JPH09302459A - Antibacterial filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antibacterial filter capable of maintaining sufficient antibacterial activity for a long time by coating the surface of a porous filter substrate with an antibacterial membrane by vapor deposition and ion irradiation at the same time. SOLUTION: An antibacterial membrane M1 consisting of at least one kind among Ag, Au, Pt, Cu, Zn, Sn, Ir and TiO2 is formed on the surface of a filter substrate S consisting of a polymeric material. Further, an adhesive layer M3 consisting of at least one kind among Ti, Cr and Si is formed between the substrate S and the membrane M1 to improve the adhesion of the membrane. Otherwise, a barrier layer M2 consisting of Au, Pt and Au is formed between the membrane M1 and adhesive layer M3 to suppress the outflow of the membrane M1 constituent into an external fluid 2 due to the cell reaction between the membrane M1 and layer M3. The membrane M1 is formed by jointly using vapor deposition and ion irradiation. Besides, mixed layers m1, m2 and m3 can be formed between the membrane M1, M2 and M3 and the respective lower layers to further improve the adhesion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial filter for filtering fluid such as liquid and gas, which has antibacterial activity.

[0002]

2. Description of the Related Art As a filter for filtering a fluid, filter paper, depending on the type and size of the object to be removed,
A filter cloth, an ultrafiltration membrane having a large number of fine holes, and the like are used. Particularly, the ultrafiltration membrane is widely used for removing bacteria and the like because it can control the pore size. When such a filter is used for a long period of time, bacteria accumulated on the membrane proliferate, clogging the pores and generating an offensive odor. Therefore, it has been attempted to impart antibacterial activity to the filter itself.

For example, according to Japanese Patent Application Laid-Open No. 2-68105, an antibacterial filter in which a silver film having antibacterial properties is formed by vapor deposition on the filter cake deposition side of a filter such as an ultrafiltration membrane, filter cloth or filter paper It is disclosed that the growth of bacteria deposited on the above can be suppressed. Also, Japanese Patent Application Laid-Open No. 4-2
According to Japanese Patent No. 2410, a filter having an ion exchanger having silver ions bonded to its surface has an antibacterial activity while the silver ions remain bound to the ion exchanger regardless of the elution of silver ions into the liquid. Therefore, it is disclosed that the activity is maintained.

In addition to the above, there has been proposed a filter in which a zeolite carrying silver ions is kneaded into a polymer material to form a filter.

[0005]

However, in the antibacterial filter according to the above-mentioned Japanese Patent Application Laid-Open No. 2-68105, since silver having antibacterial activity is provided as a film on the filter surface, sufficient antibacterial activity is obtained in the initial stage of use. Although effective, the film formed by vapor deposition is inferior in adhesiveness, so that partial peeling easily occurs during use, and it is difficult to maintain sufficient antibacterial activity for a long time.

Also, in the antibacterial filter according to the above-mentioned Japanese Patent Laid-Open No. 4-22410, since the ion exchanger to which silver ions are bound is adhered using the binder, the ion exchanger is easily peeled off during use. , It is difficult to maintain sufficient antibacterial activity for a long time. Also,
With the filter in which the above-described silver ion-supported zeolite is kneaded, sufficient antibacterial activity cannot be obtained on the filter surface.

Therefore, the present invention is a filter having antibacterial activity, which has sufficient antibacterial activity to suppress the growth of bacteria and the like deposited on the filter, and which is used while maintaining the activity for a long time. An object of the present invention is to provide an antibacterial filter that can do the above.

[0008]

In order to solve the above problems, the antibacterial filter of the present invention is selected from metal having antibacterial activity and ceramic having antibacterial activity on the surface of a porous filter substrate made of a polymer material. At least 1
It is coated with an antibacterial film composed of various substances.

