the immersion time is 45s;

[0079] S3: The liquid film is exposed to a humid environment with an absolute humidity of 45gH2O / kg. The liquid film is placed vertically and air is blown on both sides of the liquid film at the same time. The angle between the airflow direction and the liquid film surface is 15°, the relative speed between the airflow and the liquid film surface is 0.4m / s, and the duration is 40s to form a semi-finished film;

[0080] S4: The semi-finished membrane is immersed in water at 30° C. for 40 seconds, thereby forming a solid membrane.

[0081] Example 3

[0082] Example 3 provides a polyethersulfone filter membrane with a support layer, which is prepared by the following method:

[0083] S1: Prepare a casting liquid, which includes the following materials in parts by weight: 15 parts of polyethersulfone with a characteristic viscosity of 0.5; 80 parts of a polar solvent; 13 parts of an additive; the viscosity of the casting liquid is 60,000 cP; wherein the polar solvent is N-methylpyrrolidone; the surfactant is sodium dodecylbenzene sulfonate; the additive is a mixture of polyvinylpyrrolidone, triethylene glycol monobutyl ether and N,N-dimethyl-3-amino-1,2-propylene glycol, and the mass ratio thereof is 3:1:1.

[0084] S2: The non-woven fabric is immersed in the casting liquid and fully immersed. After the immersion is complete, a polyethersulfone layer with approximately the same thickness on both sides is scraped out with a scraper to form a liquid film; wherein the inclination angle between the non-woven fabric and the casting liquid surface is 30°, the temperature of the casting liquid is 30°C, and the immersion time is 40s;

[0085] S3: The liquid film is exposed to a humid environment with an absolute humidity of 15gH2O / kg. The liquid film is placed vertically and air is blown on both sides of the liquid film at the same time. The angle between the airflow direction and the liquid film surface is 25°, and the relative speed between the airflow and the liquid film surface is 0.3m / s. The duration is 30s to form a semi-finished film.

[0086] S4: The semi-finished membrane is immersed in water at 30° C. for 35 seconds, thereby forming a solid membrane.

[0087] Example 4

[0088] Example 4 provides a polyethersulfone filter membrane with a support layer, which is prepared by the following method:

[0089] S1: Prepare a casting liquid, which includes the following substances in parts by weight: 18 parts of polyethersulfone; 85 parts of polar solvent; 2 parts of surfactant; 15 parts of additives; the viscosity of the casting liquid is 45000 cP; the polar solvent is dimethyl sulfoxide; the surfactant is diethanolamine lauric acid; the additive is a mixture of polyvinyl pyrrolidone, triethylene glycol monobutyl ether and N,N-dimethyl-3-amino-1,2-propylene glycol, and the mass ratio thereof is 3:1:1.

[0090] S2: The non-woven fabric is immersed in the casting liquid and fully immersed. After the immersion is complete, a polyethersulfone layer with approximately the same thickness on both sides is scraped out with a scraper to form a liquid film; wherein the inclination angle between the non-woven fabric and the casting liquid surface is 5°, the temperature of the casting liquid is 30°C, and the immersion time is 50s;

[0091] S3: The liquid film is exposed to a humid environment with an absolute humidity of 25gH2O / kg. The liquid film is placed vertically and air is blown on both sides of the liquid film at the same time. The angle between the airflow direction and the liquid film surface is 0°, and the relative speed between the airflow and the liquid film surface is 0.5m / s. The duration is 50s to form a semi-finished film.

[0092] S4: The semi-finished membrane is immersed in water at 30° C. for 45 seconds, thereby forming a solid membrane.

[0093] Example 5

[0094] Example 5 provides a polyethersulfone filter membrane with a support layer, which is prepared by the following method:

[0095] S1: Prepare a casting liquid, which includes the following substances in parts by weight: 13 parts of polyethersulfone; 75 parts of polar solvent; 2 parts of surfactant; 10 parts of additives; the viscosity of the casting liquid is 35000 cP; wherein the polar solvent is N,N-dimethylformamide; the surfactant is triethanolamine; the additive is a mixture of polyvinyl pyrrolidone, triethylene glycol monobutyl ether and N,N-dimethyl-3-amino-1,2-propylene glycol, and the mass ratio thereof is 3:1:1.

[0096] S2: The non-woven fabric is immersed in the casting liquid and fully immersed, and a polyethersulfone layer with approximately the same thickness on both sides is scraped out with a scraper to form a liquid film; wherein the inclination angle between the non-woven fabric and the casting liquid surface is 20°, the temperature of the casting liquid is 30°C, and the immersion time is 55s;

[0097] S3: The liquid film is exposed to a humid environment with an absolute humidity of 35gH2O / kg. The liquid film is placed vertically and air is blown on both sides of the liquid film. The angle between the airflow direction and the liquid film surface is 0°, and the relative speed between the airflow and the liquid film surface is 0.5m / s. The duration is 55s, and a semi-finished film is formed.

