Hollow fiber membrane filament and method for producing same, oxygenation membrane

Abstract

The application provides a hollow fiber membrane filament and a preparation method thereof, an oxygenation membrane and an oxidation device. The preparation method of the hollow fiber membrane filament comprises the following steps: quantitatively feeding a reinforcing filament, a casting solution and a cavity-forming fluid to a spinneret, and extruding to obtain a nascent hollow fiber membrane filament; the spinneret comprises a first channel, a second channel and a third channel arranged in sequence from inside to outside; a plurality of reinforcing filaments are fed to the third channel, the plurality of reinforcing filaments are uniformly arranged along the circumference of the third channel, each reinforcing filament comprises a plurality of filaments, the casting solution is fed to the second channel, and the cavity-forming fluid is fed to the first channel; the nascent hollow fiber membrane filament is solidified and formed; the solidified and formed nascent hollow fiber membrane filament is soaked in an extracting agent to form membrane pores; and the nascent hollow fiber membrane filament after removal of a diluent is subjected to heat treatment. The hollow fiber membrane filament has good tensile resistance and can resist stretching during braiding, thereby improving the performance of the oxygenation membrane.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a hollow fiber membrane filament, a preparation method thereof and an oxygenation membrane. BACKGROUND

[0002] The oxygenation membrane, as one of the core materials of an extracorporeal membrane oxygenation (ECMO) device, is a key part of a medical emergency device that provides breathing support. The oxygenation membrane usually adopts the form of a hollow fiber membrane filament, oxygen is introduced into the internal flow channel, and gas exchange is performed with carbon dioxide in the blood outside, so as to adjust the oxygen and carbon dioxide content of the blood.

[0003] The oxygenation membrane adopts a weaving method to design the flow channel. If the strength of the hollow fiber membrane filament is not enough, the weaving will cause the micro-holes on the hollow fiber membrane filament to be stretched and deformed, which is not conducive to gas exchange and can easily cause plasma leakage, resulting in a short service life of the oxygenation membrane. SUMMARY

[0004] The present application aims to provide a hollow fiber membrane filament, a preparation method thereof and an oxygenation membrane, which aims to improve the strength of the hollow fiber membrane filament and prolong the service life of the oxygenation membrane.

[0005] To achieve the above-mentioned purpose, the present application comprises a preparation method of a hollow fiber membrane filament, comprising the following steps:

[0006] Quantitatively feeding a reinforcing filament, a casting solution and a lumen-forming fluid to a spinneret, and extruding to obtain a nascent hollow fiber membrane filament; the spinneret comprises a first channel, a second channel and a third channel arranged in sequence from the inside to the outside; the reinforcing filament is fed to the third channel in strands, and each strand of the reinforcing filament comprises a plurality of filaments; the casting solution is fed to the second channel, and the casting solution comprises a polyolefin and a diluent; the lumen-forming fluid is fed to the first channel;

[0007] Solidifying and shaping the nascent hollow fiber membrane filament;

[0008] Soaking the solidified and shaped nascent hollow fiber membrane filament in an extractant to remove the diluent; and,

[0009] Performing heat treatment on the nascent hollow fiber membrane filament after the diluent is removed.

[0010] Optionally, a plurality of strands of the reinforcing filament are fed to the third channel, and the plurality of strands of the reinforcing filament are uniformly arranged along the circumference of the third channel.

[0011] Optionally, the material of the reinforcing filament comprises polyethylene terephthalate; and / or,

[0012] The polyolefin includes poly(4-methyl-1-pentene), and the diluent includes at least one of dioctyl adipate, dioctyl phthalate, triacetin, and castor oil.

[0013] Optionally, the preparation method further includes: pre-treating the reinforcing filaments to increase surface roughness of the reinforcing filaments.

[0014] Optionally, the pre-treating includes: soaking the reinforcing filaments in an alkaline solution.

[0015] Optionally, in the casting solution, the mass percentage of the polyolefin is not greater than 30%.

[0016] Optionally, after the casting solution and the reinforcing filaments are extruded through a spinneret, the nascent hollow fiber membrane filaments pass through a gas gap section to form the nascent hollow fiber membrane filaments; and a temperature of the nascent fiber membrane filaments in the gas gap section is 180°C to 240°C.

