Preparation method of heavy ion microporous composite filtration membrane and application thereof

Abstract

The application discloses a preparation method of a heavy ion microporous composite filtration membrane and application thereof, and relates to the technical field of membrane separation preparation, wherein the preparation method comprises the following steps: step one, compounding a nuclear pore membrane on the upper side of a first base material; step two, preparing a casting solution, and then casting the casting solution on a second base material to form a nascent membrane after scraping; step three, performing a blowing operation on the nascent membrane to obtain a pre-phase separation membrane; step four, immersing the pre-phase separation membrane in a coagulation bath to perform a solidification operation, and obtaining a solidified membrane; step five, performing an area stretching operation on the solidified membrane, and then performing a cleaning operation in pure water, and then performing a drying operation after the cleaning operation to obtain a microfiltration membrane; and step six, compounding the microfiltration membrane on the upper side of the nuclear pore membrane to obtain a composite filtration membrane. The preparation method of the heavy ion microporous composite filtration membrane improves the liquid stopping effect, filtration flux and flux stability of the filtration membrane by compounding the first base material, the nuclear pore membrane and the microfiltration membrane.

Description

Technical Field

[0001] This invention relates to the field of membrane separation preparation technology, and in particular to a method for preparing a heavy ion microporous composite filter membrane and its application. Background Technology

[0002] Nuclear pore membranes (heavy ion microporous membranes) are a new type of filtration membrane used for precision filtration and particle sieving, currently mainly used in medical and consumer filtration products. However, pure nuclear pore membranes have drawbacks such as low porosity and poor flux stability. Therefore, it is necessary to study their combination with other membrane structures to explore more applications and improve their filtration performance.

[0003] In the prior art, the patent publication number CN111974229A, "A Novel Composite Membrane and Its Production Method", can combine a nucleopore filter membrane and a mixed cellulose membrane together. It has a built-in pre-filtration function. The nucleopore filter membrane has a strong dirt-holding capacity and is not easy to clog. The pre-filter fiber membrane that is used in conjunction with it does not easily shed fibers, has low adsorption and good high temperature resistance. At the same time, it effectively solves the problem that the nucleopore membrane cannot be assembled with automated equipment due to static electricity.

[0004] In the field of medical filtration, filtration height is a crucial performance characteristic of filtration membranes. It is typically related to membrane pore size; generally, smaller pore sizes result in higher filtration height. However, smaller pore sizes can negatively impact filtration flux and flux stability. Especially during infusion filtration, membranes with poor flux stability can reduce the infusion rate over time, potentially affecting patient health. Therefore, a comprehensive consideration of filtration membrane filtration effectiveness, flux, and flux stability is necessary. However, the aforementioned existing technologies do not address this aspect, resulting in poor filtration effectiveness, flux, and flux stability in their membranes. Summary of the Invention

[0005] This invention provides a method for preparing a heavy ion microporous composite filter membrane and its application, in order to solve the problems of the lack of reliable liquid-stopping effect, poor filtration flux and flux stability of existing filter membranes.

[0006] On one hand, the present invention provides a method for preparing a heavy ion microporous composite filter membrane, comprising the following steps:

[0007] Step 1: Composite a nuclear pore membrane on the upper side of the first substrate.

[0008] Step 2: Prepare casting solution, cast the casting solution onto the second substrate, and coat it to form a primary film.

[0009] Step 3: Perform a blowing operation on the primary membrane to obtain a pre-separated membrane.

[0010] Step four: Immerse the pre-separated membrane in a coagulation bath for curing to obtain a cured membrane.

[0011] Step 5: Perform area stretching on the cured membrane, wash it in pure water, and then dry it to obtain a microfiltration membrane.

[0012] Step 6: Composite the microfiltration membrane onto the upper side of the nuclear pore membrane to obtain a composite filtration membrane.

[0013] The composite filtration membrane has a structure consisting of a first substrate layer, a core pore membrane layer, and a microfiltration membrane layer from bottom to top. The microfiltration membrane layer has a structure consisting of a second substrate sublayer from bottom to top and a porous membrane sublayer that is phase-separated and solidified on the second substrate sublayer by the casting solution.

[0014] In one possible implementation, in step one, the first substrate is a first meltblown nonwoven fabric with a thickness of 1-100 micrometers, a pore size of 0.1-20 micrometers, and a porosity of 30%-60%.

[0015] The thickness of the nuclear pore membrane is 1-100 micrometers, the pore size is 0.02-20 micrometers, and the porosity is 1%-20%.

[0016] The composite method is hot pressing, with a temperature of 80-150℃, a time of 10-30 seconds, and a pressure of 0.1-1 bar.

