JP2000218140A - Module incorporated with membrane and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a residual organic solvent and to obtain a module which does not cause the deterioration of not only membranes in the module but also of a main body by specifying the concentration of the organic solvent in a packing liquid or in water after being preserved with ultrapure water put in the module when no packing liquid is absent. SOLUTION: A module incorporated with separation membranes and others is used in various applications. As regards the membranes, the organic solvent solution of a polymer is adjusted and formed in the shapes of a membrane, a hollow fiber membrane, and others. Since the residual organic solvent of the module is minimized, the concentration of the organic solvent in a packing liquid or in water after being preserved at 80 deg.C for 24 hr with ultrapure water put in the module when the packing liquid is absent is set up at 50 ppb or below, preferably at 30 ppb or below. Only by a process in which the assembled module is irradiated with electron beams preferably in a ratio of 1-5 kGy, the organic solvent in the packing liquid can be decomposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a module incorporating a film having a small amount of residual organic solvent, and more particularly to a module incorporating a film having a reduced amount of residual organic solvent and preventing deterioration of the film and the module, and a method of manufacturing the module. Things.

[0002]

2. Description of the Related Art Conventionally, modules used in the medical field such as artificial kidneys or in water treatment are equipped with a separation membrane or a semipermeable membrane. An organic solvent is usually used for forming such a separation membrane or a semipermeable membrane.However, the organic solvent used in this film formation is generally difficult to be removed from the membrane after the film formation, and particularly has a high boiling point. In the case of a polar solvent, it remains at a high concentration, and due to the effect of the remaining organic solvent, membrane deterioration or module deterioration occurs, and there is a concern about the effect on safety when using the module in water treatment or medical use. . In particular, in the case of membranes used for blood purification in medical applications, the membrane cleaning should be strengthened to remove residual organic solvents, and the membrane should be washed using not only room temperature water but also high temperature hot water, or high pressure. Steam sterilization has been carried out to reduce the residual amount of organic solvents. However, with these methods,
Note that the amount of the residual organic solvent could not be suppressed to 50 ppb or less.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have intensively studied the decomposability of a residual organic solvent in order to overcome the above-mentioned problems, and as a result, have reached the present invention.

[0004] An object of the present invention is to reduce the residual organic solvent,
It is an object of the present invention to provide a module incorporating not only a film incorporated in the module but also a film which does not cause deterioration of the main body.

It is another object of the present invention to provide a method for manufacturing the above module, which can efficiently remove the residual organic solvent by a simple process without requiring a complicated process.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to achieve the above object. In the module of the present invention, there is provided a module incorporating a membrane. In this case, the organic solvent concentration in water after ultrapure water is put in the module and stored at 80 ° C. for 24 hours is not more than 50 ppb, and the membrane is, for example, polysulfone or polymethyl. Examples include a separation membrane and a semi-permeable membrane made of methacrylate or the like.

The method for producing a module according to the present invention is characterized in that an organic solvent is decomposed by irradiating an electron beam to a module incorporating a membrane, and the concentration of the remaining organic solvent becomes 50 ppb or less. Irradiate electron beam up to. By the irradiation of the electron beam, a polar solvent having a high boiling point can be rapidly decomposed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Modules incorporating membranes such as separation membranes and semi-permeable membranes are used for various purposes such as general industrial use, water treatment and blood treatment. In particular, the blood processing module can be used for various purposes such as plasma exchange therapy and artificial dialysis treatment in medical applications, as well as medical uses and industrial uses such as artificial livers, endotoxin filters, and bioreactors. Special consideration must be given to safety because of the interaction.

[0009] The membrane incorporated in the module of the present invention comprises:
It is obtained by preparing an organic solvent solution of the polymer constituting the membrane and shaping it into a membrane or a hollow fiber membrane or the like. At this time, the organic solvent used is taken in and remains in the formed membrane. . The organic solvent is a good solvent for the polymer and varies depending on the type of the polymer used.

[0010] Examples of the polymer used in the present invention include polysulfone and polymethyl methacrylate. The organic solvent used includes methylene chloride (boiling point: 39.95 ° C.) and chloroform (boiling point: 61.95 ° C.).
2 ° C.), 1-methyl-2-pyrrolidone (boiling point: 202
C), N, N-dimethylacetamide (boiling point: 164.
5-166 ° C), tetrahydrofuran (boiling point: 65-6)
7 ° C.), dimethyl sulfoxide (boiling point: 189 ° C.) and the like.

