Method for manufacturing polyketone hollow fiber separation membrane and polyketone hollow fiber separation membrane manufactured using the same

Abstract

The method for producing a polyketone hollow fiber separation membrane according to the present invention includes the steps of: heating a mixture of polyketone and a diluent to melt the polyketone to prepare a dope solution; removing air bubbles present in the dope solution; spraying the dope solution from which air bubbles have been removed through a hollow fiber nozzle to obtain polyketone hollow fibers; immersing the polyketone hollow fibers in a cooling water tank to extract the diluent from the polyketone hollow fibers; and winding up the polyketone hollow fibers immersed in the cooling water tank to obtain a polyketone hollow fiber separation membrane.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polyketone hollow fiber separation membrane and a polyketone hollow fiber separation membrane produced using the same. [Background technology]

[0002] In the fine chemical industry, separation and / or purification / concentration processes are extremely important, accounting for 10-70% of the total operating costs. Distillation, adsorption, extraction, and other commonly known separation techniques have the disadvantage of consuming a lot of energy and having low process efficiency relative to cost.

[0003] Meanwhile, the technology using separation membranes is a process in which separation is performed by applying pressure to the separation membrane, and therefore consumes less energy than other separation processes, making it cheaper. In addition, it has the advantage of being able to save energy due to its simple process configuration.

[0004] However, in the fine chemical industry, which uses various organic solvents, polymer separation membranes have the disadvantage of dissolving or swelling in organic solvents, making them difficult to apply to separation processes in the semiconductor and pharmaceutical industries, which are representative fine chemical industry fields.

[0005] Specifically, organic solvents are currently widely used in various high-value-added industrial fields, such as biotechnology, oil refining, catalysts, semiconductors, and pharmaceuticals, for substance synthesis or process separation, purification, concentration, etc. When conventional water treatment polymer separation membranes are applied to the fine chemical industry, which primarily uses organic solvents, membrane performance is significantly reduced due to membrane swelling or hardening caused by the organic solvent.

[0006] Recently, organic solvent nanofiltration (OSN), which solves these problems and can be applied to various fine chemical industries, has attracted attention from both academia and industry. OSN is a new technology for separation and purification processes that uses polymers with high solvent resistance to separate solutes or compounds with a molecular weight of 200-1000 g / mol from organic solvents. When applied to various fine chemical industries, organic solvent-resistant separation membranes are expected to enable the reuse of expensive organic solvents and the separation and particle recovery of various raw materials from organic solvents.

[0007] There are two main methods for manufacturing polymeric separation membranes: non-solvent induced phase separation (NIPS) and thermally induced phase separation (TIPS). Membranes manufactured by the TIPS method are primarily microfiltration (MF) and ultrafiltration (UF) membranes. Compared to membranes manufactured by the NIPS method, they have the advantage of large pores, making it easier to explain the behavior of membrane structure formation depending on the polymer concentration and cooling temperature. Polymers that can be used with the TIPS method include polypropylene (PP), polyethylene (PE), polyvinylidene fluoride (PVDF), cellulose acetate (CA), poly(ethylene-chlorotrifluoroethylene) (ECTFE), and polyketone (PK). In this method, green solvents such as PEG, PC, GTA, TEP, and glycerine, as well as phthalate-based compounds such as DMP (dimethyl phthalate), DEP (diethyl phthalate), DBP (dibuthyl phthalate), and DOP (diocthyl phthalate) are mainly used as diluents.

[0008] Polymers primarily used in the OSN field must have high resistance to organic solvents, but most polymers are soluble in organic solvents, so they must be coated or have their chemical resistance increased through interfacial polymerization or crosslinking reactions.Most of the materials used for modification require expensive additives, and the modification reaction takes a long time, which increases the cost of the separation membrane manufacturing process and makes quality control very difficult.

[0009] Meanwhile, polyketone is a type of polyolefin polymer that has recently been attracting attention as a polymer material that can be used not only for engineering materials but also as a material for separation membranes that can be applied to special separation processes using organic solvents as the raw solution. However, its use is limited because it is somewhat difficult to dissolve even in strong solvents.

[0010] Korean Patent Publication Nos. 2017-0087240, 2015-0033424, and 1734894 describe methods for manufacturing flat-type or hollow-fiber membranes using polyketone polymers, and polyketone separation membranes manufactured by the methods. The polyketone separation membranes manufactured by these methods utilize the traditional non-solvent-induced phase separation method. However, because few organic solvents are available that can dissolve polyketone polymers, the polyketone is added to hexafluoroisopropanol or to an aqueous solution of three metal salts: zinc chloride (ZnCl2), calcium chloride (CaCl2), and lithium chloride (LiCl). However, because the solubility of polyketone polymers in aqueous metal salt solutions, which are not organic solvents, is very limited, the weight percentage of polyketone polymer in the aqueous solution must not exceed 2-10 wt%, which can be a major factor in weakening the mechanical strength of the separation membrane. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Republic of Korea Patent Publication No. 2017-0087240 (2017.07.28) [Patent Document 2] Republic of Korea Patent Publication No. 2015-0033424 (2015.04.01) [Patent Document 3] Republic of Korea Patent No. 1734894 (2017.05.04) Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention aims to solve the shortcomings of conventional polyketone flat membranes or hollow fiber membranes, and provides a method for producing polyketone hollow fiber separation membranes that have excellent chemical resistance and mechanical properties in a separation membrane process using a strong organic solvent as the raw solution.

