KR101424422B1 - Manufacturing method of ECTFE hollow fiber membrane - Google Patents

Abstract

 The present invention relates to a process for producing a polyethylene chlorotrifluoroethylene (hereinafter abbreviated as "ECTFE") hollow fiber membrane, which comprises preparing a spinning solution comprising polyethylene chlorotrifluoroethylene (ECTFE), an inorganic additive and a solvent step; Spinning the spinning solution through a spinning nozzle at a temperature of 100 to 200 ° C to form a hollow fiber; And a step of immersing the spun hollow fiber in an external coagulating solution, thereby minimizing a decrease in water permeability due to the hydrophobicity of ECTFE, thereby satisfactorily improving the water permeability of the ECTFE hollow fiber membrane and satisfying the excellent rejection rate So that the filtration efficiency can be improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyethylene chlorotrifluoroethylene (ECTFE) hollow fiber membrane,

More particularly, the present invention relates to a method for producing hollow fiber membranes made of polyethylene terephthalate (hereinafter abbreviated as " ECTFE "). More particularly, the present invention relates to a hollow fiber membrane excellent in mechanical properties such as abrasion resistance and tensile strength, And a method for producing a hollow fiber membrane using ECTFE which is a fluorine-based material stable in an environment.

The separation membrane technology is a highly separation technology for almost completely separating and removing the materials to be treated present in the treatment water according to the pore size, the pore distribution and the membrane surface charge of the membrane. In the water treatment field, the production of high quality drinking water and industrial water, And clean production processes related to the development of waste water treatment and reuse, and free circulation systems are expanding and are becoming one of the key technologies to be noticed in the 21st century.

The membrane for water treatment may be a hollow fiber membrane. The hollow fiber membrane has a hollow-ring shape, which is advantageous in that it has a larger membrane area per module unit than a flat membrane. If the water treatment separator has a hollow fiber membrane structure, the membrane may be cleaned by backwashing to remove sediments by passing a clean liquid in a direction opposite to the filtration direction, air scrubbing for removing sediments by shaking the membrane by introducing air bubbles into the module Can be effectively used.

Polymeric materials used in the water treatment process using membrane technology include polysulfone, polyethersulfone, polyacrylonitrile, polyethylene, polypropylene, cellulose (cellulose) actate) and polyvinyldene fluoride (hereinafter referred to as " PVDF "). In particular, in recent years, a fluorine-based polymer material having a stain resistance from an organic pollution source has been attracting attention as a water treatment separator material due to a negative charge atmosphere.

  The fluorine-based PVDF membrane is disadvantageous in that it has a low heat resistance and chemical resistance but is resistant to alkalinity, thus limiting the cleaning process and hence the life of the membrane. In order to overcome these disadvantages, efforts have been made to use ECTFE, which is excellent in mechanical properties such as abrasion resistance and tensile strength, and thermal properties, and which is stable in acidic and basic environments, as a water treatment material. ECTFE is a copolymer polymer in which the ethylene group and the chlorotrifluoroethylene group are repeated at a constant ratio, and is a stable material in the entire pH range.

The hollow fiber membrane using ECTFE material can be manufactured by using the thermally induced phase separation (TIPS) method. The TIPS process is a method in which the temperature is increased to the vicinity of the melting point of the polymer, In addition to the polymer, it includes additives such as diluents.

However, since the heat-induced phase separation method is required to maintain a high temperature of 200 ° C or more, a large amount of energy is required. Due to its nature, it is difficult to produce a dense pore film. Thus, it is difficult to manufacture a film having a pore size of 0.1 μm or less. . In addition, when discharging the solution for preventing export to the outermost part of the triple nozzle, the composition of the discharging solution and the coagulation tank are different from each other, and the composition of the coagulating liquid changes with time and the reproducibility is reduced.

Accordingly, a method for producing an ECTFE membrane having a simple manufacturing process and a low cost and high flow rate and high strength property is proposed. The polymer is dissolved in a solvent to lower the melting temperature, and a solution and a coagulation bath, There has been development of an ECTFE membrane manufacturing method using noo-solvent phase separation (NIPS), which induces solidification by mass exchange of materials.

