KR20200072113A - Antibacterial inorganic composition, steel sheet coated antibacterial inorganic composition and manufacturing method for the same - Google Patents

Abstract

The present invention relates to an antibacterial inorganic composition, which does not contain chromium (Cr) to be environmentally friendly and has antibacterial properties, a steel sheet coated with the antibacterial inorganic composition and a manufacturing method thereof, wherein the antibacterial inorganic composition includes a sol-gel solution prepared by mixing silane and an acid catalyst, and an inorganic antibacterial aqueous solution containing 0.5 wt% of silver ions. Since the antibacterial inorganic composition does not contain chromium (Cr), the antibacterial inorganic composition is environmentally friendly, and by coating a composition containing an inorganic silver component, it is possible to obtain an effect having antibacterial properties and heat resistance.

Description

Antimicrobial inorganic composition, coated steel sheet coated with an antimicrobial inorganic composition, and its manufacturing method {ANTIBACTERIAL INORGANIC COMPOSITION, STEEL SHEET COATED ANTIBACTERIAL INORGANIC COMPOSITION AND MANUFACTURING METHOD FOR THE SAME}

The present invention relates to an antimicrobial inorganic composition, a coated steel sheet coated with an antimicrobial inorganic composition, and a method for manufacturing the same, more specifically, it does not contain chromium (Cr), and thus is an environmentally friendly antimicrobial inorganic composition and an antimicrobial inorganic composition It relates to a coated steel sheet and its manufacturing method.

The post-treatment agent for galvanized steel sheet is coated with zinc or aluminum or a zinc-aluminum alloy-plated steel sheet, or coated with a mixture of magnesium and aluminum and zinc on a coated steel sheet surface to primarily protect the plating layer from the outside. It aims to prevent oxidation by and oxidation by acid and base.

Due to the characteristics of the plated steel sheet, an oxidation reaction on the surface, that is, a corrosion product, may easily occur due to an external factor, and the most widely used method for suppressing the occurrence of such a corrosion product forms a film on the surface. As a method of forming a film on the surface, there are physically forming a film of an inorganic or organic component and a chemical conversion film method of generating a film by a chemical reaction such as chromate treatment.

The coating thus formed can improve the corrosion resistance, blackening resistance, acid resistance, etc. of the plated steel sheet by protecting the plating layer. Also, by imparting functionality to such a film, it is possible to improve the high processability or antimicrobial properties, thereby giving specialty to the use of the plated steel sheet. have.

In general, a method that is frequently used to protect the surface of a plating layer is a method of performing a chromate treatment. However, the chromate treatment contains toxic hexavalent chromium (Cr ⁶⁺ ) ions, which has a detrimental effect on the human body, and is currently in use in the metal industry due to strict regulations on chromate treatment.

Due to this problem, chromium-free chromium-free (Cr-free) organic coating treatment is widely used. Korean Patent Publication Nos. 10-2006-0025942 and 10-2006-0059012 disclose technologies that impart antibacterial properties to organic resins.

However, this technique is a technique using an inorganic antibacterial agent or an organic antibacterial agent in an organic resin, and the components of the antibacterial agent in the form of a foreign material in the organic resin that acts as a crosslinking agent (binder) due to the difference in the components cannot be combined with the coating and its function there is a problem.

Due to this, the durability of the film itself may be good, but there is a problem in that the properties of the contained antibacterial agent rapidly decrease after a certain time. In addition, there is a problem that is vulnerable to heat resistance due to the limitation of the organic component. That is, in an environment that is generally used, the deterioration of the organic component by heat applied from the steel sheet or the outside does not occur, but if the steel sheet is installed in an environment exposed to heat, the organic antibacterial agent inside the organic resin denatures and its properties decrease. , In the case of the inorganic antibacterial agent, there is a problem in that the organic resin layer serving as a crosslinking agent is damaged, thereby losing its function as an antibacterial agent and deteriorating its properties.