[0017] Optionally, the nascent hollow fiber membrane filaments pass through a coagulation bath tank containing a cooling liquid, and the cooling liquid is used to cool the nascent hollow fiber membrane filaments to coagulate the nascent hollow fiber membrane filaments.

[0018] Optionally, a liquid surface of the cooling liquid is divided into multiple regions by a partition.

[0019] Optionally, after the nascent hollow fiber membrane filaments are coagulated and formed, and before the nascent hollow fiber membrane filaments are soaked in an extractant, the preparation method further includes: performing multi-stage stretching on the nascent hollow fiber membrane filaments to stretch and orient the polyolefin.

[0020] Optionally, after the diluent in the nascent hollow fiber membrane filaments is removed, and before the nascent hollow fiber membrane filaments are heat treated, the preparation method further includes: stretching the nascent hollow fiber membrane filaments to elastically deform the hollow fiber membrane filaments.

[0021] To achieve the above object, the present application further provides a hollow fiber membrane filament, which is prepared by the preparation method of the hollow fiber membrane filament as described in any one of the preceding embodiments.

[0022] Optionally, the hollow fiber membrane filament has an oxygen flux of 0.9ml / cm 2 *min*bar to 8ml / cm 2 *min*bar, and a plasma leakage resistance time of 180h to 280h.

[0023] Optionally, the hollow fiber membrane filament has a tensile strength of 100cN to 525cN, an elongation at break of 50% to 266%, and an implosion pressure greater than 0.3Mpa.

[0024] To achieve the above object, the present application further provides an oxygenation membrane woven by the hollow fiber membrane filaments according to any one of the preceding.

[0025] Compared with the prior art, the hollow fiber membrane filaments and the preparation method thereof, and the oxygenation membrane have the following advantages:

[0026] The preparation method of the aforementioned hollow fiber membrane filaments comprises the following steps: quantitatively feeding a plurality of reinforcing filaments, a casting solution, and a cavity-forming fluid to a spinneret, and extruding to obtain a nascent hollow fiber membrane filament; wherein the spinneret comprises a first channel, a second channel, and a third channel arranged in sequence from inside to outside; the plurality of reinforcing filaments are fed to the third channel, the plurality of reinforcing filaments are uniformly arranged along the circumference of the third channel, and each of the reinforcing filaments comprises a plurality of monofilaments; the casting solution is fed to the second channel, and the casting solution comprises polyolefin and a diluent; the cavity-forming fluid is fed to the first channel; the nascent hollow fiber membrane filament is solidified and formed; the solidified and formed nascent hollow fiber membrane filament is soaked in an extracting agent to remove the diluent and form membrane pores; and the nascent hollow fiber membrane filament after the diluent is removed is heat treated. The reinforcing filaments are used to improve the strength of the hollow fiber membrane filaments, so that the hollow fiber membrane filaments have good tensile strength and effectively resist stretching.

[0027] In particular, when each of the reinforcing filaments comprises a plurality of monofilaments, on the one hand, the bonding area of the reinforcing filaments and the polyolefin can be improved, the bonding strength can be improved, and thus the strength of the control fiber membrane filaments can be improved; on the other hand, the surface uniformity of the hollow fiber membrane filaments can be improved under the premise of ensuring the reinforcing strength of the reinforcing filaments, and the membrane pores can be prevented from being blocked. In this way, when the hollow fiber membrane filaments are woven to form an oxygenation membrane, the hollow fiber membrane filaments can resist stretching during the weaving process, reduce deformation of the membrane pores, and make the oxygenation membrane have good plasma leakage resistance and prolong the plasma leakage resistance time of the oxygenation membrane. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings are used to better understand the present application and do not constitute an improper limitation on the present application. Among them:

[0029] Figure 1 is a flow chart of the preparation method of the hollow fiber membrane filaments provided by an embodiment of the present application;

[0030] Figure 2 is a structural schematic diagram of the spinneret used in the preparation method of the hollow fiber membrane filaments of the embodiment of the present application;

[0031] Figure 3 is a sectional view of the spinneret used in the preparation method of the hollow fiber membrane filaments provided by the embodiment of the present application;

[0032] Figure 4 is a scanning electron microscope photo of the outer surface of the hollow fiber membrane filament prepared in Embodiment One of the present application;

[0033] Figure 5 is a scanning electron microscope photo of the inner surface of the hollow fiber membrane filament prepared in Embodiment One of the present application.