[0098] S4: The semi-finished membrane is immersed in water at 30° C. for 45 seconds, thereby forming a solid membrane.

[0099] Comparative Example 1

[0100] Example 1 provides a polyethersulfone filter membrane with a support layer, which is prepared by the following method:

[0101] S1: preparing a casting solution, wherein the casting solution comprises the following materials in parts by weight: 15 parts of polyethersulfone; 80 parts of a polar solvent; and 12 parts of an additive; the viscosity of the casting solution is 30,000 cP; wherein the polar solvent is N,N-dimethylacetamide; and the additive is polyvinyl pyrrolidone;

[0102] S2: immersing the non-woven fabric in the casting solution and fully immersing it, scraping out polyethersulfone layers of approximately the same thickness on both sides with a scraper, and then forming a liquid film; wherein the inclination angle between the non-woven fabric and the casting solution surface is 50°, the temperature of the casting solution is 30°C, and the immersion time is 40s;

[0103] S3: exposing the liquid film to a humid environment with an absolute humidity of 10 gH2O / kg for 40 seconds to form a semi-finished film;

[0104] S4: The semi-finished membrane is immersed in water at 10° C. for 30 seconds, thereby forming a solid membrane.

[0105] I. Structural Characterization

[0106] The polyethersulfone filter membranes obtained in each embodiment and comparative example were characterized by scanning electron microscopy in longitudinal section and on two outer surfaces, and then the required data were obtained; the specific results are shown in the following table:

[0107] Note: The polyethersulfone filter membrane of the present invention is a symmetrical membrane, comprising two polyethersulfone layers. Although the thickness, average pore size, surface pore density and other structural features of the two polyethersulfone layers have certain differences, they can be basically regarded as the same. Therefore, the average value is used to represent the actual value. For example, the thickness of the polyethersulfone layer in the table actually means the average thickness of the two polyethersulfone layers, which is obtained by dividing the sum of the thicknesses of the two polyethersulfone layers by 2; the surface pore density of the polyethersulfone layer in the table actually means the average value of the surface pore density of the two polyethersulfone layers, which is obtained by dividing the sum of the surface pore density of the two polyethersulfone layers by 2; the surface pore density of the polyethersulfone layer refers to the pore density of the first holes with a pore size of 1-20 μm on the surface of the polyethersulfone layer away from the support layer; in addition, since the thickness of the polyethersulfone material on the first fibers on both sides is also basically the same, the average value is also used to represent the actual value; the thickness of the polyethersulfone material on each side in the table actually means the average value of the thickness of the polyethersulfone material on both sides, which is obtained by dividing the sum of the thickness of the polyethersulfone material on both sides by 2;

[0108] Thickness unit: μm;

[0109] Aperture unit: μm;

[0110] Density unit: holes / 10000μm 2 ;

[0111] The average fiber diameter unit: μm;

[0112]

[0113]

[0114]

[0115]

[0116] Depend on Figure 1-3 It can be concluded from the data in the above table that the polyethersulfone filter membrane prepared by the method of the present invention has an obvious three-layer structure including a support layer and two polyethersulfone layers, and the polyethersulfone layers are located on both sides of the support layer; and the surface of the polyethersulfone layer has a certain regular pore size distribution, and the porous layer has a certain regular fiber distribution; the polyethersulfone layer and the support layer are tightly combined, so that the polyethersulfone filter membrane can adapt to the impact of the filtrate with high pressure; and the polyethersulfone filter layer has a larger average pore size, the filtration speed of the polyethersulfone filter membrane is larger, and the filtration time is short.

[0117] 2. Performance Test

[0118] The membranes obtained in each example were tested for transverse tensile strength, longitudinal tensile strength and peel strength using a universal testing machine. The specific results are shown in the following table:

[0119]

[0120]

[0121] It can be seen from the above table that the polyethersulfone filter membrane prepared in the present invention has greater mechanical properties, and its transverse tensile strength and longitudinal tensile strength are both greater; and the peel strength between the polyethersulfone layer and the support layer is greater, so that the polyethersulfone filter membrane can adapt to the impact of high-pressure filtrate;.

[0122] Water bubble point test (test device such as Figure 4 )

[0123] Experimental steps:

[0124] Step 1: Close the air pressure regulator 2, open the air pressure regulator 1, make the pressure higher than the tested pressure, take out the wetted filter membrane to be tested, and install it on the filtration device.

[0125] Step 2: Fill the reservoir with 80% of the test solution, increase the air pressure, and stop pressurizing when it reaches about 80% of the bubble point. It is necessary to confirm that the filter membrane in the reservoir has not yet produced bubbles.

[0126] Step 3: Slowly increase the pressure. When all bubbles appear on the filter membrane, read the pressure at this time as the bubble point.