Accordingly, the ECTFE membrane was prepared by the non-solvent phase transition method, thereby reducing energy consumption and various pore structure and pore size control. However, the hydrophobicity of the ECTFE caused a problem of low water permeability.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for producing an ECTFE hollow fiber membrane having a high water permeability and rejection ratio, which is required for a water treatment membrane.

 SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems,

(1) preparing a spinning solution containing polyethylene chlorotrifluoroethylene (ECTFE), an inorganic additive and a solvent; (2) spinning the spinning solution through a spinning nozzle at a temperature of 100 to 200 ° C to form a hollow fiber; And (3) immersing the spun hollow fiber in an external coagulating solution. The present invention also provides a method for producing an ECTFE hollow fiber membrane.

According to a preferred embodiment of the present invention, the inorganic additive is silica-based, lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), Magnesium Chloride (MgCl _2), calcium chloride (CaCl _2), magnesium sulfate (MgSO ₄ ), lithium nitrate (LiNO ₃ ), titanium dioxide (TiO ₂ ), and alumina (Al ₂ O ₃ ).

According to another preferred embodiment of the present invention, the spinning stock solution of step (1) may further comprise a hydrophilic organic compound.

According to another preferred embodiment of the present invention, the hydrophilic organic compound is selected from the group consisting of glycol series, vinyl type monomer or polymer, And glycerol. ≪ / RTI >

According to another preferred embodiment of the present invention, the vinyl monomer or polymer may be an ethylene vinyl acetate (EVA) based polymer.

According to a preferred embodiment of the present invention, the solvent of step (1) is selected from the group consisting of N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, triacetin, dibutylphthalate and dioctyl And phthalates.

The spinning stock solution in the step (1) may include 10 to 70 parts by weight of ECTFE and 0.5 to 50 parts by weight of a hydrophilic additive based on 100 parts by weight of the solvent.

According to another preferred embodiment of the present invention, the hydrophilic organic compound may include 0.5 to 49 parts by weight based on 100 parts by weight of the solvent.

According to a preferred embodiment of the present invention, the spinning nozzle of the step (2) is a double tubular spinning nozzle, and the spinning stock solution of the step (1) is discharged to the outer tube of the double tubular spinning nozzle, The inner coagulant can be discharged through the inner tube of the tubular spinning nozzle.

According to another preferred embodiment of the present invention, the spinning nozzle of the step (1) is a triple-tubular spinning nozzle, and the spinning stock solution of the step (1) is discharged into an intermediate tube of a triple tubular spinning nozzle, And at the same time, as the outermost pipe, at least one selected from the group consisting of glycol series, glycerol series, N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide and dimethylformamide Can be discharged.

According to a preferred embodiment of the present invention, the internal coagulant may be any one or more selected from the group consisting of N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, glycol series and glycerol have.

According to another preferred embodiment of the present invention, the external coagulating solution in the step (3) is at least one selected from the group consisting of water, N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, glycerol, Or a sequence of a plurality of sequences.

According to another preferred embodiment of the present invention, in the step (3), the distance from the nozzle to the surface of the external coagulating liquid may be 0 to 15 cm.

The process for preparing an ECTFE hollow fiber membrane according to the present invention can produce a separation membrane at a lower temperature than that of a conventional heat-induced separation process, and can induce micropore formation, thereby producing a separation membrane having an average pore size of 0.1 μm or less. In addition, it is possible to provide an ECTFE hollow fiber membrane having improved filtration efficiency by satisfactorily improving the water permeability of the ECTFE hollow fiber membrane while minimizing a decrease in water permeability due to the hydrophobicity of the ECTFE.

1 is a cross-sectional view of a double tubular spinning nozzle for producing a hollow fiber membrane according to the present invention.
2 is a cross-sectional view of a triple tubular nozzle for producing a hollow fiber membrane according to the present invention.
3 is a SEM photograph of a cross section of an ECTFE hollow fiber membrane according to an embodiment of the present invention.
4 is a SEM photograph of a section of an ECTFE hollow fiber membrane according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail with reference to the accompanying drawings.