[0034] [Reference numerals are explained as follows]:

[0035] 10 - spinneret, 11 - first passage, 12 - second passage, 13 - third passage, 14 - filament hole. DETAILED DESCRIPTION

[0036] The present application is described below by way of specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the present specification. The present application can also be implemented or applied by other different specific embodiments, and each detail in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the drawings provided in the present embodiments only schematically illustrate the basic concept of the present application, and thus the drawings only show the components related to the present application without drawing the number, shape and size of the components in actual implementation, and the type, number and ratio of each component in actual implementation can be arbitrarily changed, and the layout type of the components can also be more complicated.

[0037] In addition, each embodiment of the following description has one or more technical features, but this does not mean that the user must simultaneously implement all the technical features in any embodiment, or can only separately implement one or all technical features in different embodiments. In other words, under the premise of implementation, those skilled in the art can selectively implement part or all of the technical features in any embodiment, or selectively implement a combination of part or all of the technical features in multiple embodiments, thereby increasing the flexibility of the implementation of the present application, based on the disclosure of the present application and according to design specifications or implementation needs.

[0038] As used in this specification, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. As used in this specification, the term "or" is generally employed in its sense of "and / or" unless the content clearly dictates otherwise, and the terms "mounting," "connected," and "connection" should be construed broadly in accordance with ordinary usage of the terms, for example, can be fixed connections, detachable connections, or integral connections. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, or it can be an internal connection of two elements or an interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] In order to make the purpose, advantages and characteristics of the present application clearer, the present application will be further described in detail below in combination with the drawings. It should be noted that the drawings are all very simplified and use non-precise proportions, and are only used to facilitate and clarify the purpose of assisting the description of the embodiments of the present application. The same or similar reference numerals in the drawings represent the same or similar parts.

[0040] The embodiment of the present application provides a preparation method of a hollow fiber membrane filament based on a thermally induced phase separation method, a flow chart of which is shown as Figure 1 The preparation method comprises the following steps:

[0041] Step S1: quantitatively feeding a reinforcing filament, a casting solution and a cavity-forming fluid to a spinneret 10 (as shown in Figure 2 and Figure 3 ), and extruding to obtain a nascent hollow fiber membrane filament.

[0042] Step S2: solidifying and forming the nascent hollow fiber membrane filament.

[0043] Step S3: soaking the solidified and formed nascent hollow fiber membrane filament in an extractant to remove the diluent and form a membrane hole. And,

[0044] Step S4: performing heat treatment on the nascent hollow fiber membrane filament with the membrane hole to obtain a hollow fiber membrane filament.

[0045] In the step S1, as Figure 2 and Figure 3As shown, the spinneret 10 is a three-channel spinneret and includes a first channel 11, a second channel 12, and a third channel 13 arranged in sequence from inside to outside, and the third channel 13 is provided with a plurality of orifices 14 at the outlet thereof, and the plurality of orifices 14 are arranged along the circumference of the third channel 13, preferably uniformly arranged along the circumference. The material of the reinforcing filaments includes but is not limited to polyethylene terephthalate (PET), and each bundle of the reinforcing filaments includes a plurality of monofilaments. The reinforcing filaments are supplied to the third channel 13 in bundles, and the reinforcing filaments correspond to pass through one of the orifices 14, so that a plurality of reinforcing filaments are uniformly arranged along the circumference of the third channel 13 when the number of orifices 14 is multiple. The casting solution is supplied to the second channel 12, and the casting solution includes polyolefin and the diluent, the polyolefin includes but is not limited to poly(4-methyl-1-pentene) (PMP), polypropylene (PP), and the diluent includes at least one of dioctyl adipate (DOA), dioctyl phthalate (DOP), glyceryl triacetate, castor oil. It should be noted that in the casting solution, the polyolefin and the diluent can be mixed uniformly, and they do not necessarily form a homogeneous solution, but also can be a uniformly dispersed suspension. The lumen-forming fluid is supplied to the first channel 11, and the lumen-forming fluid includes but is not limited to nitrogen.

