KR20190002390A - Method for Antimicrobial Treatment Using Zinc Aluminate - Google Patents

Abstract

The present invention relates to a method for antimicrobial treatment, which can provide excellent durability by maintaining transparency without dissolving harmful substances even by water or acid. More specifically, the present invention relates to a method for antimicrobial treatment, which deposits a zinc aluminate thin film on a surface of a substrate.

Description

TECHNICAL FIELD The present invention relates to a zinc-aluminate thin film,

The present invention relates to an antibacterial treatment method which is excellent in durability and economical, because no harmful substances are dissolved by water or acid and transparency is maintained.

Various chemical substances are flooded by industrialization and environmental pollution is getting serious. While many harmful substances and germs pollute the living environment, there is a lot of interest in removing environment pollutants by improving living standards and creating a safe living environment.

As glass is transparent and beautiful, it is widely used as interior and exterior materials for construction, and reinforced glass, which is easily broken and weak in heat, has been widely used. As a result, the surface material, Furniture and the like. Recently, the use of glass as a display panel such as a TV, a monitor, a mobile phone, and a digital camera has become common as electronic devices are integrated on a glass panel. Further, the application range of an interactive display such as a touch screen is expanding not only a one-sided display that provides an image, but a trend. Such display panel materials are often exposed to sweat, saliva, dust, grease, tobacco smoke, and moisture, and because of the heat generated by the device itself, they provide favorable conditions for bacterial growth, Every time the hand touches the glass, there is a risk of infection with bacteria.

Food storage containers or cosmetic containers which are easily supplied with nutrients are not only easy to reproduce, but also contaminated by bacteria because the stored contents are directly ingested into the mouth or brought into contact with the skin. When the container is made of a material resistant to heat such as glass or ceramics, it can be sterilized periodically to ensure safety. However, the container made of synthetic resin is easily contaminated, and when heat is applied, deformation may occur or a harmful substance may be eluted.

Various methods of antibacterial treatment methods have been developed to solve this problem. The antimicrobial treatment method should have excellent antimicrobial properties, and should not only have excellent durability so that antimicrobial activity can be maintained for a long time, but also should not release harmful substances after antimicrobial treatment. The pH of perspiration is usually 4 to 6.6, and the acidity of many substances including lactic acid bacteria and organic acids including kimchi is acidic. Therefore, display panels and food storage containers must maintain durability especially in acidic conditions. In addition, there should be no change in color or transparency by the antibacterial treatment, and the antibacterial treatment should be economically uniform regardless of the shape of the treated material.

The antimicrobial treatment method using silver is the most widely used method, and as the nanotechnology has been recently connected, it is possible to exhibit a high effect while using a small amount of silver (Patent No. 10-0671982). However, the use of nanotechnology is reduced, but silver is still expensive, so a more economical antibacterial treatment method is needed. In addition, silver nanoparticles are excellent in antibacterial properties due to their large surface area ratio to volume, but they are known to exhibit strong toxicity to humans and the environment, thus raising concerns over a wide range of applications.

Japanese Patent Registration No. 10-1514329 discloses an antibacterial treatment method using zinc oxide and calcium oxide instead of silver nanoparticles as an antibacterial substance. Zinc oxide and calcium oxide have advantages in that they can be economically treated with antibacterial agents as compared with nano silver. Zinc is a constituent element of various enzymes. It is involved in the synthesis and degradation of biomolecules such as carbohydrates, proteins, and nucleic acids, and is a trace element essential for living bodies involved in growth, bone formation, reproductive and immune functions. However, if zinc is dissolved in an antimicrobial container, it may cause excessive zinc ingestion. Excessive intake of zinc may cause irregular muscle function, lethargy, gastrointestinal disorder, copper deficiency, decreased nutritional status, impaired immune function and decreased HDL cholesterol .

Patent No. 10-0671982 Patent No. 10-1514329

The present invention provides an economical antibacterial treatment which can be applied uniformly to a large area regardless of the shape of the substrate without using expensive silver to solve the problems of the antibacterial treatment method according to the prior art, And a method thereof.

It is another object of the present invention to provide a safe and durable antimicrobial treatment that can be used without any change in color and composition even when used for a long period of time because the harmful component does not dissolve in immersion in water as well as water and there is no change in light transmittance and surface roughness Method.

In order to accomplish the above object, the present invention relates to an antibacterial treatment method characterized by depositing a zinc aluminate (ZnAl ₂ O ₄ ) thin film on the surface of a substrate.

In the present invention, the term "substrate" refers to an object for the purpose of antibacterial treatment, and is not limited to its shape, use, or material. For example, the substrate may be a flat substrate used for a display panel, a concave container for holding food, or a bottle containing cosmetics or the like.

The zinc aluminate thin film obtained by antibacterial treatment according to the present invention was found to be excellent in durability because the zinc and aluminum were eluted less than 0.05 ppm even under acidic conditions of water or even pH 4 and the surface roughness and light transmittance after immersion hardly changed there was.