As described above, the conventional ECTFE hollow fiber membrane has a low water permeability due to the hydrophobicity of ECTFE.

Accordingly, the present invention provides a process for producing an ECTFE hollow fiber membrane, comprising the steps of: (1) preparing a spinning stock solution containing polyethylene chlorotrifluoroethylene (ECTFE), an inorganic additive and a solvent; (2) (3) a step of immersing the hollow fiber yarn in an external coagulating solution, thereby producing a hollow fiber membrane of ECTFE The rejection rate was maintained while minimizing the decrease of the water permeability due to the hydrophobicity, thereby solving the above-mentioned problem.

 The step (1) above produces a spinning stock solution comprising polyethylene chlorotrifluoroethylene (ECTFE), an inorganic additive and a solvent. It is difficult to produce a homogeneous ECTFE hollow fiber because a uniform and continuous supply of raw materials is not achieved when the inorganic additive is added in the TIPS method at a temperature of 200 ° C or higher by applying a conventional extruder.

The inorganic additive is silica-based, lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), Magnesium Chloride (MgCl _2), calcium chloride (CaCl _2), magnesium sulfate (MgSO _4), lithium nitrate (LiNO _3), Titanium dioxide (TiO ₂ ) or alumina (Al ₂ O ₃ ), and the like, most preferably silica-based.

The spinning stock solution in the step (1) may further include a hydrophilic organic compound, and may be more effective in improving water permeability than when containing only an inorganic additive. The hydrophilic organic compound may be glycol-based, vinyl-based monomer or polymer, glycerol, or the like. Examples of the glycol series may include polyethylene glycol, ethylene glycol, propylene glycol, diethylene glycol, triacetin, and polyoxazoline. Examples of the vinyl monomer or the polymer include polyvinyl pyrrolidone, ethylene vinyl acetate (EVA) Alcohol, and the like. The hydrophilic organic compound is most preferably an EVA-based compound such as ethylene vinyl acetate (EVA).

The solvent of step (1) is not particularly limited as long as ECTFE and the hydrophilic additive are completely dissolved uniformly without forming a precipitate, and more preferably N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide , Dimethylformamide, triacetin, dibutyl phthalate or dioctyl phthalate, and the like.

If the temperature is lower than 100 ° C, the ECTFE is not dissolved and the hollow fiber membrane may not be produced. When the temperature exceeds 200 ° C, it is difficult to produce a hollow fiber having a low pore size .

The spinning stock solution in the step (1) may include 10 to 70 parts by weight of ECTFE and 0.5 to 50 parts by weight of the inorganic additive, based on 100 parts by weight of the solvent. If the ECTFE is less than 10 parts by weight, the viscosity may be too low to produce the hollow fiber. If the ECTFE is more than 70 parts by weight, the viscosity of the ECTFE is too high, which makes it difficult to discharge the mixture through the spinneret. If the amount of the inorganic additive is less than 0.5 part by weight, the water permeability can not be improved. If the amount is more than 50 parts by weight, the mechanical strength of the hollow fiber membrane is decreased.

The hydrophilic organic compound may further comprise 0.5 to 49 parts by weight based on 100 parts by weight of the solvent. If the amount of the hydrophilic organic compound is less than 0.5 parts by weight, the water permeability can not be improved. If the amount is more than 49 parts by weight, the mechanical strength of the hollow fiber membrane may decrease.

In the step (2), the spinning stock solution is spun through a spinning nozzle at a temperature of 100 to 200 ° C. The spinning stock solution may be manufactured outside the spinning nozzle and introduced into the spinning nozzle, or may be formed inside the spinning nozzle. If the temperature of the spinning nozzle is less than 100 ° C, the ECTFE does not dissolve and the hollow fiber membrane may not be manufactured. If the temperature exceeds 200 ° C, it is difficult to produce a hollow fiber having a low pore size.