Korean Patent Publication No. 10-2006-0025942 (2004.08.26) Korean Patent Publication No. 10-2006-0059012 (2006.06.01) Korean Patent Publication No. 10-2006-0121726 (2006.11.29)

The present invention was devised to solve the above problems, and does not contain chromium (Cr), thereby providing an environmentally friendly and antibacterial property, and having an antibacterial inorganic composition having heat resistance, a coated steel sheet coated with an antibacterial inorganic composition, and a method of manufacturing the same The purpose is to provide.

In order to achieve the above object, the antimicrobial inorganic composition according to a preferred embodiment of the present invention is applied to a plated steel sheet to form a chromium-free (Cr-free) coating having antimicrobial properties, in the antibacterial inorganic composition, silane (silane) A sol-gel solution prepared by mixing a peroxy acid catalyst; And 0.5% by weight of an inorganic antibacterial aqueous solution containing silver ions.

Here, the inorganic antibacterial solution may be provided in an amount of 0.1 to 5.0% by weight based on the weight of the sol-gel solution.

In addition, the silane may be provided in any one or combination of at least two or more of epoxy silane, amino silane, and alkoxy silane.

More specifically, the sol-gel solution may be prepared by mixing 3 to 40% by weight of silane and 1 to 5% by weight of an acid catalyst in an aqueous solution.

For example, the silane may be provided as any one of 8 to 20% by weight of epoxy silane, 3 to 7% by weight of amino silane, and 8 to 12% by weight of alkoxy silane.

Alternatively, the silane may be provided in a combination of at least two or more of 10-15% by weight of epoxy silane, 5% by weight of amino silane, and 5-20% by weight of alkoxy silane.

And, in order to achieve the above object, a method of manufacturing a plated steel sheet coated with an antimicrobial inorganic composition according to a preferred embodiment of the present invention, rolls or sprays any one antimicrobial inorganic composition on the plated steel sheet. -Coating step of coating by Spray-Squeezing method; And a drying step of drying by hot air, induction heating, or near infrared heating so that the surface temperature of the coated steel sheet coated with the antibacterial inorganic composition is 100 to 200°C.

In addition, in order to achieve the above object, a plated steel sheet coated with an antimicrobial inorganic composition according to a preferred embodiment of the present invention is prepared by applying any one of the antimicrobial inorganic compositions at a dry film weight of 0.1 to 1.5 g/m ² Can be.

According to the antimicrobial inorganic composition according to the present invention, the coated steel sheet coated with the antibacterial inorganic composition and its manufacturing method, it is not environmentally friendly because it does not contain chromium (Cr), and is coated with a composition containing an inorganic silver component, thereby providing antibacterial properties. An effect having heat resistance can be obtained.

In order to help understanding the features of the present invention, the antibacterial inorganic composition, the coated steel sheet coated with the antibacterial inorganic composition, and the manufacturing method thereof will be described in more detail below.

In addition, in order to help the understanding of the embodiments described below, in addition to the reference numerals to the components of each of the accompanying drawings, it is noted that the same components have the same reference numerals as possible even though they are displayed on different drawings. . In addition, in describing the present invention, when it is determined that detailed descriptions of related well-known structures or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

Hereinafter, the present invention will be described in detail.

The present invention relates to an antimicrobial inorganic composition that is applied to a plated steel sheet to form a chromium-free (Cr-free) film having antimicrobial properties, silver ions in a sol-gel solution prepared by mixing silane and an acid catalyst. It is prepared by mixing the contained inorganic antibacterial aqueous solution. Here, the silane is provided with an organic silane. By coating the antimicrobial inorganic composition thus prepared on a plated steel sheet, it is possible to improve the antibacterial properties, heat resistance, corrosion resistance, and blackening resistance of the plated steel sheet.

