JPH02293029A - Sterilizing porous membrane - Google Patents

Abstract

PURPOSE:To fix iodine even in a porous membrane made of a material incapable of binding iodine without deteriorating its water filtering function by fixing elutable iodine on the surfaces of at least a part of the pores of the membrane with a fixing agent. CONSTITUTION:The thin film of a fixing agent of an acrylonitrile-based resin, a polyamide-based resin, etc., is formed on the whole or a part of the surface of the pore of the porous membrane such as a hollow-fiber membrane made of the PE, PP, etc., incapable of binding iodine. The thickness of the thin film is controlled so that the characteristic of the membrane such as water permeability is not deteriorated. An iodine soln. is then brought into contact with the film of the fixing agent to bind the iodine to the film. When water is treated with the porous membrane as the filter membrane, a trace amt. of iodine is gradually eluted into water and diffused, and a sterilizing effect is produced over the whole surface of the membrane. In addition, the water permeated through the membrane also contains iodine, and exerts a sterilizing effect.

Description

[Detailed Description of the Invention] [; Icheon Field of Telecommunications Industry] The present invention has excellent sterilizing properties and uses only 1 J of water! The present invention relates to a porous membrane useful as an LA membrane.

[Prior art] Iodine is well known to have excellent bactericidal properties.
Since ancient times, it has been widely used for external medicinal purposes such as iodine tincture.

Iodine has a bactericidal effect even in extremely small amounts, so for example,
By continuously administering a very small amount of iodine to the water in a container that is replaced batchwise or continuously with fresh water, the sterilization effect of the water in the container can be sustained over a long period of time. can. Moreover, if extremely high iodine is continuously administered to the water flowing through the waterway in the upstream part, sterilized water can always be obtained in the downstream part.

Such continuous administration of iodine can be easily carried out by immobilizing iodine on the wall of a container or waterway that comes into contact with water in a state where it can be gradually eluted.

For example, Japanese Patent Publication No. 60-1337 by the present inventors discloses a polymer resin that has permanent bactericidal properties due to the binding of iodine and can exhibit the bactericidal effect by leaching out iodine as described above. Molded products are described.

As the constituent material of this polymer resin molding, materials having an iodine binding ability such as polyaxronitrile, polyamide, polyvinyl alcohol, and cellulose acetate are used.

[Problem to be solved by the invention] The present inventors have discovered that water is 1%! From the viewpoint that if iodine is fixed in a common porous membrane in such a way that it can be gradually eluted, iodine will have a long-term bactericidal effect on the porous membrane itself and on the filtered water that has passed through the porous membrane. Various studies were conducted on effective fixing methods to porous membranes.

At that time, iodine cannot be directly bonded to porous membranes made of materials that do not have iodine binding ability, such as polyethylene and polypropylene, so iodine cannot be directly bonded to porous membranes made of these materials. An effective fixation method was needed.

The present invention has been made to solve the above problems,
The purpose is to provide a technology that can fix iodine even in a porous membrane made of a material without iodine binding ability, without sacrificing its water filtration function.

[A Thousand Steps to Solve the Problem] The bactericidal porous membrane of the present invention has iodine immobilized on the surface of at least some of the pores of the pores using a fixing agent in a state where it can be eluted. be.

In addition, porous in the present invention! The term "at least some of the pore surfaces" refers to all or part of the pore inner surfaces and pore outer surfaces of the porous membrane.

The porous membrane constituting the sterilizing porous membrane of the present invention includes:
Any porous membrane that can bind iodine via a fixing agent can be used without any restrictions.

In particular, the configuration of the present invention is particularly useful when the porous membrane is made of a resin material that does not have iodine binding ability, such as polyethylene, polypropylene, polytetrafluoroethylene, or the like.

There are no particular restrictions on the form of the porous membrane, and any desired form such as a sheet or hollow fiber may be used. It has the advantage that it can be suitably applied to porous hollow fibers made of polyethylene, polypropylene, polytetrafluoroethylene, etc., which have a continuous porous structure.