According to the antibacterial filter of the present invention, since the antibacterial substance is provided as a film on the surface of the filter substrate, it has an antibacterial activity sufficient to suppress the growth of bacteria and the like deposited on the filter. In the antibacterial filter of the present invention, the antibacterial film is formed on the surface of the filter substrate. In that case, if necessary, it may be formed over the entire surface or on the surface on the filter cake deposition side. Good. In addition, without reducing the size of the hole significantly,
An antibacterial film may be formed on the inner surfaces of the pores as long as they can be normally used as a filter.

The type of the filter substrate of the present invention is not particularly limited as long as it can form a film on the surface such as an ultrafiltration membrane, a filter cloth and a filter paper. Examples of the polymer material include polyurethane, polyethylene, polypropylene and the like, which are commonly used as filter materials, and are not particularly limited. Examples of the metal having the antibacterial activity include Ag having a strong antibacterial activity. In addition, noble metals such as Au, Pt, and Ir, and Cu, Zn, and the like.
Sn or the like can also be used. Examples of the ceramic having antibacterial activity include TiO _{2 and the} like.

The thickness of the antibacterial film is 50 nm or more and 5 μm or more.
It is desirable that the thickness be about the following or less, but this is because the film thickness is 50 n.
If it is smaller than m, it is difficult to cover the irregularities on the surface of the filter substrate entirely and there is a risk that sufficient antibacterial activity may not be obtained. This is because peeling easily occurs along the line. The film thickness is appropriately determined within the above range according to the material of the film, the material of the filter substrate, the pore diameter of the filter substrate, and the like. For example, if the pore size of the filter substrate is small,
It is conceivable that the film thickness is appropriately reduced without significantly reducing the hole diameter by forming a film on the inner peripheral surface of the hole or the edge of the hole.

In the antibacterial filter of the present invention, it is conceivable to have an adhesion layer made of at least one of Ti, Cr and Si between the filter substrate and the antibacterial film. Each of these adhesive layer materials has relatively good compatibility with both the polymer material and the antibacterial membrane material, and plays a role of enhancing the adhesiveness between the filter substrate and the antibacterial membrane. For example, when the antibacterial film is an Ag film, a Ti adhesion layer can be employed.

Further, it is conceivable that the antibacterial filter of the present invention has a barrier layer made of Au or Pt or both of them between the adhesion layer and the antibacterial film.
For example, when the antibacterial film is an Ag film and the adhesion layer is a Ti layer, a barrier layer made of Au or Pt can be used. Without a barrier layer, oxygen may diffuse through the antimicrobial film, in which case the oxygen reaches the interface between the antimicrobial film and the adhesion layer, and the antimicrobial film is likely to peel off at this portion. . In addition, when the barrier layer is not provided, the antibacterial film constituting material is easily diffused into the adhesion layer, and in this case, the antibacterial film is easily peeled off. The diffusion of the substance can be suppressed, and the adhesion of the antibacterial film can be improved. When the barrier layer is not provided, a battery reaction is likely to occur between the antibacterial film and the adhesion layer, and when the battery reaction occurs, the antibacterial film constituent atoms are ionized and flowed out of the film into the external fluid. However, Au or (and) P which is electrochemically more noble than the antibacterial film constituent element
By forming the barrier layer composed of t between the antibacterial film and the adhesion layer, it is possible to suppress the flow-out of the atoms constituting the antibacterial film due to the battery reaction.

In the antibacterial filter of the present invention, when the antibacterial film only has the antibacterial film, the antibacterial film is formed, and when the antibacterial film and the adhesive layer are provided, either or both of the antibacterial films are formed. When it has a barrier layer and an adhesion layer, it is considered that at least one film (layer) is formed by an ion vapor deposition thin film forming method using both vapor deposition and ion irradiation.

Thus, the ion irradiation surface is activated by the action of the irradiation ions, and a mixed layer of the both is formed between the formed film (layer) and the lower layer, thereby forming the film (layer). Adhesion is improved. Peeling is less likely to occur even when the filter is bent. The irradiation ions include nitrogen ions, hydrogen ions, inert gas ions (helium (He) ions, neon (Ne) ions, argon (A).
r) ion, krypton (Kr) ion, xenon (X
e) Ions etc.) can be used.