[0013] Another object of the present invention is to provide a method for producing a polyketone hollow fiber separation membrane that has uniform pore sizes and is capable of suppressing membrane swelling.

[0014] Another object of the present invention is to provide a polyketone hollow fiber separation membrane having excellent chemical resistance and mechanical properties.

[0015] Another object of the present invention is to provide a polyketone hollow fiber separation membrane having uniform pore sizes and capable of suppressing membrane swelling. [Means for solving the problem]

[0016] The present invention provides a method for producing a polyketone hollow fiber separation membrane, including the steps of: heating a mixture of polyketone and a diluent to melt the polyketone to prepare a dope solution; removing air bubbles present in the dope solution; spraying the dope solution from which air bubbles have been removed through a hollow fiber nozzle to obtain polyketone hollow fibers; immersing the polyketone hollow fibers in a cooling water bath to extract the diluent from the polyketone hollow fibers; and winding the polyketone hollow fibers immersed in the cooling water bath to obtain a polyketone hollow fiber separation membrane.

[0017] The present invention also provides a polyketone hollow fiber separation membrane produced by the above-mentioned method for producing a polyketone hollow fiber separation membrane. [Effects of the Invention]

[0018] The method for producing a polyketone hollow fiber separation membrane according to the present invention has the advantage that it can produce a polyketone hollow fiber separation membrane having excellent chemical resistance and mechanical properties. Specifically, the method for producing a polyketone hollow fiber separation membrane according to the present invention has the advantage that it can produce a polyketone hollow fiber separation membrane having excellent chemical resistance and mechanical properties by using a thermally induced phase separation method.

[0019] Furthermore, the method for producing a polyketone hollow fiber separation membrane according to the present invention has the advantage that it is possible to produce a polyketone hollow fiber separation membrane having a uniform pore size and capable of suppressing membrane swelling.

[0020] Furthermore, the polyketone hollow fiber separation membrane according to the present invention has the advantages of excellent chemical resistance, excellent mechanical properties, uniform pore size, and suppressed membrane swelling. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram illustrating a method for manufacturing a polyketone hollow fiber separation membrane according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram showing the formation behavior of a polymer film at the interface between a dope solution and another solution in a thermally induced phase separation process. [Figure 3] 1 is a scanning electron microscope (SEM) image of a polyketone hollow fiber separation membrane manufactured according to an embodiment of the present invention. [Figure 4] FIG. 2 is a graph showing the pure water permeability of a polyketone hollow fiber separation membrane manufactured according to an embodiment of the present invention. [Figure 5] FIG. 2 is a graph showing the breaking strength and elongation of a polyketone hollow fiber separation membrane manufactured according to an embodiment of the present invention. [Figure 6] FIG. 1 is a graph showing the chemical resistance test results of a toxic organic solvent for a polyketone hollow fiber separation membrane manufactured according to an embodiment of the present invention. [Figure 7] FIG. 1 is a graph showing the change in mechanical strength after evaluation of long-term chemical resistance of a polyketone hollow fiber separation membrane manufactured according to an embodiment of the present invention. [Figure 8] FIG. 1 is a graph showing the results of water permeability analysis of a polyketone hollow fiber separation membrane prepared according to an embodiment of the present invention after being exposed to an organic solvent for 4 months. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described in more detail below.

[0023] In the present invention, when a member is described as being "located on" another member, this includes not only the case where the member is in direct contact with the other member, but also the case where another member is interposed between the two members.

[0024] When a part of the present invention is described as "comprising" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0025] <Manufacturing method of polyketone hollow fiber separation membrane> One aspect of the present invention relates to a method for producing a polyketone hollow fiber separation membrane, including the steps of: heating a mixture of polyketone and a diluent to melt the polyketone to prepare a dope solution; removing air bubbles present in the dope solution; spraying the dope solution from which air bubbles have been removed through a hollow fiber nozzle to obtain polyketone hollow fibers; immersing the polyketone hollow fibers in a cooling water bath to extract the diluent from the polyketone hollow fibers; and winding the polyketone hollow fibers immersed in the cooling water bath to obtain a polyketone hollow fiber separation membrane.

[0026] In the present invention, the polyketone hollow fiber separation membrane may be a porous hollow fiber separation membrane.

[0027] In the present invention, the term "porous" means that the interior or surface of a polyketone hollow fiber separation membrane contains pores, and may be used in a manner commonly understood by a person having ordinary skill in the art to which this application pertains.

[0028] The pores may have a diameter of several nm to several tens of μm, and the porosity of the porous structure may be 60 to 90%, but is not limited to these.

[0029] Polyketone (PK) is a semi-crystalline thermoplastic resin generally composed of ethylene and carbon monoxide in the repeating unit CH2CH2C=O. This crystalline structure promotes strong intermolecular interactions within the molecule, giving it the advantage of excellent resistance to organic solvents. This helps to suppress membrane swelling caused by solvents, which is the most important factor in producing organic solvent-resistant separators.