[0017] In one possible implementation, in step two, the casting solution comprises: a first organic solvent, a polymer, and a hydrophilic additive.

[0018] The mass ratio of the first organic solvent, the polymer, and the hydrophilic additive is 1:10%-40%:10%-40%.

[0019] In one possible implementation, in step two, the first organic solvent includes one or more of dimethyl sulfoxide, dimethylformamide, caprolactam, N-ethylpyrrolidone, dimethylacetamide, and N-methylpyrrolidone.

[0020] The polymers include one or more of the following: polyethersulfone, polyamide, polyvinylidene fluoride, polyvinyl alcohol, cellulose acetate, chitosan, polystyrene pyrrolidone, polyimide, polyamide, polylactic acid, polycaprolactone, polycarbonate, polyaniline, and polyacrylonitrile.

[0021] The hydrophilic additives include one or more of polyvinyl alcohol, polyethylene glycol, polyethyleneimine, and polyvinylpyrrolidone.

[0022] In one possible implementation, in step two, the second substrate is a second meltblown nonwoven fabric with a thickness of 1-100 micrometers, a pore size of 0.1-20 micrometers, and a porosity of 30%-60%.

[0023] In one possible implementation, in step three, the temperature of the blowing operation is 10-30℃, the humidity is 60%-80%, the wind speed is 1-4m / s, and the duration is 10-60s.

[0024] In one possible implementation, in step four, the curing operation takes 60-600 seconds, and the coagulation bath is a mixture of a second organic solvent and water, wherein the mass ratio of the second organic solvent to water is 1:2-20.

[0025] The second organic solvent includes one or more of dimethyl sulfoxide, dimethylformamide, caprolactam, N-ethylpyrrolidone, dimethylacetamide, and N-methylpyrrolidone.

[0026] In one possible implementation, in step five, the area stretching operation is performed by a stretching factor of 1.1 to 1.5 times.

[0027] In one possible implementation, in step six, the compounding method is hot pressing, wherein the hot pressing temperature is 80-150°C, the time is 10-30 seconds, and the pressure is 0.1-1 bar.

[0028] On the one hand, the present invention also provides an application of the above-mentioned heavy ion microporous composite filter membrane in medical filtration, including: infusion filtration.

[0029] The preparation method and application of the heavy ion microporous composite filter membrane of the present invention have the following advantages:

[0030] By composited a first substrate, a nucleoporous membrane, and a microfiltration membrane, the liquid-stopping effect, filtration flux, and flux stability of the filtration membrane are improved. The microfiltration membrane is manufactured by casting a casting solution onto a second substrate, followed by air blowing, curing, and stretching. By adjusting the composition, component ratio, structure, and process parameters of the first substrate, the nucleoporous membrane, the second substrate, and the casting solution, the hydrophilicity of the filtration membrane is improved while reducing its impact on other properties (including liquid-stopping effect, filtration flux, and flux stability), preventing blood backflow, and thus improving infusion safety. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A schematic flowchart illustrating a method for preparing a heavy ion microporous composite filter membrane according to an embodiment of the present invention;

[0033] Figure 2 This is a cross-sectional structural diagram of a filter provided in an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1-Shell, 2-Drain plate, 3-Composite filter membrane, 11-Inlet, 12-Outlet. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] like Figure 1 As shown, this embodiment of the invention provides a method for preparing a heavy ion microporous composite filter membrane, comprising the following steps:

[0038] Step 1: Composite a nuclear pore membrane on the upper side of the first substrate.

[0039] Step 2: Prepare casting solution, cast the casting solution onto the second substrate, and coat it to form a primary film.

[0040] Step 3: Perform a blowing operation on the primary membrane to obtain a pre-separated membrane.

[0041] Step four: Immerse the pre-separated membrane in a coagulation bath for curing to obtain a cured membrane.

[0042] Step 5: Perform area stretching on the cured membrane, wash it in pure water, and then dry it to obtain a microfiltration membrane.

[0043] Step 6: Composite the microfiltration membrane onto the upper side of the nuclear pore membrane to obtain a composite filtration membrane.

[0044] The composite filtration membrane has a structure consisting of a first substrate layer, a core pore membrane layer, and a microfiltration membrane layer from bottom to top. The microfiltration membrane layer has a structure consisting of a second substrate sublayer from bottom to top and a porous membrane sublayer that is phase-separated and solidified on the second substrate sublayer by the casting solution.

