JP3465018B2 - Antibacterial laminate - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antibacterial laminate which exhibits bactericidal properties, antibacterial properties and antifungal properties (hereinafter collectively referred to as antibacterial properties) over a long period of time.

[0002]

2. Description of the Related Art Conventionally, as an antibacterial agent having a bactericidal, antibacterial and antifungal effect (hereinafter collectively referred to as an antibacterial effect), silver or copper in a metallic or ionic state has been known. As a method of containing these antibacterial agents on the surface of a molded body or a structure (hereinafter simply referred to as a structure),
For example, an antibacterial and antifungal treatment method for ceramics and enamel has been proposed in which silver phosphate powder is laminated on the surface of the ceramics or enamel and fired (JP-A-6-234584).

A method utilizing an antibacterial action by a photocatalyst such as titanium oxide is also known. For example, Japanese Patent Laid-Open No. 6-
No. 209985 proposes a method in which a photocatalyst is carried on the surface of a wall material of a building, and the interior of the room is subjected to antibacterial treatment by light hitting the wall material.

The above-mentioned antibacterial agents such as metals and metal ions have an advantage of exhibiting an antibacterial action even in a dark place, but have a drawback that the effect is reduced when the surface is soiled or dead bodies of bacteria are accumulated. is there. The antibacterial agent (metal ion) is
A system that continuously supplies inorganic metal ions to the surface of the structure is required because it decreases with time due to desorption, peeling, and the like, and activity decreases. On the other hand, the photocatalyst can photodecompose pollutants and carcasses, so that it can maintain a clean surface and continue the antibacterial action, but if it does not have a sufficient amount of light, it does not exhibit the action.
For this reason, various methods have been proposed in which the two are combined to compensate for each other's drawbacks.

A structure using a combination of an antibacterial agent and a photocatalyst, for example, an enamel, includes an enamel layer containing an antibacterial agent and a photocatalyst (FIG. 2 ), and a photocatalyst containing an antibacterial agent in advance. A photocatalyst is concentrated on the surface of the enamel by applying a coating agent to the surface of the enamel (Fig. 3 ), or a photocatalyst layer is provided on the surface of the enamel and an antibacterial agent is carried or fixed on the surface of the enamel ( Fig. 4 ) is known. However, none of the above techniques can be said to satisfy the requirements for both antibacterial action and its sustainability due to insufficient antibacterial action or insufficient sustainability of action.

[0006]

DISCLOSURE OF THE INVENTION In order to solve the above-mentioned problems of the conventional antibacterial structure, the present inventors have used silver ions (silver salt) as an antibacterial agent and titanium oxide particles as a photocatalyst. As a concrete example, the antibacterial enamel steel plate containing the same was examined, especially as to its structure. For example, in the structure shown in FIG. 2 , it was found that the titanium oxide particles (photocatalyst) were buried in the enamel layer and could not work sufficiently. It was also found that the structure shown in FIG. 3 or FIG. 4 reduces the antibacterial agent (silver ion) and reduces the antibacterial effect after long-term use.

[0007]

Means for Solving the Problems The present inventor has further studied and found that when the enamel layer contains an antibacterial agent and a photocatalyst, the antibacterial agent exudes little by little on the surface for a long period of time to maintain the antibacterial effect. On the other hand, it was found that the photocatalyst does not show any antibacterial action except those exposed on the surface. Further antimicrobial agent, as shown in FIG. 3 or FIG. 4,
When concentrated on the surface, it quickly desorbs and loses its antibacterial action, whereas when dispersed in the enamel layer, it retains the antibacterial action for a long time without desorption, while the photocatalyst is highly effective on the surface. It was also found that the concentrated antibacterial action has a higher antibacterial effect, and even if it is concentrated on the surface, it will not be desorbed for a long period of time if it is immobilized and the antibacterial effect is maintained.

Therefore, if a structure in which the antibacterial agent is dispersed in the enamel layer and the photocatalyst is concentrated and immobilized on the surface, the combined effect of both can be most efficiently exhibited. The present invention has been made based on such knowledge, and such a concept (structure) was created by the present inventor. It was also found that the effect of such a structure can be applied not only to the enamel steel plate but also to the coated steel plate and the stainless steel plate containing the antibacterial agent.