[0030] In addition, polyketone is a polymer with superior chemical and mechanical properties compared to polyamide, polyester, and other materials used in existing engineering plastics, making it suitable for producing organic solvent-resistant separators.

[0031] Therefore, the polyketone hollow fiber separation membrane according to the present invention, which is manufactured using polyketone, has advantages of excellent chemical resistance, excellent mechanical properties, and suppressed swelling.

[0032] Specifically, the polyketone has a linear alternating structure, with each unsaturated hydrocarbon molecule containing substantially carbon monoxide. Ethylenically unsaturated hydrocarbons suitable for use as polyketone prospheres have up to 20 carbon atoms, preferably up to 10. Ethylenically unsaturated hydrocarbons can be aliphatic, such as ethene and α-olefins, e.g., propene, 1-butene, isobutene, 1-hexene, and 1-octene, or can be arylaliphatic, containing aryl substituents on other aliphatic molecules, particularly aryl substituents on ethylenically unsaturated carbon atoms. Examples of arylaliphatic hydrocarbons among ethylenically unsaturated hydrocarbons include styrene, p-methylstyrene, p-ethylstyrene, and m-isopropylstyrene.

[0033] The polyketones preferably used in the present invention are copolymers of carbon monoxide and ethene or terpolymers of carbon monoxide, ethene and a second ethylenically unsaturated hydrocarbon having at least 3 carbon atoms, in particular terpolymers of carbon monoxide, ethene and an α-olefin such as propene.

[0034] The polyketone used in the present invention has a number average molecular weight (M n ) is 100 to 200,000, preferably 10,000 to 200,000, more preferably 50,000 to 200,000, and particularly preferably 90,000 to 200,000. In this case, the produced polyketone hollow fiber separation membrane has the advantage of having excellent mechanical strength, which is preferable.

[0035] The method for producing a polyketone hollow fiber separation membrane according to the present invention includes the step of preparing a dope solution by heating a mixture of a polyketone and a diluent to melt the polyketone. Specifically, the method for producing a polyketone hollow fiber separation membrane according to the present invention may prepare a dope solution by heating a mixture of a polyketone and a diluent to a temperature equal to or higher than the melting point of the polyketone to melt the polyketone.

[0036] The polyketone and diluent mixture may be heated to a temperature above the boiling point of the aqueous refrigerant in the cooling water bath (quenching bath).

[0037] In one embodiment of the present invention, the temperature to which the mixture of the polyketone and the diluent is heated may be a temperature equal to or higher than the melting point of the polyketone and equal to or lower than the boiling point of the polyketone.

[0038] The melting point of the polyketone used in the present invention may be in the range of 175 to 300°C, preferably 190 to 270°C, more preferably 200 to 220°C. The dope solution in which the polyketone and diluent are uniformly mixed and the separation membrane are produced at a temperature within the melting point of the polyketone, preferably 190 to 270°C, more preferably 200 to 220°C.

[0039] Specifically, the temperature of 200 to 220°C may be a temperature above the melting point of the polyketone polymer, specifically, above the melting point of the polyketone polymer whose melting point has been slightly lowered by the diluent, and below the boiling point of the aqueous refrigerant. The method for producing a polyketone hollow fiber separation membrane according to the present invention is carried out by uniformly mixing the polyketone and the diluent at a temperature within the above range and then lowering the temperature to solidify the polyketone.

[0040] For the production of polyketones, the method for producing polyketones disclosed in U.S. Patent No. 4,843,144 can be used, but is not limited to this. For example, polyketones can be produced by contacting carbon monoxide and a hydrocarbon monomer under polymerization conditions in the presence of a catalyst composition suitably formed from a palladium compound, an anion of a dihydrohalogen acid having a pKa of less than 6, or preferably less than pKa of 2 (measured in water at 18°C), and a bidentate phosphorus ligand.

[0041] In still another embodiment of the present invention, the dope solution may contain 10 to 50 wt % of the polyketone and 50 to 90 wt % of the diluent, based on 100 wt % of the total dope solution. Preferably, the polyketone is contained in an amount of 15 to 45 wt %, more preferably 20 to 40 wt %, based on 100 wt % of the total dope solution, and the diluent is contained in an amount of 55 to 85 wt %, more preferably 60 to 80 wt %, based on 100 wt % of the total dope solution.

[0042] When the polyketone and the diluent are contained within the above ranges, it is advantageous in that a polyketone hollow fiber separation membrane having excellent durability can be produced.

[0043] To prepare the polyketone hollow fiber separation membrane according to the present invention, first, 10 to 50 wt % of polyketone and 50 to 90 wt % of a diluent are mixed at a temperature of preferably 190 to 270°C, more preferably 200 to 220°C, for 3 to 5 hours to prepare a dope solution.

[0044] The diluent may be any diluent that can lower the melting point of the polyketone and disperse the polyketone polymer finely and uniformly at high temperatures.