The antibacterial inorganic composition according to an embodiment of the present invention is prepared by mixing an inorganic antibacterial aqueous solution containing 0.5% by weight of silver ions in a sol-gel solution prepared by mixing a silane and an acid catalyst. That is, the inorganic antibacterial aqueous solution is prepared by containing 0.5% by weight of silver ions in an aqueous solution (water). And, the antimicrobial inorganic composition of the present invention is prepared by mixing 0.1 to 5.0% by weight of an antibacterial aqueous solution relative to the weight of the sol gel solution.

Furthermore, the antimicrobial inorganic composition according to an embodiment of the present invention may be used in an amount of 0.1% by weight or less based on the total weight of the silicone antifoaming agent for improving the workability of the solution in addition to the silane and the acid catalyst. In addition, a neutral type PE wax may be used to improve the processability of the coated steel sheet coated with a solution having an antibacterial component. At this time, the content of PE wax used depends on the processability, and is preferably used at 2% by weight or less compared to the total solution.

Here, it is more effective to use an organic acid rather than an inorganic acid as the acid catalyst used. In particular, formic acid and acetic acid are stable in forming a sol-gel compound during synthesis.

The sol-gel solution is prepared by mixing a silane and an acid catalyst.

Here, the silane may be provided in any one or a combination of two or more of epoxy silane, amino silane, alkoxy silane.

An organosilane compound may be used alone or as a water-soluble agent as a post-treatment agent on a plated steel sheet coated with zinc, aluminum, zinc, and an aluminum alloy. At this time, silane that can be used may be phenyl silane, epoxy silane, methyl silane, vinyl silane, alkyl silane, alkoxy silane, amino silane, and the like. When used alone or in a water-soluble manner, such a silane is difficult to form a film containing silane as a main component on the surface of a plated steel sheet, and it is difficult to secure the performance required for the thickness of the film to protect the plating layer.

In order to compensate for these disadvantages, the required performance can be secured through a sol-gel solution using silane. The sol-gel solution can generally be prepared by hydrolyzing, condensing, and polymerizing a metal alkoxide under an acid or base catalyst. At this time, as the acid catalyst used, nitric acid, sulfuric acid, hydrochloric acid, formic acid, acetic acid, and the like can be used in various ways. However, for a more stable reaction, the type is determined according to the type of silane used. In the present invention, it is possible to have various properties by the functional groups of the silane through chemical changes to hydrolyze the silane using an acid catalyst and synthesize it into an oligomeric sol. At this time, the silane to be used may be used by mixing only one or two or more of the silanes mentioned above.

Here, when the hydrolysis using an acid catalyst is used, the amount of the silane relative to the total weight is determined. When the sol-gel reaction is used, it is preferably used at 1 to 5% by weight relative to the total solution. When used in excess of 5% by weight, the acid value (acidity) of the entire solution increases in addition to the role as a catalyst, and when applied to the surface of the plated steel sheet, there is a problem that the surface layer may be partially damaged by a rapid surface reaction by acid. In addition, when used in an amount of less than 1% by weight, the role as a catalyst is insufficient, and thus the hydrolysis reaction is slow or does not proceed completely, resulting in a decrease in stability as a sol-gel solution. That is, when additives other than the sol-gel solution are added, problems such as stability may be caused. In this case, the acid catalyst used is more effective to use an organic acid than an inorganic acid. In particular, formic acid and acetic acid are stable in forming a sol-gel compound during synthesis.

In order to select a silane having excellent corrosion resistance among phenyl silane, epoxy silane, methyl silane, vinyl silane, alkyl silane, alkoxy silane, and amino silane, it was evaluated under ASTM-B117 condition, and the most suitable condition for generating rust less than 5% after 72 hours ( ◎) was evaluated in Table 1 and Table 2 below.

Table 1 below shows that the corrosion resistance test was performed by synthesizing the organic acid catalyst in one silane in a sol-gel solution using 1 to 2% by weight, and the numbers in the table indicate the weight% of the silane to the total weight of the sol-gel solution.

