KR100192711B1 - Production method of inorganic microbicide with silver - Google Patents

Abstract

More particularly, the present invention relates to a method for producing an inorganic antibacterial agent containing (Ag), and more particularly, to a method for producing an inorganic antibacterial agent containing silver (Ag) by adding a silver compound from the beginning into a reaction slurry and calcining it at an appropriate temperature of 800 to 1,200 ° C to be stably bound to the zirconium phosphate crystalline structure (Ag) -containing zirconium phosphate crystals having high heat stability, UV stability, and high whiteness.

Description

A method for producing an inorganic antibacterial agent containing silver (Ag)

The accompanying drawings are X-ray diffraction analysis charts of the inorganic antibacterial agent prepared in Example 1.

More particularly, the present invention relates to a method for preparing silver (Ag) -containing inorganic antibacterial agent, and more particularly, to a method for producing silver (Ag) -containing inorganic antimicrobial agent by adding a silver compound from the beginning into a reaction slurry and calcining at an appropriate temperature of 800 to 1200 占 폚, (Ag) -containing zirconium phosphate crystals with high heat stability, UV stability and whiteness.

It has been well known from the past that silver has antimicrobial properties. Thus, various antimicrobial agents having silver ions supported on a carrier have been proposed. However, since silver ions themselves are unstable in exposure to heat and light, It needs to be supplemented. For example, in order to improve the stability of silver ions (stability against heat and light), a technology for preventing discoloration by coexisting ammonium ions in the process of ion exchange of silver ions in zeolite (U.S. Patent No. 4,938,958) But it has not reached the fundamental solution.

Zirconium phosphate has a fine particle size and is excellent in heat resistance, chemical resistance and weather resistance, and is useful as an inorganic antibacterial agent carrier, and silver inorganic antibacterial agent containing zirconium phosphate as a carrier is already well known.

Various synthetic methods such as calcination method, wet method and hydrothermal method are known as conventional methods for producing zirconium phosphate inorganic zirconium phosphate containing silver (Ag). Most of these methods are crystalline zirconium phosphate, which is then immersed in an aqueous solution containing silver ions And then performing ion exchange. [Japanese Patent Application Laid-open No. 3-83905 (1994) 3-83906]. However, these methods are time-consuming because the crystalline zirconium phosphate powder is obtained and then the ion-exchanged silver is post-treated, and the filtration, washing and pulverizing processes are repeatedly performed. There is also known a method for making zirconium phosphate which is a heat-containing crystalline zirconia by the hydrothermal method only for a silver compound not containing a halogen ion (JP-A-5-97414), but there is a restriction that a raw material should not have halogen ions .

Accordingly, the present inventors have made efforts to improve the method for producing inorganic antibacterial agent containing silver (Ag) by using crystalline zirconium phosphate as a carrier, and as a result, they have found that the compound is added in the early stage of the reaction, The present invention has been completed by omitting a cleaning process which is usually carried out.

Accordingly, it is an object of the present invention to provide an economical synthesis method which can easily obtain an antimicrobial agent in which silver ions and zirconium phosphate are firmly bonded to each other, which reduces the cannon production time and simplifies the process as much as possible. The product manufactured by this method has a feature that it contains a large amount of silver and maintains durability for a long period of time without causing any discoloration even under heat and UV irradiation.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for producing an inorganic antibacterial agent containing silver (Ag) in zirconium phosphate, wherein a water-soluble reaction solution containing a silver (Ag) compound, a phosphate compound and a zirconium compound is adjusted to pH 3 to 7, , Drying immediately without washing, and then calcining at 800 to 1200 ° C to produce an inorganic antibacterial agent.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for producing an inorganic antibacterial agent containing silver (Ag) in zirconium phosphate, wherein the silver (Ag) compound is added at the initial stage of the reaction and reacted under specific reaction conditions (pH, (Ag) -containing zirconium phosphate crystals of 3 to 15 wt% and a Hunter Color Test Value L of 99.0.

