KR101733848B1 - Manufactured method of polymer resin composition having increasing hydrophilicity and mechanical strength for preparing of filter membrane - Google Patents

Abstract

Specifically disclosed is a polymer resin composition for improving the physical strength of a hydrophilic polymeric filtration membrane. More specifically, it relates to a polymeric resin composition for improving the physical strength of a hydrophilic polymeric filtration membrane, A polymer resin composition for producing a filter membrane and a method for producing a polymer filter membrane using the same are disclosed. (A) preparing a polymer solution by mixing a hydrophobic polymer base resin, a first solvent and a hydrophilic organic additive; (b) preparing a hydrophilic inorganic additive in the form of a sol; And (c) adding the hydrophilic inorganic additive to the polymer solution. The present invention also provides a method for producing a polymeric filter membrane using the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a polymeric resin composition for producing a filter film having improved hydrophilicity and mechanical strength,

The present invention relates to a method for producing a polymer resin composition for producing a filter membrane, and more particularly, to a method for producing a polymer resin composition for producing a filter membrane having improved hydrophilicity and mechanical strength.

A polymer filter membrane is used for separation of liquid or gas in various fields such as medicine field, semiconductor field, battery field, biotechnology field, dairy product, beverage and food field, and water treatment field.

The polymer filtration membrane is an important factor for determining the efficiency and economical efficiency of the separation process of the material. Examples of the polymer filtration membrane include a sintered membrane obtained by injecting and sintering polymer particles into a mold, a crystalline polymer film or a hollow fiber A stretched film for imparting porosity or a thermally induced phase change film prepared by mixing a polymer film with a thin film at a temperature higher than the melting point of the polymer or a tracking etching film prepared by irradiating the polymer film with radiation and immersing it in an etching solution, And a phase change film formed by a solvent exchange method formed by immersing a homogeneous solution containing a resin in a non-solvent.

At present, a solvent exchange method is mainly used to commercially manufacture a microfiltration membrane or an ultrafiltration membrane. Recently, a method of casting a polymer solution and precipitating it in a non-coagulating tank (Nonsolvent Induced Phase Separation) has been used.

On the other hand, as the porous polymer membrane, polymers such as polysulfone, polyethersulfone, cellulose acetate, and polyvinylidene fluoride are usually used. Polymers other than cellulose acetate are hydrophobic polymers, and the accumulation of microorganisms or suspended substances lowers filtration performance and shortens the service life. For this purpose, a hydrophilic polymer is prepared by a non-solvent-derived phase transformation process to increase the hydrophilicity and to have a high permeation flux, but it has a weak physical strength and is easily broken or damaged for long-term use .

Korean Patent Publication No. 2007-0072120 discloses a method for producing hydrophilicity of an asymmetric filtration membrane by adding polymethylmethacrylate as a hydrophilic additive to a hydrophobic polymer solution. Such hydrophilization method has an advantage of being excellent in compatibility with a hydrophobic polymer and maintaining hydrophilicity almost permanently, but it is difficult to lower the physical strength of the membrane due to the low brittleness of the hydrophilic additive polymethylmethacrylate.

International Patent Publication No. 2006/006340 relates to a method for improving the hydrophilicity of a polyvinylidene fluoride film for water treatment, comprising a step of polymerizing a polyvinylidene resin, a step of adding titanium oxide and an organic liquid, , Melt-extruding the mixed composition, and extracting the solvent. However, titanium oxide, which is an inorganic additive in granular form, is detached from the polyvinylidene fluoride membrane when it is in contact with water for a long time, and the hydrophilization effect is not permanent. If the removed additive is mixed with the filtrate, There is no difficulty. In the case of titanium oxide, there is a problem that the economical efficiency is low as an additive for a water treatment film.

