JPH11333268A - Separation membrane excellent in adhesive property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a separation membrane having such an excellent adhesive property that a liquid drop due to absorption of moisture is not formed on a surface of a membrane even after the membrane is left under an atmosphere within a range of a specified relative humidity for a specified time by using saccharides comprising a monosaccharide and a polysaccharide as a hydrophilizing agent and/or a membrane structure retaining agent. SOLUTION: In an accurate filtration membrane used as a primary structure of a filter device, a separation membrane for an artificial dialysis or the like, at least one kind of saccharide selected from the group of monosaccharides and polysaccharides is used as a hydrophilizing agent and/or a membrane structure retaining agent. By this method, even after the membrane has been left under an atmosphere of a relative humidity ranging 50-60% for one hour or more, a droplet of liquid due to moisture absorption is not formed and the membrane with good adhesion between an adhesive and the separation membrane and a raised yield in module assembling is obtained. In this case, as the monosaccharides, e.g. glucose and the like, as the polysaccharides, e.g. trehalose and the like and as a material for the separation membrane, e.g. polysulfone and the like are used and the separation membrane is formed in a flat membrane shape or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separation membrane from industrial use such as a microfiltration membrane and an ultrafiltration membrane to medical use such as an artificial dialysis membrane.

[0002]

2. Description of the Related Art Separation membranes have been known for a long time.
It is used as a main component of the filter. For example, in medical applications, it is widely used in artificial dialysis machines and the like.
This artificial dialysis machine has been used by many people over a long period of time, and has contributed to prolonging the life of many patients with chronic renal failure. Separation membranes for seawater desalination for industrial use are used for producing ultrapure water and the like, and the ultrapure water is used for producing semiconductors and the like. When the separation membrane is incorporated into a module, the separation membrane may be dried and adhered because it is liquid-tightly divided into a supply liquid side and a permeate liquid side. Since the separation membrane usually has a porous structure, in order to maintain the porous structure in a desired state during drying,
Alternatively, a so-called pore retaining agent is used to prevent drying shrinkage. Further, in a film made of a hydrophobic substance, a hydrophilic agent may be contained in the film in order to ensure hydrophilicity after drying.

[0003] Glycerin, polyethylene glycol, or the like is generally used as a pore retaining agent or a hydrophilizing agent of a hollow fiber membrane for hemodialysis.

[0004]

However, a separation membrane using glycerin, polyethylene glycol, or the like as a pore retaining agent or a hydrophilizing agent absorbs moisture during storage between spinning and assembly into a module. Droplets may be generated. If a lot of droplets are generated,
When bonding the separation membrane, droplets form a film in the gap between the separation membranes, making it difficult for the adhesive to enter here, and eventually the adhesive is not filled, so that liquid-tight formation inside and outside of the membrane can not be made and it is defective. Become. For this reason, the film before bonding often has to be stored in an atmosphere of low humidity, but in order to prevent moisture absorption, it is necessary to lower the environmental humidity of the film to about 40% in accordance with the hygroscopicity of, for example, glycerin. Yes, this requires significant capital investment in the storage environment and running costs for dehumidification. Polyurethane is mainly used for bonding modules in artificial dialysis machines, but glycerin and polyethylene glycol react with urethane during bonding, which may generate leaching by-products. Some tests exceeded the dialysis-type artificial kidney device standard.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve these drawbacks, and as a result, have found that the relative humidity is 50 to 6%.
It has been found that a separation membrane in which no moisture droplets are generated on the membrane surface after being allowed to stand for 1 hour in an atmosphere of 0% has good adhesiveness between the adhesive and the separation membrane and can improve the module assembly yield. Was. Further, the separation membrane characterized by being provided with at least one membrane pore-retaining agent or a hydrophilizing agent selected from monosaccharides or polysaccharides has a low hygroscopic property and a low adhesiveness between the adhesive and the separation membrane. It has been found that the generation of leaching by-products from the bonded portion can be extremely reduced, and the present invention has been achieved.

That is, the present invention is as follows. A separation membrane having excellent adhesion, characterized in that no droplets due to moisture absorption are observed on the membrane surface after being left for 1 hour in an atmosphere having a relative humidity of 50% to 60%. A separation membrane having excellent adhesion, wherein a saccharide is used as a hydrophilizing agent and / or a membrane structure retaining agent. The separation membrane having excellent adhesion as described above, wherein the saccharide is at least one selected from the group consisting of monosaccharides and polysaccharides.

In the present invention, a temperature of 25 ° C. and a relative humidity of 5
The separation membrane is allowed to stand for 1 hour in an atmosphere of 0 to 60%, and the surface of the separation membrane is observed with a 50-fold loupe. Even in the case of storage, the occurrence of poor adhesion is small, and a high yield can be obtained in module assembly, which is preferable. 5
The generation of a small amount of droplets observed at a magnification exceeding 0 times (for example, 100 times or more) does not significantly affect the generation of a defective rate of modularization.

Further, in the present invention, when a monosaccharide or polysaccharide is used as a membrane pore retaining agent or a hydrophilizing agent, a separation membrane having low hygroscopicity and little adhesion failure can be obtained. Furthermore, when monosaccharides or polysaccharides are used as the pore retaining agent or the hydrophilizing agent, surprisingly, even when a urethane-based adhesive used for bonding the module of the artificial dialysis membrane is used, generation of eluting by-products occurs. Can be suppressed.