As an immobilizing agent that mediates the fixation of iodine to the inner wall surface of the pores, it can bind so that iodine can be gradually eluted, has excellent adhesion to the porous membrane, and is suitable for immobilizing the iodine on the pore surface of the porous membrane. Various materials can be used as long as they do not impair the functions of the porous membrane when retained, and may be selected as appropriate depending on the type of porous membrane used.

Examples of the fixing agent include acrylonitrile resin, polyamide resin, polyvinyl alcohol resin,
Polymer materials with iodine binding ability, such as cellulose acetate resins and proteins, can be easily coated with iodine by the coagulation method described below, and with a strong binding force that allows the required extremely small amount of iodine to be produced. This is preferred because it can easily be bound to the immobilizing agent.

In addition, if sterilization can be achieved within the range in which iodine is eluted and diffused when the porous membrane is in contact with water, the fixation of iodine by the fixing agent will affect all of the pore surfaces of the porous 71 membrane. It does not have to be done on the entire surface, and may be done on a part of the surface.

However, in order to maintain the bactericidal effect over a long period of time, it is preferable to fix a larger amount of iodine within a range where the 11-hyperfunctionality is not impaired by the attachment of the fixing agent.

As such a method, a method is suitable in which a thin film of a fixing agent is formed on the entire surface or a part of the pore surface of the porous membrane, and iodine is bonded evenly to the thin film. The thickness of the thin film of the fixing agent is preferably set to a level that does not impair the properties of the porous material 11i, such as water permeability.

Solidification of iodine using a fixing agent on a porous membrane. For example, after forming a film of a fixing agent on the pore surface of a porous membrane,
A method can be used in which iodine is bonded to the fixed cutting coating.

Formation of the fixing agent film can be carried out, for example, by immersing a solution of a polymeric material as a fixing agent on the pore surface of the porous membrane in a solution that can solidify the polymeric material, and The solidification of the polymer material can be easily carried out by the method of forming the fluorine on the surface of the pores of the porous material 11q.

In addition, a solution of a polymeric material as a fixing agent is applied to a porous ′ζ′t
I+! ;! A method may be used in which the polymeric material is attached to the pore surface of the porous material and then dried to remove the solvent, thereby forming a film of the polymer material on the porous pore surface.

Iodine can be bound to the fixing agent coating by a method such as bringing an iodine solution into contact with the fixing agent coating formed on the pore surface of the porous membrane.

The above operating conditions for forming the fixing agent film and binding iodine can be appropriately selected depending on the type of porous membrane, the type of fixing agent, the desired amount of iodine fixed, and the like.

When forming a film of a fixing agent on a porous membrane, the concentration of the fixing agent in the fixing agent solution is preferably in the range of 0.2 to 1% by weight.

In addition, the iodine concentration of the iodine/potassium iodide aqueous solution used to bond iodine to the fixative film is 0.1.
~0.4 a+ol/j? Preferably the river is in the range of

The sterilizing porous membrane of the present invention having the configuration described above is
Iodine is fixed on at least a portion of the pore surface of the porous membrane so that it can be gradually eluted, so when this porous membrane is used as a filtration membrane to treat water, iodine can be extracted from the porous membrane. Although the bottle is extremely small, it gradually dissolves and diffuses into the water, providing a sterilizing effect over the entire surface of the porous membrane.

In addition, the water that has passed through the porous membrane also contains iodine and has a bactericidal effect.

This bactericidal effect lasts until all of the fixed iodine dissolves, and its duration is determined by the state of iodine fixation.

Therefore, if you want to maintain the bactericidal effect, it is necessary that iodine be bound to the immobilizing agent with a strong bonding force that allows the extremely small amount of iodine to dissolve, and it will easily fall off if it is simply attached or weakly adsorbed. Therefore, it is only possible to maintain the bactericidal effect over a long period of time.

The strength of the bond between the immobilizing agent and iodine can be determined, for example, by immersing porous l9 on which iodine has been immobilized in a sodium thiosulfate aqueous solution and measuring the amount of sodium thiosulfate consumed, or by measuring the degree of discoloration of the porous membrane. You can know it by observing it.

For example, if iodine is simply attached or adsorbed by weak binding force, when a porous membrane with fixed iodine is immersed in an aqueous solution of sodium thiosulfate at room temperature, the porous membrane will turn a brownish brown characteristic of iodine in a very short time. can be observed to disappear.