In the present invention, the module itself incorporating the membrane may be manufactured by a commonly known method, and any steps may be taken after processing into a module after film formation.

One of the features of the present invention is to reduce the remaining organic solvent in such a module as much as possible. Specifically, the concentration of the organic solvent in the filling solution, or the absence of the filling solution in the module, Put ultrapure water into
After storing at 0 ° C. for 24 hours, the concentration of the organic solvent in water was adjusted to 50.
ppb or less, preferably 30 ppb or less. By reducing the residual organic solvent in this way,
The deterioration of the film itself and the deterioration of the module body can be suppressed.

In the present invention, surprisingly, it is possible to decompose the organic solvent in the filling liquid only by irradiating the assembled module with an electron beam. It is possible to manufacture the above-mentioned module which does not cause a safety problem in processing-related and medical applications.

The irradiation of the electron beam is applied to a module filled with a filling liquid such as pure water or physiological saline, a module in which the hollow fiber is in a dry state, and a module in which a humectant such as glycerin is attached to the hollow fiber. You can do it.

The electron beam used in the present invention is preferably an electron beam having a high dose density, for example, 5 × 10 ^{2 to} 5 × 10 ⁵ kGy / hr, and the output is preferably 1 KW or more. When the dose density is lower than the electron beam and the radiation dose per unit time is small (about 1/1000) as in the conventional γ-ray irradiation,
Sufficient organic solvent decomposition cannot be obtained. Regarding the energy of the electron beam, an electron beam having a higher energy is better from the viewpoint of material permeability, but there is an upper limit to the energy that can be actually used. Preferably, if the energy is 5 MeV to 10 MeV, a commercially available electron beam accelerator can be used.

The dose of the electron beam irradiated in the present invention cannot be specified because it depends on the concentration of the remaining polar organic solvent before irradiation, but is preferably 1 KGy to 50 KGy, more preferably 1 KGy to 30 KGy, In particular,
For example, if the residual organic solvent is about 100 ppm, 15K
Gy is required, and the remaining organic solvent is 50 pp.
m or less, the residual solvent concentration can be reduced to 50 ppb or less even at a dose of 5 KGy or less. Therefore, in order to reduce the irradiation dose, it is desirable that the module incorporating the film be cleaned as much as possible before irradiation to reduce the residual organic solvent concentration as much as possible.

Modules incorporating the membrane of the present invention include modules used for general industry, water treatment, blood treatment, and the like. In particular, plasma exchange therapy, artificial dialysis treatment, Furthermore, it is suitable for blood processing modules such as dialysers used for medical applications such as artificial livers, endotoxin filters, and bioreactors.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

[0019]

(Example 1) A polysulfone-based hollow fiber (inner diameter 200 µm, film thickness 40 µm) type artificial dialyzer formed from a polymer solution in which polysulfone was dissolved using N, N-dimethylacetamide (hereinafter referred to as DMAc) as an organic solvent. After washing, the concentration of DMAc in the filling solution of the dialyzer was set to 120 p.
pm. Next, when this dialyzer (module) was irradiated with an electron beam of 15 KGy, the concentration of DMAc in the filling liquid became 20 ppb or less. For the measurement of the absorbed dose, a CTA film dosimeter embedded in the center of the module having the largest diameter was used (the absorbed dose was measured by the same method in the following Examples and Comparative Examples).

The residual DMAc was measured by a GC-MS method (a method combining gas chromatography and mass spectrum analysis).