The spinning nozzle may be a double tubular spinning nozzle, and Fig. 1 is a sectional view of a double tubular spinning nozzle 5 for discharging the spinning solution. The spinning stock solution in the step (1) may be discharged to the outer tube 2 of the double tubular spinning nozzle 5 and the inner coagulant may be simultaneously discharged to the inner tube 1 of the double tubular spinning nozzle.

The internal coagulant is used for internal hollow formation and is not particularly limited as long as it is uniformly mixed with ECTFE and can be mixed at the time of immersion in an external coagulating liquid. More preferred are polyethylene glycol, ethylene glycol, propylene glycol, diethylene Glycol series such as glycol, glycerol, N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide or dimethylformamide.

In addition, the spinning nozzle may be a triple tubular spinning nozzle, and FIG. 2 shows a cross-sectional view of a triple tubular spinning nozzle 10. In the case of the triple tubular spinning nozzle 10, the spinning stock solution of the step (1) is discharged to the intermediate tube 12 of the triple tubular spinning nozzle, the inner coagulant is discharged to the inner tube 11, Examples of the tube 13 include a glycol series such as polyethylene glycol, ethylene glycol, propylene glycol and diethylene glycol, glycerol, N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide or dimethylformamide can do. The above-mentioned solvent for discharging to the outermost pipe 13 may further contain ECTFE in an amount of 15 parts by weight or less based on 100 parts by weight of the solvent. When ECTFE is contained in an amount exceeding 15 parts by weight, the surface is formed with a layer, and the permeability can be drastically reduced.

In the step (3), the hollow fiber is discharged or immersed in an external coagulating solution to form a hollow fiber membrane.

The external coagulating liquid is not particularly limited as long as it can exchange substances with the spinning stock solution, but it is more preferable to use glycol based materials such as polyethylene glycol, ethylene glycol, propylene glycol and diethylene glycol, water, N-methylpyrrolidone, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, glycerol, and the like. The temperature of the external coagulating solution is preferably from -10 to 120 ° C. If the temperature is lower than -10 ° C., the process unit cost increases sharply. If the temperature exceeds 120 ° C., the phase separation of the hollow fiber is delayed, There is a drawback that it becomes impossible.

The air gap, which is the distance from the spinning nozzle to the surface of the external coagulating liquid, can be from 0 to 15 cm. In the case of 0 to 5 cm, it is preferable to discharge through a double tubular spinning nozzle, and in the case of 5 to 15 cm, it is preferable to discharge through a triple tubular spinning nozzle. When the air gap exceeds 15 cm, the linear velocity of the spinning liquid discharged from the spinning nozzle sharply increases and the time for staying in the external coagulating liquid is insufficient so that the length of the coagulating bath containing the external coagulating liquid should be long There is a disadvantage in that it is inefficient in space and production unit cost due to a problem.

The hollow fiber formed in the step (3) can be wound and drawn. It can be stretched at a draw ratio of 1.1 to 5.0 times the natural take-up speed by solution discharge. If the stretching ratio is less than 1.1 times, the effect of pore control and strength increase due to stretching is insufficient. If the stretching ratio is more than 5.0 times, there is a problem that the mechanical properties are deteriorated due to the occurrence of cutting or film thickness reduction.

The secondary stretching can be performed after winding and drawing the drawn hollow fiber. The secondary stretching after winding can be performed at a stretching temperature of 15 to 150 DEG C at a stretching ratio of 1.1 to 5.0 times the hollow fiber length. When the stretching ratio is less than 1.1 times, the effect of increasing the strength due to the second stretching is insufficient. When the stretching ratio is more than 5.0 times, it is difficult to maintain the hollow structure and it is difficult to form a uniform pore.

The secondary elongating solution is not particularly limited as far as it is a non-solvent mixture for the spinning liquid solvent in the step (1), but more preferably glycerol, ethylene glycol, polyethylene glycol having a molecular weight of 400 or less, or water.

The secondary elongation after winding can be stretched at a stretching speed of 0.5 to 20 m / min. When the elongation is less than 0.5 m / min, the productivity is lowered. When the elongation is more than 20 m / min, Is too large.

