KR100231262B1 - The process for producing hollow fiber membrane having an improved rewettability - Google Patents

Abstract

The present invention is 5 to 25% by weight of polysulfone (polysulfone) hydrophobic polymer, 1 to 25% of hydrophilic polymer polyvinylpyrrolidone (PVP) and 0.05 to 5% by weight of nonionic surfactant dimethylacetamide , DMAC), normal-dimethylpyrrolidone, dimethyl sulfoxide and mixtures thereof, and spun in a double tube nozzle having a diameter of 0.05 to 0.1 mm and an external diameter of 0.1 to 2 mm and solidifying with water and then hydrophilic with solvent. It relates to a method for producing a hollow fiber membrane characterized in that the polymer is extracted and then dried, by using a nonionic surfactant as in the present invention, it is possible to produce a hollow fiber membrane excellent in resorbability.

Description

Manufacturing method of hollow fiber membrane with excellent reabsorption

The present invention relates to a method for preparing a hollow fiber membrane having excellent reabsorbability and water permeability by adding and spinning a surfactant to a polymer solution (dope solution) during the preparation of the ultrafiltration membrane.

Generally, the hollow fiber membrane is a membrane in the form of a tube of about 1 mm and has a characteristic of selectively moving a material through a wall. Such hollow fiber membranes are mainly used for dialysis, hemofiltration, ultrafiltration and water treatment. The material of the hollow fiber membrane is mainly composed of hydrophobic polymers such as polysulfone and aromatic polyamide. Since hydrophobic polymers have problems in water treatment due to such hydrophobicity, studies on hydrophilization of membranes have been conducted.

For example, 12 to 20% by weight of hydrophobic polymer of polysulfone, 2 to 10% by weight of hydrophilic polymer polyvinylpyrrolidone (PVP), a polymer solution consisting of a solvent, an aprotic solvent and 25% by weight A method for producing hollow fiber membranes by wet spinning an internal coagulant consisting of a degree of water is proposed in US Pat. No. 4,906,375. However, the hollow fiber membranes produced by this method have a low hydrophilicity and a small permeate flux, so that their use is very limited.

In addition, a process of absorbing glycerin into the membrane is commonly used as a method of hydrophilizing the membrane, which is a high production cost of the membrane and requires a separate hydrophilization process, and glyceline is eluted when used to contaminate the tube. Is holding.

An object of the present invention is to solve the above problems, to solve the hydrophilization process of the hollow fiber membrane by adding a surfactant in the preparation of the polymer solution without a separate device and excellent resorption of inexpensive hollow fiber membrane It is to provide a manufacturing method.

That is, the present invention is 5 to 25% by weight of a polysulfone (polysulfone) hydrophobic polymer, 1 to 25% of a hydrophilic polymer polyvinylpyrrolidone (PVP), 0.05 to 5% by weight of a nonionic surfactant dimethylacetamide (dimethylacetamide, DMAC), normal-dimethylpyrrolidone, dimethyl sulfoxide and mixtures thereof in 50 to 85% by weight of the inner tube diameter of 0.05 to 0.1mm and the outer diameter of 0.1 to 2mm spinning in a double tube nozzle and water It relates to a method for producing a hollow fiber membrane, characterized in that after the coagulation in the solvent and the hydrophilic polymer is extracted and dried.

Hereinafter, the present invention will be described in detail.

The use of polysulfone and polypyrrolidone used to hydrophilize the hollow fiber membrane in the present invention is already known and will be omitted in the description of the present invention.

In the present invention, a low molecular weight surfactant having a molecular weight of 500 to 1000 was used in an amount of 0.05 to 5% by weight in order to hydrophilize the hollow fiber membrane to improve resorbability. The surfactant used may be selected from polyoxyethylenealkylamine, cocoamineoxide (Barlox12) and polyoxyethylene sorbitan monooleate (Tween 80) as a nonionic surfactant. Preferably polyoxyethylene sorbitan monooleat exhibits the best effect.

When the molecular weight of the surfactant is less than 500, it is easily washed off with water to lose hydrophilicity. When the molecular weight exceeds 1000, it takes a long time for the surfactant to penetrate into the hollow fiber membrane. In addition, when the content of the nonionic surfactant is less than 0.05% by weight, the hydrophilization and resorption properties desired in the present invention cannot be satisfied, and when the content of the nonionic surfactant exceeds 5% by weight, the effect is proportional to the degree of addition. The scope of the invention is most preferred since it does not increase.

The hollow fiber membrane is not particularly limited, but the hydrophobic polymer polysulfone and the hydrophilic polyvinylpyrrolidone (PVP) and the nonionic surfactant may be dimethylacetamide (DMAC), It is dissolved in 50 to 85% by weight of normal-dimethylpyrrolidone, dimethyl sulfoxide and mixtures thereof. The inner tube is 0.05 to 0.1 mm in diameter and the outer diameter is 0.1 to 2 mm. After the external coagulation in water circulating at ℃ ℃ the manufactured hollow fiber is wound on a winder. The hollow fiber wound on the winder is cut to a certain length, and then the solvent and the hydrophilic polymer are extracted and dried to prepare a hollow fiber membrane.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