Ochoa et al. (Journal of Membrane Science, 2003, p203-211) disclose a method of improving the hydrophilicity of a polyvinylidene fluoride membrane by using a hydrophilic additive, polymethyl methacrylate, There is a problem that the hydrophilic effect is less than the addition amount of the methyl methacrylate additive and the mechanical strength of the membrane is lowered.

Yu et al. (Journal of Membrane Science, 2009, p257-265.) Disclose a method of improving the hydrophilicity and physical strength of a polyvinylidene fluoride hollow fiber membrane using silicon oxide as an inorganic additive , There is a problem that the addition amount of silicon oxide which can improve the mechanical stability and hydrophilicity of the film is limited.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a polymer resin composition for manufacturing a filter membrane capable of improving the physical strength of a hydrophilic polymeric filtration membrane. Specifically, the present invention not only improves physical strength of a hydrophilic polymeric filtration membrane, And to provide a method for producing a polymeric filter membrane using the polymeric resin composition for the production of a filter membrane using an additive that is used to have a higher hydrophilicity.

According to an aspect of the present invention, there is provided a method of preparing a polymer solution, comprising: (a) preparing a polymer solution by mixing a hydrophobic polymer base resin, a first solvent, and a hydrophilic organic additive; (b) preparing a hydrophilic inorganic additive in the form of a sol; And (c) adding the hydrophilic inorganic additive to the polymer solution. The present invention also provides a method for producing a polymeric resin composition for producing a filter membrane.

The polymer solution comprises 1 to 50% by weight of the hydrophobic polymer base resin, 1 to 80% by weight of the first solvent, and 0.01 to 50% by weight of the hydrophilic organic additive. do.

The hydrophobic polymer base resin may be selected from the group consisting of polyethersulfone (PES), polysulfone (PSf), polyethercetone (PEK), polyetherketone (PEEK), sulfonated polymer, polyvinylidene fluoride PVDF), polytetrafluoroethylene (PTFE), polyvinylidene chloride (PVDC), chlorinate polyvinyl chloride (CPVC), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and ethylene chlorotrifluoro Ethylene (ECTFE). The present invention also provides a method for producing a polymeric resin composition for producing a filter membrane.

The hydrophilic organic additive may be at least one selected from the group consisting of polyacrylonitrile (PAN), polyethylene oxide (PEO), polyvinyl acetate (PVAc), polyvinyl alcohol (PVA), polymethylmethacrylate (PMMA), polypropylene glycol And at least one selected from the group consisting of polyethylene oxide-polypropylene oxide block copolymer (PEO-PPO-PEO).

The hydrophilic inorganic additive is added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polymer solution.

The hydrophilic inorganic additive is at least one selected from the group consisting of titania (TiO ₂ ), silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zinc oxide (ZnO), and zirconia (ZrO ₂ ) A method for producing a polymer resin composition for producing a filter membrane is provided.

And the step (b) is performed by mixing a silica precursor and a second solvent.

The silica precursor may be at least one selected from the group consisting of tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), trimethoxymethylsilane (MTMS), and dimethyldiethoxysilane (DMDEOS) A method for producing a polymer resin composition for producing a filter membrane is provided.

According to another aspect of the present invention, there is provided a method for preparing a polymeric resin composition, And a non-solvent-derived phase transformation step of precipitating the applied polymer resin composition into a non-solvent.

And the filtration membrane has a flat membrane type or hollow fiber type structure.

According to the present invention, a hydrophilic organic additive is mixed with a hydrophobic organic base additive to improve the hydrophilic property of a filtration membrane. In addition, in order to improve hydrophilicity and physical strength, a hydrophilic organic additive is mixed with a hydrophilic organic additive in a hydrophobic polymer base resin, The hydrophilization ability is improved not only in the case of adding the existing hydrophilic organic additive but also in maintaining the physical strength and also in the case of operating the long term membrane A method for producing a polymeric resin composition for manufacturing a filter membrane and a method for producing a polymeric filter membrane using the same can be provided.

