JPH04118034A - Polysulfone-based hollow yarn film and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a film having stable hydrophilic property for a long term by using a polysulfone-based hollow yarn film containing a complex of polyvinyl pyrrolidone and polyvalent acid and having a fixed value or more of permeable velocity. CONSTITUTION:Spinning raw liquid composed of a polysulfone-based resin, polyvinyl pyrrolidone, polyalkylene glycol, polyvalent acid and common solvent is spinned from an annular nozzle. Then, the polysulfone-based hollow yarn film having 50-2000Angstrom average pore diameter of fine pores on one side face, 70-85% void ratio of fine porous film and containing >=0.5wt.% the complex of polyvinyl pyrrolidone and polyvalent acid to the polysulfone-based resin and having >=500l/hr.m<2>.kg/cm<3> the permeable velocity, it obtd. The film obtd. with such a way displays the stable hydrophilic property for a long term.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polysulfone-based hollow fiber membrane and a method for producing the same. - More specifically, the present invention relates to a polysulfone-based hollow fiber membrane with excellent hydrophilicity and a method for producing the same.

[Prior Art] In recent years, techniques using selectively permeable membranes in separation operations have been put into practical use in various fields. For example, cellulose-based, polyamide-based, polyacrylonitrile-based, polyvinyl alcohol-based, polysulfone-based resins are used as the material for the mock membrane. In particular, polysulfone resins are attracting a lot of attention due to their physical and chemical properties such as heat resistance, acid resistance, alkali resistance, and oxidation resistance, and polysulfone resins are also used for separation using fat as a membrane material. One thing that has happened is that technology has made remarkable progress.

However, since polysulfone resin is a hydrophobic σ resin, it has low hydrophilicity and is a lecture material that is difficult to get wet with water.
Membranes made of polysulfone resin have a low water permeation rate.

Glossy of Apply F. Polymer Science (Vol. 20, p. 2377-2394 (1976)),
(Volume 2, p165-180 (+977)), (Volume 2
Vol. 1, p. 1883-+900 (1977)) describes a method of obtaining a membrane by spinning a spinning dope containing polyhinylviroli), as well as the structure and water permeability of the resulting pattern. 5 people are listed.

However, in the method described herein, even though polyvinylvicrytone is used, which has an effect of improving hydrophilicity, some of the polyvinylvicrytone may be eluted after film formation. If a large amount of polyvinyl vicritone is used to prevent this, it is difficult to completely prevent elution. If polyvinyl vicritone elutes, it is not only difficult to obtain stable membrane performance over a long period of time, but also increases costs.

[Problem to be Solved by the Invention J] JP-A-58-104940 describes a method of using high molecular weight polyvinylvicrytone to prevent elution of polyvinylpyrrolidone. Although this method shows an improvement in the elution of polyvinyl vicritone over the method disclosed in the Journal of Applied Polymer Science, this method does not elute polyvinyl vicritone over a long period of time. It is difficult to completely prevent this.

In addition, JP-A No. 63-97205, No. 63-97634, and No. 632241108 disclose methods for reducing the elution of polyvinylpyrrolidone, which include treatment with radiation, ultraviolet rays, or high temperature;
This method cannot necessarily be said to be industrially preferable.

Mano, Special [jJl No. 63-97202, JP-A-63
JP-A-99325 describes a method for producing a highly water permeable pattern using polyvinylpyrrolidone.

However, since the methods described in these documents contain a non-solvent for polysulfone, such as a low-boiling point liquid such as water or methanol, in the spinning dope, the spinning dope tends to become unstable, making it difficult to adopt industrially. It is.

Therefore, an object of the present invention is to provide a polysulfone hollow fiber membrane that exhibits particularly stable hydrophilicity over a long period of time, and a method for producing the same.

[Means for Solving the Problems] In order to achieve the above object, the present inventors have made extensive studies,
This led to the present invention. However, the present invention provides a microporous membrane having a polysulfono-based resin as a main component, the average pore size of the micropores on at least one side of the membrane being 50 Å to 2000 Å, and the porosity being 70 to 85%. 0,5 for polysulfone resin
% by weight of polyvinyl vinyl. ! J+'4 many, ■yo.

Yo. 8, including the body, and the water permeability rate is 50 [1ρ/hr-tn”
The present invention provides a polysulfone-based hollow fiber membrane exhibiting a weight of less than 1 kg/cm'2, and a method for producing the same.

The hollow fiber membrane of the present invention has an average pore diameter of 50 Å to at least one surface of the membrane, that is, the inner surface or outer surface of the hollow fiber membrane.
There are 2000 people. The average pore diameter of the micropores on the membrane surface is determined by measuring the diameters of about 1000 pores using a scanning electron microscope with a magnification of 50,000 times. The diameter of a non-circular hole is determined by the diameter of at most one stone inscribed in the hole.