The monosaccharide used in the present invention is glucose,
Galactose, mannose, xylose, arabinose and the like are preferred. As the polysaccharide used in the present invention, trehalose, maltose, cellobiose, lactose and the like are preferable.

The material of the separation membrane to which the present invention is applied is not particularly limited. Examples thereof include polysulfone, polyethersulfone, polyacrylonitrile, cellulose, cellulose acetate, polyamide, and methyl methacrylate. Is mentioned. Further, the separation membrane of the present invention can be applied to any shape such as a flat membrane, a hollow fiber, and a tube. However, a plurality of flat membranes or a large number of hollow fiber membranes having an outer diameter of 500 μm or less are liable to be defective at the time of adhesion. The present invention has a great effect on bundles (usually 1000 or more). The membrane can be applied to any use such as a reverse osmosis membrane, an ultrafiltration membrane, a microfiltration membrane, an artificial dialysis membrane, and a blood separation membrane.

[0011]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

Example 1 A hollow fiber membrane made of a polyethersulfone polymer was prepared as the hollow fiber membrane for hemodialysis to which the membrane pore retaining agent of the present invention was applied by the following method. 20% by weight of polyether sulfone, 55% by weight of N-methyl-2-pyrrolidone, polyethylene glycol (molecular weight 2
00) A uniform spinning dope comprising 25% by weight was prepared.
Liquid paraffin is used as a hollow internal solution, and the spinning solution is 100
And simultaneously extruded from the double spinneret at 10 ° C.
immersed in water at 30 ° C. provided at a spinning speed of 80 cm below.
It was wound at m / min. The obtained hollow fiber membrane was immersed in a 20% by weight trehalose aqueous solution, and then dried to produce a module.

At room temperature 2 to confirm the hygroscopicity of the hollow fiber
By changing the relative humidity at 5 ° C., the state of water droplet adhesion on the surface of the hollow fiber was confirmed with a microscope. Those without water droplets are desirable as the pore-holding agent. Table 1 shows the results.

[0014]

[Table 1]

After 9600 hollow fibers were bundled and left for 1 hour in an atmosphere of 55% humidity, a module having an effective length of 25 cm was assembled using urethane as an end adhesive (effective film). Area 1.5 m ² ). Pressurized air (760 mmHg) was sent to the hollow portion of the completed module, and the internal pressure of the hollow portion was measured with the end sealed.
The pressure drop for 5 minutes was measured, and those with a pressure drop of 20 mmHg or more were judged as leak products. Module 1
Zero batteries were produced and the leak rate was determined. Table 2 shows the results.

[0016]

[Table 2]

The ultrafiltration speed (hereinafter abbreviated as UFR) of the above-mentioned module at 37 ° C. pure water, the temperature 37 ° C., the blood side flow rate 200 ml / min, the dialysate flow rate 500 ml / min, Ultrafiltration volume 0ml / mi
Under the conditions of n, the clearance of urea, vitamin B12, and myoglobin was measured. Table 3 shows the results.

[0018]

[Table 3]

A dissolution test was conducted on the bonded portion of the hollow fiber. The dissolution test method is as follows. Cut the adhesive part of one dialyzer into 1 cm square, add 200 ml of RO water,
Shake and extract at 70 ° C. for 2 hours. After standing to cool, the supernatant is
Diluted 50 times with O water, and compared with RO water at a wavelength of 220
The maximum value of the absorbance at -270 nm was measured. The smaller the absorbance, the smaller the amount of eluted matter, which is desirable as a membrane pore retaining material. Table 4 shows the results.

[0020]

[Table 4]

As a comparative example, the same measurement was performed on a hollow fiber obtained by using a 50% by weight aqueous solution of glycerin as a membrane pore retaining agent.

From the results shown in Table 1, it was shown that when trehalose was used as the pore retaining agent, the moisture absorption was significantly reduced as compared with the case where glycerin was used, and no moisture absorption was observed in a normal relative humidity range.

From the results shown in Table 2, when trehalose was used as the pore-retaining agent, compared with that using glycerin,
The yield of module assembly is improving.

From the results shown in Table 3, it was shown that trehalose was able to retain the membrane pores, and that a filtration performance equivalent to that of a hemodialyzer prepared using a conventional membrane pore retaining material was obtained.

From the results shown in Table 4, it can be seen that when trehalose is used as the pore-holding agent, the elution amount is significantly reduced as compared with the case where glycerin is used.

[0026]

According to the present invention, the separation membrane produced by using the membrane pore retaining agent of the present invention does not absorb moisture at the time of module production, so that there is no occurrence of adhesion failure, and the performance is equivalent to the separation membrane using glycerin. The amount of elution from the bonding portion of the obtained module can be significantly reduced.

Claims (3)

[Claims] 1. The method according to claim 1, wherein the atmosphere is at a relative humidity of 50% to 60%.
A separation film having excellent adhesion, characterized in that no liquid droplets are generated on the film surface due to moisture absorption after being left for a long time. 2. A separation membrane having excellent adhesiveness, wherein a saccharide is used as a hydrophilizing agent and / or a membrane structure retaining agent. 3. The separation membrane according to claim 2, wherein the saccharide is at least one selected from the group consisting of monosaccharides and polysaccharides.