1 is a graph showing the results of X-ray diffraction analysis of polyvinylidene fluoride membranes prepared according to Examples 2 and 3 and Comparative Examples 1 and 2 of the present invention,
2 is a photograph showing the results of optical microscope measurement of polyvinylidene fluoride hollow fiber membranes prepared according to Example 4 and Comparative Example 3 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Throughout the specification, when an element is referred to as "including " an element, it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

The present inventors have found that, in the case of using a hydrophilic inorganic additive added for improving hydrophilicity and an inorganic additive added for mechanical strength improvement in the polymer resin composition for producing a filter membrane, hydrophilicity and mechanical strength improvement are difficult to be compatible with each other, As a result of the research, it has been found that when the hydrophilic inorganic additive is added to a polymer solution mixed with a hydrophilic organic additive in the form of a sol, the hydrophilicity is further increased while maintaining the mechanical strength.

Accordingly, the present invention provides a method for preparing a polymer solution, comprising: (a) preparing a polymer solution by mixing a hydrophobic polymer base resin, a first solvent, and a hydrophilic organic additive; (b) preparing a hydrophilic inorganic additive in the form of a sol; And (c) adding the hydrophilic inorganic additive to the polymer solution.

The step (a) is a step of preparing a polymer solution containing a hydrophobic polymer base resin. The polymer base resin is a place where pores are formed, forming a basic skeleton of a filtration membrane produced from a polymer resin composition to be finally produced.

The polymeric base resin may be a conventional polymer resin applied to a filtration membrane such as a microfiltration membrane or an ultrafiltration membrane in the technical field to which the present invention belongs. The polymeric resin may be, for example, polyethersulfone (PES), polysulfone (PSf) (PEK), polyisothiocarbonate (PEEK), sulfonated polymer, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) Polyvinylidene fluoride (PVDF-HFP), ethylene chlorotrifluoroethylene (ECTFE) and the like may be applied, and polyvinylidene fluoride (PVDF), preferably polyvinylidene fluoride Can be applied. The polyvinylidene fluoride (PVDF) may have a weight average molecular weight of 50,000 to 2,000,000.

In the present invention, the polymer base resin may be contained in the polymer solution in an amount of 1 to 50 wt%, preferably 5 to 40 wt%. In other words, in consideration of the mechanical properties of the polymeric filtration membrane prepared using the polymeric resin composition according to the present invention, and the difficulty in controlling the pore shape and the distribution of the polymeric base resin, Is advantageously controlled in the above-mentioned range.

The first solvent ensures that the polymer solution has an appropriate viscosity and that the polymer base resin can be sufficiently dissolved. Examples of such a first solvent include dimethylacetamide (DMAc), dimethylformamide (DMF), N-methyl-pyrrolidinone (NMP), N-octyl-pyrrolidinone, N-phenyl-pyrrolidinone, (DMSO), sulfolane, catechol, ethyl lactate, acetone, ethyl acetate, butyl carbitol, monoethanolamine, butyrolactone, diglycolamine,? -Butyrolactone, tetrahydrofuran The organic solvent is preferably selected from the group consisting of alcohols, ethers, alcohols, ethers, alcohols, ethers, alcohols, ethers, alcohols, ethers, alcohols, mates, diethyl ether, ethyl benzoate, acetonitrile, ethylene glycol, glycerol, dioxane, methylcarbitol, monoethanolamine, Perfluoro-1, 2-dimethylcyclohexane, and perfluorohexane (type) may be used singly or in combination of two or more. (DMAc), dimethylacetamide (DMAc), dimethylacetamide Formamide (DMF), N- methyl-pyrrolidinone (NMP), there are dimethyl sulfoxide (DMSO) or sulfolane can be used.