[0009] That antibacterial laminate according to the present invention, under
Antibacterial gold formed on at least one surface of the base material
Antibacterial layer containing genus and / or antibacterial metal ion
And exhibit a photocatalytic function formed on the surface of the antibacterial layer
A photocatalyst layer containing that substance is characterized laminate der Rukoto consisting. Such an antibacterial laminate exhibits antibacterial properties for a long period of time. In the present invention, the substance having a photocatalytic function is preferably exposed on the outermost surface of the laminate.

The antibacterial metal is preferably at least one selected from silver, copper and zinc, and the antibacterial metal ion is preferably at least one selected from silver ion, copper ion and zinc ion. It is also possible to use an organic antibacterial agent such as an ammonium salt type or a cyclic nitrogen sulfur compound type. The substance having a photocatalytic function is preferably titanium oxide. The antibacterial layer usually contains a binder, for example enamel, glass or resin.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The antibacterial laminate according to the present invention will be specifically described below. Antibacterial laminate according to the present invention, under
Antibacterial gold formed on at least one surface of the base material
Antibacterial layer containing genus and / or antibacterial metal ion
And exhibit a photocatalytic function formed on the surface of the antibacterial layer
And a photocatalyst layer containing a substance.

FIG. 1 shows a partial sectional view of the antibacterial laminate according to the present invention . The antibacterial laminate 1 has a base material 2, an antibacterial layer 3 formed on at least one surface of the base material 2, and a photocatalyst layer 4 formed on the surface of the antibacterial layer 3. There is.

The material of the base material 2 may be appropriately selected depending on the use and manufacturing conditions of the antibacterial laminate, and includes metals, various resins, ceramics, ceramics, glass, and composites thereof (for example, steel). , Stainless, aluminum, etc., the surface of which is coated with various resins, ceramics, glass, etc.). The base material 2 is not particularly limited, but a baking step of the photocatalyst layer 4 is usually added during the production of the antibacterial laminate, and thus a material that can withstand the baking temperature is desirable.

As a more specific example, when the antibacterial laminate is an enamel plate, the base material 2 is, for example, a metal plate such as an iron plate, a steel plate, an aluminum plate, and a zinc plate on these metal plates. Those subjected to surface treatment such as aluminum plating, aluminum-zinc alloy plating, iron-zinc alloy plating, chemical conversion treatment, and chromate treatment are used. Among these, it is preferable to use a metal plate that has been subjected to surface treatment such as plating and has corrosion resistance and weather resistance. When the antibacterial laminate is a tile, ceramic is used as the base material. The base material 2 will be described mainly with respect to a plate-shaped body, but the following antibacterial layer 3 is used.
The shape is not limited as long as the photocatalyst layer 4 can be formed.

The antibacterial layer 3 is formed on at least one surface of the base material 2 and contains an antibacterial metal and / or an antibacterial metal ion. Here, the antibacterial property
It is meant to include all bactericidal properties, antibacterial properties, and antifungal properties. That is, it means preventing the growth of bacteria and mold, and killing bacteria and mold. Although the mechanism of antibacterial action of the antibacterial metal or the antibacterial metal ion is not clear, the antibacterial metal and / or the antibacterial metal ion contained in the antibacterial layer 3 is known as a metal or a metal ion exhibiting an antibacterial effect. Those mentioned are not particularly limited. Examples of the antibacterial metal or antibacterial metal ion usually include silver, copper, zinc, titanium, tungsten and the like in a metal state or an ionic state. Antibacterial layer 3
May contain two or more kinds of metals, and may contain both metals and metals in an ionic state. Among these, silver, copper, zinc, silver ions, copper ions, and zinc ions are preferable.

In order to include the metal in the ionic state in the antibacterial layer 3, a substance containing antibacterial metal ions may be used when forming the antibacterial layer 3. Examples of this substance include nitrate ion, sulfate ion, halogen ion, especially chlorine ion,
Examples thereof include salts having acetate ions, lactate ions, sulfur ions and the like as counterions of the above metal ions, and zeolite, apatite, silica, glass, titania, zirconium phosphate, aluminum phosphate carrying the above metal ions. Hereinafter, a substance containing an antibacterial metal and an antibacterial metal ion may be referred to as an antibacterial agent. In addition, ammonium salts such as benzalnicomb chloride, fatty acid esters,
Organic antibacterial agents such as cyclic nitrogen sulfur compounds may also be used. These organic antibacterial agents are suitable when a resin is used as the binder described later.