The thickness of the zinc aluminate thin film is preferably 3 to 100 nm. When the thickness of the zinc aluminate thin film is too thin, the zinc aluminate thin film can not be uniformly deposited. As the thickness of the thin film becomes thicker, the amount of the raw material for forming the thin film increases and the time for forming the thin film increases. . In addition, if the thickness of the thin film is too large, the light transmittance is decreased, so that the thickness of the thin film is preferably not more than 100 nm, more preferably 10 to 40 nm.

In the present invention, the zinc aluminate thin film is most preferably deposited by sputtering in view of uniformity of the thin film, ease of large-area coating, and ease of treatment regardless of the shape of the substrate. However, , Brushing and the like can also be applied. In the case of depositing a zinc aluminate thin film by sputtering, it is possible to use a ceramic target prepared by mixing ZnO and Al ₂ O ₃ powder as a target so that the Al content is 70 to 85 at% and then sintering. When the content of Al is out of the above range, ZnO or Al ₂ O ₃ is mixed in the thin film in addition to zinc aluminate. The ceramic target can be produced according to a conventional sputtering target manufacturing method, and the sintering treatment is preferably performed at 1400 to 1500 ° C.

Particularly, when the aluminate thin film of the present invention is deposited by sputtering, a thin film having excellent durability and light transmittance can be obtained by room temperature deposition. The term " normal temperature " means the temperature in the atmosphere without any additional heating or cooling operation. Therefore, polymer materials such as PET (polyethylene terephthalate) and polyimide as well as ceramics and metals as well as paper materials weak in heat can be used as substrates as well as the glass described in the following examples, so that the antibacterial treatment of the present invention can be widely used Can be applied. However, it may be deposited at a high temperature (400 DEG C or less), which is a normal sputtering condition, and it is not excluded.

As described above, according to the antibacterial treatment method of the present invention, antimicrobial treatment can be uniformly applied to a large area regardless of the shape of the substrate by a sputtering method without using an expensive raw material.

The antimicrobial treatment method of the present invention is capable of stable treatment at room temperature and can be widely applied irrespective of the material, shape, and use of the substrate.

In addition, the zinc aluminate thin film formed by the antibacterial treatment method of the present invention has no change in color and light transmittance because aluminum or zinc ions are not eluted even when immersed in water as well as water. Therefore, it can be used safely even when it comes in contact with perspiration, acid rain or acidic food. It is also useful for antimicrobial treatment of display panel, surface material of electronic equipment, container, etc., which is frequently used for sweat and acidic materials Can be used.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an XRD diffraction spectrum showing phase characteristics according to the aluminum content of the target.
2 is a graph showing the degree of elution of zinc upon immersion of a thin film according to the aluminum content of the target.
FIG. 3 is a UV spectrum showing the change in light transmittance upon immersion of ZnO and AZO thin films according to the aluminum content of the target.
FIG. 4 is a graph showing the light transmittance and ion elution rate of the zinc aluminate thin film according to the pH of the needle index. FIG.
5 is a SEM image showing the change in surface roughness upon immersion of a thin film according to the aluminum content of the target.
6 is an image showing antibacterial properties of a zinc aluminate thin film.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, these embodiments are merely examples for explaining the content and scope of the technical idea of the present invention, and thus the technical scope of the present invention is not limited or changed. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention based on these examples.

[Example]

Example 1: Characteristic evaluation of thin film according to aluminum content of sputtering target

1) Production of sputtering target

ZnO and Al ₂ O ₃ powders were mixed at different mixing ratios and heat treated at 1000 ° C for 10 hours. Then, the ceramic compact was compression-molded into a 2-inch circle at a pressure of 5 tons, and sintered at 1500 ° C for 4 hours (purity 99.99%).

2) Deposition of thin film

The tempered glass substrate (5 cm x 10 cm x 700 m, Corning Gorilla) was cleaned and debris was removed from the surface using N2 gas. Then, the thin film was deposited at room temperature using the target prepared according to the ratios of ZnO and Al ₂ O ₃ powders in 1) using rf sputtering method and the properties thereof were evaluated. The rf power applied to the target was 50 W, the working pressure was maintained at 2.6 Pa, the deposition rate was about 1.8 nm / min, and 10 sccm (standard cc / min) Ar gas was used as the sputtering gas. The thickness of the thin film was controlled by the deposition time. Experimental results of the thin film deposited to a thickness of 30 nm were described in the following examples, unless otherwise noted.

3) XRD diffraction pattern analysis of deposited thin films

The XRD diffraction patterns of the thin films deposited in 2) were analyzed to determine the influence of Al content in the target on the phase of the thin film. FIG. 1 is a spectrum showing the result. When ZnO was targeted, a ZnO thin film was formed. When the Al content was 10 at%, a ZnO (AZO) thin film doped with Al was formed. When the content of Al was further increased to use a target mixed at an atomic ratio of 50:50, ZnO and zinc aluminate (ZnAl ₂ O ₄ ) phases coexisted in the thin film. When the content of aluminum was further increased, the ZnO phase disappeared, and only the zinc aluminate phase was present, indicating that a zinc aluminate thin film was formed.