The physical strength (rupture strength of 18.5) was determined by evaluating the strength and elongation characteristics of the film (tensile test using Tensilon).
It was confirmed that no change was observed in gf). Also,
Even after re-measurement after 6 months, there was no change of 18.3 gf. In the tensile test, the initial sample length was 50 mm and the tensile speed was 50 m
m / min, temperature 25 ° C., humidity 50-60%. (Comparative Example 1) A polysulfone-based hollow fiber type dialyzer in which the concentration of dimethylacetamide (DMAc) in the filling solution was adjusted to 120 ppm, which was the same as in Example 1, was used at 500 ml / m2.
The blood side nozzle was washed with ultrapure water for 15 minutes in. The concentration of residual dimethylacetamide was 1.2 ppm. (Comparative Example 2) A polysulfone-based hollow fiber artificial dialyzer in which the concentration of DMAc in the filling solution was adjusted to 120 ppm as in Example 1 was washed with ultrapure water from the blood side nozzle at 500 ml / min for 15 minutes. And with hot water at 80 ° C for 15
Washed for minutes. The concentration of residual DMAc was 120 ppb. (Comparative Example 3) After washing a polysulfone-based hollow fiber type artificial dialyzer in which the concentration of DMAc in the filling solution was adjusted to 120 ppm as in Example 1 with ultrapure water from the blood side nozzle at 500 ml / min for 15 minutes. After washing with hot water at 80 ° C. for 15 minutes, γ-rays were irradiated at 25 Gy. The concentration of residual DMAc was 112 ppb. (Example 2) When the polysulfone hollow fiber artificial dialyzer subjected to the washing treatment of Comparative Example 1 was further irradiated with an electron beam of 5 KGy, the DMAc concentration in the filling solution was 20 ppb.
It became the following. It was confirmed that no change was observed in the physical strength (no change from 18.3 gf) by evaluating the elongation characteristic of the film (tensile test with Tensilon). Also,
Even after one month measurement, there was no change of 18.2 gf. (Example 3) When the polysulfone-based hollow fiber type artificial dialyzer subjected to the washing treatment of Comparative Example 2 was further irradiated with an electron beam of 5 KGy, the DMAc concentration in the filling solution was 20 ppb.
It became the following. The physical strength (from 18.5 gf to 1) was determined by evaluating the elongation characteristic of the film (tensile test using Tensilon).
No change was observed in 8.3 gf).
One month later, there was no change to 18.5 gf. (Example 4) When the polysulfone-based hollow fiber type artificial dialyzer subjected to the washing treatment of Comparative Example 3 was further irradiated with an electron beam of 5 KGy, the concentration of DMAc in the filling solution was 20 ppb.
It became the following. The physical strength (from 18.1 gf to 1) was determined by evaluating the elongation characteristic of the film (tensile test using Tensilon).
No change was observed in 8.2 gf).
In addition, it was 18.2 gf even after one month. Example 5 A polysulfone-based hollow fiber (inner diameter: 200 μm, film thickness: 40 μm) type artificial dialyzer molded from a polymer solution in which polysulfone was dissolved using DMAc as an organic solvent was washed, and the module was dried. Next, this dialyzer (module) was irradiated with an electron beam of 15 KGy. After the ultrapure water was put in this module and stored at 80 ° C. for 24 hours, the DMAc concentration in the water was 20 ppb or less. (Comparative Example 4) A drying module prepared in the same manner as in Example 5 was irradiated with 25 KGy of γ-rays. After adding ultrapure water in this module and storing it at 80 ° C. for 24 hours, the DMAc concentration in the water was 1.5 ppm.

[0022]

According to the present invention, the amount of the remaining organic solvent is small even in a module incorporating a film produced using a polar solvent having a high boiling point, and the film and the module are deteriorated by the influence of the remaining organic solvent. Thus, a module can be obtained in which safety during use in water treatment and medical applications is ensured.

Claims (6)

[Claims] In a module incorporating a membrane, the concentration of the organic solvent in the filling liquid or the concentration of the organic solvent in water after ultrapure water is placed in the module and stored at 80 ° C. for 24 hours when there is no filling liquid, A module incorporating a membrane, which is 50 ppb or less. 2. The module according to claim 1, wherein the membrane is a separation membrane or a semipermeable membrane. 3. The module according to claim 1, wherein the membrane is a polysulfone membrane, and the organic solvent is N, N-dimethylacetamide. 4. A module incorporating the membrane according to claim 1, which is used for medical applications. 5. The method for producing a module incorporating a film according to claim 1, wherein the module incorporating the film is irradiated with an electron beam to decompose the remaining organic solvent. 6. The method according to claim 5, wherein the irradiation amount of the electron beam is 1 to 50 KGy.