The stiffness is due to the fact that iodine, which is attached or adsorbed by weak binding force, is concentrated by sodium thiosulfate and desorbed from the porous membrane in a very short period of time.

On the other hand, iodine bound with strong binding strength is difficult to react with sodium thiosulfate, so even if a porous membrane with iodine bound with strong binding strength is immersed in an aqueous solution of sodium thiosulfate, the porous membrane will not react with sodium thiosulfate. The brown color characteristic of iodine is maintained for a long time.

[Examples] The present invention will be explained in more detail below using Examples and Comparative Examples.

In addition, the bactericidal properties and water permeability in the following Examples and Comparative Examples were measured according to the following methods.

(1) Measurement of bactericidal activity: Test porous hollow fibers with a length of 1 cm were placed side by side on an agar medium inoculated with Staphylococcus aureus (Et!Kanpudan Aureus), and incubated at 37°C for 24 hours. Culture was carried out for a period of time, and the presence or absence of bacterial growth around the test sample was observed to determine the bactericidal effect.

(Toshitada) ○: No bacterial growth was observed around the sample.
A halo consisting of areas with no bacterial growth was clearly formed.

△: Observation of bacterial growth around the sample Not a clear halo shape growth was not recognized.

X: Bacterial growth is observed around the sample. It was.

(2) Water permeability iitl + constant; 400 sample porous hollow fibers were bundled in a U-shape, each hollow fiber was opened [one part was hardened with resin, and placed in a predetermined position in a container with the structure shown in Figure 1]. A filtration module was fabricated by fixing it.

The effective length of the porous hollow fiber sample was 16 cm, and the length of the buried portion within the resin 3 was 1 cm.

This '6! The i-filtration module was immersed in ethyl alcohol at 25° C. for 30 minutes to make the porous hollow fibers hydrophilic, and then washed with water. In this state, water is supplied from the water inlet 4, and water is permeated from the outer wall surface of the hollow fiber toward the hollow part at a water pressure of 1 kg/cIn2 for 1 minute, and the amount of water discharged from the water inlet 5 is measured. From the results, the amount of water permeation per unit surface area of the hollow fiber was calculated, and this was defined as water permeability (mu/min.cm).

Example 1 A porous polyethylene hollow system (trade name: EHF270T, outer diameter 380 μm, inner diameter 270 μm, manufactured by Mitsubishi Rayon Co., Ltd.) was mixed with 50% by weight of acrylonitrile and 50% by weight of vinyl chloride.
0.5 parts by weight of an acrylonitrile polymer dissolved in 99.5 parts by weight of dimethylformamide was immersed for 1 minute in a solution at 25°C, and the solution was squeezed, thereby adhering the acrylonitrile polymer solution to the hollow fibers. Change the amount to 285”*
I made it owf.

Subsequently, this hollow fiber was immersed in water at 30°C for 1 minute,
After coagulating the acrylonitrile resin, wash thoroughly with water,
Next, it was dried for 2.1 hours at 60°C using a vacuum dryer.
A porous polyethylene hollow fiber having a thin film of acrylonitrile resin formed on the surface having a porous structure was obtained.

When the outer surface of this porous polyethylene hollow fiber was observed using an electron microscope, it was confirmed that a thin film of acrylonitrile resin was evenly formed on the surface of the porous structure.

Next, this porous hollow fiber having a thin film of acrylonitrile resin was immersed in a 20°C aqueous solution containing 0.31 Ilol/IL of iodine and 1 mol/42 potassium iodide for 1 hour, and then thoroughly washed with water. A porous hollow fiber in which iodine was bonded to a thin film of acrylonitrile resin was obtained.

The obtained porous hollow fibers were colored brown and had a 0.
1 mol/42 sodium thiosulfate aqueous solution at 20°C
Even after being immersed in water for 24 hours, the brown colored state was maintained, indicating that iodine was strongly bound to the thin film of acrylonitrile resin.

Table 1 shows the measurement results of the bactericidal properties and water permeability of this iodine-fixed porous hollow fiber.