The acceleration voltage during ion irradiation varies depending on the ion species, the material of the ion irradiation surface, etc., but is 100 V or more and 2 kV.
It is desirable to set it to the following level. This is because if the voltage is less than 100 V, the ion-irradiated surface is not sufficiently activated and the film adhesion is weak, and if it is more than 2 kV, the heat of the ion irradiation may deteriorate the filter substrate. Because it is big.

In the antibacterial filter of the present invention, it is conceivable to use a filter substrate whose surface is cleaned by ion irradiation before film formation. In this case, the film adhesion is further improved.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 (A), (B), (C) and (D) are enlarged sectional views of a part of the antibacterial filter which is an embodiment of the present invention. The antibacterial filter shown in FIG. 3A has Ag, Au, Pt, Cu, Zn, Sn, Ir and Ti on the surface of a filter substrate S made of a polymer material.
Antibacterial film M1 made of at least one of O ₂
Are formed. The filter substrate S is provided with a large number of small holes (not shown), and the membrane M is also formed on the inner peripheral surface of the small holes.
1 is formed. This antibacterial filter has a practically sufficient antibacterial activity because the antibacterial substance is applied to the surface of the filter substrate S as the film M1.

The antibacterial filter shown in FIG. 2B is the same as the filter shown in FIG.
1 and the adhesion layer M3 made of at least one of Ti, Cr, and Si. This antibacterial filter has good film adhesion because the adhesion layer M3 has good compatibility with both the substrate S and the film M1.

The antibacterial filter shown in FIG. 6C has the antibacterial film M1 and the adhesion layer M3 in the filter shown in FIG.
The barrier layer M2 made of Au, Pt or Au and Pt is formed between In this antibacterial filter, due to the presence of the barrier layer M2 made of an electrochemically stable substance, oxygen diffuses from the outside through the film M1 and the film M
No. 1 and the layer M3 at the interface, or partial peeling of the film M1 due to diffusion of the constituent components of the film M1 into the layer M3, and the structure of the film M1 associated with the battery reaction between the film M1 and the layer M3. The loss of components into the external fluid is suppressed.

The antibacterial filter shown in FIG. 7D is the same as the filter shown in FIG. 7C, except that the antibacterial film M1, the barrier layer M2 and the adhesion layer M3 are all formed by the ion deposition thin film forming method. And mixing layers m1, m2, and m3 are provided between the layers and the lower layers. This antibacterial filter, due to the presence of the mixed layers m1, m2, m3,
The adhesion between the antibacterial film M1 and the barrier layer M2, between the barrier layer M2 and the adhesion layer M3, and between the adhesion layer M3 and the filter substrate S is better.

It is also conceivable that the antibacterial filter shown in FIG. 3C has only one or two mixed layers. Also in the antibacterial filter of FIG. (A), it is considered that the antibacterial film M1 is formed by the ion deposition thin film forming method, and in the antibacterial filter of FIG. (B), the antibacterial film M1 or (and) It is considered that the adhesion layer M3 is formed by the ion deposition thin film forming method.

Incidentally, in each of the antibacterial filters, similar films are formed on the inner surfaces of a large number of holes (not shown).
Further, FIG. 2 is a diagram showing a schematic configuration of a film forming apparatus capable of manufacturing the antibacterial filter according to the present invention. This apparatus has a vacuum container 1, and inside the container 1, a holder 2 for supporting a film-forming filter substrate S and an electron beam evaporation source 3 and an ion source 4 are provided at positions facing the holder 2. A film thickness monitor 5 and an ion current measuring device 6 are arranged near the holder 2. Further, the container 1 is provided with an exhaust device 11 so that the inside of the container 1 can be kept at a predetermined degree of vacuum.