[0046] The casting solution is extruded through the second channel 12 of the spinneret 10 to form a circular annular liquid stream, and the circular annular liquid stream passes through the air gap section and forms the nascent hollow fiber membrane filaments. In this process, the polyolefin in the circular annular liquid stream diffuses and wraps the reinforcing filaments, so that the reinforcing filaments are located in the middle of the circular annular liquid stream. In this way, the hollow fiber membrane filaments prepared by the embodiment of the present application include the reinforcing filaments, so as to achieve the purpose of enhancing the tensile strength of the hollow fiber membrane filaments. When the hollow fiber membrane filaments are woven to form an oxygenation membrane, the hollow fiber membrane filaments effectively resist stretching, reduce membrane hole deformation, and prolong the anti-plasma leakage time. The reason why each bundle of the reinforcing filaments includes a plurality of filaments is that the surface area of a single filament is small compared to a plurality of filaments, resulting in a small contact area between the reinforcing filaments and the polyolefin, and a small bonding strength. Moreover, in the case of a single filament, if the diameter of the single filament is small, the reinforcing effect of the reinforcing filaments on the tensile strength of the hollow fiber membrane filaments is limited, which is insufficient to meet the use requirements, but when the diameter of the single filament is large, it will cause the surface uniformity of the hollow fiber membrane filaments to decrease, and even block the membrane holes, resulting in a decrease in gas flow, and the gas exchange performance of the oxygenation membrane will be poor.

[0047] Optionally, the reinforcing filaments can have a specification of at least one of 30D / 24F, 30D / 30F and 30D / 50F, where 30D / 24F means that the weight of the reinforcing filaments is 30g per 9000m, and each bundle of the reinforcing filaments includes 24 monofilaments, 30D / 30F means that the weight of the reinforcing filaments is 30g per 9000m, and each bundle of the reinforcing filaments includes 30 monofilaments, and 30D / 50F means that the weight of the reinforcing filaments is 30g per 9000m, and each bundle of the reinforcing filaments includes 50 monofilaments. In the casting solution, the mass percentage of the polyolefin is not more than 30%. In addition, the length of the air gap section can be 0.1cm to 30cm, which is determined according to actual conditions. The temperature of the nascent hollow fiber membrane filaments in the air gap section is between 180°C and 240°C, which makes the polyolefin in the nascent hollow fiber membrane filaments have good fluidity in the air gap section, and is beneficial to better wrapping the reinforcing filaments.

[0048] In the step S2, the nascent hollow fiber membrane filaments pass through a coagulation bath tank containing a cooling liquid, and the nascent hollow fiber membrane filaments are cooled by the cooling liquid to coagulate. Preferably, the coagulation bath tank is also provided with a partition plate, which divides the liquid surface of the cooling liquid into multiple areas, and the nascent hollow fiber membrane filaments are immersed in the cooling liquid from one area and cooled below the partition plate. This is because the material of the nascent hollow fiber membrane filaments still has a certain fluidity when initially immersed in the cooling liquid, and a large liquid surface is prone to fluctuation, which in turn drives the surface material of the nascent fiber membrane filaments to flow, resulting in uneven thickness and outer diameter of the coagulated nascent hollow fiber membrane filaments. By dividing the liquid surface of the cooling liquid into multiple smaller areas by the partition plate, the fluctuation of the liquid surface can be effectively reduced, which is beneficial to improve the uniformity of the wall thickness and outer diameter of the nascent hollow fiber membrane filaments. In addition, in the coagulation bath tank, the surface layer of the nascent hollow fiber membrane filaments first contacts the cooling liquid and forms a polyolefin-rich phase, and then forms a dense skin layer.

[0049] Further, please refer back to Figure 1, the preparation method further comprises a step S0 of pretreating the reinforcing filaments to increase the surface roughness of the reinforcing filaments, so as to increase the contact area between the polyolefin and the reinforcing filaments in the subsequent process and improve the bonding strength. The step S0 is performed before the step S1, and the method of the pretreatment is not particularly limited in the embodiments of the present application and can be selected according to actual needs. For example, when the material of the reinforcing filaments comprises PET, the pretreatment can immerse the reinforcing filaments in a low-concentration alkaline solution to increase the surface roughness of the reinforcing filaments through a hydrolysis reaction of PET. The alkaline solution is, for example, a NaOH solution with a mass fraction of 5%, but it should be noted that the immersion time is controlled to avoid excessive hydrolysis of PET, which can cause the reinforcing filaments to break.