In the present invention, the first solvent may be contained in the polymer solution in an amount of 1 to 80 wt%, preferably 10 to 70 wt%, and more preferably 20 to 60 wt%. That is, the polymer base resin contained in the polymer solution can be sufficiently dissolved, while giving a proper viscosity required for the production of the polymeric filtration membrane and taking into consideration the difficulty in control of the pore shape and distribution, 1 < / RTI > solvent is advantageously controlled in the above-mentioned range.

The hydrophilic organic additive is added for hydrophilizing the hydrophobic polymer base resin. The hydrophilic organic additive may include components commonly used in the technical field of the present invention, such as polyacrylonitrile (PAN), polyethylene oxide (PEO), polyvinyl Polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polypropylene glycol (PPG) and polyethylene oxide-polypropylene oxide block copolymer (PEO-PPO-PEO) And preferably polymethylmethacrylate (PMMA) can be used.

In the present invention, the hydrophilic organic additive may be contained in the polymer solution in an amount of 0.01 to 50% by weight, preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight. If the content of the hydrophilic organic additive is less than 0.01% by weight, the degree of hydrophilization of the polymer base resin may be insufficient. If the content of the hydrophilic organic additive exceeds 50% by weight, the mechanical strength of the produced filtration membrane may be decreased.

The steps (b) and (c) may include adding a hydrophilic inorganic additive to the polymer solution to maintain the physical strength of the filtration membrane added to the polymer solution and further improve the hydrophilization ability. In the invention, a hydrophilic inorganic additive is prepared in a sol form and added to the polymer solution.

The content of the hydrophilic inorganic additive is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, most preferably 0.1 to 1 part by weight based on 100 parts by weight of the polymer solution. If the content of the hydrophilic inorganic additive is less than 0.01 part by weight, the effect on the hydrophilicity and physical strength of the membrane may be insufficient. If the content of the hydrophilic inorganic additive exceeds 10 parts by weight, the compatibility with the hydrophilic organic additive may decrease, It is very important to adjust the content of the hydrophilic inorganic additive appropriately.

Examples of such a hydrophilic inorganic additive include titania (TiO ₂ ), silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zinc oxide (ZnO) and zirconia (ZrO ₂ ) ₂ ) may be used.

As a preferred example of a method for producing a hydrophilic inorganic additive in the form of a sol, a silica sol can be prepared by mixing a silica precursor and a second solvent. As the silica precursor, tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), trimethoxymethylsilane (MTMS) and dimethyldiethoxysilane (DMDEOS) may be used. As the second solvent, Ethanol, hydrochloric acid, distilled water or the like may be used alone or in combination.

It is important that the silica precursor is uniformly dispersed in the polymer solution. In the present invention, when the content of the silica sol is 50 to 70% by weight of the silica precursor, 20 to 40% by weight of ethanol and 5 to 20% by weight of distilled water, Respectively.

On the other hand, the polymer resin composition may further include an additive in order to control physical properties and uses of the polymer membrane to be produced, and the shape and size of the pores formed on the surface or inside of the membrane. The additives may include conventional components capable of achieving such a purpose. Examples of the additives include polyethylene glycol, polyoxyethylene-polyoxypropylene block copolymer, polyvinylpyrrolidone (PVP), lithium chloride (LiCl), lithium perchlorate (LiClO ₄ ), methanol, ethanol, isopropanol, acetone, phosphoric acid, propionic acid, acetic acid, pyridine, polyvinylpyridine and the like. The content of the additive may be adjusted in consideration of the above-mentioned object, and may be preferably 0.1 to 50 parts by weight, more preferably 1 to 20 parts by weight based on 100 parts by weight of the polymer solution.

According to another embodiment of the present invention, there is provided a method for producing a polymeric resin composition, comprising the steps of: And a non-solvent-derived phase transformation step of precipitating the applied polymer resin composition into a non-solvent.

The polymeric resin composition may be applied on a predetermined substrate in a thickness of 10 to 300 탆, preferably in a thickness of 50 to 250 탆.