[0045] In yet another embodiment of the present invention, the diluent may include one or more selected from the group consisting of polyethylene glycol (PEG), dimethyl sulfone (DMSO), sulfolane, dimethyl sulfonic acid (DMSO), pentanediol, hexanediol, diethyl phthalate, dimethyl phthalate, and glycerin.

[0046] In terms of dispersibility of the polyketone polymer, the diluent may preferably be polyethylene glycol, dimethyl sulfone or glycerin.

[0047] The dope solution may be prepared using a high-temperature mixer. Since the polyketone dope solution has a characteristic that phase separation occurs very quickly due to slight differences in temperature, the high-temperature mixer for mixing the dope solution should be maintained at a temperature in the range of 200 to 220°C.

[0048] When preparing the dope solution through the high-temperature mixer, the inside of the high-temperature mixer may be purged with an inert gas such as, but not limited to, non-reactive nitrogen, if necessary.

[0049] The polyketone hollow fiber separation membrane according to the present invention may further include a step of removing bubbles present in the dope solution. Removing the bubbles is advantageous because it improves the mechanical strength of the resulting polyketone hollow fiber separation membrane.

[0050] The method for removing bubbles present in the dope solution is not limited to this, but for example, the dope solution can be removed by stirring the dope solution.

[0051] The step of stirring the dope solution may be performed at a speed of 10 to 800 rpm for 1 to 12 hours, preferably at a speed of 10 to 500 rpm, more preferably at a speed of 10 to 100 rpm, and the low-speed stirring is preferably maintained for 1 to 9 hours, more preferably for 1 to 3 hours, in order to remove residual bubbles.

[0052] The method for producing a polyketone hollow fiber separation membrane according to the present invention includes a step of spraying the dope solution, from which air bubbles have been removed, through a hollow fiber nozzle to obtain polyketone hollow fibers. Specifically, the method for producing a polyketone hollow fiber separation membrane according to the present invention involves moving the dope solution, from which air bubbles have been removed, through a gear pump to a hollow fiber nozzle and then spraying it to obtain polyketone hollow fibers (FIG. 1).

[0053] Specifically, referring to FIG. 1, the method for producing a polyketone hollow fiber separation membrane according to the present invention may include spraying the prepared dope solution through a hollow fiber nozzle to obtain polyketone hollow fibers, and then immersing the obtained polyketone hollow fibers in a cooling water bath described below to rapidly solidify them, thereby producing a polyketone hollow fiber separation membrane by a thermally induced phase separation method.

[0054] The method for producing polyketone hollow fibers by spraying the dope solution through a nozzle is not limited to the present invention. For example, the bore solution sprayed into the nozzle may be, but is not limited to, one or more selected from the group consisting of polyethylene glycol (PEG), dimethyl sulfone (DMSO), sulfolane, dimethyl sulfonic acid (DMSO), pentanediol, hexanediol, diethyl phthalate, dimethyl phthalate, and glycerin, and may be a method commonly used in the art. The ratio of the dope solution to the bore solution may be, but is not limited to, 2:8 to 4:6.

[0055] The present invention does not limit the discharge speed of the dope solution and the bore solution.

[0056] The nozzle may have a hole with an inner diameter (ID) of 0.1 to 1 mm and an outer diameter (OD) of 0.9 to 2 mm, but is not limited thereto, and any spray nozzle commonly used in the industry may be used depending on the purpose.

[0057] The air gap, which is the distance between the nozzle and the surface of the refrigerant in the cooling water tank, is not limited in the present invention. For example, the air gap can be adjusted to provide an appropriate tension depending on the shape of the polyketone hollow fiber separation membrane.

[0058] Meanwhile, the degree of phase separation is a very important study to understand the cooling-induced phase separation behavior that occurs between the polymer and the diluent, and such phase separation behavior plays an important role in determining the structure of the separation membrane.

[0059] In the thermally induced phase separation method used in the present invention, solid-liquid and liquid-liquid phase separation behaviors are caused by the concentration of polyketone and the affinity between polyketone and diluent.

[0060] Without being limited by theory, when a polymer, i.e., a polyketone, and a diluent exist as a single phase at high temperatures and are cooled through a metastable region, nuclei are generated, and the generated nuclei grow during phase separation, resulting in a spherical membrane structure. In this case, solid-liquid phase separation behavior occurs, which has the advantage of making it easy to predict the membrane structure. However, since this can be controlled by changing the cooling rate, polymer concentration, and the interaction between the polymer and the diluent, sufficient optimization is required.

[0061] On the other hand, when the temperature is cooled through the unstable region, nuclei are not generated by the spinodal decomposition mechanism, and phase separation occurs while the polymer and diluent remain interconnected. Over time, the structure continues to grow, resulting in an interconnected separation membrane structure. In this case, liquid-liquid phase separation behavior occurs, and a porous bicontinuous or cellular structure may be formed.

[0062] In the thermally induced phase separation process, when the polymer dope solution (polymer A / diluent B) comes into contact with solution C (the bore solution or the refrigerant in the cooling water tank), the compatibility between polymer A and solution C or between diluent B and solution C is very important. The compatibility comparison is shown in Figure 2.