[0045] Example 1

[0046] For example, step one is as follows: hot-pressing a core-pore membrane onto the upper side of the first meltblown nonwoven fabric. The hot-pressing temperature is 120°C, the time is 30 seconds, and the pressure is 0.5 bar. The first meltblown nonwoven fabric is made of polypropylene, with a thickness of 50 micrometers, a pore size of 20 micrometers, and a porosity of 60%. The core-pore membrane is made of polycarbonate, with a thickness of 20 micrometers, a pore size of 10 micrometers, and a porosity of 10%.

[0047] For example, step two involves stirring dimethyl sulfoxide, polyethersulfone, and polyvinyl alcohol in a mass ratio of 1:30%:30% to obtain a casting solution. This casting solution is then cast onto a second meltblown nonwoven fabric and coated to form a nascent film. The second meltblown nonwoven fabric is made of polypropylene, with a thickness of 50 micrometers, a pore size of 20 micrometers, and a porosity of 60%.

[0048] For example, step three is: blowing the nascent membrane with a temperature of 30°C, a humidity of 80%, a wind speed of 3 m / s, and a duration of 40 s to obtain a pre-separated membrane.

[0049] For example, step four is: immersing the pre-separated membrane in a coagulation bath for curing, the curing time being 300s, the coagulation bath being a mixture of dimethylformamide and water, the mass ratio of dimethylformamide to water being 1:3.

[0050] For example, step five is: stretching the cured membrane by 1.3 times, washing it in pure water, and drying it to obtain a microfiltration membrane.

[0051] For example, step six is: hot-pressing the microfiltration membrane onto the upper side of the nuclear pore membrane at a temperature of 120°C for 30 seconds and a pressure of 0.5 bar to obtain a composite filtration membrane.

[0052] Example 2

[0053] For example, step one is as follows: hot-pressing a core-pore membrane onto the upper side of the first meltblown nonwoven fabric. The hot-pressing temperature is 100°C, the time is 20 seconds, and the pressure is 0.5 bar. The first meltblown nonwoven fabric is made of polypropylene, with a thickness of 40 micrometers, a pore size of 20 micrometers, and a porosity of 50%. The core-pore membrane is made of polycarbonate, with a thickness of 15 micrometers, a pore size of 5 micrometers, and a porosity of 7%.

[0054] For example, step two involves stirring dimethyl sulfoxide, polyethersulfone, and polyvinyl alcohol in a mass ratio of 1:20%:20% to obtain a casting solution. This casting solution is then cast onto a second meltblown nonwoven fabric and coated to form a nascent film. The second meltblown nonwoven fabric is made of polypropylene, with a thickness of 40 micrometers, a pore size of 20 micrometers, and a porosity of 50%.

[0055] For example, step three is: blowing the nascent membrane with a temperature of 20°C, a humidity of 70%, a wind speed of 2 m / s, and a duration of 30 s to obtain a pre-separated membrane.

[0056] For example, step four is: immersing the pre-separated membrane in a coagulation bath for curing, the curing time being 200s, the coagulation bath being a mixture of dimethylformamide and water, the mass ratio of dimethylformamide to water being 1:5.

[0057] For example, step five is: stretching the cured membrane by 1.2 times, washing it in pure water, and drying it to obtain a microfiltration membrane.

[0058] For example, step six is: hot-pressing the microfiltration membrane onto the upper side of the nuclear pore membrane at a temperature of 100°C for 20 seconds and a pressure of 0.5 bar to obtain a composite filtration membrane.

[0059] Example 3

[0060] For example, step one is as follows: hot-pressing a core-pore membrane onto the upper side of the first meltblown nonwoven fabric. The hot-pressing temperature is 80°C, the time is 10 seconds, and the pressure is 0.5 bar. The first meltblown nonwoven fabric is made of polypropylene, with a thickness of 30 micrometers, a pore size of 20 micrometers, and a porosity of 40%. The core-pore membrane is made of polycarbonate, with a thickness of 10 micrometers, a pore size of 3 micrometers, and a porosity of 5%.

[0061] For example, step two involves stirring dimethyl sulfoxide, polyethersulfone, and polyvinyl alcohol in a mass ratio of 1:10%:10% to obtain a casting solution. This casting solution is then cast onto a second meltblown nonwoven fabric and coated to form a nascent film. The second meltblown nonwoven fabric is made of polypropylene, with a thickness of 30 micrometers, a pore size of 20 micrometers, and a porosity of 40%.

[0062] For example, step three is: blowing the nascent membrane with a temperature of 10°C, a humidity of 60%, a wind speed of 1 m / s, and a duration of 20 s to obtain a pre-separated membrane.

[0063] For example, step four is: immersing the pre-separated membrane in a coagulation bath for curing, the curing time being 100s, the coagulation bath being a mixture of dimethylformamide and water, the mass ratio of dimethylformamide to water being 1:10.