The step of applying the polymer resin composition onto the substrate can be applied without limitation to a coating or coating method of a conventionally known polymer resin. For example, in the step of applying the polymer resin composition, it is possible to uniformly coat the entire surface of the base material by using a casting knife applying device that performs line injection.

As the substrate to be used for coating, a nonwoven fabric, a polyester resin, a polyethylene resin, a polypropylene resin, a cellulose acetate, or a resin blended therewith may be used. Further, the base material may have various forms depending on the specific form or characteristics of the filtration membrane to be produced. Specifically, the base material may have a flat membrane type or a hollow fiber type structure.

The non-solvent-derived phase change step is a step of forming a film according to the coagulation treatment, wherein the applied polymer resin composition is precipitated in a non-solvent to form an inner pore and a film. As the coagulation solvent to be used, various organic solvents, water, glycols and the like which do not dissolve the polymer membrane may be used, and preferably a coagulation solvent in which water, water and an organic solvent, or water and glycols are mixed can be used , More preferably water may be used. The temperature of the coagulation solvent used is preferably 0 to 90 ° C, more preferably 5 to 50 ° C, and most preferably 10 to 30 ° C.

The method for producing a polymeric filtration membrane may further include washing and drying the resultant product of the non-solvent-derived phase transformation step. Specifically, the resultant non-solvent-derived phase transformation step is washed with a solvent that does not dissolve and then dried at a constant temperature to finally obtain a polymeric filtration membrane. For washing, acetone, methanol, ethanol, water and the like can be used, and preferably water at 20 to 90 ° C can be used. Further, after washing, the resultant is dried at a temperature of 20 to 200 ° C, preferably 40 to 100 ° C, to finally obtain a microporous polymeric filtration membrane.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, the following examples are illustrative of the present invention, and the present invention is not limited to the examples described below.

Example  One

(TEOS), 27% by weight of ethanol, 0.5% by weight of hydrochloric acid and 10.5% by weight of distilled water at 60 to 70 ° C to prepare a silica sol as a hydrophilic inorganic additive. On the other hand, in order to prepare the polymer solution, 11% by weight of polyvinylidene fluoride (PVDF), 86% by weight of dimethylacetamide (DMAc) as a solvent and 3% by weight of polymethylmethacrylate (PMMA) as a hydrophilic organic additive Were mixed to prepare a polymer solution. The polymer solution was added to the prepared polymer solution in an amount of 0.1 part by weight based on 100 parts by weight of silica sol to prepare a polymer resin composition. The polymeric resin composition was cast while controlling the thickness of the casting knife to 200 占 퐉 while maintaining the polymeric resin composition at 25 占 폚 and precipitated in water (20 占 폚) for 12 hours to form a polymer membrane. The polymer membrane thus formed was washed with distilled water at 30 占 폚 for 1 to 2 hours Washed and then dried in a dry oven at 25 DEG C for 24 hours to prepare a final polyvinylidene fluoride membrane.

Example  2

A polyvinylidene fluoride membrane was prepared in the same manner as in Example 1, except that silica sol was added in an amount of 1 part by weight in Example 1.

Example  3

A polyvinylidene fluoride membrane was prepared in the same manner as in Example 1, except that silica sol was added in an amount of 3 parts by weight in Example 1.

Example  4

A double layer hollow fiber membrane was prepared as follows.

40% by weight of polyvinylidene fluoride (PVDF), 44.5% by weight of gamma-butyrolactone, 10% by weight of N-methylpyrrolidone (NMP), 50% by weight of ethylene glycol EG), 3% by weight of polyvinylpyrrolidone (PVP), and 0.5% by weight of lithium chloride (LiCl).

The polymer resin composition for surface layer was prepared by mixing 11% by weight of polyvinylidene fluoride (PVDF), 86% by weight of dimethylacetamide (DMAc) as a solvent and 3% by weight of polymethylmethacrylate (PMMA) as a hydrophilic organic additive 1 part by weight of silica sol as a hydrophilic inorganic additive prepared by the same method as in Example 1, 10 parts by weight of polyvinylpyrrolidone (PVP) and 1 part by weight of lithium chloride (LiCl) were added to 100 parts by weight of the polymer solution, Respectively.