[0063] Referring to Figure 2, if the compatibility between polymer A and solution C is higher than the compatibility between diluent B and solution C, the polymer and solution C will come into better contact at the interface, forming a dense polymer layer in this area.

[0064] On the other hand, if the compatibility between diluent B and solution C is higher than that between polymer A and solution C, diluent B will come into contact with solution C more, the polymer concentration at the interface will decrease, and a porous structure will be formed.

[0065] On the other hand, in the case of the outer surface, the compatibility between polymer A and solution C (quenching bath) is higher, so a dense surface structure appears in which polymer A gathers at the outer interface.

[0066] The method for producing a polyketone hollow fiber separation membrane according to the present invention includes a step of immersing the polyketone hollow fiber in a cooled water bath to extract the diluent from the polyketone hollow fiber.

[0067] The polyketone hollow fiber is immersed in the cooling water bath to rapidly solidify it, and a polyketone hollow fiber separation membrane can be obtained by a thermally induced phase separation method.

[0068] The refrigerant may be an aqueous refrigerant, and specifically, the refrigerant may include at least one selected from the group consisting of water and an organic solvent.

[0069] The organic solvent may be contained in an amount of 5 to 50% by weight, preferably 10 to 50% by weight, and more preferably 30 to 50% by weight, relative to 100% by weight of the aqueous refrigerant.

[0070] In short, the aqueous refrigerant is preferably a mixture of water and an organic solvent, and in this case, the organic solvent is preferably contained in the above-mentioned range, with water being the remainder.

[0071] When the above range is satisfied, it is preferable in terms of appropriately increasing the size of the pores in the formed separation membrane.

[0072] The organic solvent preferably contains a water-soluble solvent, which facilitates extraction of the diluent, separation of the refrigerant, and cleaning. Specifically, the organic solvent may be a water-soluble solvent.

[0073] The organic solvent is preferably one or a mixture of two or more selected from dibutyl phthalate, dioctyl phthalate, γ-butyrolactone, diethyl phthalate, propylene glycol, ethylene glycol, glycerol triacetate, polyethylene glycol, and glycerol.

[0074] The refrigerant may have a temperature of 4 to 70° C., preferably 10 to 40° C., more preferably 20 to 30° C., and most preferably room temperature. When the temperature of the refrigerant is within the above range, the polyketone hollow fiber separation membrane can have uniform pores, which is preferable.

[0075] The method for producing a polyketone hollow fiber separation membrane according to the present invention includes a step of winding up the polyketone hollow fiber immersed in the cooling water bath to obtain a polyketone hollow fiber separation membrane.

[0076] The winding may be performed using a winder, and since excessive tension may cause the polyketone hollow fiber to break, a tension adjusting means may be provided, but is not limited to this.

[0077] The winding speed may be, but is not limited to, 55 to 120 rpm, preferably 60 to 100 rpm, and more preferably 70 to 80 rpm, but is preferably within the above range, since this can prevent the polyketone hollow fiber from breaking due to excessive tension.

[0078] Furthermore, the polyketone hollow fiber separation membrane obtained using the winder may be further subjected to washing and drying processes as necessary, but is not limited thereto.

[0079] For example, the polyketone hollow fiber separation membrane may be subjected to a first and second washing using ethanol, followed by drying at 20 to 60°C.

[0080] The method for producing a polyketone hollow fiber separation membrane according to the present invention suppresses the phenomenon of a decrease in mechanical strength after rapid solidification through a heat-induced phase separation method using a polyketone having excellent chemical resistance and heat resistance and a diluent capable of uniformly dispersing the polyketone. Furthermore, the pores of the microfiltration or ultrafiltration separation membrane can be freely controlled through a mutual solvent reaction between the diluent and the polyketone, and a solution such as a bore solution or a refrigerant in a cooling water tank. This has the advantage of being able to produce a separation membrane with significantly superior performance compared to conventional production methods using metal salts.

[0081] <Polyketone hollow fiber separation membrane> Another aspect of the present invention relates to a polyketone hollow fiber separation membrane produced by the above-mentioned method for producing a polyketone hollow fiber separation membrane.

[0082] That is, another aspect of the present invention relates to a polyketone hollow fiber separation membrane manufactured by a method for manufacturing a polyketone hollow fiber separation membrane, the method including the steps of: heating a mixture of polyketone and a diluent to melt the polyketone to prepare a dope solution; removing air bubbles present in the dope solution; spraying the dope solution from which air bubbles have been removed through a hollow fiber nozzle to obtain polyketone hollow fibers; immersing the polyketone hollow fibers in a cooling water bath to extract the diluent from the polyketone hollow fibers; and winding the polyketone hollow fibers immersed in the cooling water bath to obtain a polyketone hollow fiber separation membrane.

[0083] The polyketone hollow fiber separation membrane according to the present invention has the advantage that it can be applied to microfiltration applications.

[0084] The polyketone hollow fiber separation membrane according to the present invention is prepared using a thermally induced phase separation method, rather than a conventional method using metal salts. Therefore, compared to separation membranes prepared by conventional methods, the polyketone content is higher, resulting in superior mechanical strength and high elongation.