The antibacterial layer 3 is usually formed from the above antibacterial agent and a binder. Any binder may be used as long as it can hold the antibacterial agent on the base material 2, and may be organic or inorganic as long as it can withstand the firing temperature of the photocatalyst layer 4. Even so,
It may be thermosetting. Examples of such a binder include enamel glaze, glass glaze, silicone resin, acrylic resin, epoxy resin, fluororesin, metal alkoxy resin, alkali silicate, cement, mortar and the like. Further, it may contain a colorant and the like, and for example, a coating material containing the above binder can be used.

In the present invention, enamel glaze is used as a binder.
It is preferably used. For enamel glaze, widely known glazes are used.
Can be, for example, TiO₂, Si O₂, Z
r O ₂MO such as₂Compounds, P₂O_Five, V₂O_FiveSuch
M₂O_FiveCompounds, Sb₂O ₃, Al₂O₃, B₂O₃ Na
Which M₂O₃Compounds, Na₂O, K₂O, Li₂Such as O
M₂MO compounds such as O compounds, ZnO, BaO, CaO
Compound, ZrF_Four, AlF₃Such as fluoride compounds
A glaze obtained from any mineral material can be used.
Among these, M₂O_FiveSystem glaze, especially P₂O_FiveDuring glaze
Glazes containing 50% by weight or more are preferred because the firing temperature is low.
Good Glaze is a mineral raw material and other ingredients as needed.
For example, it may contain water or the like.

It is desirable that the antibacterial agent and the binder are used so that the antibacterial agent content of the antibacterial layer 3 is finally 0.1 to 20% by weight, preferably 0.5 to 5% by weight. When forming the antibacterial layer 3, it is desirable that the antibacterial agent is well dispersed in the binder. The antibacterial layer 3 is usually formed by forming a film on at least one surface of the substrate 2 from a mixture of an antibacterial agent and a binder, and drying or baking the film. The film may be formed by any method such as coating or spraying. Further, the drying or firing of the film varies depending on the kind of the binder and the like, but when the above enamel glaze is used as the binder, it is usually fired at about 500 to 800 ° C. In the present invention, the antibacterial layer 3 has a thickness of 10 μm or more, preferably about 10 to 1000 μm.
The antibacterial layer 3 only needs to be formed on at least one surface of the base material, and may be formed on one surface or both surfaces when the base material is a plate, for example.

The photocatalyst layer 4 is a substance exhibiting a photocatalytic function.
On the surface of the antibacterial layer 3 as described above.
Has been formed. As a substance that exhibits a photocatalytic function,
Any substance that is photoactive enough to produce active oxygen
Good. Specifically, widely used photocatalysts are widely used.
Can be used, for example TiO₂, ZnO, SrTiO
₃, SnO₂, GaP, CdS, CdSe, MoS, F
e₂O₃, WO₃, K _FourNbO₁₇, KTaO₃For
Can be Hereinafter, these substances are referred to as photocatalysts.

[0021] For example TiO ₂ is superoxide ion on the surface with ultraviolet hits (· O ₂ ^-), a hydroxyl group radical (· OH) is generated. This · O ₂ ^-, · O
H has an antibacterial action, a purifying action of decomposing organic substances such as oil, and a deodorizing action. In the present invention, among the photocatalysts,
TiO ₂ (titanium oxide) is preferably used. TiO
₂ is preferable because the anatase type shows a higher antibacterial action than the rutile type.

A photocatalyst having a primary particle size of 100 nm or less exhibits a sufficient antibacterial action and is therefore preferable. More preferably, it is 1 to 50 nm. The photocatalyst layer 4 may contain a binder in addition to the photocatalyst. The binder is preferably one that transmits light, particularly ultraviolet light, and examples thereof include silicone, silica, and fluororesin.

In the present invention, the photocatalyst needs to exist in a state capable of absorbing light, and the photocatalyst may be embedded in the binder as long as it is a binder that transmits light, particularly ultraviolet rays. It is preferably exposed.
A commercial product may be used as a material containing a photocatalyst and a binder. For example, a titanium oxide sol liquid obtained by mixing a titanium oxide sol and / or titanium oxide powder with a binder may be used. More specifically, C
ZG220 (manufactured by Taki Chemical Co., Ltd.) and the like can be mentioned.