The silver (Ag) compound used as an antimicrobial material in the present invention is preferably water-soluble to improve solubility. Silver nitrate (AgNo ₃ ), silver nitrate (CH ₃ CO ₂ Ag), silver carbonate (Ag ₂ CO ₃ ), and the like can be used as the silver compound. Among them, silver nitrate is particularly preferable because of its high solubility. The silver (Ag) compound is added so as to maintain 3 to 15 parts by weight based on 100 parts by weight of the total weight of the inorganic antibacterial agent. If the silver content is less than 3 parts by weight, excellent antimicrobial effect upon addition of the silver compound can not be obtained, If the amount is more than 15 parts by weight, the degree of whiteness decreases sharply due to storage for a short period of time.

It is preferable that the phosphoric acid compound and the zirconium compound used as the carrier in the present invention are also water-soluble to improve solubility. Specific examples of the phosphoric acid compound include phosphoric acid (H ₃ PO ₄ ), sodium dihydrogen phosphate (NaH ₂ PO ₄ ), disodium hydrogen phosphate (Na ₂ HPO ₄ ), sodium phosphate (Na ₃ PO ₄ ), ammonium dihydrogen phosphate NH ₄ H ₂ PO _4), phosphoric acid susoyi ammonium _{(NH 4) 2 HPO 4)} , ammonium phosphate _{(NH 4) 3 PO 4)} , potassium dihydrogen phosphate (KH ₂ PO _4), phosphoric acid susoyi potassium (K ₂ HPO ₄ ), it is such as potassium phosphate (K ₃ PO _4). And Specific examples of the zirconium compound of zirconium oxychloride _{(ZrOCl 2 · xH 2 O)} , oxy-sulfate, zirconium _{(ZrOSO 4 · xH 2 O)} , zirconium oxynitrate _{(ZrO (NO 3) 2 ·} xH 2 O), zirconium nitrate (Zr (NO ₃ ) ₄ .xH ₂ O) and zirconium sulfate (Zr (SO ₄ ) ₂ .xH ₂ O).

The zirconium compound and the phosphoric acid compound are mixed and mixed in an aqueous solution state, and the crystal form of zirconium phosphate produced in the firing process varies depending on the molar ratio of the zirconium compound and phosphate compound, and the silver (Ag) The amount of the bar and phosphate compound is preferably 0.4 to 2.0 molar ratio based on 1 mol of the zirconium compound.

The process for producing the silver-containing inorganic antibacterial agent according to the present invention will be described in more detail as follows.

First, an amorphous zirconium phosphate is prepared by mixing an aqueous solution of phosphoric acid and an aqueous solution of zirconium, and an aqueous solution of silver (Ag) is added dropwise thereto at a reaction temperature of 40 to 80 ° C so that the concentration of silver ions does not deviate locally at 300 to 500 rpm Stir well. The pH of the reaction slurry is then adjusted to a range of from 3 to 7, preferably from 3.5 to 5.5, in order to prevent corrosion of the reactor by the acid and coprecipitate the remaining zirconium compound into an oxide. The pH can be adjusted by adding an acid or an alkali to the reaction slurry. As preferred acids, inorganic acids such as nitric acid and sulfuric acid can be used. As alkali, hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide Can be used.

After filtering the zirconium phosphate slurry containing silver (Ag) and drying it directly without washing, it is calcined at 800 to 1,200 ° C. for 1 to 2 hours to obtain crystals in which silver (Ag) is stably supported, Remove the salt. Then, finally, the calcination product is crushed to obtain silver supported crystalline zirconium phosphate powder.

The inorganic antibacterial agent prepared by the above-described manufacturing process contains silver (Ag), so that the antimicrobial activity by the silver (Ag) component is exhibited well. In addition, by binding a high amount of silver (Ag) component in a zirconium phosphate lattice very stably, the inorganic antibacterial agent does not change color even when exposed to light for a long time, and has high antibacterial power for a long time.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but it should be understood that the invention is not construed as being limited thereto.

[Example 1]

Zirconium oxychloride; it is created and _{(ZrOCl 2 · 8H 2 O 644g} ) was dissolved in a pure aqueous solution of zirconium oxychloride (600g), ammonium dihydrogen phosphate: dissolving _{(NH 4 H 2 PO 4 115g} ) in pure water (1,600g) An ammonium dihydrogen phosphate aqueous solution was prepared. The two aqueous solutions were mixed with stirring at a stirring speed of 400 rpm. To the resulting amorphous zirconium phosphate was slowly added an aqueous solution of silver nitrate in which silver nitrate (45 g) was dissolved in pure water (100 g), and the pH was adjusted to 5.0 by adding 01 wt% sodium hydroxide. The reaction slurry was stirred at 85 캜 for 30 minutes, filtered, dried at 110 캜 and calcined at 1,000 캜 for 1 hour and pulverized to obtain a white inorganic antibacterial fine powder.