[0085] In addition, the polyketone hollow fiber separation membrane according to the present invention has advantages of having uniform pore size, excellent mechanical strength, and excellent resistance to organic solvents.

[0086] In another embodiment of the present invention, the polyketone hollow fiber separation membrane may have a pure water permeability of 10 to 270 LMH / bar, specifically 30 to 250 LMH / bar, more specifically 80 to 100 LMH / bar. The polyketone hollow fiber according to the present invention has excellent pure water permeability and can be used as a microfiltration membrane in separation processes using organic solvents.

[0087] The polyketone hollow fiber separation membrane may have a tensile strength of 5 to 15 MPa, specifically 5 to 10 MPa, and more specifically 5 to 8 MPa.

[0088] The polyketone hollow fiber separation membrane may have an elongation of 15 to 50%, specifically 20 to 40%, and more specifically 20 to 35%.

[0089] The tensile strength may be measured using a universal tensile strength tester. Specifically, the tensile strength can be obtained by pulling a polyketone hollow fiber separation membrane of a certain size of 50 mm at a speed of 50 mm / min and measuring the tensile strength and elongation at the moment of breakage.

[0090] The polyketone hollow fiber separation membrane according to the present invention exhibits excellent tensile strength and elongation, and can therefore be applied to various industries that require long-term operation and high mechanical performance.

[0091] The polyketone hollow fiber separation membrane according to the present invention has advantages of excellent chemical resistance and mechanical properties, and also has uniform pore size and excellent effect of suppressing membrane swelling.

[0092] Specifically, the polyketone hollow fiber separation membrane according to the present invention can be applied not only to the field of water purification and water treatment, but also to various fields that require separation in organic solvents, such as oil refining, medicine, and catalysts, due to the excellent chemical resistance and heat resistance of polyketone, and can bring about the effects of efficiency and cost economy.

[0093] Hereinafter, the present specification will be described in detail through examples to explain the present specification in more detail. However, the examples according to the present specification may be modified into various other forms, and the scope of the present specification should not be construed as being limited by the examples detailed below. The examples of the present specification are provided to more completely explain the present specification to those skilled in the art. In addition, "%" and "parts" indicating contents below are by weight unless otherwise specified.

[0094] (1) Manufacturing of polyketone hollow fiber separation membranes The polymer used to manufacture the hollow fiber separation membrane was M330A, a product of Hyosung Polyketone. The diluent and inner solution were polyethylene glycol 300 (PEG300) (100%, SAMCHUN), dimethyl sulfone (DMSO2) (>99.0%, Tokyo Chemical Industry Co., Ltd.), and glycerin (>99.0%, DAEJUNG). Water used in the experiments was purchased from an ultrapure water production system.

[0095] Figure 1 shows a schematic diagram of the hollow fiber membrane manufacturing equipment. The polymer and diluents were mixed in the reactor at the appropriate concentrations and stirred at 210°C for 6 hours under a nitrogen atmosphere to prepare the dope solution. The resulting dope solution was then transferred to the hollow fiber nozzle via a gear pump and sprayed. The inner solution required for hollow fiber fabrication was the same for all conditions: PEG300. This solution, along with the dope solution, was transferred to the hollow fiber nozzle via a gear pump and sprayed. The hollow fiber membranes sprayed from the nozzle were then passed through a cooling water bath to solidify and extract the diluent from the membrane. They were then wound onto a winder and stored in ultrapure water to produce polyketone hollow fiber membranes according to the diluent. Detailed spraying conditions for the hollow fiber membranes are listed in Table 1 below.

[0096] [Table 1]

[0097] (2) Experimental example Analysis of the surface properties of polyketone hollow fiber membranes A scanning electron microscope (S5410, JEOL) was used to observe the inner and outer surfaces and cross-sectional structure of the polyketone hollow fiber membrane prepared according to the manufacturing example. For accurate cross-sectional analysis, the membrane was immersed in liquid nitrogen and broken, and the prepared sample was gold coated for 40 seconds to pretreat the sample before analysis. The results are shown in Figure 3 below.

[0098] Specifically, Figure 3 shows the cross-section (a) and the inner surface (b) and outer surface (c) structures for different diluents used in the manufacture of polyketone hollow fiber membranes. Figure 3(a) shows that when PEG300 and glycerine were used as diluents, the cross-sectional pores formed a sponge-like structure, indicating liquid-liquid phase separation. Furthermore, when DMSO2 was used, a spherical structure was clearly visible in the cross-sectional structure, confirming that the membrane formed exhibited solid-liquid phase separation, unlike the membranes manufactured using the other two diluents. Figures 3(b) and 3(c) show the surface analysis results for the inner and outer surfaces of hollow fibers depending on the diluent.

[0099] In the case of the inner surface of PEG300 and glycerine, it can be seen that the compatibility between the diluent and the internal bore resolution is higher, resulting in the formation of uniform pores.In addition, it was shown that the pores on the inner surface of the hollow fiber membrane made with PEG300 were more open than those made with glycerine, and this can be confirmed through the water permeability results.