In addition, the hollow fiber membrane of the present invention has a porosity of 70 to 85% throughout the membrane.
It is. The porosity was determined by changing the dry hollow fibers to wet ones, and
It can be calculated from the difference between ettfl and Dry weight.

The polysulfone resin used in the present invention is a polymer whose main component is the polymer shown in (A) or (B) below, and (A) is a polymer other than the polymer shown in (13) 2. It may be included in a range that does not impede the effects of the present invention.

(X, X', Y, Y' represent substituents of the Hensen ring,
For example, hydrogen, methyl, halogen, nitro, sulfonic acid (or its salt), carboxylic acid (or its salt), quaternary ammonium (or its salt), etc., a%b, c,
d represents an integer of O to 4, and R represents, for example, 113 L Sot. ) The polyvinylpyrrolidone used in the present invention is
H,) ``Polyvinylpyrrolidone is preferably one with a high molecular weight from the point of view of preventing elution, and usually one with a molecular weight of 160,000 to 100,000 is preferred because it is easy to obtain. Copolymers with vinyl compounds are also included.

Polyalkylene glycol has an average degree of polymerization of 200 to 100,000, preferably 400 to 2, from the viewpoint of membrane permeation performance.
0000 is desirable. Examples of such polyalkylene glycol include polyethylene glycol and polypropylene glycol.

Polysulfone resin, polyvinylpyrrolidone, and polyalkylene glycol are dissolved in these common solvents, such as dimethylformamide,
Examples include tumedelacetamide, N-methyl-2-pyrrolidone, nomethylsulfoquinto, and the like. These solvents can be used alone or in combination.

The polyhydric acid used in the present invention may be any acid that is soluble in the above-mentioned solvent and contains three or more carboxyl groups, phenol groups, or sulfuric acid groups in one molecule, and polymer acids are particularly preferred. Examples of such polyacids include tannic acid, polyacrylic acid, copolymers of isobutyne and maleic anhydride and their hydrolysates, copolymers of vinyl ether and maleic anhydride, and copolymers thereof. Copolymers of maleic anhydride and vinyl compounds such as hydrolysates, copolymers of ethylene and maleic anhydride and their hydrolysates, and their hydrolysates, copolymers of vinyl acetate and itaconic acid, and their hydrolysates; Examples include saponified products and sulfuric esters of polyvinyl alcohol.

It is desirable that the complex of polyvinylpyrrolidone and polyhydric acid be strong in order to prevent elution. Acids are preferably used. A part of the polyhydric acid can also be used in the form of an inorganic salt such as sodium or potassium within a range that can be dissolved in the above solvent.

When the polyhydric acid and polyvinylpyrroliton are dissolved in the above-mentioned solvent, they form a homogeneous solution, and when placed in acidic to neutral water, they form a complex that becomes cloudy and water-insoluble.

Next, a method for manufacturing the polysulfone hollow fiber membrane of the present invention will be explained. The polysulfone-based hollow fiber membrane of the present invention is produced by extruding a spinning stock solution consisting of a polysulfone resin, polyvinylpyrrolidone, polyalkylene glycol, polyhydric acid, and a common solvent thereof through an annular nozzle using a wet method or a dry-wet method. It can be made by

The polysulfone resin in the spinning dope is preferably 15 to 25% by weight, the polyalkylene glycol is 50 to 150% by weight of the polysulfone, the polyvinylpyrrolidone is 0.5 to 15% by weight of the polysulfone, and the polyacid is 10 to 15% by weight of the polysulfone. 1000% by weight is preferred, and the total amount of polyvinylpyrrolidone and polyhydric acid is 75% by weight of the polysulfonate.
It is preferable that it is below. These are uniformly dissolved in a solvent such as dimethylformamide, tumedelacetamide, N-methyl-2-pyrrolidone, and nomethylsulfokind, or a mixture thereof, and used as a spinning dope.

The spinning dope is extruded from an annular nozzle into an external coagulation bath which also has coagulability while injecting an internal coagulation liquid such as water or a mixture of water and a solvent into the core of the nozzle. Before entering the coagulation bath, it may be passed through humidified air maintained at various humidity levels as required. Polyhydric acid and polyvinylpyrrolidone form a complex when they come into contact with water, and most of it remains in the polysulfone membrane. Most of the polyethylene glycol and solvent are eluted from the membrane.

The hollow fibers are further washed with water, if necessary with warm water of about 60°C to 90°C, and dried at a temperature of about room temperature to 105°C.
A polysulfone hollow fiber membrane of the present invention.