[Examples 2 to 7]

The inorganic antibacterial agent fine powder was prepared according to the manufacturing conditions shown in Table 1 below and the manufacturing procedure of Example 1, and the silver content, pH and firing conditions were changed.

[Comparative Example 1]

The reaction slurry prepared in Example 1 was agitated at 85 캜 for 30 minutes, washed thoroughly with distilled water (12 1), dried at 110 캜, fired at 1,000 캜 for 1 hour and pulverized to obtain inorganic antibacterial fine powder.

[Comparative Example 2]

The slurry obtained in Example 1 was stirred at 85 캜 for 30 minutes, filtered, sufficiently washed with distilled water (12 1), dried at 110 캜 and immediately pulverized without being subjected to a sintering process to obtain inorganic microbicide fine powder .

[Comparative Example 3]

The inorganic antibacterial agent fine powder was prepared according to the manufacturing conditions of Table 1 and the manufacturing procedure of Example 1, and the silver content, pH and firing conditions were changed.

[Experimental Example 1]

The physical properties of the inorganic antibacterial agent powders prepared in Examples 1 to 7 and Comparative Examples 1 to 11 were measured by the following methods, and the results are shown in Table 1 below.

The crystal structure was measured by X-ray diffraction analysis using Ni filter and Cu-Ka line, and the antibacterial activity was evaluated by microbial test.

The whiteness degree was measured with a colorimeter (CR-300; Hunter Color Test Value L) after exposure to UV for 30 days after the preparation to measure discoloration (change with time) by UV irradiation. The test method was KSL 5113-92 to be.

The content of silver (Ag) was measured by atomic absorption spectrophotometry (AAS) and the test method was KSM 0016-90.

(a) Immediately filtration, drying, washing and grinding without firing.

The reason why discoloration (over time) is emphasized is that commercialized antimicrobial products in industrial application of inorganic antibacterial agents change colors due to heat and light over time, thereby causing a lot of problems by damaging the value of the product , Silver (Ag) -containing zeolite and silver (Ag) -containing calcium phosphate, etc., are difficult to apply industrially easily due to changes with time depending on the manufacturing method.

In general, as the silver (Ag) content is lower, the whiteness of the inorganic antibacterial powder product is increased and the discoloration phenomenon may be slightly lowered by UV exposure. However, if the content is too small, it is difficult to exhibit sufficient antibacterial activity. For example, inorganic antibacterial agents should be highly effective in the application of powdered inorganic antibacterial agents such as plasticizers and paints in a very small amount (about 0.1 to 3%).

In Comparative Example 5 and Comparative Example 6, the silver (Ag) content was 16.5% by weight and 19.6% by weight, respectively, but they exhibited excellent antibacterial activity. However, whiteness decreased rapidly due to storage for a short period of time, It is necessary to adjust the silver (Ag) content appropriately because the increase of the silver (Ag) content is not remarkable. Therefore, in order to satisfy economical efficiency and antibacterial ability at the same time, it is optimal to contain 3 to 15% of silver.

According to the results shown in Table 1, the degree of whiteness changes according to the firing temperature and the firing time. Comparative Example 11 is a case where the firing temperature is as low as 600 占 폚 and the fading phenomenon occurs from the beginning of the production and commercialization as a product is impossible. In Comparative Example 9, the firing temperature is as high as 1220 占 폚, And it is possible to discolor over time. It can be seen that proper firing temperature is a very important factor for the production of inorganic antibacterial agent.

In the production process according to the present invention, it is preferable that the firing temperature in the range of 800 to 1200 占 폚 is maintained so as to maintain a high whiteness without changing color over time.

It is preferable that the pH is maintained in an acidic or neutral range within a reasonable range, but strong acidity or basicity should be avoided because corrosion of the reactor is prevented and the residual zirconium compound is coprecipitated into an oxide. Therefore, it is preferable that the pH of the reaction slurry is maintained in the range of 3 to 7.