Next, a concrete example of manufacturing the antibacterial filter shown in FIG. 1D according to the present invention by using the apparatus shown in FIG. 2 will be described. As the film formation filter substrate S, one made of polyurethane was used. Prior to film formation, the surface of the filter substrate S was ultrasonically cleaned with an alcoholic organic solvent and then dried at 60 ° C. for 30 minutes. Then, the filter substrate S is placed in the container 1 of the apparatus shown in FIG.
Is carried in, and after being supported by the holder 2 so that a film is formed on the surface on which filter cake is deposited when the filter is used, the inside of the container 1 is evacuated to a vacuum of 1 × 10 ⁻⁶ Torr or less by operating the exhaust device 11. I took it.

Then, using the electron beam evaporation source 3, Ti
Are evaporated and vapor-deposited on the filter substrate S supported by the holder 2 and, at the same time, Ar ions from the ion source 4
The deposition surface was irradiated with an acceleration voltage of 00 V to form a Ti adhesion layer M3 having a layer thickness of 50 nm on the substrate S. Accordingly, a mixed layer m3 of the base S and the adhesion layer M3 was formed at the interface between the two.

Then, similarly to the formation of the Ti adhesion layer M3, Pt vapor deposition and Ar ion irradiation are performed at the same time to form Ti.
A Pt barrier layer M2 having a layer thickness of 50 nm was formed on the adhesion layer M3. Accordingly, a mixed layer m2 of the adhesion layer M3 and the Pt barrier layer M2 was formed at the interface between the two. Then
Similar to the formation of the Ti adhesion layer M3 and the Pt barrier layer M2, Ag vapor deposition and Ar ion irradiation are performed simultaneously to form an Ag antibacterial film M having a thickness of 1 μm on the Pt barrier layer M2.
1 was formed. Accordingly, a mixed layer m1 of the Pt barrier layer M2 and the Ag antibacterial film M1 was formed at the interface between the two.

During the film formation, the vacuum degree in the vacuum chamber 1 was maintained at about 5 × 10 ^-5 Torr. Thus, FIG.
As shown in (D), an antibacterial filter was obtained in which an adhesion layer M3, a barrier layer M2 and an antibacterial film M3 were formed in this order on one surface of the filter substrate S. Next, the antibacterial filter obtained according to the embodiment of the present invention, the antibacterial filter having an Ag film formed on the substrate S by the ion plating method (Comparative Example 1), and the Ag film on the substrate S by the sputter deposition method. With respect to the formed antibacterial filter (Comparative Example 2), the state of the film immediately after film formation was visually observed. In addition, each of the antibacterial filters was left in a high temperature and high humidity environment at a temperature of 90 ° C. and a humidity of 95% for up to 100 hours, during which time an X-cut tape test (JIS K5400)
The film adhesion was evaluated by a tape peeling test (used without cutting due to the shape characteristics of the test article) according to the above. The results are shown in the following table. Immediately after film formation Film state in X-cut tape test 0 hours 10 hours 50 hours 100 hours Example No peeling No peeling No peeling No peeling No peeling Comparative Example 1 No peeling Peeling Peeling Peeling Peeling Comparative Example 2 No peeling Peeling The antibacterial filter according to the embodiment of the present invention, in which each film (layer) is formed by the ion deposition thin film forming method, has a good film adhesion even after being left for 100 hours in a high temperature and high humidity environment. Showed sex. On the other hand, in each of the antibacterial filters according to Comparative Examples 1 and 2 in which a similar film was formed without using ion irradiation, no film peeling was observed immediately after the film formation. It can be seen that peeling has occurred even before being left in, and it is difficult to put into practical use.