[0127] NOTE: Typically bubbles emerge from near the center of the filter.

[0128] Water flow rate test (test device such as Figure 5 )

[0129] Experimental procedures

[0130] Step 1: Install the filter membrane to be tested on the vacuum filtration bracket, close valve 2 on the vacuum filtration bracket, open valve 1, start the vacuum pump, adjust the pressure to the test pressure -5KPa, and then close valve 1.

[0131] Step 2: Put 50 ml of test liquid (water) into the plastic measuring cylinder of the vacuum filtration support, open valve 2, start timing from a certain scale and stop timing at another scale;

[0132] Step 3: After the test is completed, record the value displayed on the stopwatch. When all the test liquid has passed through the filter membrane, close valve 2 on the bracket and remove the filter membrane.

[0133] Water bubble point (kPa) Flow rate / s Example 1 37 2.8 Example 2 38 3.0 Example 3 34 2.5 Example 4 30 2.2 Example 5 32 2.4 Comparative Example 1 39 3.4

[0134] Filtration accuracy test: The interception efficiency of the filter membrane obtained in each example was tested.

[0135] Experimental equipment: Tianjin Logan particle counter KB-3; Experimental preparation: press Figure 6 Assemble the experimental device, ensure that the device is clean, and rinse the device with ultrapure water; take a filter membrane with a diameter of 47 mm, install it in the butterfly filter, and ensure that the assembled filter has good airtightness.

[0136] Experimental steps:

[0137] Pour the challenge liquid into the storage tank, pay attention to the exhaust of the butterfly filter, pressurize it to 10kPa, and use a clean bottle to collect the filtrate downstream of the butterfly.

[0138] The number of particles in the filtrate and the original solution was tested using a particle counter.

[0139] Interception efficiency:

[0140] Where:

[0141] η───Interception efficiency, %;

[0142] n0───Number of particles in the stock solution, average value of 5 groups of counts, pieces;

[0143] n1───The number of particles in the filtrate, the average value of 5 groups of counts, pieces.

[0144] The interception efficiency test results of each example are as follows:

[0145] 5.0μm 6.0μm Example 1 ≥99.0％ - Example 2 ≥99.0％ - Example 3 ≥99.0％ - Example 4 ≥99.0％ Example 5 ≥99.0％

[0146] It can be seen from the above table that the polyethersulfone filter membrane of the present invention has a large filtration accuracy, can effectively remove impurities, and ensure filtration quality.

[0147] When polyethersulfone membrane is used in inkjet field, Figure 7 As shown, the ink cartridge of the printer includes a large chamber and a small chamber, and the polyethersulfone filter membrane is located between the large chamber and the small chamber; in normal times, the ink in the large chamber first enters the small chamber through the polyethersulfone filter membrane, and the polyethersulfone filter membrane mainly plays a filtering role to prevent large particles in the large chamber from entering the small chamber and then affecting the inkjet quality; when performing inkjet printing, the polyethersulfone filter membrane mainly plays the role of a valve to prevent the ink in the small chamber from entering the large chamber, so that the small chamber maintains a higher pressure to continuously discharge ink, thereby ensuring the inkjet quality.

[0148] When polyethersulfone membranes are used in infusion filters in the medical field, such as Figure 8As shown, the infusion filter includes a shell, the shell has an inlet and an outlet, and the polyethersulfone filter membrane is located between the inlet and the outlet. The polyethersulfone filter membrane can remove micro-particles in the liquid medicine, and the active ingredients in the liquid medicine can pass through the polyethersulfone filter membrane and then enter the human blood circulation system to treat the diseased area; and the polyethersulfone filter membrane has a faster filtration speed and a short filtration time, ensuring the normal delivery speed of the liquid medicine.

[0149] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A polyethersulfone filter membrane with a support layer, comprising a support layer and two polyethersulfone layers, wherein the polyethersulfone layers are respectively located on both sides of the support layer, and the two polyethersulfone layers have the same thickness, characterized in that: The support layer includes first fibers interwoven to form a mesh structure and polyethersulfone materials bonded to the first fibers, and the polyethersulfone materials on the first fibers are connected to the polyethersulfone layer; the thickness of the polyethersulfone materials on each side of the first fibers is at least 10 μm, which accounts for at least 45% of the total thickness of the support layer; The supporting layer is a non-woven fabric; The method for preparing the polyethersulfone filter membrane with a support layer comprises the following steps: S1: preparing casting solution; S2: Immerse the non-woven fabric in the casting liquid to form a liquid film; when the non-woven fabric is immersed in the casting liquid at an angle, the inclination angle between the non-woven fabric and the surface of the casting liquid is 3-40°.

2. The polyethersulfone filter membrane with a support layer according to claim 1, characterized in that: The average diameter of the first fibers in the support layer is 3-11 μm; the porosity of the mesh structure formed by the first fibers interweaving with each other in the support layer is 30-80%.