The secondary elongated hollow fiber can be immersed in an alkali solution to induce hydrophilization. The alkali solution decomposes the added inorganic additive to form a free volume in the membrane structure to increase the porosity and porosity of the membrane. The alkali solution further contacts the hydrophilic organic compound to form a hydroxyl group (-OH) in the structure Thereby increasing the interfacial tension in the membrane. The alkali solution may be prepared by dissolving NaOH, KOH, or the like in a solvent such as water, methanol, ethanol, isopropanol or acetone, and the pH of the alkali solution of the alkali solution may be 10 or more. When the PH of the alkali solution is less than 10, the hydrophilization induction reaction may not occur.

The alkali solution is adjusted to 15 to 90 占 폚 and can be dipped for 5 minutes or more to induce hydrophilization. When the temperature of the alkali solution is less than 15 ° C, the hydrophilicization induction reaction is not easy, and when the temperature exceeds 90 ° C, three-dimensional shrinkage of the film may occur. When immersed in an alkali solution for less than 5 minutes, induction of hydrophilization does not sufficiently take place, so that an efficient process can not be achieved.

The ECTFE hollow fiber membrane prepared by the above-described method may contain an inorganic additive in polyethylene chlorotrifluoroethylene (ECTFE). The inorganic additive is silica-based, lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), Magnesium Chloride (MgCl _2), calcium chloride (CaCl _2), magnesium sulfate (MgSO _4), lithium nitrate (LiNO _3), Titanium dioxide (TiO ₂ ), alumina (Al ₂ O ₃ ), and the like, and most preferably silica-based.

The ECTFE hollow fiber membrane may further include a hydrophilic organic compound. The hydrophilic organic compound may be a glycol-based monomer, a vinyl monomer, a polymer, or a glycerol. Examples of the glycol series may include polyethylene glycol, ethylene glycol, propylene glycol, diethylene glycol, triacetin, and polyoxazoline. Examples of the vinyl monomer or the polymer include polyvinyl pyrrolidone, ethylene vinyl acetate (EVA) Alcohol, and the like. The hydrophilic organic compound is most preferably an EVA-based compound such as ethylene vinyl acetate (EVA).

The inorganic additive may include 0.1 to 30 parts by weight based on 100 parts by weight of polyethylenechlorotrifluoroethylene (ECTFE), and 0.1 to 94 parts by weight of the hydrophilic organic compound.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

≪ Example 1 >

74% by weight of N, N-dimethylacetamide, 25% by weight of ECTFE polymer (Halar XPH-793, Solvay) and 1% by weight of hydrophobic silica as a solvent were mixed to prepare a homogeneous polymer solution at 150 ° C.

The bubbles contained in the polymer solution were removed using a vacuum pump, and then transferred to a triple-tubular nozzle maintained at 150 ° C by using a gear pump. Then, 100% of glycerol was discharged at 8 ml / min at the outermost portion of the nozzle, and the air gap was fixed at 5 cm. Further, a mixed solution of 60% by weight of N, N-dimethylacetamide and 40% by weight of diethylene glycol was discharged as an internal coagulant.

The discharged liquid was subjected to solidification through a coagulation tank maintained at a constant temperature of 80 ° C to prepare an ECTFE hollow fiber having an outer diameter of 1.0 mm and an average pore size of 0.03 μm.

≪ Examples 2 to 4 >

ECTFE hollow fiber was prepared in the same manner as in Example 1 except that the solvent used was changed to N-methylpyrrolidone, dimethylsulfoxide, and dimethylformamide, respectively.

≪ Example 5 >

An ECTFE hollow fiber was produced in the same manner as in Example 1, except that the solvent used was mixed at a ratio of N-methylpyrrolidone and N, N-dimethylacetamide in a volume ratio of 1: 1.

≪ Example 6 >

The formation of the spinning solution and the ECTFE hollow fiber were carried out in the same manner as in Example 1 except that the spinning temperature was changed to 120 캜.

≪ Example 7 >

The ECTFE hollow fiber was prepared in the same manner as in Example 1 except that the spinning solution was formed and the spinning temperature was changed to 180 ° C and the solvent was changed to N-methylpyrrolidone.