The polysulfone-based hollow fiber membrane of the present invention is produced by extruding a spinning dope consisting of a polysulfone resin, polyvinylpyrrolidone, polyalkylene glycol, and a common solvent thereof through an annular nozzle by a wet method or a wet-dry method, and simultaneously extruding an internal injection liquid and/or It can also be produced by using a solution containing a polyhydric acid or a salt of a polyhydric acid as an external coagulation bath. A solution containing a polyhydric acid or a salt of a polyhydric acid may not be used in the internal injection liquid or external coagulation bath, but a solution containing a polyhydric acid or a salt of a polyhydric acid may be used in a separate treatment bath. It may be carried out in combination.

The existence of a complex of polyvinylpyrrolidone and polyhydric acid in a polysulfone hollow fiber membrane is due to the fact that the polysulfone hollow fiber membrane is dissolved in a solvent that dissolves polysulfone resin, such as dimethylformamide, and hollow fiber insoluble matter is removed. You can check whether it remains or not by observing it each time.

When using a copolymer of maleic anhydride and a vinyl compound as the polyhydric acid, the internal injection liquid or external coagulation bath that has coagulability should be made alkaline, or one of the subsequent treatment baths should be made alkaline first. can be produced by hydrolyzing a part of the maleic anhydride moiety and making any of the subsequent treatment baths acidic.

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these in any way.

All parts are by weight.

Example 1 18 parts of polysulfone (Udel P-1700),
Polyethylene glycol (Sanyo Chemical PEG #
600) 21.6 parts, polyvinylpyrrolidone (G, A,
A transparent homogeneous solution consisting of 0.2 parts manufactured by Company F (n = 100) and 59.6 parts of dimethylformamide was prepared and used as a spinning stock solution.

Dimethylformamide/water = 80/2 as internal coagulation liquid
While injecting a solution consisting of 0 (weight ratio), the stock solution temperature was 4.
It was coagulated in an external coagulation bath consisting of water at 40°C under the conditions of 0°C, dry zone length of 10 ha, dry zone atmosphere of 40°C, and relative humidity of 80%. Further, most of the polyethylene glycol and solvent were removed through a water washing bath with a residence time of 20 minutes and a 90°C hot water washing bath with a residence time of <10 minutes, and then rolled into a frame and dried at 75°C for 4 hours to obtain an inner diameter of 320 μm.
A polysulfone hollow fiber membrane having an outer diameter of 450 μm was obtained. The average pore diameter of the micropores on the inner surface of the membrane was 400 Å, and the porosity was 79%.

When a module was fabricated using 30 hollow fiber membranes with a length of 20 cta and water was passed under external pressure, the water permeability based on the external surface area of water at 25°C was 2500 ρ/hr-m'・at
It was II. Furthermore, when a 1% by weight solution of colloidal silica from 450 people was used, it showed a fractionation property of cutting 98%.

A module was made with an external pressure of 0.8P based on the external surface, and after passing water at H1/min for 1 hour, it was stopped for 24 hours, and
After a period of time, the water in the module was removed and the amount of potassium permanganate consumed was 0.2 g/g.
It was confirmed that there was almost no eluate.

The nitrogen content of the dried hollow fiber membrane was determined by the Micro Kjeldahl method and was found to be 0.33% by weight, indicating that most of the polyvinylpyrrolidone used remained. In addition, when the dried hollow fiber membrane was dissolved in dimethylformamide, it was confirmed that hollow fiber insoluble matter remained and a complex was formed between polyvinylpyrrolidone and a hydrolyzate of polyisobutylene maleic anhydride alternating copolymer. I was able to do that.

Example 2 Polysulfony/ (Udel P-1700) 19
Polyethylene glycol (#600 manufactured by Sanyo Chemical Co., Ltd.)
) 22FRI, 0.7 part of polyvinylpyrrolidone (K-90 manufactured by G, A, F), 58% dimethylformamide.
A polysulfone hollow fiber membrane was prepared in the same manner as in Example 1, except that a spinning stock solution consisting of 3 parts was used, and a solution consisting of 0.6 parts of tannic acid, 75 parts of dimethylformamide, and 24.4 parts of water was used as the internal coagulation liquid. was created. The average diameter of the micropores on the inner surface of the membrane was 250 Å, and the porosity was 78%.

Membrane performance was measured in the same manner as in Example 1, and the water permeability was 2000 (s"hr-ate), and the fractionability was 35% when using a liquid with a colloidal glue strength of 1% by weight from 135 people.
, 450 people cut 9.9% of colloid when using 1% by weight liquid.

Potassium permanganate consumption is 0.2 mg/L.Nitrogen content in the film determined by microkercoeur method is 0.36%.
Met. Furthermore, it was confirmed that a polyvinylpyrrolidone complex was formed by dissolving the hollow fiber membrane in trimethylformamyl l- as in Example 1.

18 parts of polysulfone (Udel P-1700),
Polyethylene glycol (Sanyo Chemical PEG #
400) 25 parts, polyvinylpyrrolidone (G, A, F
-90) 0.7 parts, dimethylformamide 56
．． A clear homogeneous solution consisting of 3 parts was used as a spinning dope.