The photocatalyst layer 4 is formed, for example, by forming a film of a mixture of a photocatalyst and a binder on the surface of the antibacterial layer 3 and drying or baking the film. The film may be formed by any method such as coating or spraying. The application temperature is usually room temperature to 100 ° C., but it is also possible to perform the application in a temperature range other than this. Although the film may be dried or baked depending on the kind of the binder and the like, in the case of titanium oxide, if it is baked at 800 ° C or higher, it becomes a rutile type. For example, when a commercially available titanium oxide sol solution is used, it is usually fired at about 150 to 600 ° C. It is also possible to use a room temperature dry type titanium oxide sol liquid. In the present invention, the thickness of the photocatalyst layer 4 is 0.0
1 to 5 μm, preferably 0.1 to 1 μm.

[0025]

[0026]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples. Example 1 The antibacterial laminate shown in FIG. 1 was manufactured. Enamel frit (composition: P ₂ O ₅ 50% by weight, Sb ₂ O ₃ 1
1% by weight, Al ₂ O ₃ 8% by weight, B ₂ O ₃ 0.5% by weight
Is mixed with a silver-based antibacterial agent (composition: silver zirconium silicate (manufactured by Toagosei Co., Ltd.) to prepare a slip, which is glazed on one side of a steel plate and baked at 500 ° C. to have an antibacterial property of 100 μm in thickness. An enamel layer was formed, the content of the silver-based antibacterial agent in the antibacterial enamel was 2% by weight, and then a titanium oxide sol solution (TAK70 Taki Kagaku Co., Ltd.) was applied to the surface of the antibacterial layer. An antibacterial enamel steel plate was manufactured by firing at 300 ° C. to form a photocatalyst layer having a thickness of 0.3 μm.

<Antibacterial Test> The antibacterial enamel steel plate obtained above was subjected to an antibacterial test on a test piece left in a normal room for 3 days and a test piece left for 3 months after production. The antibacterial test was carried out by applying the Escherichia coli solution to the test piece by a predetermined method (in accordance with the antibacterial activity test method I film adhesion method of the Society for Inorganic Antibacterial Agents such as silver) and leaving it in the dark for 24 hours or in black light.
After irradiating with light of mW / cm ² for 4 hours, the number of bacteria in the bacterial solution recovered from the surface of the test piece was measured by culturing, and the ratio of dead bacteria was determined. The results are shown in Table 1. Even after 3 months, the bactericidal rate was 99% or more both in the dark and after irradiation with light, showing a sufficient antibacterial action.

Comparative Example 1 An antibacterial laminate of the embodiment shown in FIG. 2 was produced. The same enamel frit as in Example 1 and silver antibacterial agent (same as Example 1).
And titanium oxide fine particles (7 nm) having photocatalytic activity are mixed to prepare a slip, which is glazed on one side of a steel plate, and 500
The product was fired at a temperature of ℃ to form an antibacterial layer having a thickness of 100 μm to produce an antibacterial enamel steel plate. The content of the silver antibacterial agent in the enamel layer was 2% by weight, and the content of titanium oxide was 10% by weight.
The obtained antibacterial enamel steel plate was subjected to the same antibacterial test as in Example 1. The results are shown in Table 1. Although the sterilization rate was high after being left in the dark in the initial stage, the sterilization rate after 3 months was significantly decreased both in the dark and after irradiation with light. Sterilization rate after light irradiation is 50%
Below, the photocatalytic effect was hardly seen.

Comparative Example 2 An antibacterial laminate of the embodiment shown in FIG. 3 was manufactured. A slip was prepared only from the same enamel frit (no antibacterial agent and no photocatalyst) as in Example 1 and glazed on one side of the steel plate.
Firing was performed at 00 ° C to form an enamel layer having a thickness of 100 µm.
Next, a mixture of a silver-based antibacterial agent (same as in Example 1) and a titanium oxide sol liquid (same as in Example 1) in an amount of 5% by weight was applied to the surface of the enamel layer and baked at 300 ° C. to a thickness of 0. .3
μm. The obtained antibacterial enamel steel plate was subjected to the same antibacterial test as in Example 1. The results are shown in Table 1. The sterilization rate at the beginning was rather low, and the sterilization rate after leaving for 3 months in a dark place was greatly reduced.