The inner hole forming bore solution was prepared by mixing dimethylacetamide (DMAc) and ethylene glycol (EG) in a weight ratio of 6: 4 and at room temperature.

The polymer solution for the support layer was discharged through a nozzle at 140 캜 through a thermal induction phase transfer method, and the polymer resin composition for a surface layer was discharged from a nozzle at room temperature through a nozzle at the same time as a nonwoven phase transfer method together with a bore solution. The amount of spinning discharge was set to be 3: 1: 2 ratio of support layer: coating layer: inner hole. The hollow fiber membrane thus formed was immersed in a coagulation bath of distilled water at 5 ° C, washed with distilled water at 40 ° C for 12 hours, and dried for 24 hours to prepare a final polyvinylidene fluoride hollow fiber membrane.

Comparative Example  One

A polyvinylidene fluoride membrane was prepared in the same manner as in Example 1, except that the hydrophilic organic additive was not added in Example 1 and 14 wt% of polyvinylidene fluoride (PVDF) was used.

Comparative Example  2

A polyvinylidene fluoride membrane was prepared in the same manner as in Example 1, except that no silica sol was added in Example 1.

Comparative Example  3

A polyvinylidene fluoride hollow fiber membrane was prepared in the same manner as in Example 4 except that no silica sol was added in the polymer resin composition for a surface layer of Example 4.

Comparative Example  4

35% by weight of polyvinylidene fluoride (PVDF) and 49.5% by weight of gamma-butyrolactone were contained in the polymer solution for the support layer of Example 4, and the amount of polyvinylpyrrolidone A polyvinylidene fluoride hollow fiber membrane was produced in the same manner as in Example 4 except that 15 parts by weight of PVP was added and 1 part by weight of tetraethoxysilane (TEOS), which is a precursor instead of silica sol, was added. Respectively.

The composition of the polymer resin composition used in the above Examples and Comparative Examples is summarized in Table 1 below.

Test Example  One

In order to measure the degree of hydrophilization of the surface of the polyvinylidene fluoride resin film prepared according to Examples 1 to 4 and Comparative Examples 1 to 4, the contact angle was measured with a contact angle meter (Phoenix 300 touch, Inc.) The results are shown in Table 2 (flat membrane) and Table 3 (hollow fiber membrane).

As shown in Table 2, in the case of the initial contact angle, the polyvinylidene fluoride membrane prepared according to Examples 1 to 3 in which silica sol as a hydrophilic inorganic additive was added was compared with Comparative Example 2 in which silica sol as a hydrophilic inorganic additive was not added The contact angle is measured to be low and hydrophilicity is improved. As the content of silica sol as a hydrophilic inorganic additive increases, the contact angle decreases and hydrophilicity improves. This shows that the hydrophilic polyvinylidene fluoride film improved in hydrophilicity by the hydrophilic organic additive, polymethyl methacrylate (PMMA), was further improved in hydrophilicity by the hydrophilic inorganic additive, silica sol.

The polyvinylidene fluoride membrane prepared according to Comparative Example 1 in which silica sol as a hydrophilic inorganic additive and polymethylmethacrylate (PMMA) as a hydrophilic organic additive were not added was used as a hydrophilic organic additive, polymethylmethacrylate PMMA) was added, hydrophilicity was lowered due to a high contact angle. This is because the hydrophilic inorganic additive silica sol and the hydrophilic organic additive polymethylmethacrylate (PMMA) are added at the same time to the hydrophilic inorganic additive silica sol as a single additive, It shows a lot of improvement.