Example 2 The porous polyethylene hollow fibers used in Example 1 were prepared by dissolving cellulose cyacetate [acetate fiber Soalon (manufactured by Yuliang Rayon Co., Ltd.)] in 99.5 parts by weight of acetone at 25°C. 1 in a solution of
After diluting for a minute, the solution was squeezed to make the amount of cellulose diacetate solution attached to the hollow fibers 265% owf.

Subsequently, this hollow fiber was immersed in water at 30°C for 1 minute,
After coagulating cellulose diacetate, wash thoroughly with water,
Next, it was dried at 60°C for 24 hours using a vacuum dryer, and a thin layer of cellulose diacetate was applied to the surface of the porous structure.
A porous polyethylene hollow fiber having a density of 1% was obtained.

When the outer surface of this porous polyethylene hollow fiber was observed using an electron microscope, it was confirmed that an uneven thin film of cellulose diacetate was formed on the surface of the porous structure.

Next, iodine was bonded to the cellulose diacetate thin film of this porous hollow fiber in the same manner as in Example 1.

The obtained porous hollow fibers were colored brown and were treated with sodium thiosulfate aqueous 'tpi. Even when immersed in the cellulose diacetate, the brown colored state was maintained, indicating that iodine was strongly bound to the thin film of cellulose diacetate.

Table 1 shows the measurement results of the bactericidal properties and water permeability of this iodine-fixed porous hollow fiber.

Example 3 The porous polyethylene hollow fibers used in Example 1 were prepared by dissolving 0.5 li parts of an acrylonitrile copolymer resin consisting of 93% by weight of acrylonitrile and 7ffl% of vinyl acetate in 99.5 parts of dimethylformamide. The hollow fibers were immersed in a solution at 25°C and squeezed to remove the adhesion of the acrylonitrile copolymer resin solution to the hollow fibers at 270% o.
It was set as wf.

Subsequently, the hollow fibers were immersed in water at 40°C for a minute to solidify the acrylonitrile copolymer resin, thoroughly washed with water, and then dried at 60°C for 24 hours using a vacuum dryer to form a porous structure. A porous polyethylene hollow fiber having a thin film of acrylonitrile copolymer resin formed on the surface was obtained.

When the outer surface of this porous polyethylene hollow fiber was observed using an electron microscope, it was confirmed that a thin film of acrylonitrile copolymer resin was evenly formed on the surface of the porous structure.

Next, iodine was bonded to the porous hollow fiber acrylonitrile copolymer resin thin film in the same manner as in Example 1.

The obtained porous hollow fibers were colored brown, and even when immersed in an aqueous sodium thiosulfate solution in the same manner as in Example 1, the brown colored state was maintained, indicating that the iodine was acrylonitrile-based copolymer. It was found that it was strongly bonded to the resin thin film.

Comparative Example 1 The sterilization properties and water permeability of the porous polyethylene hollow fibers used in Example 1 were measured. The results are shown in Table 1.

Table [Effects of the invention] Water a that effectively utilizes the bactericidal properties of iodine according to the present invention
A suitable porous membrane was provided.

In water filtration using a filtration module manufactured by incorporating the iodine-fixed porous membrane of the present invention as a filtration membrane,
Microorganisms such as bacteria captured by the filter membrane are porous 1l5! The iodine gradually eluted from the water effectively kills germs. Therefore, it is possible to effectively prevent bacteria from propagating in the filters 14 and 11Q, clogging the filter membrane, and causing deterioration and abnormal odor in the filtered water.

[Brief explanation of drawings]

Figure 1 shows water permeability itI! FIG. 2 is a schematic cross-sectional view showing the configuration of a filtration module manufactured at the time of the test. 1: Filtration module 2: Porous hollow fiber 3: Resin 4, 5, Water port Patent applicant Mitsubishi Rayon Co., Ltd.

Claims (1)

[Scope of Claims] 1) A bactericidal porous membrane in which iodine is immobilized on the surface of at least some of the pores of the porous membrane with a fixing agent in a state where it can be eluted. 2) The sterilizing porous membrane according to claim 1, wherein the porous membrane is a porous hollow fiber.