Example
1-1 Example
1-2 Example
1-3 Example
1-4 Example
1-5 Example
1-6 Example
1-7 Example
1-8 Example
1-9 Example
1-10 Epoxy silane 5 10 15 20 Vinyl silane 5 10 Methyl silane 5 10 Amino silane 5 Alkoxy silane 10 Corrosion resistance △ ◎ ◎ ○ X X △ △ ○ ○

As shown in Table 1, in the present invention, when using one silane, epoxy silane, amino silane, and alkoxy silane having excellent corrosion resistance (◎, ○) were used.

In addition, the weight ratio of silane was used by selecting 8 to 20% by weight of epoxy silane, 3 to 7% by weight of amino silane, and 8 to 12% by weight of alkoxy silane.

Table 2 below shows that the corrosion resistance test was performed by mixing two or more silanes and synthesizing them into a sol-gel solution using 1 to 2% by weight of an organic acid catalyst, and the numbers in the table indicate the weight percent of silane to the total weight of the sol-gel solution. Shows.

Example
2-1 Example
2-2 Example
2-3 Example
2-4 Example
2-5 Example
2-6 Example
2-7 Example
2-8 Example
2-9 Example
2-10 Epoxy silane 10 10 10 10 10 10 10 10 15 15 Vinyl silane 5 Methyl silane 5 Amino silane 5 5 5 10 10 5 5 Alkoxy silane 5 5 10 5 10 10 20 Corrosion resistance △ X ○ ○ ○ ◎ △ △ ◎ ◎

As shown in Table 2 above, in the present invention, when two or more silanes are mixed and used, relatively excellent corrosion resistance (◎, ○) is a mixture of epoxy silane and amino silane, epoxy silane and alkoxy silane, epoxy silane and amino A mixture of silane and alkoxy silane was used.

In addition, the weight ratio of the silane may be provided by a combination of at least two or more of 10 to 15% by weight of epoxy silane, 5% by weight of amino silane, 5 to 20% by weight of alkoxy silane.

For example, 10% by weight of epoxy silane and 5% by weight of amino silane (Example 2-3), 10% by weight of epoxy silane and 5% by weight of alkoxy silane (Example 2-4), Mixing 10% by weight of epoxy silane and 5% by weight of amino silane and 5% by weight of alkoxy silane (Example 2-5), 10% by weight of epoxy silane and 5% by weight of amino silane and 10% by weight of alkoxy silane (Example 2-6), 15% by weight of epoxy silane and 5% by weight of amino silane and 10% by weight of alkoxy silane (Example 2-9), and 15% by weight of epoxy silane and 5% by weight A mixture of% amino silane and 20% by weight alkoxy silane (Example 2-10) can be used.

In the present invention, an inorganic component was selected to improve heat resistance, and silver (Ag) was selected from among inorganic components to improve antibacterial properties.

Silver (Ag) is an ingredient that is not only antibacterial and harmless to the human body, but also suitable for environmental friendliness.

The silver component is present in the ionic form of Ag ⁺ , which is uniformly distributed by the acid catalyst component having the same charge in the sol-gel solution. In this way, Ag ⁺ ions uniformly distributed in the sol-gel solution are applied to the surface of the plated steel sheet, and the gelation proceeds and is uniformly distributed inside the film as it is dried, so that the antibacterial performance can be maintained uniformly and the heat resistance performance is uniform. .

In addition, the inorganic antibacterial aqueous solution containing 0.5% by weight of silver ions is used so that 0.1 to 5.0% by weight of the sol-gel solution is mixed. That is, the silver content should be adjusted within a range that does not cause a decrease in corrosion resistance, blackening resistance, etc., which are physical properties of the plated steel sheet.

Table 3 below shows the specific results of physical properties by varying the weight of the inorganic antibacterial aqueous solution relative to the weight of the sol-gel solution. The numbers in the table represent weight percent.