3. The polyethersulfone filter membrane with a support layer according to claim 1, characterized in that: The peel strength between the polyethersulfone layer and the support layer is at least 1.0 N / mm.

4. The polyethersulfone filter membrane with a support layer according to claim 1, characterized in that: The polyethersulfone filter membrane has a transverse tensile strength of at least 20 MPa and a longitudinal tensile strength of at least 25 MPa.

5. The polyethersulfone filter membrane with a support layer according to claim 1, characterized in that: The thickness of the polyethersulfone filter membrane is 65-140 μm, and the thickness of each polyethersulfone layer is 5-40 μm.

6. The polyethersulfone filter membrane with a support layer according to claim 1, characterized in that: The average pore size of the polyethersulfone layer is 4-10 μm; The surface of the polyethersulfone layer away from the support layer contains first holes with a pore size of 1-20 μm, and the pore density is 40-200 holes / 10000 μm. 2 .

7. The polyethersulfone filter membrane with a support layer according to claim 6, characterized in that: The first hole comprises (a) The first largest pores have a pore size of 7-20 μm and a pore density of 10-50 pores / 10000 μm 2 ; (b) The first small hole has a pore size of 1-7 μm and a pore density of 30-150 pores / 10000 μm 2 .

8. The polyethersulfone filter membrane with a support layer according to claim 1, characterized in that: The water bubble point of the polyethersulfone filter membrane is 25-40KPa.

9. The polyethersulfone filter membrane with a support layer according to claim 1, characterized in that: The polyethersulfone layer includes second fibers, the second fibers are connected to the polyethersulfone material in the support layer, and the average diameter of the second fibers is 0.5-8 μm.

10. A method for preparing a polyethersulfone filter membrane with a support layer according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: preparing a casting solution, wherein the casting solution comprises the following materials in parts by weight: 10-20 parts of polyethersulfone; 70-90 parts of a polar solvent; and 5-20 parts of an additive; S2: Immersing the nonwoven fabric in the casting solution to form a liquid film; S3: placing the liquid film in a humid environment and blowing air on both sides of the liquid film at the same time; the relative speed and relative angle between the airflow on both sides and the surface of the liquid film are the same; the duration is at least 30 seconds, forming a semi-finished film; S4: Immerse the semi-finished film in water at 20°C-40°C for solidification to form a solid film.

11. The method for preparing a polyethersulfone filter membrane with a support layer according to claim 10, characterized in that: The viscosity of the casting solution in S1 is 10000 cP-80000 cP.

12. The method for preparing a polyethersulfone filter membrane with a support layer according to claim 10, characterized in that: The polar solvent is at least one of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide; The additive is a mixture of polyvinyl pyrrolidone, triethylene glycol monobutyl ether and N,N-dimethyl-3-amino-1,2-propylene glycol, and the mass ratio thereof is 3:1:

1.

13. The method for preparing a polyethersulfone filter membrane with a support layer according to claim 10, characterized in that: The casting solution also includes 1-3 parts of a surfactant; the surfactant is at least one of pentaerythritol, sodium dodecylbenzene sulfonate, diethanolamine lauric acid, triethanolamine and sodium dodecyl sulfate.

14. The method for preparing a polyethersulfone filter membrane with a support layer according to claim 10, characterized in that: In S2, the temperature of the casting solution is 20-40°C, and the immersion time is at least 40 seconds.

15. The method for preparing a polyethersulfone filter membrane with a support layer according to claim 10, characterized in that: In S3, the humid environment refers to an environment with an absolute humidity of 10gH2O / kg-50gH2O / kg.

16. The method for preparing a polyethersulfone filter membrane with a support layer according to claim 10, characterized in that: In S3, the relative speed between the airflow and the liquid film surface is at least 0.3 m / s; and the angle between the airflow direction and the liquid film surface is 0-30°.

17. Use of a polyethersulfone filter membrane with a support layer according to any one of claims 1 to 9, characterized in that: The polyethersulfone filter membrane is used in infusion filters in the medical field; The infusion filter comprises a shell, wherein an inlet and an outlet are arranged on the shell, and the polyethersulfone filter membrane is located between the inlet and the outlet.

18. Use of a polyethersulfone filter membrane with a support layer according to any one of claims 1 to 9, characterized in that: The polyethersulfone filter membrane is used in a printer in the inkjet field; the ink cartridge of the printer includes a large bin and a small bin, the large bin is used to store ink; the small bin is used to spray ink; the polyethersulfone filter membrane is located between the large bin and the small bin; The average pore size of the polyethersulfone layer is 4.5-8 μm; The surface of the polyethersulfone layer away from the support layer contains holes with a pore size of 1-20 μm, and the pore density is 60-150 holes / 10000 μm 2 .

Images