Next, the antibacterial activity against Escherichia coli was evaluated for the antibacterial filter and the untreated filter substrate S on which no film was formed, which were obtained in the above-mentioned Examples of the present invention. The antibacterial activity was evaluated by the viable cell count (colony forming unit) by the shake flask method defined in JIS L1902.
/ ml) for 24 hours after the start of culture. The results are shown in the following table. Cultivation time after filter addition (hours) 0 4 8 24 Example 5.0 × 10 ⁵ 3.0 × 10 ⁴ 1.7 × 10 ⁴ Below detection limit Untreated 3.2 × 10 ⁵ 4.0 × 10 ⁴ 2.0 × 10 ⁴ 2.6 × 10 ⁴ The antibacterial filters of the examples of the present invention showed strong bactericidal activity, and the viable cell count was below the detection limit 24 hours after the addition of the filter. On the other hand, in the untreated filter substrate S, such a decrease in the viable cell count was not observed.

[0029]

EFFECTS OF THE INVENTION According to the method of the present invention, a filter having antibacterial activity, which has sufficient antibacterial activity to suppress the growth of bacteria and the like deposited on the filter and maintains the activity for a long time It is possible to provide an antibacterial filter that can be used.

[Brief description of drawings]

FIG. 1 (A), (B), (C) and (D) are enlarged cross-sectional views of a part of an antibacterial filter which is an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a film forming apparatus capable of manufacturing an antibacterial filter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 11 Evacuation device 2 Film-forming article support holder 3 Electron beam evaporation source 4 Ion source 5 Film thickness monitor 6 Ion current measuring device S Filter substrate M1 Antibacterial film M2 Barrier layer M3 Adhesive layer m1, m2, m3 Mixed layer

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area C23C 14/48 C23C 14/48 D

Claims (9)

[Claims] 1. A surface of a porous filter substrate made of a polymeric material is coated with an antibacterial film made of at least one substance selected from a metal having antibacterial activity and a ceramic having antibacterial activity. An antibacterial filter characterized in that the film is formed by an ion vapor deposition thin film forming method using both vapor deposition and ion irradiation. 2. The metal having antibacterial activity is silver (A
g), gold (Au), platinum (Pt), copper (Cu), zinc (Zn), tin (Sn) and iridium (Ir), and the ceramic having antibacterial activity is titanium dioxide (TiO ₂ ). The antibacterial filter according to claim 1. 3. The antibacterial film has a thickness of 50 nm or more and 5 μm.
The antibacterial filter according to claim 1 or 2, which is m or less. 4. An adhesion layer made of at least one substance selected from titanium (Ti), chromium (Cr) and silicon (Si) is formed on the surface of a porous filter substrate made of a polymer material. Silver (Ag), gold (Au), platinum (Pt), copper (Cu), zinc (Zn), on the outside of the adhesion layer,
An antibacterial filter comprising an antibacterial film formed of at least one substance selected from tin (Sn), iridium (Ir) and titanium dioxide (TiO ₂ ). 5. The antibacterial filter according to claim 4, wherein at least one of the adhesion layer and the antibacterial film is formed by an ion vapor deposition thin film forming method using both vapor deposition and ion irradiation. 6. The antibacterial film has a thickness of 50 nm or more and 5 μm.
The antibacterial filter according to claim 4 or 5, which is m or less. 7. An adhesion layer made of at least one substance selected from titanium (Ti), chromium (Cr) and silicon (Si) is formed on the surface of a porous filter substrate made of a polymer material. A barrier layer made of gold (Au) or platinum (Pt) or gold and platinum is formed outside the adhesion layer, and silver (Ag), gold (Au), platinum (Pt), copper (Cu) is formed outside the barrier layer. ), Zinc (Zn), tin (Sn),
An antibacterial filter comprising an antibacterial film formed of at least one substance selected from iridium (Ir) and titanium dioxide (TiO ₂ ). 8. The film (layer) of at least one of the adhesion layer, the barrier layer and the antibacterial film is formed by an ion deposition thin film forming method using both deposition and ion irradiation. The described antibacterial filter. 9. The antibacterial film has a thickness of 50 nm or more and 5 μm.
The antibacterial filter according to claim 7 or 8, which is m or less.