[0100] The hollow fiber membrane prepared using DMSO2 was confirmed to exhibit a spherical structure due to solid-liquid phase separation behavior, unlike the other two membranes mentioned above. The inner surface was slowly cooled, allowing sufficient time for phase separation, resulting in a porous structure, while the outer surface, which was rapidly cooled, exhibited a slightly denser structure compared to the inner surface.

[0101] Pure water permeability analysis The pure water permeability of the polyketone hollow fiber separation membrane manufactured in the manufacturing example is shown in FIG.

[0102] The pure water permeability of the hollow fiber separation membrane was measured using the cross-flow filtration method. The experiment was carried out by preparing a separation membrane stored in ultrapure water with a length of 14-16 cm and cutting it to about 2.4 cm. 2 After setting the separation membrane to a size suitable for connection to the permeation experiment device, the experiment was carried out three times or more under the same conditions, and the average value was used.

number

[0103]

number

[0104] V: Total amount of permeate that passes through the separation membrane (L) A: Effective area of ​​the separation membrane used in the measurement (m 2 ) Δt: Time it takes for water to permeate (h) ΔP: Measured pressure (bar)

[0105] As can be seen from Figure 4, the membrane prepared with PEG300 exhibited a permeability of approximately 130 LMH, while DMSO2 exhibited the highest permeability of approximately 250 LMH, and glycerine exhibited the lowest permeability of approximately 15 LMH. Referring to Figure 3, excluding DMSO2, which exhibited the highest permeability, the structures of the polyketone hollow fiber membranes prepared with PEG300 and glycerine exhibit identical structures, indicating a sponge structure with interconnected pores, and the cross-sections, outer surfaces, and inner surfaces all show similar trends. However, when comparing the inner surfaces in Figure 3(b), it can be seen that PEG300 has better compatibility with the bore solution than glycerine, resulting in the formation of more and more uniform pores. This suggests that the polyketone hollow fiber membrane prepared with PEG300 exhibits a higher permeability.

[0106] Mechanical property analysis The breaking strength and elongation of the polyketone hollow fiber separation membrane produced in the production example are shown in FIG.

[0107] The mechanical properties of the polyketone hollow fiber membrane were analyzed using a universal tensile strength tester (Tensometer 2020). Specifically, a 50mm hollow fiber membrane was pulled at a speed of 50mm / min to measure the tensile strength and elongation (tensile stress) at the moment of breakage. The analyzed results were confirmed to be reproducible through repeated experiments at least three times.

[0108] As can be seen from Figure 5, the tensile strengths for each diluent were 8 MPa, 6 MPa, and 8 MPa, and the elongations were approximately 35, 20, and 35%. This is because, as can be seen from the SEM characterization and phase separation behavior during the TIPS process in Figure 3, the PEG300 and glycerine samples, whose pores are uniformly connected to each other, are believed to have higher breaking strength and elongation.

[0109] Mechanical properties are one of the important factors that affect long-term operation and performance in various industries that use separation membrane processes, and these mechanical properties are determined by the type and concentration of materials, the structure of the separation membrane, pores, etc. The polyketone hollow fiber separation membrane according to the present invention has excellent mechanical properties and is therefore believed to be applicable to various industrial fields that require long-term operation and excellent performance.

[0110] Chemical resistance analysis Figures 6 to 8 show the results of analyzing various characteristics that appear when organic solvents are applied to the polyketone hollow fiber separation membranes manufactured according to the manufacturing examples. Based on the above results, we chose a membrane manufactured with PEG300, which has the best pure water permeability among membranes with a sponge structure.

[0111] Specifically, we conducted a chemical resistance test against solvents, which is the most important factor for organic solvent-resistant separation membranes. All hollow fiber separation membranes were thoroughly dried in a dryer, then sampled at the same weight and stored in DMAc, DMF, DMSO, and NMP, which are known to be strong organic solvents. The samples stored in the solvents were taken out every week, washed with ultrapure water to remove any remaining organic matter, and then thoroughly dried for more than 24 hours to check for changes in weight.

[0112] First, Figure 6 is a graph showing the results of chemical resistance analysis of the prepared polyketone hollow fiber membrane to organic solvents. The membrane was evaluated over a six-month period to determine whether it was suitable for use as an organic solvent-resistant membrane.

[0113] The organic solvents used in this experiment were DMAc, DMF, DMSO, and NMP, which are toxic solvents commonly used in the fine chemical industry as well as the separation membrane industry. As a result, when the chemical resistance of the manufactured polyketone hollow fiber separation membrane to organic solvents was evaluated, all four solvents showed a weight loss rate of less than 2.5%.

[0114] Next, Figure 7 shows the results of measuring the mechanical strength of the membranes evaluated for long-term chemical resistance. The membranes were washed and thoroughly dried after being exposed to four different organic solvents, and then evaluated. Changes were observed over a six-month period. The results confirmed that the breaking strength maintained the initial strength of approximately 8 MPa throughout the six-month evaluation period, despite long-term exposure to the solvents. The elongation showed approximately half the elongation of the initial sample after one month of exposure to the organic solvent, but did not gradually decrease thereafter, maintaining the same value. This suggests that when polymeric membranes are exposed to organic solvents, they harden over time, making them prone to breaking. These results confirm the membrane's suitability for use as an organic solvent-resistant membrane. In particular, the breaking strength remained unchanged from the initial sample, even after long-term exposure to the organic solvent, demonstrating excellent results.