Dimethylformamide/water = 50/as internal coagulation liquid
While injecting a solution at 37°C consisting of 50% (weight: 1 ratio), the temperature of the stock solution was 37°C, the dry zone length was 70 mm, the atmosphere in the dry zone was 37°C, and the relative humidity was 95%.
Coagulation occurred in an external coagulation bath consisting of water at 5°C.

After staying in the coagulation bath for 10 seconds, it was passed through an aqueous solution of 0.3% by weight of sodium acrylate and 0.3% by weight of concentrated hydrochloric acid for 3 minutes, thoroughly washed with water, and then placed in a hot air dryer at 105°C for 3 minutes. After drying for a period of time, a polysulfone hollow fiber membrane was obtained. The obtained film is an example! Like 2 and 2, it has a hydrophilic membrane, with a water permeability of 18001! / *"hr・8 [garden]. Fractionability showed a cut of 90% when using 1% by weight colloidal silica solution, and as in Example I, a complex of polyvinylpyrrolidone was formed. It was confirmed that the average diameter of the micropores on the inner surface of the membrane was 100 Å,
The porosity was 79%.

The consumption amount of potassium permanganate was 1.5 mg/C, and the nitrogen content in the film determined by the microkercoeur method was 0.
, 25%.

Example 4 19 parts of polysulfone (tldel P-1700), 22 parts of polyethylene glycol (PEG #600),
0.3 parts of polyisobutyne maleic anhydride alternating copolymer,
A transparent homogeneous solution consisting of 0.7 parts of polyvinylpyrrolidone (K-90) and 58 parts of dimethylformamide was prepared and used as a stock solution.

Tumethylformamide/water as internal coagulation liquid - 77,5
/ 22.5 (weight ratio) under the conditions of stock solution temperature of 40℃, dry zone length of 7011, and dry zone atmosphere of 40℃ and relative humidity of 80%.
40g/L at ℃! It was coagulated in an external coagulation chamber consisting of an aqueous sodium hydroxide solution. Furthermore, the water was heated at 80°C through a water washing tank opened for 3 minutes and a 36.5 g/l hydrochloric acid aqueous solution tank for the same <10 minutes, and a 90°C hot water washing tank for the same <20 minutes and the same <10 minutes. Let dry for 4 hours,
Polysulfone hollow fibers having an inner diameter of 450μ and an outer diameter of 570μ were obtained. The obtained hollow fiber membrane was a hydrophilic membrane similar to Examples 1 to 3, and the water permeability was 1500 t/s"hr-at+
*Met.

Fractionability showed a cut of 99% when using 450 people's 1% by weight colloidal silica solution. The nitrogen content in the film determined by the microkercool method was 0.37%, and the amount of potassium permanganate consumed was 0.5 mg/l. The average pore diameter of the hollow fiber membrane and inner surface micropores is 400 Å, and the porosity is 78%.
Met.

[Effects of the Invention] According to the present invention, a polysulfone-based hollow fiber membrane containing a complex of polyvinylpyrrolidone and a polyhydric acid can be obtained. The composite becomes strong with a small amount of polyvinylpyrrolidone, and the membrane of the present invention has almost no eluate in water at a pH level of pl+10 or less, such as ordinary tap water, and can be passed through water as is in a dry state. Since it is a highly hydrophilic membrane, it is widely used in water purifiers, blood treatment, treatment of bacterial cell-containing liquids, and water recovery from activated sludge wastewater.

Patent applicant RiRashi Co., Ltd.

Claims (1)

[Scope of Claims] 1. A microporous membrane whose main component is a polysulfone resin, the average pore size of the micropores on at least one side of the membrane is 50 Å to 2000 Å, and the porosity is 70 to 85%; Contains a complex of polyvinylpyrrolidone and polyhydric acid in an amount of 0.5% by weight or more based on polysulfone resin, and has a water permeation rate of 500 l/h.
A polysulfone hollow fiber membrane exhibiting r.m^2.kg/cm^2 or more. 2. In a method for producing a polysulfone-based hollow fiber membrane by a wet method or a dry-wet method, a spinning stock solution consisting of a polysulfone resin, polyvinylpyrrolidone, polyalkylene glycol, polyhydric acid, and a common solvent thereof is extruded from an annular nozzle for spinning. A method for producing a polysulfone hollow fiber membrane. 3. In a method for producing a polysulfone hollow fiber membrane by a wet or dry-wet method, a spinning dope consisting of a polysulfone resin, polyvinylpyrrolidone, polyalkylene glycol, and a common solvent thereof is extruded from an annular nozzle, and an internal coagulating liquid and A method for producing a polysulfone-based hollow fiber membrane, characterized in that/or a solution containing a salt of a polyvalent acid is used as an external coagulation liquid.