≪ Example 8 >

An ECTFE hollow fiber was produced in the same manner as in Example 1 except that titanium dioxide was used instead of silica.

≪ Example 9 >

A mixture of 60 wt% of N, N-dimethylacetamide, 20 wt% of ECTFE polymer (Halar XPH-793, Solvay), 17 wt% of diethylene glycol, 2 wt% of ethylene vinyl alcohol and 1 wt% of hydrophobic silica The ECTFE hollow fiber was produced in the same manner as in Example 1.

≪ Example 10 >

An ECTFE hollow fiber was produced in the same manner as in Example 9, except that ethylene vinyl acetate was used instead of ethylene vinyl alcohol.

≪ Comparative Example 1 &

ECTFE hollow fiber was prepared in the same manner as in Example 1 except that 75% by weight of N, N-dimethylacetamide and 25% by weight of ECTFE polymer (Halar XPH-793, Solvay) were used as a solvent.

≪ Comparative Example 2 &

The ECTFE hollow fiber was produced in the same manner as in Example 1 except that the mixing temperature and the nozzle temperature were changed to 220 ° C.

<Experimental Example>

The pure water permeability and rejection rate of the hollow fiber membranes prepared in Examples 1 to 10 and Comparative Examples 1 and 2 were measured by the following methods, and the results are shown in Table 1.

1. Measurement of pure water permeability

The hollow fiber membrane module thus prepared was supplied with pure water at room temperature at 2.0 atmospheres on one side of the module by DEAD-END method, and the amount of permeated water was measured

After which the permeation amount per unit time, unit membrane area, and unit pressure was calculated.

2. Measurement of rejection rate

BSA (bovine serum albumin, Aldrich, Mw 66,000) was added to pure water at room temperature

To prepare an aqueous solution having a concentration of 1,000 ppm. The aqueous solution was supplied to one side of the manufactured hollow fiber membrane module at a pressure of 2.0 kg / cm ² , and the BSA concentration dissolved in the permeated aqueous solution and the initially supplied raw water was measured using an ultraviolet spectrophotometer (Cary-100) Respectively.

Thereafter, the relative ratio of the absorption peaks measured at a wavelength of 278 nm was calculated using the following equation

The BSA exclusion rate was determined as a percentage.

Excretion rate (%) = (concentration of the raw liquid - permeation concentration) / (concentration of the raw liquid) x 100

division menstruum Temperature
(° C) Hydrophilic additive Pure permeability
(l / m ² hr) Average pore size (μm) BSA exclusion rate
(%) abandonment weapon Example 1 N, N-dimethylacetamide 150 - Silica 350 0.03 97.7 Example 2 N-methylpyrrolidone 150 - Silica 540 <0.03 97.9 Example 3 Dimethyl sulfoxide 150 - Silica 760 0.06 84.7 Example 4 Dimethylformamide 150 - Silica 850 0.25 48.3 Example 5 N-methyl pyrrolidone,
N, N-dimethylacetamide 150 - Silica 395 0.08 80.45 Example 6 N, N-dimethylacetamide 120 - Silica 200 0.03 95.4 Example 7 N, N-dimethylacetamide 180 - Silica 550 0.11 67.3 Example 8 N, N-dimethylacetamide 150 - Titanium dioxide 380 0.19 60.6 Example 9 N, N-dimethylacetamide 150 Diethylene glycol, ethylene vinyl alcohol Silica 1,075 0.06 90 Example 10 N, N-dimethylacetamide 150 Diethylene glycol, ethylene vinyl acetate Silica 2,170 0.1 96.1 Comparative Example 1 N, N-dimethylacetamide 150 - - 150 <0.03 99.9 Comparative Example 2 N, N-dimethylacetamide 220 Diethylene glycol, ethylene vinyl alcohol Silica 6,840 1.8 0

 As shown in Table 1, Examples 1 to 10 in which the inorganic additive was mixed showed a significantly higher pure water permeability than the Comparative Example in which the inorganic additive was not mixed. In Examples 1 to 10, it can be seen that the BSA elimination rate is maintained at a high level while the pure water permeability is remarkably increased as compared with the Comparative Example.