[0050] The preparation method further comprises a step S5 of stretching the nascent hollow fiber membrane filaments in multiple stages to stretch and orient the polyolefin and improve the mechanical properties of the nascent hollow fiber membrane filaments. The step S5 is performed after the step S2 and before the step S3.

[0051] Further, the preparation method further comprises a step S6 of stretching the nascent hollow fiber membrane filaments to cause elastic deformation of the nascent hollow fiber membrane filaments. The step S6 is performed after the step S3 and before the step S4, so that the nascent hollow fiber membrane filaments after elastic deformation can be fixed in the step S4 and subjected to heat treatment in a fixed state to avoid bending deformation of the nascent hollow fiber membrane filaments during heat treatment. Here, the elastic deformation refers to a recoverable deformation, and the length of the nascent hollow fiber membrane filaments after stretching can be 105% of the length in a natural state (i.e., an unstretched state).

[0052] Further, the present application also provides a hollow fiber membrane filament prepared by the above preparation method. The oxygen flux of the hollow fiber membrane filament is 0.9ml / cm 2 *min*bar~8ml / cm 2 *min*bar, the plasma leakage resistance time is 180h~280h, the tensile strength is 100cN~525cN, the elongation at break is 50%~266%, and the implosion burst pressure is greater than 0.3Mpa.

[0053] Further, the present application also provides an oxygenation membrane and an oxygenation device comprising the oxygenation membrane, wherein the oxygenation membrane is woven by the above hollow fiber membrane filament.

[0054] Next, some embodiments will be described by way of example to illustrate the preparation method and properties of the hollow fiber membrane filament.

[0055] <Embodiment One>

[0056] In this embodiment, the reinforcing filaments are PET filaments, and the number of strands is 5, and the specification of each strand is 30D / 24F. In the casting solution, the polymer is PMP, the diluent is DOP, and the mass percentage of the polymer is 30%. The material is extruded through the spinneret 10 by using a double screw extruder, and the nascent hollow fiber membrane filaments are formed through the air gap section, wherein the extrusion temperature is 250°C, the extrusion rate is 3.5 g / min, the cavity-forming fluid is nitrogen, the flow rate of nitrogen is 5.5 ml / min, and the length of the air gap section is 20 mm. The nascent hollow fiber membrane filaments are sequentially solidified, stretched, extracted, and formed into membrane pores, stretched and elastically deformed, and heat treated for setting, wherein the initial temperature of the cooling liquid is 30°C, the extractant is isopropyl alcohol, and the heat treatment temperature is 70°C and the time is 2 h.

[0057] The inner diameter of the hollow fiber membrane filaments prepared in this embodiment is 294 um, and the outer diameter is 379 um. The scanning electron microscope photos of the outer surface of the hollow fiber membrane filaments are shown in Figure 4 , and the scanning electron microscope photos of the inner surface are shown in Figure 5 , and Figure 4 and Figure 5 It can be clearly seen that the outer surface of the hollow fiber membrane filaments is uniform and dense, and uniform membrane pores are formed on the inner surface.

[0058] The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filaments are tested by using conventional methods in the art, and the test results are shown in Table 1.

[0059] <Example Two>

[0060] The difference between this embodiment and Example One is that in the casting solution, the mass percentage of the polymer is 35%, and the inner diameter of the hollow fiber membrane filaments prepared is 213 um, and the outer diameter is 392 um.

[0061] The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filaments prepared in this embodiment are shown in Table 1.

[0062] <Example Three>

[0063] The difference between this embodiment and Example One is that in the casting solution, the mass percentage of the polymer is 40%, and the inner diameter of the hollow fiber membrane filaments prepared is 201 um, and the outer diameter is 382 um.

[0064] The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filaments prepared in this embodiment are shown in Table 1.

[0065] <Example 4>

[0066] The difference between this example and Example 1 is that the mass percentage of the polymer in the casting solution is 45%, and the inner diameter of the hollow fiber membrane filament prepared is 222 um, and the outer diameter is 384 um. The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament prepared in this example are shown in Table 1.