[0064] For example, step five is: stretching the cured membrane by 1.1 times, washing it in pure water, and drying it to obtain a microfiltration membrane.

[0065] For example, step six is: hot-pressing the microfiltration membrane onto the upper side of the nuclear pore membrane at a temperature of 80°C for 10 seconds and a pressure of 0.5 bar to obtain a composite filtration membrane.

[0066] Example 4

[0067] In this embodiment, the first meltblown nonwoven fabric in step one is made of polyethylene, and the core-pore membrane is made of polyvinylidene fluoride. The second meltblown nonwoven fabric in step two is also made of polyethylene. The remaining steps and conditions are the same as in embodiment one.

[0068] Example 5

[0069] In this embodiment, the first meltblown nonwoven fabric in step one is made of polyethylene, and the core-pore membrane is made of polyvinylidene fluoride. The second meltblown nonwoven fabric in step two is also made of polyethylene. The remaining steps and conditions are the same as in embodiment two.

[0070] Example 6

[0071] In this embodiment, the first meltblown nonwoven fabric in step one is made of polyethylene, and the core-pore membrane is made of polyvinylidene fluoride. The second meltblown nonwoven fabric in step two is also made of polyethylene. The remaining steps and conditions are the same as in embodiment three.

[0072] Example 7

[0073] In this embodiment, the casting solution in step two is obtained by stirring dimethylformamide, polyvinylidene fluoride, and polyethylene glycol in a mass ratio of 1:30%:30%. The coagulation bath in step four is a mixture of caprolactam and water, with a mass ratio of caprolactam to water of 1:3. The remaining steps and conditions are the same as in Example 1.

[0074] Example 8

[0075] In this embodiment, the casting solution in step two is obtained by stirring dimethylformamide, polyvinylidene fluoride, and polyethylene glycol in a mass ratio of 1:20%:20%. The coagulation bath in step four is a mixture of caprolactam and water, with a mass ratio of caprolactam to water of 1:5. The remaining steps and conditions are the same as in Example 2.

[0076] Example 9

[0077] In this embodiment, the casting solution in step two is obtained by stirring dimethylformamide, polyvinylidene fluoride, and polyethylene glycol in a mass ratio of 1:10%:10%. The coagulation bath in step four is a mixture of caprolactam and water, with a mass ratio of caprolactam to water of 1:10. The remaining steps and conditions are the same as in Example 3.

[0078] Comparative Example 1

[0079] A 5-micron unsupported polyethersulfone filter membrane was selected as Comparative Example 1.

[0080] Comparative Example 2

[0081] A 10-micron unsupported polyarylsulfone filter membrane was selected as Comparative Example 2.

[0082] The performance of the filter membranes in Examples 1 to 9 and Comparative Examples 1 to 2 were characterized by tests, and the performance comparison is shown in Table 1.

[0083]

[0084] Table 1

[0085] As can be seen from Table 1, the filter membrane prepared by the present invention has high liquid-stopping height and hydrophilicity.

[0086] The filter membranes from Examples 1 to 9 and Comparative Examples 1 to 2 were respectively made into circular filters with a diameter of 10 mm. Flux tests were conducted using 100 ml of Xiangdan injection solution, 100 ml of Xiangdan diluted 5 times, 100 ml of glucose solution, and 100 ml of glucose diluted 5 times as test solutions. The flux comparison table is shown in Table 2 (flux unit is ml / (min × cm²)):

[0087]

[0088] Table 2

[0089] As can be seen from Table 2, the filter membrane prepared by the present invention has high filtration flux and flux stability.

[0090] This invention also provides an application of the above-mentioned heavy ion microporous composite filter membrane in medical filtration, including infusion filtration. By applying the filter membrane prepared by this invention in the preparation of infusion filters, the infusion filter's liquid-stopping effect, filtration flux, and flux stability can be improved.

[0091] like Figure 2As shown, an embodiment of the present invention provides a filter, including: a housing 1, a plurality of diversion plates 2 are fixedly connected horizontally from top to bottom on the inner wall of the housing 1, a composite filter membrane 3 is fixedly connected horizontally on any side of each diversion plate, and the side of each composite filter membrane 3 away from the diversion plate 2 is fixedly connected horizontally to the inner wall of the housing 1, an inlet 11 is provided on the upper side of the housing 1, and an outlet 12 is provided on the lower side, the first substrate layer of the composite filter membrane 3 faces the outlet 12, and the microfiltration membrane layer faces the inlet 11.

[0092] In this embodiment, the composite filter membrane 3 is in sheet form. In other possible embodiments, it may also be in cylindrical form or other existing filter membrane forms.