In the case of the initial contact angle of the polyvinylidene fluoride double layer hollow fiber membrane prepared according to Example 4 and Comparative Example 3, as compared with Comparative Example 3 in which silica sol as the hydrophilic inorganic additive was not added as shown in Table 3, It can be seen that the contact angle of the double layer hollow fiber membrane produced according to Example 4 is reduced and the hydrophilicity is improved. In addition, the initial contact angle was increased in Comparative Example 4 prepared by adding tetraethoxysilane (TEOS), which is a precursor for preparing silica sol, as an inorganic additive. This indicates that tetraethoxysilane (TEOS) is unsuitable as a hydrophilic inorganic additive, and that the silica sol form prepared using this as a precursor helps improve hydrophilicity.

On the other hand, it can be seen that the contact angle is generally lower than that of Example 2 made of a flat membrane by adding silica sol which is the same hydrophilic inorganic additive. This is because a small amount of the hydrophilic inorganic additive and hydrophilic organic additive were lost due to the high temperature of the support layer discharged by the heat induction phase transfer method in the process of discharging the double layer hollow fiber membrane through the nozzle.

Test Example  2

In order to measure the pure water permeation flux of the polyvinylidene fluoride membrane produced by Examples 1 to 3 and Comparative Examples 1 and 2, the average value of the pure water permeation flux was measured at a vacuum of 0.1 bar using a circular porous plate having a diameter of 40 mm , And the results are shown in Table 2 above.

The permeation flux of Examples 1 and 2 in which silica sol was added was increased compared to the permeation flux of the polyvinylidene fluoride membrane prepared according to Comparative Example 2 in which silica sol as a hydrophilic inorganic additive was not added. This is a result of the improvement of hydrophilicity of the membrane by silica sol which is a hydrophilic inorganic additive.

On the other hand, the permeation flux of the polyvinylidene fluoride membrane prepared according to Example 3 in which the content of the silica sol was 3 parts by weight or more was remarkably decreased. This is because when the content of the silica sol, which is a hydrophilic inorganic additive, exceeds a certain amount, coagulation phenomenon of silica sol occurs to block the pores of the membrane.

Test Example  3

In order to measure the pure permeate flow rate of the polyvinylidene fluoride hollow fiber membrane prepared according to Example 4, Comparative Examples 3 and 4, four hollow fiber membrane samples having an effective membrane length of 10 cm were inserted into a tubular tube, -end type membrane module was fabricated. The distilled water was introduced into the module at a pressure of 1 kg / cm 2, and the amount of water permeated to the outside from the inside of the hollow fiber membrane was measured to measure the pure permeation flux per unit area. The results are shown in Table 3 above.

The permeation flux of the polyvinylidene fluoride double layer hollow fiber membrane prepared according to Example 4 in which silica sol as a hydrophilic inorganic additive is added is higher than that of Comparative Example 3 in which silica sol is not added. It was found that the permeation flux of the double layer hollow fiber membrane produced by adding the hydrophilic organic additive, polymethyl methacrylate (PMMA), together with the hydrophilic inorganic additive silica sol, was higher than that of the double layer hollow fiber membrane prepared by adding the hydrophilic organic additive , Which is a result of the improvement of hydrophilicity of the membrane by silica sol which is a hydrophilic inorganic additive.

Test Example  4

In order to confirm the crystal structure of the polyvinylidene fluoride membranes prepared according to Examples 2 and 3 and Comparative Examples 1 and 2, X-ray diffraction analysis was performed with a radiation source of 40 kV, 20 to 30 mA and a scanning angle of 5 to 50 ° And the results are shown in Fig.

As shown in Fig. 1 (a), the crystal structure of the film prepared according to Comparative Example 1 in which polymethylmethacrylate (PMMA) as a hydrophilic organic additive was not added showed peak values of 18 °, 20 °, 26 ° and 40 ° Phase with < / RTI > However, as shown in Fig. 1 (b), the crystal structure of the film prepared by Comparative Example 2 to which polymethylmethacrylate (PMMA) as a hydrophilic organic additive was added showed a β-phase having peaks at 20 ° and 36 ° . This is because the crystal structure of polyvinylidene fluoride is changed by polymethyl methacrylate (PMMA) which is a hydrophilic organic additive.