[0067] <Example 5>

[0068] In this example, the reinforcing filament is a PET filament, and the number of strands is 3, and the specification of each strand is 30D / 24F. In the casting solution, the polymer is PMP, the diluent is a mixture of DOP and DOA, and the mass percentage of the polymer is 35%, the mass percentage of DOP is 50%, and the mass percentage of DOA is 15%. The material is extruded through the spinneret 10 using a double screw extruder, and the nascent hollow fiber membrane filament is formed through the air gap section, wherein the extrusion temperature is 250°C, the extrusion rate is 3.5 g / min, the cavity-forming fluid is nitrogen, the flow rate of nitrogen is 5.5 ml / min, and the length of the air gap section is 20 mm. The nascent hollow fiber membrane filament is then sequentially solidified, stretched and oriented, extracted and diluent, stretched and elastically deformed, and heat treated to be shaped, to obtain a hollow fiber membrane filament, wherein the initial temperature of the cooling liquid is 30°C, the extractant is isopropyl alcohol, and the heat treatment temperature is 70°C for 2 h.

[0069] The inner diameter of the hollow fiber membrane filament prepared in this example is 210 um, and the outer diameter is 372 um. The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament are shown in Table 1.

[0070] <Example 6>

[0071] The difference between this example and Example 5 is that the specification of each strand of the reinforcing filament is 30D / 30F, and the inner diameter of the hollow fiber membrane filament prepared is 203 um, and the outer diameter is 376 um.

[0072] The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament prepared in this example are shown in Table 1.

[0073] <Example 7>

[0074] The difference between this example and Example 5 is that the specification of each strand of the reinforcing filament is 30D / 50F, and the inner diameter of the hollow fiber membrane filament prepared is 213 um, and the outer diameter is 375 um.

[0075] The tensile strength, oxygen flux, internal burst pressure and plasma leakage resistance time of the hollow fiber membrane filament prepared in this example are shown in Table 1.

[0076] <Example Eight>

[0077] In this example, the reinforcing filament is PET filament, and the number of strands is 1 strand, and the specification is 30D / 30F. In the casting solution, the polymer is PMP, the diluent is a mixture of DOP and triacetin, and the mass percentage of the polymer is 35%, the mass percentage of DOP is 50%, and the mass percentage of triacetin is 15%. The material is extruded through the spinneret 10 using a double screw extruder, and the nascent hollow fiber membrane filament is formed through the air gap section, wherein the extrusion temperature is 250°C, the extrusion rate is 3.5 g / min, the cavity forming fluid is nitrogen, the flow rate of nitrogen is 5.5 ml / min, and the length of the air gap section is 20 mm. The nascent hollow fiber membrane filament is then sequentially solidified, stretched and oriented, extracted and diluent, stretched and elastically deformed, and heat treated for setting, to obtain a hollow fiber membrane filament, wherein the initial temperature of the cooling liquid is 30°C, the extractant is isopropyl alcohol, and the heat treatment temperature is 70°C for 2 h.

[0078] The inner diameter of the hollow fiber membrane filament prepared in this example is 223 um, and the outer diameter is 378 um, and the tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament are shown in Table 1.

[0079] <Example Nine>

[0080] The difference between this example and Example Eight is that the number of strands of the reinforcing filament is 2 strands, and the inner diameter of the hollow fiber membrane filament prepared is 226 um, and the outer diameter is 371 um.

[0081] The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament prepared in this example are shown in Table 1.

[0082] <Example Ten>

[0083] The difference between this example and Example Eight is that the number of strands of the reinforcing filament is 3 strands, and the inner diameter of the hollow fiber membrane filament prepared is 188 um, and the outer diameter is 362 um.

[0084] The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament prepared in this example are shown in Table 1.

[0085] <Example Eleven>

[0086] The difference between this embodiment and embodiment eight is that the number of the reinforcing filaments is four, and the inner diameter of the reinforcing fiber membrane filament prepared is 194 um, and the outer diameter is 376 um.

[0087] The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament prepared in this embodiment are shown in Table 1.