Comparative example Example
3-1 Example
3-2 Example
3-3 Example
3-4 Sol-gel solution 100 100 100 100 100 Inorganic antibacterial aqueous solution X 0.5 One 3 5 Antibacterial X ○ ◎ ◎ ◎ Corrosion resistance ◎ ◎ ◎ ◎ ○ Blackening resistance ◎ ◎ ◎ ◎ ◎ Heat resistance ◎ ◎ ◎ ◎ ◎

As shown in Table 3, a sol-gel solution in which an inorganic antibacterial aqueous solution containing 0.5% by weight of silver ions is mixed, i.e., an antibacterial and physical property is measured by applying an antibacterial inorganic composition to a plated steel sheet, and the inorganic antibacterial aqueous solution is 5%. Less than, preferably, when contained in 0.5 to 3% by weight, while having antibacterial properties, it is possible to maintain excellent corrosion resistance, blackening resistance, heat resistance.

Here, corrosion resistance was evaluated according to ASTM-B117 standard, and blackening resistance was evaluated by laminating under 50% relative humidity conditions at 50°C and loading at 20 kgf/cm ² , and heat resistance at 200°C, 300°C, and 400°C for 20 minutes. By heating, the presence or absence of discoloration of the color difference ΔE≤3 before and after heating was checked, and relative evaluation was performed based on the most suitable state (◎).

And, the antimicrobial property is a comparison by measuring the bacteria reduction rate between the anti-bacterial plated steel sheet and the non-microbial plated steel sheet, and is tested by applying the pressure bonding method according to KCL-FIR-1003:2018 As a result, strains used are E. coli (Escherichia coli ATCC 8739), Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATCC 6538P, Pneumonia (Klebsiella pneumoniae ATCC 4352), MRSA (Methicillin Staphylococcus) aureus subsp. aureus ATCC 33591). With respect to these strains, based on the sample with the coating and the sample without the coating with the antimicrobial inorganic composition of the present invention, the bacteria reduction rate after 24 hours incubation was confirmed. [CFU: Colony Forming Unit, bacteria reduction rate [%] = (Blank-Sample) / Blank X 100, based on concentration after 24 hours]

Here, the specimen was coated with an antimicrobial inorganic composition in which 0.5% by weight of an inorganic antibacterial aqueous solution was mixed to a plated steel sheet to evaluate the antibacterial properties of the plated steel sheet (Example 3-1) forming a dry film.

The evaluation results are listed in Table 4 below, and all show a decrease of more than 99.9% of bacteria. Accordingly, in the case of Examples 3-2 to 3-3, wherein the content of the inorganic antibacterial aqueous solution is more than 0.5% by weight, it is judged that it will show an antibacterial property equal to or higher.

division Initial concentration
[CFU/mL] Concentration after 24 hours
[CFU/mL] Bacteria reduction rate
[%] Coliform No treatment 3.1 X 10 ⁵ 1.2 X 10 ⁶ - Antibacterial treatment 3.1 X 10 ⁵ <10 99.9 Pseudomonas aeruginosa No treatment 1.5 X 10 ⁵ 1.6 X 10 ⁶ - Antibacterial treatment 1.5 X 10 ⁵ <10 99.9 Staphylococcus aureus No treatment 3.5 X 10 ⁵ 6.7 X 10 ⁶ - Antibacterial treatment 3.5 X 10 ⁵ <10 99.9 Pneumonia No treatment 1.6 X 10 ⁵ 1.0 X 10 ⁶ - Antibacterial treatment 1.6 X 10 ⁵ <10 99.9 MRSA No treatment 2.9 X 10 ⁵ 6.4 X 10 ⁶ - Antibacterial treatment 2.9 X 10 ⁵ <10 99.9

As shown above, the antimicrobial inorganic composition according to the embodiment of the present invention contains a silver component, and is excellent in antibacterial and heat resistance, and also excellent in corrosion resistance, blackening resistance and heat resistance.

Hereinafter, a method of manufacturing a coated steel sheet by coating an antibacterial inorganic composition according to an embodiment of the present invention on a coated steel sheet will be described.