Example 2: Evaluation of durability of zinc aluminate thin film

1) Comparison of dissolution of zinc ions by immersion according to Al content in target

Glass formed with a thin film for antibacterial treatment in 2) of Example 1 was immersed in 15 mL of DI water. After 3 days, the concentration of zinc dissolved in water was measured by ICP-OES (OPTIMA 7300 DV, Perkin-Elmer USA). The results are shown in FIG.

As can be seen from FIG. 2, the concentration of zinc contained in the needle index was about 2.3 to 2.4 ppm in the ZnO thin film after 3 days, and the elution of zinc rapidly decreased as the content of Al in the target increased. Zinc aluminate thin films formed by using Al target of 70 ~ 85at% decreased the elution of zinc by using 50at% Al target with zinc aluminate and ZnO. And the content thereof was 0.05 ppm or less.

2) Comparison of change of light transmittance and surface roughness by immersion according to Al content in target

Glasses having a thin film for antibacterial treatment in Example 1, 2) were immersed in 15 ml of DI water for 30 days, and the light transmittance of the UV region was measured by HP 8453 UV-VIS spectrophotometer. As shown in FIG. Fig. 3 shows the light transmittance according to the aluminum content in the target, and Fig. 4 shows the light transmittance of the zinc aluminate thin film prepared with the target containing 85 at% Al. In order to confirm the effect of the pH of the immersion solution on the light transmittance and the dissolution of zinc or aluminum, the zinc aluminate thin film was immersed in the acid solution, and the solubility and the light transmittance were measured and shown in FIG. For the control of acidity, a 7: 3 (v / v) mixture of sulfuric acid and nitric acid similar to acid rain was used.

The solubility of zinc in the zinc aluminate thin film was less than 0.05ppm and the solubility of Al was also less than 0.05ppm when the pH was 4.0 or higher. It was confirmed that at pH 3.5, about 0.2 ppm of Al ions were dissolved. In general, the acidity ratio is less than pH 5.6, but the acid ratio of pH 4 or less is rarely observed. Since the pH of the vinegar and the pH of the perspiration are also 4.0 or more, the pH of the environment in everyday life is 4.0 or more, so that the solubility of Al in ordinary conditions is also 0.5 ppm or less.

3, the initial transparency of the ZnO thin film was much lower than that of the glass, but the transparency was largely changed by immersion. After 30 days of immersion, the transparency of the ZnO thin film was similar to that of the glass substrate, I could guess that there was a change. AZO thin films showed less change of transparency than ZnO thin films, but also 3 ~ 5% less transparency. On the other hand, the light transmittance of the zinc aluminate thin film was almost the same as that of the free glass, and no significant change in transparency was observed even when immersed in water or an acidic pH index of pH 4.

5 is a SEM image of the surface of the thin film after immersion according to the Al content in the target. In the case of a ZnO thin film or a zinc aluminate thin film (Al content is 70 at% or more) It showed uniform, dense and smooth thin film shape even after immersion, and it was confirmed that when the AZO thin film was present, the sheet was formed on the surface after immersion. The nanosheet observed in the AZO thin film is a Zn-Al bilayer constant oxide produced by the reaction of AZO thin film with water at the time of immersion as disclosed in the registered patent No. 10-1703124 of the present inventors.

Example 3: Evaluation of antibacterial property

A 30 nm-thick zinc aluminate was deposited using the target containing 85 at% of Al by the method in 2) of Example 1, and the antibacterial property was evaluated.

Antibacterial property against FITI testing & Research Institute (Korea) of Staphylococcus aureus (Staphylococcus aureus, American Type Culture Collection No. 6538) and gram-negative bacteria E. coli (Escherichia coli, American type Culture Collection No. 8739) Gram-positive bacteria to the request (FITI Testing & Research Institute, Antimicrobial Products-Test for antimicrobial and activity and efficacy, JIS Z 2801: 2010).

Antibacterial properties were tested using a glass substrate that was not coated as a control. Experimental conditions were determined by counting the number of colonies by the method described in JIS (Japanese Industrial Standard) Z 2801 after culturing at RH 90% and 35 ± 1 ° C for 24 hours.

FIG. 6 is a photograph of the culture of E. coli and S. aureus bacteria for 24 hours, in which a-1 and b-1 are uncoated glass substrates, a-2 and b-2 are glass substrates on which a zinc aluminate thin film is formed . The results are shown in FIG. As shown in FIG. 6, colonies of E. coli and Staphylococcus aureus were formed on the glass substrate itself, but colonies were not observed on the zinc aluminate specimen after culturing, indicating excellent antibacterial properties.

More specifically, Table 1 shows the results of the measurement of the antibacterial properties. The glass with the zinc aluminate thin film showed 99.99999% reduction of E. coli and 99.99668% reduction of S. aureus against uncoated glass as a control.

Claims (4)

Wherein the zinc aluminate thin film is deposited on the surface of the substrate.
The method according to claim 1,
Wherein the zinc aluminate thin film has a thickness of 3 to 100 nm.
3. The method according to claim 1 or 2,
Wherein the zinc aluminate thin film is deposited by sputtering.
The method of claim 3,
Wherein the deposition is performed at room temperature.

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