[0088] <Embodiment twelve>

[0089] The difference between this embodiment and embodiment eight is that the number of the reinforcing filaments is five, and the inner diameter of the reinforcing fiber membrane filament prepared is 208 um, and the outer diameter is 384 um.

[0090] The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament prepared in this embodiment are shown in Table 1.

[0091] <Comparative example>

[0092] The difference between this comparative example and embodiment one is that the raw material for preparing the hollow fiber membrane filament does not include reinforcing filaments, and the mass percentage of the polyolefin in the casting solution is 35%, and the inner diameter of the hollow fiber membrane filament prepared is 202 um, and the outer diameter is 382 um. The tensile strength, oxygen flux, internal burst pressure, and plasma leakage resistance time of the hollow fiber membrane filament prepared in this comparative example are tested, and the test results are shown in Table 1.

[0093] It should be noted that the purpose of measuring the internal burst pressure is to compare the influence of not adding reinforcing filaments and adding reinforcing filaments on the combination stability of the hollow fiber membrane filament. The internal burst pressure refers to slowly punching nitrogen into the inside of the hollow fiber membrane, slowly increasing the pressure, and when irreversible deformation or rupture occurs, the pressure received in the hollow fiber membrane is its internal burst pressure. If the internal burst pressures corresponding to the two situations are quite different, it means that the combination ability of the reinforcing filaments and the material is not good. On the contrary, it means that the combination ability of the reinforcing filaments and the material is good, and it will not adversely affect the internal burst performance of the hollow fiber membrane filament.

[0094] Table 1

[0095]

[0096]

[0097] From Table 1, it can be seen that in the embodiment of the present application, the setting of the reinforcing filaments does not adversely affect the internal burst pressure of the hollow fiber membrane filaments, and also improves the tensile strength and elongation at break of the hollow fiber membrane filaments, so that when the hollow fiber membrane filaments are woven to form an oxygenation membrane, the micropores on the hollow fiber membrane filaments are not easily stretched and deformed, so as not to affect gas exchange, nor easily cause plasma leakage, so that the service life of the hollow fiber membrane filaments and the oxygenation membrane prepared therefrom is prolonged. That is, under the premise that the hollow fiber membrane filaments have a required oxygen flux, the hollow fiber membrane filaments have a longer plasma leakage resistance time, so that when the hollow fiber membrane filaments are used to manufacture an oxygenation membrane, the oxygenation membrane has a longer service life.

[0098] In addition, the reason why the oxygen flux of the hollow fiber membrane filaments prepared in Example Four is low is that the mass fraction of the polymer in the casting solution is relatively high, which increases the number of crystal nuclei in the reaction system, and the increased spherulites compress the volume of the diluent in or between the spherulites, so that the pore size is correspondingly reduced after the diluent is extracted. Therefore, in a more preferred technical solution, the mass fraction of the polymer in the casting solution can be less than or equal to 30%.

[0099] It can be found from Comparative Example Eight to Example Twelve that under the same conditions, the more the number of reinforcing filaments, the better the tensile strength of the obtained hollow fiber membrane filaments. In particular, when the number of reinforcing filaments is 3 to 5, the tensile strength of the hollow fiber membrane filaments is significantly enhanced. It can also be found from Comparative Example Eight and Comparative Example that the concentration of the polymer also has a certain effect on the tensile strength of the hollow fiber membrane filaments.

[0100] The polymer PMP is easily soluble in DOP and DOA, and slightly soluble in triacetin. It can be found from Comparative Example Two and Example Twelve that the oxygen flux of the hollow fiber membrane filaments prepared in Example Twelve is greater than that of the hollow fiber membrane filaments prepared in Example Two. Also, it can be found from Comparative Example Six and Example Ten that the oxygen flux of the hollow fiber membrane filaments prepared in Example Ten is greater than that of the hollow fiber membrane filaments prepared in Example Six. This is related to the solubility of the diluent to the polymer, specifically, the addition of triacetin in the dual-component diluent in Example Twelve reduces the solubility of the diluent to the polymer compared with the single-component diluent in Example Two. Similarly, although both Example Ten and Example Six use dual-component diluents, the diluent in Example Ten is composed of DOP with a larger solubility and triacetin with a smaller solubility, while the diluent in Example Six is composed of DOP and DOA both with a larger solubility. Obviously, the solubility of the diluent in Example Ten is smaller than that of the diluent in Example Six to the polymer.