The method of manufacturing a plated steel sheet according to an embodiment of the present invention is coated with the antimicrobial inorganic composition described above on a plated steel sheet by a roll coating or spray-squeezing method, and the antimicrobial inorganic composition is coated. It is manufactured by drying by hot air, induction heating, or near-infrared heating so that the surface temperature of the coated steel sheet is 100 to 200°C.

There are various methods for forming a film on the surface of a plated steel sheet using an inorganic component as a main component. It is used in various ways such as conversion coating, immersion, roll coating or spray-squeezing. Among the above-described film forming methods, a roll coating or spray-squeezing method is widely used because it can form a film of less than about 5 μm on the surface of a plated steel sheet. That is, the above two methods have an advantage in that they are easy to produce, such as managing film thickness and drying. Therefore, in the present invention, the antimicrobial inorganic composition was coated on a plated steel sheet by a roll coating or spray-squeezing method.

Then, the coated steel sheet coated with the antimicrobial inorganic composition of the present invention was dried by heating the surface temperature of the coated steel sheet to 100 to 200°C through a heating method such as hot air, induction heating, or near infrared ray.

Here, the plated steel sheet may be selected from the group consisting of galvanized steel sheet, 55% Al-Zn-based galvalume (Galvalume) steel sheet, aluminum plated steel sheet, zinc and aluminum alloy plated steel sheet containing magnesium, and magnesium alloy plated steel sheet.

In the plated steel sheet produced through this method, it is preferable that the antibacterial inorganic composition is applied at a dry film weight of 0.1 to 1.5 g/m ² . That is, when the antimicrobial inorganic composition is applied at a weight of less than 0.1 g/m ² , the target antibacterial property cannot be achieved, and when applied at a weight of more than 1.5 g/m ^2, the amount of silver ions is increased to increase the manufacturing cost. There is.

As described above, although the present invention has been described by a limited number of embodiments and drawings, the present invention is not limited by this, and the technical idea of the present invention and the following will be described by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the equivalent scope of the claims to be described.

Claims (8)

In the antimicrobial inorganic composition is applied to a plated steel sheet to form a chromium-free (Cr-free) coating having antibacterial properties,
A sol-gel solution prepared by mixing a silane and an acid catalyst; And
Inorganic antibacterial aqueous solution containing 0.5% by weight of silver ions;
Antibacterial inorganic composition comprising a.
According to claim 1,
The inorganic antibacterial aqueous solution,
Antibacterial inorganic composition, characterized in that provided in 0.1 to 5.0% by weight relative to the weight of the sol-gel solution.
According to claim 1,
The silane,
An antimicrobial inorganic composition, characterized in that it is provided in any one or a combination of at least two of epoxy silane, amino silane, and alkoxy silane.
According to claim 1,
The sol-gel solution,
An antimicrobial inorganic composition comprising 3 to 40% by weight of silane and 1 to 5% by weight of an acid catalyst in an aqueous solution.
According to claim 4,
The silane,
An antimicrobial inorganic composition comprising 8 to 20% by weight of epoxy silane, 3 to 7% by weight of amino silane, and 8 to 12% by weight of alkoxy silane.
According to claim 4,
The silane,
10 to 15% by weight of an epoxy silane, 5% by weight of an amino silane, 5 to 20% by weight of an alkoxy silane, antimicrobial inorganic composition characterized in that it is provided by a combination of at least two or more.
A coating step of coating the antimicrobial inorganic composition of any one of claims 1 to 6 on a plated steel sheet by a roll coating or spray-squeezing method; And
A drying step of drying by hot air, induction heating, or near infrared heating so that the surface temperature of the coated steel sheet coated with the antibacterial inorganic composition becomes 100 to 200°C;
Method of manufacturing a plated steel sheet comprising a.
A plated steel sheet in which the antimicrobial inorganic composition of any one of claims 1 to 6 is applied at a dry film weight of 0.1 to 1.5 g/m ² .