The accompanying drawings are X-ray diffraction analysis charts of the inorganic antibacterial agent prepared in Example 1, and it can be confirmed that the inorganic antibacterial agent of the present invention has a good crystal.

[Experimental Example 2]

In order to measure the antibacterial activity against the inorganic antibacterial agent prepared in the above Examples and Comparative Examples, the following experiment was carried out.

Inorganic antibacterial powder samples were diluted in sterile distilled water to 10 w / v% and added to sterile high nutrient broth (3 g of juice, 5 g of peptone, 8 g of NaCl, 15 g of agar, 1 l of distilled water). Escherichia coli KCTC 1041 (strain A) and Staphylococcus aureus ATCC 65389 (strain B) were cultured in a liquid medium for 12 hours and then diluted and applied to the medium containing the antimicrobial agent. The medium was used as a control. The medium was incubated at 37 ° C for 24 hours, and the number of viable cells was measured. The antimicrobial activity was measured by comparing the inhibition rate with the control. The antimicrobial activity according to the concentration (%) is shown in Table 2 below.

According to the results in Table 2, it can be seen that the antibacterial power is closely related to the content of silver (Ag) contained in the inorganic antibacterial agent. As the content of silver (Ag) increases, the antimicrobial activity per unit mass of the antimicrobial agent is excellent. However, when the content of the antimicrobial agent is excessive, the ultraviolet and thermal stability of the final antimicrobial agent is greatly deteriorated. In the case of the production method according to the present invention, the inorganic antibacterial agent contains silver (Ag) in an amount of 3 to 15% by weight and the whiteness is not less than 99.0 (Hunter Color Test Value L).

In addition, it can be seen that the inorganic antibacterial agent finally produced according to the production conditions has inorganic antimicrobial elimination excellent in UV stability, which contains a large amount of silver (Ag) but does not cause discoloration. The crystalline antimicrobial agent is usually prepared by washing and drying the powder synthesized by the hydrothermal method, or by mixing the reactants in powder form from the beginning and calcining the mixture, or by heating and refluxing for a long time. However, the present invention is characterized in that the firing condition and the pH are limited to the range of the firing temperature, and the washing process is shortened. Generally, only the residual silver ions (Ag +) and impurities are washed to obtain a stable powder. However, in the production method of the present invention, the reactants are added at the same time in the initial stage of the reaction and mixed and stirred. There is no excellence.

Claims (4)

A method for producing an inorganic antibacterial agent containing silver (Ag) in zirconium phosphate is characterized in that a water-soluble reaction solution containing silver (Ag) compound, phosphoric acid compound and zirconium compound is adjusted to pH 3 to 7, stirred at normal pressure, Wherein the inorganic antimicrobial agent is dried immediately without a process, and then calcined at 800 to 1200 占 폚. The method according to claim 1, wherein the silver (Ag) compound is selected from silver nitrate (AgNO ₃ ), silver acetate (CH ₃ CO ₂ Ag) and silver carbonate (Ag ₂ CO ₃ ) Containing inorganic antibacterial agent. As the phosphate compound according to claim 1, wherein the phosphoric acid (H ₃ PO _4), phosphoric acid hydrogen sodium (NaH ₂ PO _4), phosphoric acid susoyi sodium (NaH ₂ HPO _4), sodium phosphate (Na ₃ PO _4), phosphoric acid ammonium _{(NH 4 H 2 PO 4)} , phosphoric acid susoyi ammonium _{(NH 4) 2 HPO 4)} , ammonium phosphate _{(NH 4) 3 PO 4)} , potassium dihydrogen phosphate (KH ₂ PO _4), phosphoric acid susoyi potassium (K ₂ HPO ₄ ), and potassium phosphate (K ₃ PO ₄ ). Stand according to claim 1, wherein the zirconium compound is zirconium oxychloride _{(ZrOCl 2 · xH 2 O)} , oxy-sulfate, zirconium _{(ZrOSO 4 · xH 2 O)} , zirconium oxynitrate _{(ZRo (NO 3) 2 ·} xH 2 O (Ag) containing inorganic antibacterial agent characterized in that the inorganic antibacterial agent is selected from zirconium nitrate (Zr (NO ₃ ) ₄ xH ₂ O) and zirconium sulfate (Zr (SO ₄ ) ₂ xH ₂ O) .