JPH0759250B2 - Membrane type filtration device manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a membrane type filtration device,
More specifically, the present invention relates to a method for manufacturing a filtration device containing a porous membrane made of a hydrophobic polymer that can be used simply and safely in use.

The filtering device referred to here is a filtering device used for medical, industrial, and general purposes.

For medical use, a plasma separator for separating blood cell components and plasma components from blood, a plasma component separator for further fractionating plasma components by molecular weight, a blood concentrator for separating only water from blood,
Examples thereof include a plasma component collection device for donating and collecting plasma components from blood from a donor. Further, for industrial use, a microfiltration cartridge, a filtration device for water or an aqueous solution such as a filter, and for general use, a home water purifier, a portable water purifier and the like.

[Prior Art] In a porous membrane made of a hydrophobic polymer, since an aqueous liquid such as blood does not wet the hydrophobic polymer, it is difficult to permeate the aqueous liquid into the fine pores of the porous membrane. A medical filtration device containing a porous membrane made of a hydrophobic polymer cannot be used as it is. Therefore, it has been proposed to preliminarily hydrophilize a porous membrane made of a hydrophobic polymer. These hydrophilization treatment methods include a method in which a low surface tension organic solvent soluble in water is permeated into micropores. , A method of substituting with water, a method of treating the porous membrane with a surfactant, a method of chemically introducing a hydrophilic group to the surface of the porous membrane, a method of coating a hydrophilic polymer on the surface of the porous membrane, and a water To penetrate into the micropores at a pressure of 5 kg / cm ² or more (JP-A-61-92675, JP-A-61-94662 and JP-A-61-10957).
No. 3).

[Problems to be Solved by the Invention] However, in the above method of infiltrating the low interfacial tension organic solvent into the micropores and then substituting with water, a large amount of water is required to wash and remove the low interfacial tension organic solvent. There is a drawback to In the method of treating with a surfactant, the surfactant is eluted into the introduced water and the filtrate, and there is a problem of filtrate contamination during use.

Also, the method of chemically introducing a hydrophilic group to the surface of the porous membrane, the reaction residue, the solvent and the like are likely to remain, there is a problem in use similar to the above, the method of coating the hydrophilic polymer, The solvent used for coating is liable to remain, which not only causes problems in use, but also when used for medical purposes, especially for blood such as biocompatibility of hydrophobic porous membrane and low activation of complement and platelets. Has the disadvantage that the good suitability of is lost by coating the surface of the hydrophobic membrane with another polymer.

Furthermore, in the method of infiltrating the water into the fine pores at a pressure of 5 kg / cm ² or more, there is no such problem as described above, but 5 kg / cm
^If a high pressure of ² or more is applied, the probability that the membrane or container will be damaged increases, and even if it is not damaged, the pore size of the porous membrane will change due to the high pressure.

[Means for Solving the Problems] Therefore, the present inventors have achieved the present invention as a result of intensive studies to solve the drawbacks of the medical filtration device incorporating the porous membrane made of these hydrophobic polymers.

That is, the present invention is a membrane-type filtration device that is made of a hydrophobic polymer and has a built-in porous membrane having an average pore diameter of 0.01 to 10 microns and that has an inlet and outlet for an aqueous solution and an outlet for filtrate. Is prepared, each space separated by the porous membrane is filled with hot water of 60 ° C. or higher, and pressure is applied through the hot water to allow water to penetrate into the fine pores of the porous membrane. The present invention provides a method for manufacturing a membrane type filtration device.

The membrane-type filtration device produced by the present invention does not use an organic solvent or a surfactant as a hydrophilization treatment agent, and the fine pores of the porous membrane are filled with water. It is safe for medical use because it does not remain, and there is no problem of filtrate contamination in industrial and general use.

The porous membrane made of the hydrophobic polymer used in the present invention is not particularly limited in its type,
Examples thereof include materials such as polyethylene, polypropylene, poly-4-methylpentene-1, polysulfone, polyether sulfone, polyvinylidene fluoride, polytetrafluoroethylene, polydimethylsiloxane, polyethylene terephthalate and nylon.

The form of the porous membrane used in the present invention is not particularly limited, and for example, a hollow fiber shape or a flat membrane shape is used.

The method for producing the porous membrane is also not particularly limited, and a known production method such as a stretching method, a wet phase separation method, a melt phase separation method, a solvent extraction method or the like can be adopted.

As the aqueous solution used in the present invention, in addition to water, a solution containing water as a main component and a non-hazardous solute other than a substance that lowers the interfacial tension can also be used. This includes pure water, distilled water, distilled water for injection, pyrogen-free water, physiological saline and the like.