[0115] Finally, Figure 8 shows the analysis results for the water permeability of polyketone hollow fiber membranes exposed to organic solvents for four months. The initial permeability was measured at approximately 106 LMH. A further measurement of approximately 96 LMH was obtained after air-drying a sample under the same conditions. This is believed to be due to the shrinkage of pores formed in the fabricated polyketone hollow fiber membrane as the membrane dried. It is confirmed that there is no significant difference in the initial permeability from membranes immersed in ultrapure water. For comparison, samples were left in each of the four organic solvents for four months. After removal, the samples were washed with ultrapure water, dried, and then evaluated and analyzed. Pure water permeability values ​​of approximately 98, 80, 99, and 85 LMH were measured for the organic solvents used (DMAc, DMF, DMSO, and NMP), respectively. DMAc and DMSO showed values ​​within the margin of error, approximately 2–3% lower than the permeability values ​​of the previous samples. DMF and NMP showed permeability values ​​approximately 15–20% lower than the previous values.

[0116] In the above preparation and experimental examples, polyketone hollow fiber membranes were prepared using thermally induced phase separation (TIPS), and the membrane structure, pure water permeability, mechanical properties, and chemical resistance were investigated when various diluents were used. When PEG300 or glycerine was used as a diluent in the preparation of polyketone hollow fiber membranes, liquid-liquid phase separation occurred, resulting in a sponge structure with interconnected pores throughout the membrane. On the other hand, when DMSO2 was used as a diluent, solid-liquid phase separation occurred, resulting in a spherical membrane structure. Due to this spherical membrane structure, the membrane prepared with DMSO2 had the highest measured pure water permeability. Furthermore, membranes prepared using PEG300 and glycerine, which exhibit a sponge structure with interconnected pores, exhibited relatively excellent mechanical properties. In the evaluation of chemical resistance, which is the most important factor for the membrane to function as an organic solvent-resistant separator, the manufactured polyketone hollow fiber membrane was measured to lose approximately 2% of its weight in toxic organic solvents for six months. Further analysis of the membrane's permeability and mechanical properties obtained from the chemical resistance evaluation also showed that the membrane had excellent results suitable for use as an organic solvent-resistant separator.

[0117] Many fine chemical industry processes that use separation membranes require separation membranes that meet various requirements for long-term operation, such as permeability, mechanical strength, chemical resistance, etc. The PK used in this study has excellent physical and chemical properties of the material itself and has sufficient performance to satisfy the various evaluation characteristics above, so it is deemed suitable for application in various industries that use organic solvents.

Claims

1. preparing a dope solution by heating a mixture of a polyketone and a diluent to melt the polyketone; removing air bubbles present in the dope solution; a step of ejecting the dope solution from which air bubbles have been removed through a hollow fiber nozzle to obtain polyketone hollow fibers; immersing the polyketone hollow fibers in a cold water bath to extract the diluent from the polyketone hollow fibers; and and winding the polyketone hollow fibers immersed in the cooling water bath to obtain a polyketone hollow fiber separation membrane, The step of ejecting the dope solution through the hollow fiber nozzle to obtain the polyketone hollow fiber includes ejecting a bore solution into the hollow fiber nozzle; The method for producing a polyketone hollow fiber separation membrane, wherein the bore solution contains at least one selected from the group consisting of polyethylene glycol (PEG), dimethyl sulfone (DMSO 2 ), sulfolane, dimethyl sulfonic acid (DMSO), and glycerin.

2. With respect to 100% by weight of the total dope solution, 10 to 50% by weight of said polyketone; and 50 to 90% by weight of said diluent; The method for producing a polyketone hollow fiber separation membrane according to claim 1, characterized in that

3. 2. The method for producing a polyketone hollow fiber separation membrane according to claim 1, wherein the temperature to which the mixture of polyketone and diluent is heated is a temperature not lower than the melting point of the polyketone and not higher than the boiling point of the polyketone.

4. The method for producing a polyketone hollow fiber separation membrane according to claim 3, wherein the mixture of polyketone and diluent is heated to a temperature of 190 to 270°C.

5. The diluent may be polyethylene glycol (PEG), dimethyl sulfone (DMSO), or ２ ), sulfolane, dimethyl sulfonic acid (DMSO), pentanediol, hexanediol, diethyl phthalate, dimethyl phthalate, and glycerin. The method for producing a polyketone hollow fiber separation membrane according to claim 1, wherein the polyketone hollow fiber separation membrane comprises one or more selected from the group consisting of methyl phthalate, methyl phthalate, methyl methacrylate ...

6. A polyketone hollow fiber separation membrane, characterized by being produced by the method for producing a polyketone hollow fiber separation membrane according to any one of claims 1 to 5.

7. The polyketone hollow fiber separation membrane according to claim 6, wherein the polyketone hollow fiber has a pure water permeability of 10 to 270 LMH / bar.

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