[0093] By installing the filter provided in the embodiments of the present invention in the existing infusion set tubing, a precision infusion set with good fluid-stopping effect, filtration throughput and throughput stability can be obtained.

[0094] This invention improves the liquid-stopping effect, filtration flux, and flux stability of the filter membrane by compositely combining a first substrate, a nucleoporous membrane, and a microfiltration membrane. The microfiltration membrane is manufactured by casting a casting solution onto a second substrate, followed by air blowing, curing, and stretching. By adjusting the composition, component ratio, structure, and process parameters of the first substrate, the nucleoporous membrane, the second substrate, and the casting solution, the hydrophilicity of the filter membrane is improved while reducing its impact on other properties (including liquid-stopping effect, filtration flux, and flux stability), preventing blood backflow, and thus improving infusion safety.

[0095] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0096] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a heavy ion microporous composite filter membrane, characterized in that, Includes the following steps: Step 1: Composite a nuclear pore membrane on the upper side of the first substrate; Step 2: Prepare casting solution, cast the casting solution onto the second substrate, and coat it with a scraper to form a primary film; Step 3: Perform a blowing operation on the primary membrane to obtain a pre-separated membrane; Step four: Immerse the pre-separated membrane in a coagulation bath for curing to obtain a cured membrane; Step 5: Perform area stretching on the cured membrane, wash it in pure water, and then dry it to obtain a microfiltration membrane; Step 6: Composite the microfiltration membrane onto the upper side of the nuclear pore membrane to obtain a composite filtration membrane; In step one, the first substrate is a first meltblown nonwoven fabric, the thickness of which is 1-100 micrometers, the pore size is 0.1-20 micrometers, and the porosity is 30%-60%. The thickness of the nuclear pore membrane is 1-100 micrometers, the pore size is 0.02-20 micrometers, and the porosity is 1%-20%. The composite method is hot pressing, wherein the hot pressing temperature is 80-150℃, the time is 10-30 seconds, and the pressure is 0.1-1 bar; In step three, the temperature of the blowing operation is 10-30℃, the humidity is 60%-80%, the wind speed is 1-4m / s, and the duration is 10-60s; In step five, the stretching ratio of the area stretching operation is 1.1-1.5 times; In step six, the composite method is hot pressing, the hot pressing temperature is 80-150℃, the time is 10-30 seconds, and the pressure is 0.1-1 bar; The composite filtration membrane has a structure consisting of a first substrate layer, a core pore membrane layer, and a microfiltration membrane layer from bottom to top. The microfiltration membrane layer has a structure consisting of a second substrate sublayer from bottom to top and a porous membrane sublayer that is phase-separated and solidified on the second substrate sublayer by the casting solution.

2. The method for preparing a heavy ion microporous composite filter membrane according to claim 1, characterized in that, In step two, the casting solution includes: a first organic solvent, a polymer, and a hydrophilic additive; The mass ratio of the first organic solvent, the polymer, and the hydrophilic additive is 1:10%-40%:10%-40%.

3. The method for preparing a heavy ion microporous composite filter membrane according to claim 2, characterized in that, In step two, the first organic solvent includes one or more of dimethyl sulfoxide, dimethylformamide, caprolactam, N-ethylpyrrolidone, dimethylacetamide, and N-methylpyrrolidone; The polymers include one or more of the following: polyethersulfone, polyamide, polyvinylidene fluoride, polyvinyl alcohol, cellulose acetate, chitosan, polystyrene pyrrolidone, polyimide, polyamide, polylactic acid, polycaprolactone, polycarbonate, polyaniline, and polyacrylonitrile. The hydrophilic additives include one or more of polyvinyl alcohol, polyethylene glycol, polyethyleneimine, and polyvinylpyrrolidone.

4. The method for preparing a heavy ion microporous composite filter membrane according to claim 1, characterized in that, In step two, the second substrate is a second meltblown nonwoven fabric with a thickness of 1-100 micrometers, a pore size of 0.1-20 micrometers, and a porosity of 30%-60%.

5. The method for preparing a heavy ion microporous composite filter membrane according to claim 1, characterized in that, In step four, the curing operation takes 60-600 seconds, and the coagulation bath is a mixture of a second organic solvent and water, with the mass ratio of the second organic solvent to water being 1:2-20. The second organic solvent includes one or more of dimethyl sulfoxide, dimethylformamide, caprolactam, N-ethylpyrrolidone, dimethylacetamide, and N-methylpyrrolidone.

6. The application of the heavy ion microporous composite filter membrane as described in any one of claims 1 to 5 in medical filtration, comprising: Infusion filtration.

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