Comparative Example 3 An antibacterial laminate of the embodiment shown in FIG. 4 was manufactured. A slip was prepared only from the same enamel frit (no antibacterial agent and no photocatalyst) as in Example 1 and glazed on one side of the steel plate.
Firing was performed at 00 ° C to form an enamel layer having a thickness of 100 µm.
Then, a titanium oxide sol liquid (same as that in Example 1) is added to 0.3 μm.
It is applied to give a thickness of 0.
An antibacterial enamel steel plate was produced by placing an amount of 1 μm of a silver-based antibacterial agent (the same as in Example 1) and baking it. The obtained antibacterial enamel steel plate was subjected to the same antibacterial test as in Example 1. The results are shown in Table 1. The sterilization rate at the beginning was rather low, and the sterilization rate after leaving for 3 months in a dark place was greatly reduced.

Example 2 An antibacterial laminate of the embodiment shown in FIG. 1 was manufactured. A silver-based antibacterial agent (same as in Example 1) was mixed with a fluororesin-based paint to prepare an antibacterial paint, which was applied on the surface of a steel sheet and dried at 150 ° C. to form an antibacterial coating layer having a thickness of 100 μm. . The content of the silver-based antibacterial agent in the antibacterial coating layer is 3% by weight. Then on the surface of the antibacterial coating layer,
A photocatalyst layer having a thickness of 0.3 μm was formed in the same manner as in Example 1 to manufacture an antibacterial coated steel sheet. The obtained antibacterial coated steel sheet was subjected to the same antibacterial test as in Example 1. The results are shown in Table 1. Even after 3 months, the bactericidal rate was 99% or more both in the dark and after light irradiation, indicating a sufficient antibacterial action.

[0032]

[0033]

[0034]

The antibacterial laminate according to the present invention has a specific structure as described above and can exhibit antibacterial properties for a long period of time.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an antibacterial laminate according to the present invention.

FIG. 2 is a partial cross-sectional view schematically showing a conventional antibacterial laminate having an enamel layer containing an antibacterial agent and a photocatalyst.

FIG. 3 is a partial cross-sectional view schematically showing a conventional antibacterial laminate having a layer containing an antibacterial agent and a photocatalyst on the surface of the enamel layer.

FIG. 4 is a partial cross-sectional view schematically showing a conventional antibacterial laminate in which a photocatalyst layer is provided on the surface of an enamel layer and an antibacterial agent is carried or fixed in the vicinity of the surface.

[Explanation of symbols]

1 Antibacterial laminate 2 Base material 3 Antibacterial layer 4 Photocatalyst layer

Front page continuation (72) Inventor Fusao Togashi 3-6-24 Uozaki Minami-cho, Higashinada-ku, Kobe-shi, Hyogo Inside Technical Research Institute, Kawatetsu Construction Materials Co., Ltd. (72) Hiroshi Nagaishi 2--18-13 Higashi Narashino, Narashino, Chiba No. 18-18 Kawamura Building Materials Co., Ltd. Technical Research Institute Hideo Takamura 2-18-13 Higashi Narashino, Narashino City, Chiba Prefecture In-Tech Research Laboratory Kawara Building Materials Co., Ltd. (72) Koji Watanabe 2-1813 Higashi Narashino, Narashino City, Chiba Prefecture (56) Reference JP-A-6-278241 (JP, A) JP-A-10-237597 (JP, A) JP-A-8-60303 (JP, A) JP-A-8 -60302 (JP, A) JP 5-253544 (JP, A) JP 2000-119955 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35 / 00 B01J 21/00-37/36

Claims (2)

(57) [Claims] 1. Formed on at least one surface of the base substrate
Antibacterial metal and / or antibacterial metal ion
Having an antibacterial layer and a photocatalyst formed on the surface of the antibacterial layer
A photocatalyst layer containing a substance exhibiting a function,
Fungal laminate. 2. The antibacterial laminate according to claim 1, wherein the substance having a photocatalytic function is exposed on the outermost surface of the laminate.