In other words, the hydrophilicity of the polyvinylidene fluoride film is improved by the hydrophilic organic additive, polymethyl methacrylate (PMMA), while the crystalline structure of the polyvinylidene fluoride changes from? To? Phase, There is a problem. However, as shown in FIG. 1 (b), the peaks of the polyvinylidene fluoride membranes prepared according to Examples 2 and 3 prepared by adding silica sol as a hydrophilic inorganic additive were increased, And the strength can be increased.

Test Example  5

The results of measurement at 70 magnification using an optical microscope (Olympus, AHMT3-513NU) to confirm the cross-sectional structure of the polyvinylidene fluoride hollow fiber membrane produced according to Example 4 and Comparative Example 3 are shown in Fig. 2 (a) And Fig. 2 (b).

As shown in FIG. 2, the polyvinylidene fluoride double-layer hollow fiber membrane has an average outer diameter of about 1300 μm and an average inner diameter of about 700 μm, and the cross-sectional structure of the surface layer is a finger structure.

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (10)

(a) preparing a polymer solution by mixing a hydrophobic polymer base resin, a first solvent and a hydrophilic organic additive;
(b) preparing a hydrophilic inorganic additive in the form of a sol; And
(c) adding the hydrophilic inorganic additive to the polymer solution;
, ≪ / RTI &
Wherein the hydrophilic organic additive is polymethyl methacrylate (PMMA)
In step (a), at least one selected from the group consisting of polyethylene glycol, polyoxyethylene-polyoxypropylene block copolymer, polyvinylpyrrolidone (PVP), lithium chloride (LiCl), lithium perchlorate (LiClO ₄ ), methanol, ethanol, isopropanol Wherein at least one additive selected from the group consisting of Acetone, Phosphoric Acid, Propionic Acid, Acetic Acid, Pyridine and Polyvinylpyridine is further added to the polymeric resin composition. The method according to claim 1,
Wherein the polymer solution comprises 1 to 50% by weight of the hydrophobic polymer base resin, 1 to 80% by weight of the first solvent, and 0.01 to 50% by weight of the hydrophilic organic additive. The method according to claim 1,
The hydrophobic polymer base resin may be selected from the group consisting of polyethersulfone (PES), polysulfone (PSf), polyethercetone (PEK), polyetherketone (PEEK), sulfonated polymer, polyvinylidene fluoride ), Polytetrafluoroethylene (PTFE), polyvinylidene chloride (PVDC), chlorinate polyvinyl chloride (CPVC), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and ethylene chlorotrifluoroethylene (ECTFE). ≪ RTI ID = 0.0 > 11. < / RTI > delete The method according to claim 1,
Wherein the hydrophilic inorganic additive is added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polymer solution. The method according to claim 1,
Wherein the hydrophilic inorganic additive is at least one selected from the group consisting of titania (TiO ₂ ), silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zinc oxide (ZnO), and zirconia (ZrO ₂ ) (Method for producing polymeric resin composition for manufacturing). The method according to claim 1,
Wherein the step (b) is performed by mixing a silica precursor and a second solvent. 8. The method of claim 7,
Wherein the silica precursor is at least one selected from the group consisting of tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), trimethoxymethylsilane (MTMS), and dimethyldiethoxysilane (DMDEOS) (Method for producing polymeric resin composition for manufacturing). Applying the polymer resin composition of claim 1 onto a substrate; And
A non-solvent-derived phase transformation step of causing the applied polymer resin composition to precipitate in a non-solvent;
Wherein the polymer filter membrane is a polymer membrane. 10. The method of claim 9,
Wherein the filtration membrane has a flat membrane type or hollow fiber type structure.

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