More specifically, in Examples 1 to 7, silica was used as the inorganic additive in different kinds of solvents or spinning temperatures. As compared with the comparative example in which the inorganic additive was not mixed, the pure water permeability was remarkably improved and the BSA elimination rate Was still high.

 Example 8 using titanium dioxide as an inorganic additive showed excellent pure water permeability, but it was found to be difficult to form dense pores as compared with Examples 1 to 7 using silica.

 It can be confirmed that the pure water permeability was further increased in Examples 9 to 10 as compared with Examples 1 to 8 in which only the inorganic additive was mixed. It was confirmed that the use of the inorganic additive and the hydrophilic organic compound mixed water- It can be seen that there is a remarkable effect. Example 10 containing ethylene vinyl acetate as a hydrophilic organic compound exhibited a higher pure water permeability than Example 9 using diethylene glycol and ethylene vinyl alcohol, and thus it was found to be most effective for improving water permeability.

 Comparative Example 2 in which a mixed solution was prepared and radiated at a temperature of 220 캜 exhibits a substantially high water permeability but does not exhibit a substantial effect on the BSA elimination ratio and thus can not function as a separator.

Claims (13)

(1) preparing a spinning solution comprising polyethylene chlorotrifluoroethylene (ECTFE), a hydrophilic organic compound, an inorganic additive and a solvent;
(2) spinning the spinning solution through a spinning nozzle at a temperature of 100 to 200 ° C to form a hollow fiber; And
(3) A method for producing an ECTFE hollow fiber membrane, which comprises immersing the hollow fiber in an external coagulating solution.
The method according to claim 1,
The inorganic additive is silica-based, lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), Magnesium Chloride (MgCl _2), calcium chloride (CaCl _2), magnesium sulfate (MgSO _4), lithium nitrate (LiNO _3), Titanium dioxide (TiO ₂ ), and alumina (Al ₂ O ₃ ).
delete The method according to claim 1,
The hydrophilic organic compound may be glycol-based, vinyl-based monomer or polymer, And glycerol. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
5. The method of claim 4,
Wherein the vinyl monomer or polymer is an ethylene vinyl acetate (EVA) based polymer.
The method according to claim 1,
The solvent of step (1) may be any one selected from the group consisting of N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, triacetin, dibutyl phthalate and dioctyl phthalate Wherein the ECTFE hollow fiber membrane is produced by a method comprising the steps of:
The method according to claim 1,
Wherein the spinning stock solution of step (1) comprises 10 to 70 parts by weight of ECTFE and 0.5 to 50 parts by weight of an inorganic additive, based on 100 parts by weight of the solvent.
The method according to claim 1,
Wherein the hydrophilic organic compound is used in an amount of 0.5 to 49 parts by weight based on 100 parts by weight of the solvent.
The method according to claim 1,
The spinning nozzle in the step (2) is a double tubular spinning nozzle,
The method for producing an ECTFE hollow fiber membrane according to claim 1, wherein the spinning stock solution of step (1) is discharged to an outer tube of a double tubular spinning nozzle, and simultaneously an inner coagulant is discharged into a tube of a double tubular spinning nozzle.
The method according to claim 1,
The spinning nozzle in the step (1) is a triple tubular spinning nozzle,
The spinning stock solution of the step (1) is discharged to an intermediate tube of a triple tubular spinning nozzle,
At the same time, the internal coagulant is discharged into the inner tube,
At the same time, discharging at least one selected from the group consisting of glycol series, glycerol series, N-methyl pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and dimethylformamide as the outermost tube. Method of manufacturing desert.
The method according to any one of claims 9 to 10,
Wherein the internal coagulant is at least one selected from the group consisting of N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, glycol series and glycerol.
The method according to claim 1,
The external coagulating solution in step (3) is any one or more selected from the group consisting of water, N-methylpyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, glycerol, By weight based on the weight of the ECTFE hollow fiber membrane.
The method according to claim 1,
Wherein the distance from the nozzle to the surface of the external coagulating liquid in the step (3) is 0 to 15 cm.

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