[0101] While the application has been disclosed in connection with the preferred embodiments provided herein, it should be understood that many modifications, substitutions, and changes can be made by those skilled in the art without departing from the spirit or scope of the application. Accordingly, it is intended that all such alterations and variations be considered as within the spirit and scope of the application as defined by the following claims, if any, and their equivalents.

Claims

1. A method for preparing hollow fiber membrane filaments, characterized in that, Includes the following steps: The reinforcing filament, casting solution, and cavity-forming fluid are quantitatively fed into the spinneret and extruded to obtain nascent hollow fiber membrane filaments; the spinneret includes a first channel, a second channel, and a third channel arranged sequentially from the inside to the outside; the reinforcing filament is fed into the third channel in strands, and each strand of the reinforcing filament includes multiple monofilaments; The casting solution is supplied to the second channel, and the casting solution includes polyolefin and diluent; the cavity-forming fluid is supplied to the first channel. The nascent hollow fiber membrane filaments are passed through a coagulation bath containing a coolant, which cools the nascent hollow fiber membrane filaments to solidify and form them; the surface of the coolant is divided into multiple regions by a partition. The solidified nascent hollow fiber membrane filaments are immersed in an extractant to remove the diluent; as well as, The nascent hollow fiber membrane fibers after the diluent has been removed are subjected to heat treatment.

2. The method for preparing hollow fiber membrane filaments according to claim 1, characterized in that, Multiple strands of the reinforcing filaments are fed into the third channel, and the multiple strands of the reinforcing filaments are evenly arranged circumferentially along the third channel.

3. The method for preparing hollow fiber membrane filaments according to claim 1, characterized in that, The reinforcing filament is made of polyethylene terephthalate; and / or... The polyolefin includes poly(4-methyl-1-pentene), and the diluent includes at least one of dioctyl adipate, dioctyl phthalate, glyceryl triacetate, and castor oil.

4. The method for preparing hollow fiber membrane filaments according to claim 1, characterized in that, The preparation method further includes: pre-treating the reinforcing wire to improve the surface roughness of the reinforcing wire.

5. The method for preparing hollow fiber membrane filaments according to claim 4, characterized in that, The pretreatment includes immersing the reinforcing wire in an alkaline solution.

6. The method for preparing hollow fiber membrane filaments according to claim 1, characterized in that, In the casting solution, the mass percentage of the polyolefin is no more than 30%.

7. The method for preparing hollow fiber membrane filaments according to claim 1, characterized in that, The casting solution and the reinforcing filament are extruded through a spinneret and pass through an air gap section to form the nascent hollow fiber membrane filament; the temperature of the nascent hollow fiber membrane filament in the air gap section is 180°C to 240°C.

8. The method for preparing hollow fiber membrane filaments according to claim 1, characterized in that, After the nascent hollow fiber membrane filaments have solidified and before being immersed in the extractant, the preparation method further includes: performing multi-stage stretching on the nascent hollow fiber membrane filaments to cause the polyolefin to be stretched and oriented.

9. The method for preparing hollow fiber membrane filaments according to claim 1, characterized in that, After removing the diluent from the nascent hollow fiber membrane filaments and before heat treatment, the preparation method further includes: stretching the nascent hollow fiber membrane filaments to cause elastic deformation of the hollow fiber membrane filaments.

10. A hollow fiber membrane filament, characterized in that, The hollow fiber membrane filaments are prepared using the method described in any one of claims 1-9.

11. The hollow fiber membrane filament according to claim 10, characterized in that, The oxygen flux of the hollow fiber membrane is 0.9 ml / cm². 2 *min*bar~8ml / cm 2 *min*bar, anti-plasma leakage time is 180h~280h.

12. The hollow fiber membrane filament according to claim 10, characterized in that, The hollow fiber membrane filament has a tensile strength of 100cN to 525cN, an elongation at break of 50% to 266%, and an internal burst pressure greater than 0.3 MPa.

13. An oxygenation membrane, characterized in that, The oxygenation membrane is woven from hollow fiber membrane filaments as described in any one of claims 10-12.

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