Further, in the present invention, a porous membrane having an average pore diameter of 0.01 to 10 microns (μm) (measured by the bubble point method) is targeted. It is difficult for hot water to penetrate into the micropores in a porous membrane with an average pore size smaller than 0.01 micron, and in a porous membrane with an average pore size larger than 10 microns, water can be made to flow into the micropores of the porous membrane by a normal method. Because you can.

The method of the present invention will be described in comparison with the conventionally known method of infiltrating water into the micropores of the porous membrane by applying a pressure of 5 kg / cm ² or more, which is conventionally known, and the present invention shows that water when heated. By positively utilizing the decrease in the interfacial tension of, for example,
-92675, 61-94662, 61-109573, etc. can infiltrate water into the fine pores of the porous membrane at a lower pressure than the known method. In the case of a filtration device using a porous membrane, particularly a filtration device used for medical purposes, a polyurethane resin is used as an adhesive for fixing the membrane, a polymer is used as a container of the filtration device, and the filtration pressure is considerably low in actual use. In many cases, it is economically inadequate to make the adhesive and the container have pressure resistance far from the pressure range for use. Also, the membrane pressure may change due to high pressure. Therefore, it is preferable to inject water into the fine pores of the porous membrane at the lowest possible pressure.
Furthermore, since the water is heated to 60 ° C. or higher before use, bacterial growth can be reduced and the problem of contamination can be reduced.

It is preferable to seal the filter device in a high temperature state and sterilize it under high pressure so that a completely sterile and pyrogen-free filter device can be provided.

The temperature of the hot water used is 60 ° C or higher, preferably 80
It is ~ 97 ° C, and when using pressurized water, warm water having a temperature of 100 ° C or higher can also be used. When the temperature of the hot water is lower than 60 ° C, even if pressure is applied through the hot water, it is difficult for water to penetrate into the fine pores of the membrane at low pressure, and the effect is low.

The pressure applied through warm water may be lower than the pressure used in the conventionally known method, preferably in the pressure range of ^{2 to} 5 kg / cm ² , and particularly preferably in the range of 2.5 to 4.5 kg / cm ² .

Further, in the present invention, the air in each space separated by the porous membrane in the membrane filtration apparatus is eliminated under reduced pressure, and then the space is filled with hot water of 60 ° C. or higher, and pressure is applied through the hot water. Is preferred.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to these examples.

(Example) Polypropylene (UBE-PP-F109K, trade name: manufactured by Ube Industries, Ltd., MFI = 9 g / 10 minutes) was spun at a spinning temperature of 210 ° C. using a hollow fiber manufacturing nozzle. The polypropylene hollow fiber obtained is heat-treated in a heated air tank at 145 ° C. for 30 minutes,
Next, at a temperature of 135 ° C, 400% of the initial length, strain rate 8.33
It was drawn at a rate of 0.1% / min and heat-treated for 15 minutes in a heated air tank at 145 ° C. while maintaining the drawn state to produce a porous polypropylene hollow fiber. The obtained porous polypropylene has an inner diameter
The thickness was 320 μm and the film thickness was 55 μm. The average pore size measured by the bubble point method (using ethanol) is 0.48 μm.
The porosity was 75%.

The porous membrane was housed in a polycarbonate housing, and both ends were fixed with a polyurethane adhesive to prepare a polypropylene porous membrane filtration device having a membrane area of 0.5 m ² . After depressurizing the internal space of this filtration device with a vacuum pump, 94 ° C warm water was filled in each space of the filtration device, and each space separated by the porous membrane passed through warm water at a pressure of 3 kg / cm ² . Pressurized.

When the water permeation rate of water was measured using this filtration device,
It showed a high water permeability of 30 l / min · m ² · kg / cm ² .

(Comparative Example) After depressurizing the internal space of the filtration device prepared in the same manner as in Example with a vacuum pump, each space of the filtration device was filled with sterile water at 25 ° C., and each space of the filtration device was hydraulically operated at room temperature. 4 kg / cm ²
Pressurized with. When the water permeation rate of water was measured using this filtration device, it showed a water permeation rate of 2.2 × 10 ^-2 l / min · m ² · kg / cm ² , and a practical water permeation rate was not obtained.

[Effects of the Invention] As described above, according to the present invention, the filtration device is filled with hot water of 60 ° C. or higher, and pressure is applied through the hot water to cause water to penetrate into the fine pores of the porous membrane. Since it is manufactured, it is possible to obtain a membrane type filtration device which can be used simply and safely and which is excellent in water permeability and filterability.

Claims (1)

[Claims] 1. A membrane-type filtration device comprising a porous membrane made of a hydrophobic polymer having fine pores having an average pore diameter of 0.01 to 10 microns and having an inlet and outlet for an aqueous solution and an outlet for a filtrate. It is characterized in that each space separated by the porous membrane is filled with warm water of 60 ° C. or more, and pressure is applied through the warm water to allow water to penetrate into the fine pores of the porous membrane. Membrane type filtration device manufacturing method.