17% by weight of polysulfone, 72% by weight of dimethylacetamide, 10% by weight of polyvinylpyrrolidone, prepared a polymer solution with 1% by weight of Tween 80 with a nonionic surfactant, and then the polymer solution was subjected to 10 μm of pores. Discharge into the appearance of the double pipe nozzle in an amount of 4 g / min through a ceramic filter having a. The composition of the internal coagulation solution was 70% by weight of dimethylacetamide and 30% by weight of water, and was discharged into the inner tube of the nozzle at a flow rate of 2 g / min. The nozzle was a double tube type with an inner tube diameter of 0.2 mm and an outer tube diameter of 0.5 mm. The polymer solution passed through the nozzle enters the coagulation solution through an air layer of 30 to 35 ° C., a relative humidity of 10 to 30%, and a height of 30 cm. The coagulation solution is water at 35 ° C. which is continuously circulated. The hollow fiber passed through the coagulation bath is wound on the winder at a speed of 20 m / min. After winding 1500 times, the hollow yarn is cut to 35 cm in length and immersed in a washing tank for 24 hours to purify water at 60 ° C., and then the solvent and the hydrophilic polymer are extracted. This hollow yarn is removed from the surface water in a centrifuge and then dried at a temperature of 50 ° C. in a drying furnace. The permeability and rejection rate of the hollow fiber membranes thus prepared are shown in Table 1.

Example 2

Except for increasing the concentration of the surfactant in the polymer solution from 1% to 3%, 17% by weight of polysulfone, 70% by weight of dimethylacetamide, 10% by weight of polyvinylpyrrolidone, and 3% by weight of Tween 80 Table 1 shows the water permeability and rejection rate of the hollow fiber membranes prepared in the same manner as in Example 1.

Example 3

No surfactant was added to the polymer solution. The composition was 17% by weight of polysulfone, 73% by weight of dimethylacetamide, and 10% by weight of polyvinylpyrrolidone. same. The cleaning solution in the washing tank was prepared by immersing the hollow fiber membrane bundles for 24 hours as water containing 1% of Tween 80, and washing and adsorbing a surfactant. The water permeability and rejection rate of the hollow fiber membranes are shown in Table 1.

Example 4

In the washing tank, the washing solution was prepared in the same manner as in Example 3 except that 3 wt% of Tween 80 was immersed in the bundle of the hollow fiber membrane for 24 hours to wash and adsorb the surfactant. The rates are shown in Table 1.

Comparative Example 1

The polymer solution was prepared in the same manner as in Example 1 except that 17 wt% of polysulfone, 73 wt% of dimethylacetamide, and 10 wt% of polyvinylpyrrolidone were used, and the permeability of the hollow fiber membrane Sex and exclusion rates are shown in Table 1.

Comparative Example 2

Table 1 shows the water permeability and rejection rate of the hollow fiber membranes, which were prepared in the same manner as in Example 3 except that the composition of the washing solution was used in the washing process in a 3% aqueous solution of glycerin.

Permeability and Exclusion Rate of Hollow Fiber Membranes Permeation Speed (ℓ / min ㎡atm) Exclusion rate (%) Permeability Test-Permeability Change in Dry Repeat (ℓ / min ㎡atm) Primary Secondary 3rd 4th Example 1 0.7 78 0.7 0.7 0.8 0.8 Example 2 0.8 75 0.8 0.8 0.8 0.9 Example 3 0.5 81 0.5 0.4 0.3 0.3 Example 4 0.5 78 0.5 0.5 0.4 0.3 Comparative Example 1 0.1 89 0.1 0.07 0.03 0.02 2 in comparison 0.3 83 0.3 0.2 0.1 0.06

The water permeability of the hollow fiber membrane was best in Example 1 and Example 2 prepared by adding the surfactant directly to the polymer solution, and Examples 3 and 4 in which the surfactant was absorbed by soaking the surfactant in the dissolved water was the next best. , Examples 5 and 6 without surfactants were the lowest. The reabsorptivity of the hollow fiber membrane was excellent in the reabsorption of the hollow fiber membrane prepared by adding the surfactant to the polymer solution. The permeability of the hollow fiber membranes absorbed by the surfactant in water dissolved in the activator was slightly decreased, while the permeability of the hollow fiber membranes containing no surfactant and the hollow fiber membranes absorbed by the glycerin was significantly decreased.

According to the present invention, as a result of confirming the structure of the hollow fiber membrane containing the surfactant by using a scanning microscope, the structure and the permeation amount, hydrophilicity and resorption property of the membrane having no surfactant were improved. Therefore, it can be widely used for the use of hemodialysis, blood filter, water treatment and the like.

Claims (4)

Dissolve 5 to 25% by weight of hydrophobic polymer polysulfone, 1 to 25% of hydrophilic polymer polyvinylpyrrolidone (PVP), and 0.05 to 5% by weight of nonionic surfactant in 50 to 85% by weight of aprotic solvent. A method for producing a hollow fiber membrane having excellent resorbability, characterized by spinning from a double tube nozzle and solidifying with water, followed by extracting the solvent and the hydrophilic polymer. The method of claim 1, wherein the aprotic solvent is dimethylacetamide (dimethylacetamide, DMAC), normal-dimethylpyrrolidone, dimethyl sulfoxide and the mixture of these to prepare a hollow fiber membrane having excellent resorption Way. The method of claim 1, wherein the double tube nozzle has an inner tube of 0.05 to 0.1 mm in diameter and an outer diameter of 0.1 to 2 mm in diameter. The method of claim 1, wherein the nonionic surfactant has a low molecular weight of 500 to 1000, polyoxyethylene alkylamine (polyoxyethylene alkylamine), cocoamine oxide (cocoamine oxide), polyoxyethylene sorbitan monooleate (polyoxyethylenesorbitanmonooleate) Method for producing a hollow fiber membrane having excellent resorbability, characterized in that selected from the group.